Mosby's Orthodontic Review

I'

...

ONTI

.

]ERYL D. ENGLISH Timo Peltomaki Kate Pham-Litschel

OS

ORTHODONTIC REVlEW

ORTHODONTIC REVlEW Jeryl D. English, DDS, MS Professor, Chairman and Program Director Department of Orthodontics The University ofTexas Dental Branch at Houston Houston, Texas

Timo Peltomaki, DDS, MS, PhD Professor and Chairman Clinic for Orthodontics and Pediatric Dentistry Center for Dental and Oral Medicine University of Zurich Zurich, Switzerland

Kate Pham-Litschel, DDS, MS Research Associate Clinic for Orthodontics and Pediatric Dentistry Center for Dental and Oral Medicine University of Zurich ZUrich, Switzerland

MOSBY ELSEVIER

ll830 Westline Industrial Drive

Sr. Louis, Missouri 63146

MOSBY'S ORTJ JODO.J\'TJC REVIEW

JSBN: 978-0-323-05007 4

Copyright© 2009, Mosby, Inc., an affiliate of Elsevier lnc.

All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical. including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permissions may be sought directly from Elsevier's Health Sciences Rights Department in Philadelphia, PA, USA: phone: (+l) 215 238 7869; fax: (+I) 215 238 2239; e - mail: [email protected]. You may also complete your request online via the Els evier Science home page

(llttp://www.elsevier.corn), by selecting 'Customer Support' and then 'Obtaining Permissions.'

NOTIC£ Orthodontics is an ever-changing field. Standard safety precautions must be followed, but as new re search

and clinical experience broaden our knowledge, changes in treatment and drug therapy may become

necessary or appropriate. Readers arc ad,•ised to check the most current product information provided

by the manufactur�r of each drug to be administered to verify the recommended dose, the method and

duration of admtnistration, and contraindications. It is the responsibility of the licensed prescriber, relying

on experience and knowledge of the patient, to determine dosages and the be�t treatment for each individual pauent. Neither the publisher nor the author assumes any liability for any injury and/or damage to persons or property ansing from this publication.

9"i -0-323-{}5007-4

Vice Presrdent arrd Publislrer: Linda Duncan Senior Editor: John Dolan

Dcvelopmerrtal Editor: Courtney Sprehe

Publishing Services Manager: Patricia Tannian

Project Manager: John Casey Designer: Andrea Lutes

Working together to grow libraries in developing countries

www.elsevier.com

Printed in China Last digit is print number: 9

8

7

6

5

4

3

2

I

I www.booka.id.org I

www.sa

bre.o rg

ontributors

Burcu Bayirli, DDS, MS, PhD Associate Professor

Thuy-Duong Do-Quang, DDS, MS Clinical Assistant Professor

Department of Orthodontics

Department of Orthodontics

School of Dentistry

The University of Texas Dental Branch at Houston

University of Detrot i Mercy Detroit, Michigan

Houston, Texas

Jeryl D. English, DDS, MS Barry S. Briss, DMD

Professor, Chairman and Program Director

Professor and Chairman

Department of Orthodontics

Department of Orthodontics

The University of Texas Dental Branch at Houston

Tufts UniVersity

Houston. Texas

School of Dental Medicine Boston, Massachusetts

Jaime Gateno, DDS, MD Professor

Peter H. Buschang, PhD Professor and Director of Orthodontic Research

Department of Surgery, Oral and Maxillofacial Surgery

Department of Orthodontics

Weill Medical College

Baylor College of Dentistry

Comell University

Dallas, Texas

New York, New York; Chairman

David A. Covell, Jr., DDS, PhD

Department of Oral and Maxillofacial Surgery

Associate Professor and Chair

The Methodist Hospital Research Institute

Department of Orthodontics

Houston, Texas

Oregon Health and Science University Portland, Oregon

Peter M. Greco, DMD Associate Clinical Professor

G. Fr�ns Currier, DDS, MSD, MEd

Department of Orthodontics University of Pennsylvania

Professor, Program Director and Chair Department of Orthodontics

Adjunct Instructor

University of Oklahoma

Department of Oral and Maxillofacial Surgery

Adjunct Professor of Pediatric Dentistry

Thomas Jefferson University of Hospital

Chair, Division of Developmental Dentistry

Philadelphia, Pennsylvania

Department of Orthodontics and Pediatric Dentistry University of Oklahoma Oklahoma City, Oklahoma

Andre Haerian, DDS, MS, PhD Adjunct Clinical Assistant Professor Department of Orthodontics and Pediatric Dentistry

Cheryl A. DeWood, DDS, MS Assistant Professor

University of Michigan Ann Arbor, Michigan

Department of Graduate Orthodontics University of Tennessee Memphis, Tennessee

Brody J. Hildebrand, DDS, MS Assistant Clinical Professor Department of Graduate Prosthodontics Baylor College of Dentistry Dallas, Texas; lntemational Team for lmplantology {ITI) Basel, Switzerland

v

vi

CONTRIBUTORS

Frank Tsung-Ju Hsieh, DDS, MSD

Laurie McNamara, DDS, MS

Assistant Professor

Adjunct Clinical Lecturer

Department of Orthodontics

Department of Orthodontics

Oregon Health and Science University

University of Michigan

Portland, Oregon

Ann Arbor, Michigan

Hitesh Kapadia, DDS, PhD Clinical and Research Assistant Professor

Peter Ngan, DMD Professor and Chair

Department of Orthodontics

Department of Orthodontics

The University of Texas Dental Branch at Houston

West Virginia University

Houston, Texas;

Morgantown, West Virginia

Assistant Professor Department of Biomedical Sciences Baylor College of Dentistry Dallas, Texas

Valmy Pangrazio-Kulbersh, DDS, MS Professor Department of Orthodontics School of Dentistry

Sunil Kapila, DDS, MS, PhD Robert W. Browne Endowed Professor and Chair

University of Detroit Mercy Detroit, Michigan

Department of Orthodontics and Pediatric Dentistry The University of Michigan Ann Arbor, Michigan

Timo Pettomaki, DDS, MS, PhD Professor and Chairman Clinic for Orthodontics and Pediatric Dentistry

Chung How Kau, BDS, MScD, MBA, PhD, Morth,

Center for Dental and Oral Medicine

RCS (Edin), DSC, RCPS, FFD RCSI (Ortho),

University of Zurich

FAMS (Ortho)

Zurich, Switzerland

Associate Professor and Director of the Facial Imaging Facility

Kate Pham-Litschel, DDS, MS

Department of Orthodontics

Research Associate

The University of Texas Dental Branch at Houston

Clinic for Orthodontics and Pediatric Dentistry

Houston, Texas

Center for Dental and Oral Medicine University of Zurich

Richard Kulbersh, DMD, MS

Zurich, Switzerland

Chairman and Program Director Department of Orthodontics School of Dentistry University of Detroit Mercy Detroit, Michigan

Stephen Richmond, BDS, MScD, PhD, DOrth, RCS (Edin), FDS, RCS (Eng), FDS, MILT Professor Department of Dental Health and Biological Sciences University Dental Hospital

Steven D. Marshall, DDS, MS Visiting Associate Professor

Cardiff University South Glamorgan, Wales

Department of Orthodontics University of Iowa

Christopher S. Riolo, DDS, MS, PhD

College of Dentistry

Private Practice

Iowa City, Iowa

Ypsilanti, Michigan

Kathleen R. McGrory, DDS, MS Clinical Director and Clinical Assistant Professor Department of Orthodontics

Michael L. Riolo, DDS, MS Adjunct Professor Department of Orthodontics

The University of Texas Dental Branch at Houston

School of Dentistry

Houston, Texas

University of Detroit Mercy Detroit, Michigan

James A. McNamara, Jr., DDS, MS, PhD T homas M. and Doris Graber Endowed Professor of Dentistry Department of Orthodontics and Pediatric Dentistry

P. Emile Rossouw, BSc, BChD, BChD (Hons-Child-Dent), MChD (Ortho), PhD,

School of Dentistry

FRCD(C) Professor and Chairman

Professor of Cell and Developmental Biology

Department of Orthodontics

School of Medicine

Baylor College of Dentistry

Research Professor

The Texas A&M University System Health Science

Center for Human Growth and Development The University of Michigan Ann Arbor, Michigan

Center Dallas, Texas

CONTRIBUTORS

Anna Maria Salas-Lopez, ODS, MS Clinical Associate Professor

Michelle Thornberg, DDS, MS Adjunct Professor

Department of Orthodontics

Department of Orthodontics

The University of Texas Dental Branch at Houston

School of Dentistry

Houston, Texas

University of Detroit Mercy Detroit, Michigan

Marc Schatzle, DDS, MS, PhD

Assistant Professor, Or. med. dent.

Angela Marie Tran, DDS, MS

Specialist in Orthodontics

Department of Orthodontics

Department of Orthodontics and Pediatric Dentistry

The University of Texas Dental Branch at Houston

Center for Dental and Oral Medicine

Houston, Texas

and Crania-Maxillofacial Surgery University of Zurich Zurich, Switzerland Kirt E. Simmons, DDS, PhD

Orhan C. Tuncay, DMD Professor and Chairman Department of Orthodontics Kornberg School of Dentistry

Assistant Professor of Surgery

Temple University

Department of Otolaryngology

Philadelphia, Pennsylvania

University of Arkansas for Medical Sciences D1rector, Craniofacial Orthodontics Department of Pediatric Dental Department

.James L. Vaden, DDS, MS Professor and Chairman

Arkansas Children's Hospital

Department of Orthodontics

wttle Rock, Arkansas

University of Tennessee Memphis, Tennessee

Karin A. Southard, DDS, MS Professor :::>epartment of Orthodontics

Sam A. Winkelmann, .Jr. , DDS, MS Associate Clinical Instructor

..;niversity of Iowa

Department of Orthodontics

owa City, Iowa

The University of Texas Dental Branch at Houston Houston, Texas

Thomas E. Southard, DDS, MS Professor and Chair

.James ..J. Xia, MD, PhD, MS

:::>epartment of Orthodontics

Associate Professor

university of Iowa

Department of Surgery, Oral and Maxillofacial

owa City, Iowa

Surgery Weill Medical College

.lohn F. Teichgraeber, MD, FACS

Cornell University

Professor

New York, New York;

:Jivision of Pediatric Plastic Surgery

Director, Surgical Planning Laboratory

:::>epartment of Surgery

Department of Oral and Maxillofacial Surgery

Jledical School

The Methodist Hospital Research Institute

ne University of Texas Health Science Center

Houston, Texas

at Houston HOuston, Texas

vii

To my orthodontic family-faculty, colleagues, residents, and alumni-for their assistance and encouragement. To my family and especially to rny wife, Kathy, whose love, encouragement, and support have helped make this book a reality. JE I

want to thank my wife, Sari, and my children Tuomo, Anna, and Saara for reminding me that there are values more precious than the field of orthodontics. TP This book is dedicated to my husband and son, Ralph and Erik Litschel. I am thankful everyday that you are in my life. KL

Preface

A

s the scope of orthodontics continues to change, so

3D images, or how long to wear a bonded lingual 3-3 retainer.

does the knowledge necessary for both the student and

Each chapter on treatment or treatment planning is subjective;

the practicing professional. Orthodontics is a clinically

we wanted expert clinicians to share their thoughts and

driven practice, with the mentorship model using case studies :>eing one of the best ways to learn. Mosby's Orthodontic Review -.eeks not onJy to answer questions, but also to provide the reader

treatment experiences when correcting various malocclusions.

.,;th the knowledge and clinical expertise to achieve successful

Numerous clinical case reports are presented, incorporating learning around real patient scenarios .

re:.uJts for the patient. The reader should understand that there

HOW IS THIS BOOK ORGANIZED?

Jie no "secrets" that make orthodontics easy. Malocclusion

In organizing this book, we begin with basic foundational

:hree dimensions. By collecting and analyzing the appropriate

of treatment planning and clinical treatment in the later

!'resents as a comp lexity of problems in three tissues and

Jata and establishing a correct diagnosis, orthodontists can

:.ocus their resources on the correct treatment plan to resolve •

information first and then delve into more subjective areas chapters. Chapter 1 is a review of craniofacial growth and development

patient s malocclusion. We believe this book provides an c:"tcellent review of orthodontic conc epts, diagnosis, treatment

with current updates based on clinical research. Chapter 2

-:-\anning, and dinical treatment, as well as providing an update

on arch development and eruption sequence.

,f current clinical information

focuses on the indications for orthodontic treatment from the

'

.

WHO IS THE INTENDED AUDIENCE FOR THIS BOOK?

is a review of the development of the occlusion with

a

focus

Ch apter 3

primary dentition to permanent dentition. Chapter 4 addresses orthodontic records and

case review. Chapter 5 di scusses 30

imaging. Chapter 6 emphasizes the diagnosis of orthodontic

\'e have written this book for three different segments of

problems in three tissues (de n tal skeletal, and soft tissue) and in

ilie orthodontic community: students and residents, general

three p lanes of space (anteroposterior, transverse, and vertical).

dentists, and orthodontists.

We have included a 3D-3T Diagnostic Grid to aid in creating

,

First, we are targeting senior dental students as they prepare

a problem list. Diagnosis is objective, but all problems must

II of the National Board Dental Exam and for their entry int o the professitm of dentistry. We are also addressing

be listed to avoid something being overlooked. Misdiagnosis is

tor Part

•rthodontic residents and recent orthodontic graduates as

they prepare for the American Board of Orthodontics (ABO)

costly when one overlooks or ignores a patient's problem such as periodontal disease

.

In Chapters 7 and 8, basic concepts in orthodontic appliances

biomechanics are discussed. The remai ning 17 chapters

.,Titten and clinical examinations. Second, we intend this book

and

to be helpful for general dentists in their clinical practices and in

focus on specific areas of orthodontic treatment; these areas

their discussion of cases with orthodontists. We have included

are subjective and depend on both the training and experience

asic cephalometries so that discussions are easily understood

of the clinician. Areas addressed in these chapters include the

.rnd communicated. Third, the experienced orthodontist who

Invisalign system, minor tooth movement, implants, hygiene,

interested in the scientific advances in orthodontics will find this review text helpfu l.

WHAT IS UNIQUE ABOUT THE FORMAT OF THIS BOOK? We have chosen to use a question-answer format for each

craniofacial deformities, and more.

WHAT IS ON THE ACCOMPANYING CD-ROM? Included on the accompanying CD-ROM

are six

sample

specific area of interest to answer a qu estion, such as the

cases treated by orthodontic residents and written i ed by the ABO for the Initial Clinical Exami­ in the format requr nation using the required ABO forms (i.e., Discrepancy Index,

mdication for removal of third molars, interpretation of

Cast-Radiograph Evaluation, and Case Management Forms).

chapter. With this format, the reader can quickly focus on a

orthodontic

xi

PREFACE

xii

Although these cases have not been endorsed by the ABO and

l t has been challenging to select the chapter topics and sequence

are not part of the ABO Clinical Examination, they reflect

them in a meaningful manner. Writing a book or a chapter in a

examples that compare to the requirements for a six-case Initial

book demands a great deal of time from the contributors. We

Clinical Exam or First Recertification Exam. We recommend

appreciate their hard work, especially when faced with publisher

residency programs use these forms on exit cases and mock

deadlines. We are extremely pleased with the contributions to

board exams given to graduating residents to familiarize them

this book. We expected more than was reasonable and got more

with the required ABO format. These forms can be downloaded

than we expected. The efforts of these authors are dear in their

from the ABO website, www.americanboardortho.org

dedication to clinical excellence.

Also included is a practice exam taken directly from Mosby's

Review for the NBDE, Part

II. This exam is composed of 70

Note from the editor

multiple-choice questions, and rationales are provided with the

I would be rem iss if I did not thank Gloria Bailey for her help

correct answers. This practice exam is designed to familiarize

in typing and formatting the chapters. I would also like to

the student with the format of the NBDE, Part II exam.

WHO ARE THE CONTRIBUTORS, AND WHY WERE THEY ASKED TO PARTICIPATE?

thank the people at Elsevier, especially Courtney Sprehe for her advice and professionalism. This book would not have come to fruition without the contributions and support of my coeditors, Drs. Peltomaki and Pham-Litschel.

I am dedicated to contributing to the education of

As we are targeting both general dentists and orthodontists for

dental students, orthodontic residents, general dentists, and

this book, we asked some of the very best clinicians/educators

orthodontists, and 1 am confident that this book will serve as

to write chapters. We also included younger faculty members

an excellent teaching resource on orthodontic diagnosis and

so that their perspectives could be included. These authors

treatment.

understand the needs of prospective students and residents, as well as what information the practicing professional will find useful.

Jeryl 0. English

Contents

1

CRANIOFACIAL GROWTH AND DEVELOPMENT, 1 Peter H. Buschang

2

DEVELOPMENT OF THE OCCLUSION, 13 Timo Peltomaki

3

APPROPRIATE TIMING FOR ORTHODONTIC TREATMENT, 22 Kate Pham-Litschel

4

ORTHODONTIC RECORDS AND CASE EVALUATION, 27 Jeryl D. English, Thuy-Duong Do-Quang, and Anna Maria Salas-Lopez

5

THREE-DIMENSIONAL IMAGING IN ORTHODONTICS, 45 Chung How Kau and Stephen Richmond

6

DIAGNOSIS OF ORTHODONTIC PROBLEMS, 52 Kathleen R. McGrory, Jeryl D. English, Barry S. Briss, and Kate Pham-Litschel

7

ORTHODONTIC APPLIANCES, 83 P. Emile Aossouw

8

BIOMECHANICS IN ORTHODONTICS, 96 Andre Haerian and Sunil Kapila

9

TREATMENT PLANNING, 104 James L. Vaden and Cheryl A. DeWood

10

TREATMENT TACTICS FOR PROBLEMS RELATED TO DENTOFACIAL DISCREPANCIES IN THREE PLANES OF SPACE, 128 Burcu Bayirli, Christopher S . Riolo, Michelle Thornberg, and Michael L. Riolo

11

PHASE 1: EARLY TREATMENT, 137 James A. McNamara, Jr., and Laurie McNamara

xiii

xiv

12

CONTENT S

THE INVISALIGN SYSTEM, 146 Orhan C. Tuncay

13

TREATMENT OF CLASS II MALOCCLUSIONS, 152 Richard Kulbersh and Valmy Pangrazio-Kulbersh

14

CLASS Ill CORRECTORS, 178 Peter Ngan

15

MINOR TOOTH MOVEMENT, 190 G. Frans Currier

16

PHASE II: NONSURGICAL ADOLESCENT AND ADULT CASES, 197 Steven D. Marshall, Karin A. Southard, and Thomas E. Southard

17

ADULT INTERDISCIPLINARY ORTHODONTIC TREATMENT, 206 Valmy Pangrazio-Kulbersh

18

IMPLANTS IN ORTHODONTICS, 220 Brody J. Hildebrand

19

MINI-SCREWS AND PALATAL IMPLANTS FOR ORTHODONTIC ANCHORAGE, 231 Marc Schatzle

20

ORAL HYGIENE: POSSIBLE PROBLEMS AND COMPLICATIONS, 239 Frank Tsung-Ju Hsieh and David A. Covell, Jr.

21

ORTHODONTICS AND CRANIOFACIAL DEFORMITIES, 244 Kirt E. Simmons

22

TEMPOROMANDIBULAR DISORDERS, 260 Peter M. Greco

23

RETENTION IN ORTHODONTICS, 265 Jeryl D. English and Hitesh Kapadia

24

SOFT-TISSUE DIODE LASER SURGERY IN ORTHODONTICS, 272 Angela Marie Tran, Jeryl D. English, and Sam A. Winkelmann

25

SECRETS IN COMPUTER-AIDED SURGICAL SIMULATION FOR COMPLEX CRANIO-MAXILLOFACIAL SURGERY, 277 James J. Xia, Jaime Gateno, and John F. Teichgraeber

MOSBYS

ORTHODONTIC REVlEW

Craniofacial Growth and Development

C

linicians require a basic understanding of growth and

characteristic patterns of growth and cortical drift. It is also

development in order to properly plan treatments

useful to understand that patients should he expected to adapt

and evaluate treatment outcomes. As determined by

skeletally to orthodontic, orthopedic, and smgical interven­

the World Health Organization, growth and development

tions and that the adaptations mimic growth patterns exhibit­

provides one of the best measures available of individuals'

ed by untreated patients. Perhaps most importantly, clinicians

health and well-being. Knowledgeable clinicians understand

must understand the tremendous therapeutic potential that

that general somatic grov.rth provides important information

the eruption and drift of teeth provide. The maxillary molars

about their patients' overall size, maturity status, and growth

and incisors, for example, undergo more eruption than infe­

patterns. Because the tin1ing of maturity events, such as the ini­

rior displacement of the maxilla, making them ideally suited

tiation of adole cent or attainment of peak growth velocity, is

for controlling vertical and AP growth.

coordinated throughout the body, information derived from

Clinicians also often do not appreciate that adults show

stature or weight can be applied to the craniofacial complex. In

many of the same growth patterns exhibited by children and

other words, the timing of peak height velocity (PHV)-a non­

adolescents, simply in less exaggerated forms. It has been well

invasive and relatively easily obtained measure-can be used

established that craniofacial growth continues though the 20s

to determine the timing of peak mandibular growth veloc­

and 30s, and perhaps beyond. Skeletal growth of adults appears

ity. Knowledge of general somatic growth is also useful when

to be predominately vertical in nature, with forward mandible

evaluating the sizes of patients' craniofacial dimensions. An

rotation in males and backward rotation in females. The teeth

individual's height and weight percentiles provide a measure

continue to erupt and compensate depending on the individ­

of overall body size, against which craniofacial measures can

ual's growth patterns. Adults also exhibit important soft tissue

be compared. For example, excessively small individuals (i.e.,

changes; the nose grows disproportionately and the lips flatten.

below the 51h percentiles in body size) might also be expected

Vertical relationships between the incisors and lips should also

to exhibit a small craniofacial complex. Finally, the reference

be expected to change with increasing age.

data available for somatic growth and maturation are based

Finally, malocclusion must be considered as a multifactorial

on large representative samples, making them more generally

developmental process. Although genes have been linked with

applicable and more precise at the extreme percentiles than

the development of Class III and perhaps Class I l division 2 malocclusions, the most prevalent forms of malocclusions are

available craniofacial reference data. Postnatal craniofacial growth is a complex, but coordi­

largely environmentally determined. Equilibrium theory and

nated, ongoing process. The cranial structures are the most

the notion of dentoalveolar compensations provide the con­

mature and exhibit the smallest relative growth rates, followed

ceptual basis for understanding how closely linked tooth posi­

by the cranial base, and then the maxillary and mandibular

tions are with the surrounding soft tissues. They also make it

structures, which are the least mature and exhibit the great­

possible to predict the type of compensations that should be

est growth potential. Knowledge about a structure's relative

expected. For example, they explain why the development of

growth is important because it serves, along with heritabil­

malocclusion is associated with various habits, assuming the

ity, as an indicator of its response potential to treatment and

habits occur regularly and are of long enough duration. In fact,

other environmental influences. It is essential that clinicians

anything that alters mandibular posture might be expected to

understand that the maxilla and mandible, the two most im­

elicit skeletal and dentoalveolar compensations. This explains

portant skeletal determinants of malocclusion, follow similar

why individuals wiili chronic airway obstructions develop skel­

growth patterns. Both are displaced anteriorly and, especially,

etal and dental malocclusions that are phenotypically similar to

inferiorly; both tend to rotate forward or anteriorly; both rotate

malocclusions associated with weak craniofacial musculature;

transversely; and both respond to displacement and rotation by

both populations of patients posture their mandibles similarly

1

MOSBY'S ORTHODONTIC REVIEW

2

and undergo similar dentoalveolar and skeletal compensations. Based on the foregoing, the following questions are intended to provide a basic-although only partial-understanding of growth and development and its application to clinical

2. What is the mid-growth spurt, and how does it apply to craniofacial growth? The mid-growth spurt refers to the increase in growth velocity that occurs in some, but not aU, children several years before the

practice.

1. At what ages do most children enter

adolescence, and when do they attain PHV? The adolescence growth spurt starts when decelerating child­

initiation of the adolescent growth spurt. Mid-growth spurts in stature and weight have been reported to occur between 6.5 and 8.5 years of age; they tend to occur more frequently in boys than

hood growth rates change to accelerating rates. During the first

girls.2·3 Based on yearly velocities, mid-gro"'rth spurts have been demonstrated for a variety of craniofacial dimensions-also

part of the growth spurt, statural growth velocities increase

between 6.5 and 8.5 years of age--occurring simultaneously

steadily until peak height velocity (PHV} is attained. Longitudi­

or slightly earlier for girls than boys.4·7 Applying mathematic

nal assessments provide the best indicators of when adolescence

models to large longitudinal samples, Buschang and colleagues8

is initiated and PHV is attained. Longitudinal studies pertain­

reported mid-growth spurts in mandibular growth for subjects

ing to North American and European children 1 show that girls

with Class 1 and Class 11 molar relationships at approximately

are advanced by approximately 2 years compared \'lith boys in

7.7 years and 8.7 years of age for girls and boys, respectively.

the age of initiation of adolescence and age of PHV. Based on the 26 independent samples of girls and 23 samples of boys, the average ages of PHY are 11.9 and 14.0 years, respectively.

3. Which skeletal indicators are most closely

associated with PHV?

Girls and boys initiate adolescence at 9.4 years and 1 1.2 years,

According to Grave and Brown,9 PHV in males and females oc­

weight usually occurs 0.3 to 0.5 year after PHV (Fig. 1-l).

hooking of the hamate, and slightly before capping of the third

respectively. Maximum adolescent growth velocity in body

curs slightly after the appearance of the ulnar sesamoid and the middle phalanx, the capping of the first proximal phalanx, and the capping of the radius. According to Fishman's10 skeletal ma­

turity indicators, capping of the distal phalanx of the 3rd finger oc­ PHV

curs less than 1 year before PHV, capping of the middle phalanx

Boys

of the 3rd finger occurs just after PHV, and capping of the middle

7

phalanx of the 5th finger occurs less than one half year after PHV.

6

Based on the cervical vertebrae, PHV occurs between the devel­ opment of the concavity on the inferior borders of the 2nd and

5

3rd vertebrae (CVMS

>-

A

g 4 Ql :::l

� u.

If) and development of a concavity on the

inferior borders of the 2nd, 3rd, and 41h vertebrae (CVMS III).11

3

4. What is the equilibrium theory of tooth position?

2

Although Brodie12 was among the first to identify the relationship between muscles and tooth position, it was

0

Weinstein and colleagues13 who experimentally established 13.4 13.5 13.6 13.7 1 3.8 13.9

14

14.1 14.2 14.3 14.4

tween the soft tissue forces. Based on a series of experiments,

Age

they concluded that: l . The forces {produced naturally or by orthodontic appli­

PHV Girls

ances) exerted on the crowns of teeth are sufficient to cause

6

tooth movements

5

2. Each tooth may have more than one stable state of equilib­ rium

>- 4

B

0 c

� 0" �

u.

that the teeth are maintained in a state of equilibrium be­

3. Even small forces

3

(3-7 gm), if applied over a long enough

period, can cause tooth movements Proffit, 14 who revisited the equilibrium theory 15 years later,

2

noted that the primary factors involved were:

I. The resting pressures of the lips, cheeks, a.nd tongue

0

11.4 1 1 .5

2. The eruptive forces produced by metabolic activity within 1 1 .6 1 1 .7 11.8 11.9

12

1 2 . 1 12.2

Age

1-1 Frequency distribution of 26 s ampl e ages of girls (B). (From Malina RM, Bouchard C, Beunen G. Ann Rev Anthropo/ 1988;17: 1 87-219.) FIG

PHV for boys (A) and

the periodontal membrane He further noted that extrinsic pressures, such as habits and orthodontic forces, can alter equilibrium, pro"vided that they are sustained for at least 6 hours each day. Proffit14 also identified head posture and growth displacements/rotations as

Craniofacial Growth and Development

•

CHAPTER 1

3

secondary factors determining equilibrium. As the manclible rotates, the incisors move as dental equilibrium is reestablished. Bjork and Skieller, 15 for example, have shown an association between changes in lower incisor angulation and tiue mandib­ ular rotation.

� Q)

5. What is the prevalence of Class II dental malocclusion among adolescents and young adults living in the United States?

12 +----�

The best direct epidemiologic evidence comes from the NationaJ Health Survey,16·17 which evaluated approximately

7400 childien between 6 and I I years of age and over 22,000 youths 12 to 17 years of age. Unilateral and bilateral disto­ clusion occurs approximately 16.1% and 22.7% of the time among Caucasian children and 7.6% and 6.0% of the time among African-American children, respectively. Comparable incidences among Caucasian youths were 17.8% and 1S.8o/o and 12.0% and 6.0% among African-American youths. Based on overjet provided by the NHANES Ill, Proffit and associ­ ates18 estimated that the prevalence of Class l l malocclusion

0

8 to 1 1

.Whites • Blacks • Hispanics

1 2 to 17

18 to 50

Age

FIG 1-2 Average mandibular alignment scores, U.S. persons, 1988-1991. (Adapted from Brunelle JA, Bhat M, Upton JA. J Dental Res 1996;75[special issue]:706-713.)

(overjet 2: S mm) decreases from over 1S.6% between 12

and 1 7 years of age to 13.4% for adults . They also showed

that C lass IT malocclusion is more prevalent among African­

.\mericans {16.5%) than Caucasians ( 14.2%) and Hispanics

6.

congenitally absent, or extracted at least 1 0 years before post­ retention records were taken. Sampson and colleagues27 also

9.1%).

What is the prevalence of incisor crowding among individuals living in the United States, and how does it change with age? ---

showed no difference in crowding between subjects whose third molars have erupted completely or partially, remained impacted, or were missing. A randomized controlled trial based on 77 patients followed for 66 months showed a 1.0

According to the initial NHANES Ill data,19 incisor irreg-

mm difference in anterior crowding between patients whose

ularities increase from an average of 1.6 mm for children

third molars had and had not been removed; the authors

to I I years, to 2.5 mm for youths 12 to 17 years, to 2.8

concluded that removal of third molars to reduce or prevent

mm for adults 18 to SO years of age. Although incidences

late crowding cannot be justified.28 Based on the

are similar at the youngest age, African-American youths

data, individuals who had erupted third molars displayed sig­

and adults show significantly less crowding than Caucasians and Hispanics. Based on the complete NHANES data set, including 9044 individuals between 15 and SO years of age, approximately 39.5% of U.S. adults have mandibular incisor

inegularities 2: 4 mm and 16.8o/o have irregularit ies 2: 7.20 Adult maJes tend to show greater crowding than females; His­

HANES

nificantly less crowding than those who did not have erupted

third molars.20

8. How does horizontal and vertical mandibular growth affect crowding? Vertical growth makes the maintenance of lower incisor align­

panics show greater crowding than Caucasians, who in turn

ment after orthodontic treatment more problematic. Based on

display greater crowding than African-Americans. Based

the notion that the lower incisors are carried into the lower lip

on the available data for untreated subjects followed longi­

as the mandibula grows anteriorly or rotates downwards, late

tudinally, rates of crowding increase precipitously between

mandibular growth has been suggested as a major contributor

50 years of age, especially during the late teens and early 20s (Fig. 1-2).20

to post-retention crowding.29 Although incisor compensation

15 and

7. Do the third molars play a role in determining crowding? Although third molars have been related with crowding,2I-24

to backward mandibular rotation has been demonstrated, 15 crowding as a result of anterior growth displacements remains to be established. However, changes in lower incisor crowd­

ing have been shown to be related to vertical g rowth. Both

treated and untreated patients who undergo greater inferior

most contemporary studies show little or no relationship. A

growth displacements of the mandible and associated greater

1979 came to the consensus that there is

�IH conference in

little or no justification for extracting third molars solely to

eruption of the lower incisors show greater crowding than those who undergo less vertical growth and less eruption. 30•31

minimize present or future crowding of the lower anterior teeth.25 Ades and co-workers26 found no difference in sub­

teen years, patients would be well advised to wear their retain­

Iects whose third molars were impacted, erupted in function,

ers into their early and mid-20s .

Since vertical mandibular growth continues well beyond the

4

MOSBY'S ORTHODONTIC REVlEW

9. How much should the mandibular incisors and molars be expected to erupt during adolescence?

perimeter increases 4 to 5 mm between 6 and 11 years of age and decreases 3 to 4 rom between 11 and 16 years. In contrast, mandibular arch perimeter increases approximately 2 to 3 mm

Based on natural structure superimpositions of the mandi­

initially and then decreases 4 to 7 mm, with greater decreases

ble performed between I 0 and IS years of age, Mc\.Yhorter-32

in females than males (Fig. l -3 ) .

showed that the mandibular central incisors and first molars

11.

erupt approximately 4.3 and 2.5 mm in males and females, respectively. Also using natural structure superimpositions, vVatanabe et al.33 demonstrated that the mandibular molars and incisors erupt at rates ranging from 0.4 to 1.2 mm/yr and 0.3 to 0.9 mm/yr, respectively. Rates of eruption were greater in

How do untreated maxillary and mandibular intermolar widths change during childhood and adolescence?

Bishara and colleagues35 reported that intermolar widths increase

7 to 8 mm between the deciduous dentition (5.0 yrs of age) and the early mixed (8.0 yrs of age) dentitions and an additional 1 to 2 mm between the early mixed and early permanent ( 12.5 yrs of age) dentitions. Between 6 (first molar fully erupted) and 16

males than females, attaining peak velocities at approximately

12 and 14 years of age for females and males, respectively. 10. How does untreated arch perimeter change

years of age, Moyers and colleagues34 showed greater increases

between the late primary dentition and the permanent dentition?

for males than females for both maxillary (4.1 versus 3.7 mm) and mandibular (2.6 versus 1.5 mm) intermolar widths. Based

Computed based on a centenary curve extending from the

on a sample of 26 subjects followed longitudinally between 12

mesial of the first molar to mesial of first molar,34 arch perimeter

and 26 years of age, DeKock36 reported no significant change for

increases during the early mixed dentition and decreases during

females and only slight increases ( 1.4 and 0.9 mm for maxilla and

and after the transition to the permanent dentition. Maxillary

mandible, respectively) in intermolar width for males ( Fig 1-4).

� 65 +1��----�����2

� 63 � 7

6

9

8

10 1 1

12

B

+-------��--�

6

13 14 1 5 1 6

9

8

7

Chronologie age

10 1 1 12 13 14 15 1 6 Chronologie age

� Male

� Male

- Female

- Female

FIG 1-3 Maxillary (A) and mandibular (B) arch perimeters between 6 a nd 1 6 years of age. (Adapted from Moyers RE, van der Linden FPGM, Riolo ML, McNamara JA Jr. Standards of human occlusal development. Monograph #5, Cran·lofacial Growth Series, Center for Human Growth and Development, University of Michigan, Ann Arbor. Michigan, 1 976.)

46 .----,

48 46 � 44 � 42 � 40 V>

A

(J)

*



38

E � :::2:

44 +-------_, ...._..... ... ... 42 ------ � �==��£ �� � t::: ����� � � == _.. .,.,.-_ --------------------� --�� ��� £ 40 �

r-

ilj

- --

38 +-----� 6

7

8

9

10

11

12

13

14

15

16

6

7

8

Chronologie age

-+-

Male

- Female

9

10

11

1 2 1 3 14 15 16

Chronologie age -+- Male --- Female

FIG 1-4 Maxillary (A) and mandibular (B) intermolar widths between 6 and 16 years of age. (Adapted from Moyers RE, van der Unden FPGM, Riolo ML, McNamara JA Jr. Standards of human occlusal development. Monograph #5, Craniofacial Growth Series, Center for Human Growth and Development, University of Michigan, Ann Arbor, Michigan, 1 976.)

B

Craniofacial Growth and Development 12.

Without treatment, how do maxillary and mandibular arch depths change during childhood and adolescence?

•

CHAPTER 1

5

How do untreated maxillary and mandibular intercanine widths change over time?

1 3.

During the transition from the deciduous to pem1anent n i cisors, intercanine width increases approximately 3 mm.37 Maxillary i n­

Maxillary and mandibular arch depths, midline distances be­

tercanine width shows a second phase of increase ( approximately

tween a line tangent to the incisors, and a line drawn tan­

1.5 mm) with the emergence of the permanent canines; mandibu­

gent to the distal crown of the deciduous second molars or

their permanent successors show different patterns of growth

lar interc anine widths decrease slightly after the emergence of the

changes . Maxillary arch depth i n creases 1 .4 and 0.9 mm in

pennanent canine.37 Bishara and co-workers35 al so reported in­

males and females, respectively, during the eruption of the

creases in maxillary and mandibular intercanine widths between

permanent incisors.37 Mandibular arch depth shows little

the deciduous and early mixed dentition; mandibular intercanine

change over the same period. With the loss of the deciduous

widths increased or decreased slightly between the early mixed and early permanent dentitions. Intcrcanine widths of children

molars, maxillary arch depth decreases 1 . 5 and 1.9 mm, while

followed by the University School Growth Study, Michigan,J.I

mandibular arch depth decreases 1.8 and 1 .7 mm in males and females, respectivcly.37 DeKock36 reported decreases ( ap­

increased approximately 3.0 mm between 6 and 9 years of age;

proximately 3.0 mm) in arch depth between 12 and 26 years

maxillary widths increased an additional 2.5 mm with the emer­

of age, with rates dim i n i shing over time. Based on subjects

gence of tile permanent canine ( Fig. l -6).

with normal occlusion, Bishara and co-workers35 showed increases

( L . l- 1 .8

What differences exist in arch widths between subjects with normal and Class II malocclusion?

14.

mm) in arch depth between the decidu­

ous and early mixed dentitions; between the mixed and early

permanent dentition, maxillary arch depths increased only

Lux and colleagues38 reported that maxillary and mandibu­

lightly (0.5-0.7 rnm) and mandibular depths decreased 2.6

lar arch intermolar widths are significantly smaller in subjects

to 3.3 mm ( F ig. 1-5) .

with Class II division 1 malocclusion than subjects with Class I

37 (/)

35

(ii Qi 33

� �

31 29 27

-- - --- --

--

11

13

15

-

---- ----- -- - - - -- - - -

19

17

25

23

21

27

Age

--+-

Male-Mx

---- Female-Mx

· -+ -

Male-Md

·

Female-Md

-o -

FIG 1 -5 Maxillary (Mx) and mandibular (Md) mo lar arch depths between 1 1 and 27 years of age. (Adapted from DeKock WH: Am J Orthod 1 972;62:56-66.)

30

35 33

A

� !!! 31 5-6 mm) does not exist, crowding is com­

clinical significance.

monly seen once the permanent lower incisors have erupted. This is called physiological crowding.

12. Is anterior spacing common once permanent

incisors have erupted?

-----

optimal one for a proper occlusion to develop. However, vari­ the second transitional period, and these variations may have Sometimes the lower second molars erupt before the second premolars. This may cause anterior drift of the first permanent molars too early and, as a consequence, space loss for the sec­ ond permanent premolars. Therefore, it is preferable that the second premolars erupt before the second permanent molars.

Despite the initial crowding of the permanent incisors in the

Since the leeway space provides the space needed by the upper

maxillary bone, spacing is a common finding in the upper

canines, they should erupt after the permanent premolars. Tf not,

A large space > 2 mm) between the upper central incisors, called midline

anterior area once the incisors have erupted.

lack of space may cause the upper canines to erupt too labially.

dwstema, may exist due to a strong labial frenwn. Upper lat­

16. What changes occur in the dental arch length during occlusal development?

eral incisors may be inclined distally due to the pressure of the erupting canines on their roots. This normal spacin g condition

Dental arch length has a special meaning in orthodontics. Arch

ugly duckling. Once the perma­

length denotes the distance from the most labial surfaces of

nent canines erupt, upper spaces usually close and uprighting

the central incisors to the line connecting the mesial (or distal)

uf the lateral incisors can be seen. On the other hand, spacing

points of the first permanent molars in the midsagittal plane.

m the upper front area is called

MOSBY'S ORTHODONTIC REVIEW

18

Measurements and changes in the dental arch dimensions are largely based on the studies of Moorrees.5 Changes in the arch length occur in two different phases during occlusal de­ velopment. During the first transitional period, upper dental arch length increases slightly (on average 0.5 mm) because of the more labial eruption of the upper permanent central inci­ sors. Essentially, this eruption pattern creates a larger dental arch circumference compared with the positions of the primary incisors. An additional increase of approximately 1 mm can be seen when the permanent lateral incisors erupt. During the second transitional period, arch length commonly decreases because the leeway space allows permanent premolars and first molars to drift forward. Therefore, the average upper dental arch length is slightly longer or the same at 3 years than at 1 5 years. In the lower dental arch, no clinically significant changes occur in the arch length during the first transitional period because lower permanent incisors erupt into the same arch circumference as the primary incisors. A considerable short­ ening of the lower dental arch length takes place during the second transitional period. As discussed earlier, larger lee­ way space in the lower compared with the upper dental arch allows more anterior migration of the premolars and molars, which leads to the shortening of the arch length. The average lower dental arch length is thus slightly longer at 3 years than at 15 years. According to Moorrees,5 2- to 3-mm shortening of the lower dental arch length can be seen from the full primary dentition to the permanent dentition.

1 7. What changes occur in the dental arch width during occlusal development?

----

-----

During the eruption of the maxillary permanent incisors, intercanine dimension (measured between primary canines) increases on average by 3 mm. Before or at the time of eruption of the permanent canines, another increase of approximately 2 mm takes place in canine to canine distance. The increase in the upper intercanine distance may be caused by the distalizing pressure of the erupting permanent incisors on the permanent canines and growth in '-vidth of the maxilla at the midpalatal suture. A steady increase (total 4-5 mm) in the distance be­ tween the upper first permanent molars can be seen after their emergence. l n the lower dental arch, a comparable increase of the intercanine distance as in the upper arch occurs during the eruption of the permanent incisors (3 mm on average). However, unlike in the upper arch, no additional increase in the canine-can ine distance takes place in the lower arch dur­ ing the later stages of dental development. This early estab­ lishment of the lower intercanine distance has an important clinical bearing in that attempts to increase lower interca­ nine distance by orthodontic means usually leads to relapse. 8 After the emergence of the molars, the distance between the lower first molars increases steadily corresponding to the upper arch. There are two ways to measure dental arch width. The more common method is to measure the distance between the

corresponding contralateral teeth at the cusp tips (e.g., interca­ nine or intermolar width). Another measurement can be made at the palatal/lingual gingival level of the teeth; this measure­ ment describes the width of the bony arch. 5 The increase in the intercanine distance is greater when measured from the cusp tips of the teeth than at the gingival level, particularly in the up­ per dental arch. This may be because the labio-lingual crown diameter of the permanent canine is greater than that of the primary canines.

18. What changes occur in the dentition once permanent teeth (excluding wisdom teeth) have erupted?

Appearance of, or actual increase of, already existing crowding, called late or secondary crowding, in the lower anterior area is a typical finding in late dental development in the late teens and early 20s. This crowding occurs before or simultaneously with the emergence of wisdom teeth and may take place both in orthodonticaUy untreated or treated subjects. Several factors are thought to play a role in this crowding in the lower anterior area.9 Maxillary and mandibular differential growth is consid­ ered to have an effect on the late crowding. Growth of the maxilla ceases earlier than growth of the mandible. Because of overbite, lower anterior teeth cannot move forward to the extent of the lower jaw growth but tilt lingually to a smaller circumference, which results in crowding. In addition, the maturation of soft tissues that occurs during the teenage period may increase the pressure from lips, causing crowding. More forward drift takes place in the lower dentition than in the upper, which also in­ creases crowding.

19. Do wisdom teeth play a role in the lower anterior crowding?

------

Eruption of wisdom teeth often occurs simultaneously with the appearance or increase in lower anterior crowding. lt is a common belief that this is because of pressure created by the erupting wisdom teeth. However, current evidence suggests that wisdom teeth play a minor role, if any, in the late lower incisor crowding. Individuals with congenitally missing third molars may also have this crowding. Thus, there is no evidence to support a recommendation to extract third molars in order to prevent late incisors crowding.IO 20- What are the most common reasons for interference with normal tooth eruption?

As stated earlier, great individual variation occurs in the timing of eruption of permanent teeth. Premature tootl1 eruption is possible, but delayed tooth eruption is more common. This may occur only on one side or on both sides of the dental arch. Reasons for the delayed tooth eruption may be divided into rare systemic factors and more frequent local factors.11 Sys­ temic factors usually involve a disease process with the whole dentition commonly affected. Bone metabolism for necessary resorption of the alveolar bone and/or roots of the primary tooth may be disturbed, and eruption may therefore be delayed

Development ofthe Occlusion • CHAPTER 2

19

or even hindered. Tf a permanent tooth fails to fully or partially

about

move from its crypt position in the alveolar process into the

infraocclusion as minor ( 1 -2 mm), and ankylosis had evidently

oral cavity without evident cause (presumably due to mal­ function of the eruption mechanism), this condition is called

"primary failure of tooth eruption. "12

early ankylosis. On the other hand, late ankylosis denotes

occurred near the time of exfoliation of a primary molar.

22. What is ectopic eruption?

Local factors that delay tooth eruption may be mechanical

Ectopic eruption of a tooth means that the tooth erupts away

eruption may take place. Local factors include supernumerary

torial underlying etiology. Sometimes a tooth erupts ectopicaUy

teeth, heavy fibrous gingival tissue because of premature loss

because of an abnormal initial position of the tooth bud. Up­

in nature, and once the obstruction is eliminated, further tooth

from the normal position. This condition can have a multifac­

of a primary tooth, crowding, and sclerotic alveolar bone. An­

per first molars and canines are most cummunJy observed to

kylosis of a tooth also causes delay or prevention of a tooth

erupt ectopically, followed by lower canines, upper premolars,

eruption. As a rule of thumb, if a permanent tooth has erupted

lower premolars, and upper lateral incisors. ln the permanent

but its counterpart does not wi thin 6 months, an eruption

dentition, the upper first molars erupt most commonly ectopi­

problem is evident and further investigation is recommended.

21 . What is tooth ankylosis and what is its clinical significance?

cally (prevalence approximately

4%) (Fig. 2-6). The molar may

then erupt too far anteriorly and make contact with the distal root of the second primary molar. As a consequence, the first permanent molar may fail to erupt on both sides or only on

.�kylosis of a tooth is defined as the

union/fusion between a

one side. h may also happen that an ectopically erupting

first

tooth and alveolar bone. This means that the periodontal liga­

permanent molar causes severe resorption (called undermining

ment is obliterated in one or more locations, and there is contact

resorption) to the roots of the second primary molar, leading

hetween the cementum of a tooth and alveolar bone. Ankylosis

to early exfoliation of that primary molar. This causes a more

more common in the primary, particularly primary molars,

anterior eruption of the first permanent molar, resulting in

2-5). Prevalence of pri­

space loss and future crowding of that quadrant. Because of

than in the permanent dentition (Fig. mary molar ankylosis is

So/o to 10%. Ankylosis is thought to be

insufficient space, the upper and lower lateral incisors may also

of

related to the noncontinuous resorption process of the roots of

erupt

the primary teeth. ln other words, during the resorption phase

this may be an early loss of the primary canines from under­

1f the root, there are periods of rest and reparation. During

mining resorption.

the reparative phase, fusion of the cement and alveolar bone may develop. Causative factors for ankylosis are currently un­ known.

An ankylosed tooth cannot erupt; consequently, the tooth

ippears to submerge with continued alveolar growth. In real­

tv, an an\...-ylosed tooth does not submerge, but when it fails to

ectopically and t oo distally. The clinical significance

23. What are eruption problems of the upper permanent canines? Canines, particularly maxillary canines, have the longest way of all teeth

to erupt from their initial position to the occlusion.

Initially the upper canines are located high in the maxilla, in

rrupt, a vertical deficiency in the occlusal level will develop as

the canine fossa, close to the base of the nose. In pre-emergent

the adjacent teeth continue erupting. The term infraocclusion is d to describe this condition and the amount of infraocclu­

roots of the lateral incisors. When the child is 9 to 1 0 years

eruption, they move downward along the distal aspect

of the

wn of an ankylosed tooth depends on when the ankylosis oc­

.:urred. lt is known that a molar erupts on average l mm yearly.

This means that if the vertical defect is large, one may speak

AG 2-5 Because of ankylosis of the lower primary second molars on both sides, a vertical deficiency in the occlusal level developed since the ankylosed teeth could not erupt and the adjacent teeth continued erupting. Note also congenital missing lower second permanent premolars, wtlich are the most commonly missing permanent teeth.

FIG 2-6 Both upper first molars have erupted ectopically, too far anteriorly. This may lead to early exfoliation of the upper second primary molars by undermining resorption and space loss in these quadrants.

MOSBY'S ORTHODONTIC REVIEW

20

old, these teeth should be palpable in the fornix between the permanent lateral incisor and the primary first molar. If not,

26. What is the relationship between occlusal development and facial growth?

ectopic eruption or impaction may be expected. Maxillary canines are the last teeth to erupt and are therefore strongly

Eruption of permanent teeth does not stop once a tooth has

influenced by spacing conditions. The canines' long path of

reached occlusion. Eruption of teeth causes an elongation of

eruption, coupled with their late emergence timing, causes

dentoalveolar processes that continues at a rate that parallels

their high prevalence of impaction (about

the rate of vertical growth of the face, and vertical growth of

2o/o).

Most of the impacted upper canines arc palatally located. In terestingly, nearly

the mandibular ramus in particular. In an optimally grow­

of patients with palatally located

ing individual, growth of the anterior and posterior face

upper canines present with anomalous (peg shaped) or

height is approximately equal. Th is means that the amount

congenitally missing upper lateral incisors. Because of this

of eruption of the anterior and posterior teeth that have al­

SOo/o

clinical link, it has been proposed that a common genetic

ready reached the occlusal contact is in balance. During the

etiology may be responsible for canine impaction and

period between

hypodontia.13•14 Another explanation of this observation

face heights increase about

could be that a guiding structure for the proper eruption

tooth erupts about

8 and 18 years of age, anterior and posterior

20 mmY·18 At the same time, each

10 mm ( l .O mm/yr) to keep contact with

of canine is missing, and, therefore, the canine is palatally

its opposing tooth. In some individuals, however, growth of

displaced.

the anterior and posterior face is not in balance, and either

(CT) study, researchers found

anterior or posterior growth rotation of the mandible occurs.

that even in cases of normal eruption of upper canines, the con­

This is followed by overeruption of posterior or anterior teeth

tinuity of the periodontal ligament of the lateral incisor may be

in posterior rotation pattern versus anterior rotation pattern,

temporarily lost v•ith no resorption sign in the root.15 When

respectively.

I n a computed tomography

the path of eruption abnormally diverges so that the canines make contact with the roots of the lateral incisors, resorp­

27. Can individuals be found with variations in the number of teeth?

tion of the incisor may be expected unrelated to the size of the dental follicle of the canine.15

24. What is a typical eruption problem of the second permanent molars? If space is not adequate for the upper second permanent molars, they will often tilt buccally and distally before their emergence and eventually erupt too buccalJy. On the con­ trary, the lower second permanent molars tend to tilt lingually

Variation in the number of teeth is a frequent finding in any patient population. Instead of the normal and

32

20

primary teeth

permanent teeth, individuals with excessive or reduced

numbers of teeth can be seen. In the permanent dentition, one

This condition hypodontia or agenesis of teeth. If more than six per­ manent teeth are missing, the condition is called oligodontia. Anodontia, which is characterized by complete failure of tooth or two teeth are often congenitally missing. is called

because of insufficient space. \>\!hen the second molars erupt

development, is extremely rare. Jf supernumerary teeth are

like this, they may not occlude properly and a scissor-bite or

present, it is called

buccal cross bite may develop. I n the scissor-bite, the upper second molar is positioned too far to the buccal and the lower second molar is too far to the lingual.

25. Which factors have an effect on tooth position?

hyperdontia.

28. How common is hypodontia, and which teeth are most often affected? Based on epidemiological studies worldwide, the prevalence of congenitally missing permanent teeth has been found to vary

a tooth is erupting, it is affected by two forces that

according to the population studied as well as to gender. Stud­

dictate its vertical position; a force causing eruption brings a

ies from Europe and Australia show prevalence of hypodontia

tooth to the oral cavity, but a force from the occlusion has an

ranging

opposing effect. In addition, external forces from the cheeks

(both Caucasians and African Americans), the prevalence is

When

between S.So/o and 6.3%, whereas in North America These numbers exclude the third molars, but when

and Lips and internal forces from the tongue play a role in the

3.9%.19

buccolingual position of a tooth. According to Proffit, 16 forces

they arc included the prevalence is considerably higher, since to 25%

from the checks, lips, and tongue are not in balance; however,

one or more \visdom teeth are missing in about

periodontally healthy teeth do not move. The balancing factor

of the subjects. On the other hand, prevalence of congenitally

is probably the periodontal ligament, an active element capa­

missing primary teeth is only

ble of stabilizing tooth position. On the other hand, if support

hypodontia is significantly higher

from alveolar bone and periodontal ligament is reduced, teeth

boys.19

are prone to move.

20%

0. 1 o/o to 0.4o/o. The prevalence of ( 1 .37 times) in girls than in

Hypodontia commonly runs in families, an indication that

Light but long-lasling forces ( force from the soft tissues

genetic factors are involved. Missing teeth can be in herited as

at rest, periodontal ligament, and gingival fibers) are more

part of a syndrome or isolated in an autosomal-dominant or

important than heavy but short-lasting forces ( b iting,

autosomal-recessive way. Several gene defects have been found

swallowing) to cause a tooth to move or to maintain its

to be associated with hypodontia. The main genes known today

position.

to be involved in hypodontia are MSXl,

PAX9,

and

AXIN2.1

Development of the Occlusion • CHAPTER 2

Individuals who are missing several teeth often have distur­ bances in ot h e r organs of ectodermal origin (e.g., a condition called ectodermal dysplasia).

The most commonly m iss in g permanent teeth are the lower second premolars (more than 40% of the m issi n g teeth), fol­ lowed by the upper laterals and upper second molars. The number of other co ngen itally missing teeth is considerably lower. As a ge ne ral rule, the last tooth within its dental group is the one most likely to be congen itall y missing. In other words, third molars are more likely to be missing than the first and ... econ d mol a r s, seco nd prem olar s more often than the first ones, and lateral incisors more often than the central incisors. 29. How common is hyperdontia? Prevalen ce ofhyperdontia is lower than that of hypodo ntia.

In the primary dentition the prevalence of hyperdontia is about 0.5% and in the permanent dentition about I%. Supernumerary teeth are most often (85%) located in the upper jaw, pa rticularly in the premaxilla area. A supernumerary tooth may be typical or atypi­ .:al in shape. An atypical supernumera ry tooth is often found in the micllin e of the premaxilla and is called a mesiodens (Fig. 2-7). Overall, mesiodens is the most prevalent supernumerary tooth, followed by extra molars, an d lower second premolars. Hyper­ don tia may also be associa ted with generalized synd romes, such .lS cleft palate, Apert, cleidocranial dysplasia, Gardner, Down, Crouzon, Sturge-Weber, orofaci al-digi tal, and Hallermann-Steiff; these syndromes are linked to hyperactivity of the dental lamina. 30. Does variation in tooth size have an effect on occlusion? \·ariation in tooth size is a rel atively common finding and may

have an effect on occlusion. It is est i m ated that the prevalence •f"tooth size d iscrepa n cy" (also called "Bolton discrepancy"20 )

FIG 2-7 Supernumerary teeth are most often located in the

upper jaw. A supernumerary tooth is seen in the midline of the premaxilla and is called a mesiodens.

21

is about 5%.21 Upper permanent l a teral incisors show the la rgest variation in size. If th ey are si gnificantly smaller o r larg­

er than average, ideal occlusion is difficult to establish. As a general rule, if t h e mesiodistal dimension of an upper lateral incisor is sm aller than that of a l ower incisor, normal overjet and overbite is difficu lt to obta i n . REFERENCES Theslcff l: Epithelial-mesenchymal signalling regulating tooth morphogenesis. J Cell Sci 2003; 1 1 6: 164 7- 1648. 2. Lee CF, Proffit WR: The daily rhythm of tooth eruption. Am J I.

Orthod Dentofacial Orthop 1995; 1 07:38-47. 3. Risinger RK, Proffit WR: Continuous overnight observation of human premolar eruption. Arch Oral Riol 1 996; 4 1 :779-789. 4. Leighton BC: The early signs of malocclusions. Trans Eur Orthodon Soc 1 969, 353-368. 5. Moorrees CFA: The dentition ofthe growi11g child. A longitudinal study ofdental development between 3 and 18 years ofage. Cam­ bridge, Massachusetts: l Iarvard University Press, 1 959. 6. Bishara SE, Hoppens BJ, Jakobsen JR, Kohout FJ: Changes in the molar rel ationshi p between the deciduous and permanent dentitions: A longit udin al study. Am 1 Orthod Dentofacial Orthop 1 988; 93: 1 9-28. 7. Anderson AA: Occlusal development in children of African American descent. Types of terminal plane relatio nsh ips in the primary dentition. A ngle Orthod 2006; 76:81 7-823. 8. Rishara SE, Ortho D, Jakobsen JR, et al: Arch width changes from 6 weeks to 45 years of age. A m } Orthod DetJtofaeial Orthop 1 997; 1 1 1 :401-409. 9. Richardson ME: The et io l ogy oflate lower arch crowding alter­ native to mesially directed forces: A review. Am 1 Orthod Dentofacial Or-thop 1 994; 105:592- 597. 10. Southard TE, Southard KA, Weeda LW: M�ial force from unerupt­ ed third molars. Am J Orthod Dentofacial Orthop 1991; 99:220-225. I I . Suri L, Gagari E, Vastardis H: Delayed tooth eruption: Pathogen­ esis, diagnosis, and treatment. A literature review. Am f Orrhod Dentofacial Orthop 2004; 1 26:432-445. 1 2 . Proffit WR, Vig KWL: Pri mary failure of eruption: A possible cause of posterior open-bite. A m ] Ortl10d 1 9 8 1 ; 80: 1 73 - 1 90. 1 3. Pi rn i en S, Arte S, Apajalahti S: Palatal displacement of canine is genetic and related to congenital absence of teeth. J Dent Res 1996; 75: 1 742- 1 746. 14. Baccetti T: A control led study of associated dental anomalies. Angle Orthod 1 998; 68:267-274. IS. Ericson S, Bjerk.lin C, Falahat B: Does the canine dental follicle cause resorption of permanent incisor roots: A computed tomo­ graphic study of erupting maxillary canines. Angle Orthod 2002; 72:95- 104. 16. Proffit WR: Equilibrium theory revisited: Factors influencing position of teeth. Angle Orthod 1 978; 48: 1 75- 186. 17. Bishara SE: Facial and dental changes in adolescents and their clinical implications. Angle Orthod 2000; 70:47 I -483. 18. Thilander B, Persson M, Adolfsson U: Roentgen-cephalometric

standards for a Swedish population. A longitudinal study be­ tween the ages of 5 and 3 I years. Eur] Ortl10d 2005; 27:370-389. 19. Polder B), Van't HofMA, Van der Linden FPGM, Kuijpers-)agtman AM: A meta-analysis of the prevalence of dental agenesis of penna­ nent teeth. Commu nity Dent Oral Epidemio/2004; 32:2 1 7-226. 20. Bolton WA: The clinical application of a tooth-size analysis. Am J Ortilod 1962; 48:504-529. W, Sarver DM: Contemporary orthodontics, 2 1 . Proffit WR, Fields H cd 4. St Louis: Mosby, 2007.

ApproprUlte Timing for Orthodontic Treatment

0

ur goal in orthodontic treatment is to provide the best possible outcome in the shortest possible time with the least biological, financial, and psychosocial cost to our patients. When those results are functionally necessary and beneficial to the psychosocial well-being of our patients, we would like to begin as soon as possible. However, if we think that beginning earlier ex'tends the duration of treatment and increases costs without sufficient warrant, we would delay treatment. Deciding when to initiate treatment may be com­ plicated, and this certainly has been debated in the orthodontic literature. In this chapter, we review the differing opinions of appropriate timing, discuss the research findings on this topic, and, based on these findings, formulate a guideline for various specific orthodontic problems. 1 . What is the definition of early treatment and

what does it involve?

Early treatment, or Phase 1 orthodontic treatment, is defined as "treatments started in either the primary or mixed denti­ tions that are performed to enhance the dental and skeletal development before the eruption of the permanent dentition. Its purpose is to either correct or intercept a malocclusion and to reduce the need or the time for treatment in the permanent dentition."1 As opposed to the conventional late orthodontic treat­ ment, when orthodontic therapy is initiated on children in the late mixed dentition stage, early treatment is often a two­ phas�:J lrt:almt:nl. Pha�e I treatment typically begins when the child is about 8 years or younger and lasts about 6 to 12 months. This is followed by intermittent observation of tran­ �ition from the mixed to the permanent dentition. Phase JI treatment, usually with the fixed orthodontic appliances on permanent teeth, begins 6 to 9 months before the eruption of the second molars.2 It has been estimated that one fourth of all patients, and one third of all children, are treated in a two-phase manner.3.4 Single phase treatments have gained popularity in contemporary orthodontics.2 Here early treatment is initi­ ated in the late mixed dentition, just before the loss of the deciduous second molars, and is followed immediately by 22

banding and bonding of the permanent teeth. Reduction in the total treatment time and better control of the leeway spaces in the transitional dentition are some advantages of this methodology.

2. What are some perceived advantages of early treatment?

In 2001, the Diplomates of the American Board of Orthodon­ tics were asked about their perception of early treatment. The following points were listed1: Ability to modify skeletal growth is one of the strongest perceived benefits of early treatment. Better and more stable treatment results are another presupposed advantage of early treatment. By correcting the malocclusion as soon as it develops, weare establishing more normal function and development. Less iatrogenic tooth dama ge may be another benefit of early treatment. The less developed roots of permanent teeth may mean more favorable biologic responses to orthodontic forces. Better cooperation is another possible justification for early treatment. Patients may be more cooperative if they are treated before they reach high school. Older children tend to have more outside interests or parental conflicts at home, making orthodontic treatment a lesser priority in their lives.5 Earlier treatment can mean an earlier finish. Patients who begin orthodontic or orthopedic treatment in the second or third grade are likely to finish Phase II before high school. Furthermore, scheduling of appointments for these patients may be easier when they are in middle school as opposed to high school. Improved patient self esteem and parental satisfaction are also listed as benefits of early treatment. There is a clear correlation between improved esthetics and psychosocial well-being. Malocclusion is listed as one of the most common reasons for teasing in children.6 Moreover, parents, teachers, and peers are more likely to respond positively to attractive children. From this standpoint, early treatment is especially beneficial to children with debilitating malocclusions.

Appropriate Timing for Orthodontic Treatment 3. What are the perceived disadvantages

CHAPTER 3

23

POSTERIOR CROSSBITE WITH A FUNCTIONAL SHIFT

of early treatment? The Diplomates of the American Board of Orthodontics were also asked to list the perceived disadvantages of early treatment1:

It is important that a posterior crossbi te with the presence of a functional shift be treated as soon as it is diagnosed to prevent the asymmetrical positioning and growth of the condyles.9 The

Variation in results and stability is listed as a major disadvantage.

true cause of such a crossbite is

a bilateral constriction of the

maxillary arch. In order to have at least one side of functioning

Increased financial cost to the patient is another drawback of a two-phase treatment.

posterior occlusion, the condyles are positioned asymmetrical­ ly within their respective fossae, resulting in the characteristic

Patient "burnout" from longer total treatment duration is a concern .

midline discrepancy in centric occlusion. If left untreated, this condition can lead to asymmetrical growth of the mandible

Iatrogenic problems may be more prevalent when starting

and possible remodeling of the glenoid fossa. tO A permanent

treatment early. These problems may include dilacera­

facial asymmetry may result and persist, even though the con­

tions of roots, decalcification under bands, impaction of

stricted maxillary arch is corrected at a later date.9

maxillary canines by prematurely up-righting the roots of the lateral incisors, and impaction of the

maxillary

second molars from the distalization of first molars.

Moreover, treatment of younger patients may be more uncertain because of the

unpredictable dynamics of

Although traditionally not considered active orthodontic treat­

ment, space maintainers

arc

important appliances in some

conditions of the primary dentition. V\Thether a space result­ ing from the premature loss of a tooth needs to be maintained

children.5

depends on the following three factors8:

----

There have been many debates about the justifications of early treatment. Orthodontists have asked if early treatment is worth the extra cost, time, and energy involved. If early treatment is dfective, just how early can treatment begin in the pri mary, early mixed, or late mixed dentition? Interesti ngly, orthodontists are more likely to recommend Phase

SPACE MANAGEMENT

growth. Treatment goals can be more definitive in older 4. What are the controversies concerning early treatment?

r

•

I if they are more experienced with early treatment,

1 . Root development: A tooth erupts when its root is 75% de­ veloped. The less developed the permanent root, the stron­ ger the recommendation for space maintenance.

2. Distance between the permanent tooth and the alveolar

crest : The amount of bone overlying the succedaneous tooth also predicts the timing of the tooth's eruption.

3. Type of tooth prematurely lost: When primary incisors are lost, space maintenance is not necessary

as

long as the pri­

mary canines have already erupted into occlusion. With the loss of a primary canine, the extraction of the contralateral

if their practices have younger children.s Yet according

canine and placement of a lower lingual holding arch are

' Johnston, clinicians "have a responsibility, individually

necessary to prevent the undesirable drifting of t he midline.

md collectively, to sift through and evaluate the available

With the loss of a primary first molar, a band and loop space

e'idence with an eye toward the delivery of 'evidence-based'

maintainer helps prevent the w1favorable mesial drifting of

reatment."7 The early treatment proposals should be based

the second primary molar. This forward sliding of the sec­

s on perceived benefits or personal experiences and more n

current research fi ndings. So what are the scientific studies suggesting about early

reatment? The following questions are reviews of studies on treatment timing, as well as suggestions of when to begin.

5. What are the problems that can be treated in the primary dentition?

-------

DIGITAL AND PACIFIER HABITS n most cases, treatment for a prolonged digital or pacifier

bit should be initiated between the ages of 4 and 6 years,

before the eruption of the permanent incisors. Keep in mind that anteroposterior dental and skeletal changes are less likely ) el f-corn:ct than are the vertical dental changes.s Anterior open bites resulting from digital sucking do not generally need

' be treated because they will likely correct spontaneously if the habit ceases before 9 years of age.s Skeletal open bite and

ond primary molar would reduce the space available for the unerupted first premolar. Finally, a space maintainer is al­ ways recommended when the primary second molar is lost before the eruption of the first permanent molar. I t seems logical that use of space maintai ners would reduce the prevalence and severity of crowding. However, the existing studies in literature do not have enough scientific weight for one to recommend for or against the use of space maintainers to prevent or reduce the severity of malocclusion in the per­ manent dentitio n . 1 1 Yet one may argue that the roles of space maintainers arc so i n tuitive that waiting for evidence of their

effectiveness may impede the benefits to the patients.

6. When should a posterior crossbite without a functional shift be treated?

-------

A maxillary constriction without a lateral shift does not carry the same urgency as one with a shift; it can be treated in the

early mixed dentition or even closer to adolescence. to, 1 2 Max­

d.tstal step molar relationship, on the other hand, may worsen

illary expansion involves manipulation of the sutures within

anless treated early.

and surrounding the maxilla. This procedure should precede

24

MOSBY'S ORTHODONTIC REVIEW

the ossification of these sutures, most likely before the onset of

therapies. An evaluation of the results at the completion of

puberty. Once the circummaxillary sutures fuse, correction

treatment suggests that skeletal effects of early treatment gener­

of this skeletal crossbite may require surgical intervention.

ally are not sustained. There is no significant difference among the

However, there is no evidence to suggest that expansion in the

three group's skeletal relationships. The apparent improvement

primary dentition is more stable than in the early-to-late tran­

in jaw relationship in the first part of the study may be due to ac­

sition dentition.12

celeration in growth, rather than an actual increase of gro·wth. The

7. When is the best time to treat crowding?

------

According to Gianelly,4•13 the best time to start treatment of

authors' message was that moderate to severe Class II malocclu­

sions do not benefit more from two-phased treatment than from a conventional one-phase treatment.

cases with mild to moderate crowding is in the late mixed den­

Independently, UniversityofFlorida (UF) underwent similar

tition, after the eruption of the first premolars. At this stage,

examination of Class II early treatrnent.15·17 With slight varia­

alignment can be achieved in about 73% of the patients pri­

tions on treatment mechanics and duration, VF also compared

marily by preserving and using the leeway space. Immediately

an observation group and a headgear/bionator group after the

after the placement of a lower lingual arch, fixed appliances

completion of Phase II therapy. Its results closely matched that

can be placed to direct the permanent teeth into the newly cre­

ofUNC's showing that despite the significant skeletal and den­

ated space. For the cases that need extractions, the timing of

tal improvements between the groups after Phase I treatment,

late mixed dentition is suitable because the first premolars are

by the end of Phase II, the differences between those who had

already erupted for extraction.4•13

received Phase I and those who had not was indistinguishable.

Serial extraction is a viable treatment for early diagnosis of

Furthermore, the range of changes in the two groups was simi­

severe crowding. The purpose of serial extractions of primary

lar, with each group having e>..'tremes of great improvement to

teeth is to encourage the early eruption of permanent premo­

severe worsening of the Class I I relationship. UF also invalidat­

lars, which themselves would be extracted. This allows for the

ed Phase I treatment to reduce the incidence of incisor trauma

remaining teeth to erupt within the alveolus, and thus simpli­ fies later orthodontic treatment.10 Serial extraction is best done

in children. After 3 years of follow up, there were no significant correlations with new incisal injury and years in treatment. In

for a severely crowded malocclusion with a normal overbite.

addition, no significant clifference was found in the post-treat­

8. Is the early treatment of open-bite malocclusion

effective? Various studies of dentoskeletal open bite treatments suggest

ment stability at 3 years. Another RCT was performed by the University of Pennsyl­ vania using headgears and Frankel appliances.21 The research­ ers asked the same question of whether early treatment for

that early functional therapy is able to intercept the malocclu­

Class II malocclusion is effective, and if so, when intervention

sion to reduce the need for treatment during adolescence. This

should begin. The results of the study suggested that headgears

is especially true in the cases of open bite caused by sustained

and functional regulators are both effective in correcting Class

oral habits. However, when these studies are reviewed for sta­

II division I malocclusions in children. Similar to the North

tistical quality, no evidence-based conclusion can be drawn. 1 4

Carolina study, this study also suggested that the appliances'

9. Is the early treatment of Class II malocclusion effective?

effects on each jaw differ. The headgear has a distal effect on the maxilla and first molars whereas the Frankel appliance re­ strains the maxilla, reclines the incisor, and advances the man­

The results of recent randomized clinical trials (RCTs) have

dible. As for the question of the best time to initiate therapy,

brought new perspectives to this debate. One of the RCTs, per­

the conclusion was that treatment in the late mixed dentition

formed at the University of North Carolina (UNC), addressed

is as effective as that in the early mixed dentition. They recom­

the benefits of early treatment on Class II division I malocclu­

mended starting treatment in the late mixed dentition as the

sions. 18·20 ln the first part of this study, patients in the mixed

first step of a one-phase treatment.

dentition with moderate to severe overjet were randomly as­ signed to three groups:

A group of researchers in Manchester, United Kingdom

made a similar study using Twin Block.22•23 As in the North

1 . Early treatment with headgears

Carolina study, the first part of this research was designed to

2. Early treatment with a bionator

address the effectiveness of early treatment for Class II division

3. Observation only The findings of this study confirm the conventional belief that

patients after completion of Phase II treatment to see if the dif­

early treatment with either headgears or functional appliances

ferences are sustained. The results showed that early treatment

I malocclusions. The second part of the research analyzed the

improves the skeletal relationships of Class II malocclusions, with

with Twin Block appliances resulted in favorable dentoalveolar

75% of the patients showing significant improvements. A head­

changes, such as reduction in overjet and correction of molar

gear produces greater changes in the maxilla, whereas a bionator brings about more mandibular changes.1 8.20

the sociopsychological benefits of early treatment and found

The second part of this study asks whether these clifferences in

that early treatment increased the patient's self-esteem as well as

outcome are sustained over time.19 This time, the same group of

patients was again randomly assigned to Phase n fixed appliance

relationships. furthermore, the Manchester group considered

reduced negative social experiences. However, measurements after the completion of Phase II showed there is no difference

Appropriate Timing for Orthodontic Treat me nt • CHAPTER 3

TABLE 3-1

25

Chapter Summary of Appropriate Treatment Timing

DECIDUOUS DENTITION

EARLY MIXED 6-8 YEARS

Digital and pacifier habits

Posterior crossbite without functional shift

Space management

Severe crowding leading to serial extractions

4-6 YEARS

Posterior crossbite with functional shift

LATE MIXED 8-11 YEARS

PERMANENT (NON-GROWING) Surgical Class I I

Mod erate to severe mandi bular crowding Class II

Class Ill malocclusions:

PERMANENT (GROWING)

Surgical Class Ill

malocclusions

facemask therapy

tletween the orthodontic results of the early treatment group .md the control group. As for the issue of self-esteem, both croups at the end of Phase 11 treatment showed similar im­

sidered earlier, but rarely before the adolescent growth spurt.

�,..ovements in sociopsychological well-being. Thus, aside from

vertical growth is generally completed at this time. Superimposi­

.m

earlier improvement i n self-esteem, it seems that early orth-

tions of serial cephalograms can more accurately determine the

> to accompl ish root movement ( F ig. 7-2). The

E.H.A.

pins had to be expe rtl y soldered to the arch wire, fitted per­ feclly into the tubes on the bands, removed as the movement ptogre�ed, moved along the arch wire, soldered a gain and fit­ ,

ted once more into the tubes on the bands. This precise and delicate procedure had to be com pleted at each patient visit, often with activation every few days, which was a laboriou� and diffic ult task and not user friendly.2

a

6. Which appliance did Angle develop in 1 9 1 5 to replace the cumbersome pin and tube appliance? The ribbon arch appliance (Fig. 7-3) was a much simpler ap­ pli an ce to construct and activate. The brackets, which were

( i n co nt rast to brackets, which have horizontal slots).

soldered to bands, consisted of a vertical slot contemporary edgew ise Bra�s pins,

inserted from the occlusal aspect of the vertical

tube, held the arch wire in place. The teeth could now freely move along the arch wire, similar to a stri ng of beads 2 .

7. Which modern appliance is based on the Ribbon

Arch appliance? The Begg appliance of Dr. Raymond Bcgg uses the vertical bracket

FIG 7-3 A and B, Angle's ribbon arch appliance. Note the wire inserted occlusally. (From Steiner CC: Angle Orthod 1 933;3(4):277.)

this appliance consists of different stages. For example, Stage

starts with the initial alignment and bite opening, Stage 2 is mosth space closure, and the final Stage 3 is where all the detail of t he oc ion is consolidatcd.2.4.5

is upside down with the arch wire inserted from the gingival aspect and then held in place with a variety of pi ns Each pin fulfills a different function (Fig. 7-4). The

elus

Begg light wire technique or appliance uses most ly round arch

The Tip-Edge bracket or appliance developed by

wires with numerous auxiliary springs inserted into the vertical

is basically a combination of the Edgewise and 13egg bracket.

slots to achieve the required tooth movement. Th e treatment with

The bracket has been modi fied to include a specialized slot-in

slot principle; however, the bracket .

8. What is the Tip-Edge bracket?

P.C. K esl i n g

Orthodontic Appliances • CHAPTER 7 an edgewise bracket that had two wedges removed each side of the slot (Fig. 7-5, A) to p rovide a bracket that

permit free crown tipping (such as with Begg) followed root up r ightin g ( Begg \N:ith auxili ary s pring and

85

9. How did the edgewise appliance evolve? En masse movement of teet h particularly in an anteroposte­ ,

rior direction, was ex tremely difficult with the ribbon arch a p

­

The initial Tip-Edge bracket had a vertical slot and

pl iance . Dr. Angle c hanged the bracket format; he placed the

wings. The Tip- Edge Plus bracket was i ntroduced in

slot in the cen ter of the bracket and fitted the bracket slot in a

.

and i n co rporated the latter as well as a horizontal slot

horizontal plane to the band rather than vert i ca lly. One could

enhanced tooth movement in the final stages of treatment

say that the vertical bracket now had its edge in a sidewise posi­ tion; arch wire insertion acco rdingly was with the edge on it s

--5, B).

side, hence the very app ropriate term edgewise appliance.2

1 0. What made the new edgewise bracket different from the original pin and tube vertical bracket? The vertical bracket had two walls and a pin h eld the arch wire i n

place. The new edgewise b racket 0.022 x 0.028 i nch i n dimen­ sion \\�th the slot opening hori zonta lly consisted of a rectangular ,

,

box with three walls within the bracket. Th e new des ign pro­ vi ded a more efficient mechanism with which to torque teeth.2

1 1 . Who started the first pure edgewise specialty practice? A student of Dr. Edward Angle, Dr. Charles H. Tweed, followed Dr. Angle's advice that one cou l d o nl y master the edgewi se ap­ pliance if the practitioner limited the practice solely to the use of this appliance. Tweed, who received the first specialty certiii.cate in Arizona, devoted 42 years to the advancement of the edgewise ap pl ian ce. The Tweed ph il osophy has undergone conte m porary changes and is st i l l taught at the Tweed Foundation for Orth

odo nt ic Research in Tucson, Arizona, where it has developed

7-4 The Begg Appliance in Stage 3; this stage uses springs. The uprighting springs as shown allow for tooth inclination. Note that these are inserted in vertical slot of the bracket and the arch wire is inserted .... v ...,,v. (From Begg PR, Kesling PC: Begg orthodontic and technique, edition 2 . Philadelphia: WB Saunders,

the reputation as one of the finest basic edgewise co u rses 2 .

1 2. How is the arch wire in the edgewise appliance held in place? Various methods are used, ran gi ng from the o r igi na l brass wi re li ga t ure to delicate stainless steel wire li gatures ; however, elastic o- rings are more often used today ( F i g 7-6, A and B). .

Remove wedges from two opposite ends of archwire slot

A

B

FIG 7-5 A, Removal of diagonally opposed corners of a conventional edgewise bracket arch wire slot to create the basic Tip-Edge bracket. B, The addition of a horizontal tunnel intersects the vertical slot, therefore the bracket profile remains low. The tipping surfaces (T) limit the degree of initial crown tippi ng, and the uprighting surfaces (U) control final tip and torque angles for a specific tooth. The central ridges (CR) provide vertical control during the noted tooth movements. (Reprinted from Kesling PC: Tip-Edge Plus Guide, edition 6. La Porte, IN: TP Orthodontics, Inc., 2006. With permission from Dr. Peter C. Kesling.)

MOSBY'S ORTHODONTIC REVIEW

86

A

B

c

0

FIG 7-6 Various means of securing arch wires into bracket slots. A, Pattern as requested by a patient. B, Stainless steel ligatures on Siamese or Twin brackets; note the tie-wings used as retention for the ligatures. C, Halloween time with powerchain to close spaces. D, Self-ligating bracket.

A

B

FIG 7-7 A, Full bands versus part B which shows direct bonding. B, SPEEDTM bracket

multi-piece construction.

The elastic o-rings arc available i n various colors, which orthodontic patients often request to provide esthetic themes such as orange and black for Halloween (Fig. 7-6, C). A signifi­ cant milestone in contemporary orthodontics is the develop­ ment of self-ligating brackets ( F ig. 7-6, D), which incorporates a spring or gate mechanism as an integral part of the bracket to secure the arch wire in place.2•3

1 3. Do all self-ligating brackets function in the same manner during active treatment? No. Larger t wi n (Damon'; In-Ovation,b and Timc3) and small­ er single brackets (SPEEDd) arc available. Moreover, active clip (SPEF.!Jd and ln-Ovation°) and passive clip ( Damon') mecha­ nisms exist.3•4 'Amerieing fac ia l

bal ance. Reduction of a protru s i o n improves facial bala n ce ( Fig. 9- 1 4) .44-4�

MOSBY ' S ORTHOD ONTIC R EVIEW

114

A

B

c

D

c

F

E

G

H

FIG 9-8 Patients who have a significant malocclusion but no serious skeletal convexity can achieve a very orthognathic profile. Patient 1 : A and 6, Pretreatment photographs; C and D, Posttreatment photographs. Patient 2: E and F, Pretreatment photographs; G and H, Posttreatment photographs. 11.

What does a skeletal pattern have to do with facial balance?

the bridge of the nose, the ala of the

nose,

and menton (Fig.

9- 1 5). These divisions of the face can be used by the clinician to

The underlying theme that surfaces from all artists and

help diagnose vertical dimension problems. For e>:cample, doe!>

orthodontic

there can­

a patient have a disproportionately long lower facial height

investigators

is the concept that

not be good balance and harmony in the lower face un­

because of vertical maxillary excess or because of excessi,·e

less the vertical climension is within normal limits. The most

chin height?52-57 Conversely, is a short facial height caused

important prerequisite for facial balance is normal vertical di­

vertical maxillary deficiency or by short chin height? By using

mension of the lower face. Poulton50 conducted a study on cer­

these accepted proportions as a guide, the patient shown in Fig.

vical traction and found that large lower anterior facial heights were most often associated with a displeasing face. ln their article

9- 16, A, has an excessive lower anterior facial height, whereas the patient shown in F ig. 9- 16, B, has diminished lower ante­

on soft- tissue profile preference, DeSmit and Dermaut51 created

rior facial height. A careful determination of the vertical pro­

three different series of nine profile photographs so that a total of more lhan 200 profiles could

be ranked by graduate dental

students. They found that differences in gender and orthodontic knowledge of the students seemed to have no significant influ­ ence on their esthetic preference. The results of their study con­ firmed the importance of anteroposterior deviations but suggest that unaesthetic facial profiles that were a result of anteroposte­

by

portions of the face is the firs I step in the diagnosis of a vertical

dimension problem.

12. What part does soft tissue overlay or a maldistribution of soft tissue have on facial balance? Facial disharmonies thai are not the result of skeletal or dental dis­

rior deviations were completely overshadowed by long-face fea­

tortion are generally the result of poor soft tissue distribution.33 •

tu res

This problem needs to be identified during differential diagnosis

the long-face feature being more unaesthetic.

11efore discussing the abnormal, it is prudent to under­

and treatment planning so that needed dental compensations can

stand the normal. The "ideal" face is vertically divided onto

be planned. The millimetric measurements of total chin thickne" and upper lip thickness are essential components in any study ot

equal thirds by horiwntal lines that approximate the hairline,

Treatment Planning • CHAPTER 9

115

8

FIG 9-10 Upper l i p thickness.

• Ma n d ib l e : mandibular posterior alveolar excess and short/long mandibular rami Other abnormalities may inclu de superiorly positioned con­ dylar fossa, obtuse cranial base angle, and condylar resorption.

D

Any of these conditions, with or without aberrant mandib­ ular gro·wth rotation, can be a causative factor in the skeletal di crepancy. It must also be understood that any malocclu­ sion may present with a combination of skeletal problems. For example, a patient with a significantly increased or decreased anterior facial height may have an anteroposterior problem and/or a transverse problem.

FIG 9-9 Patients with more lip fullness will achieve a 1n01e pleasing face. Patient 1 : A, Pretreatment photograph. 8, Posttreatment photograph. Patient 2: C, Pretreatment photograph. 0, Posttreatment photograph.

I

iaaal balance. Upper Lip thickness is measured from the greatest

14.

curva

ture of the labial surface of the maxillary central incisor to

� vermilion border of the upper lip. The total chin thickness is

ll"lc:3:>ured horizontally from the NB (

THE VERTICAL COMPONENT OF THE SKELETAL PATTERN PUZZLE

What factors influence a skeletal pattern in the vertical plane?

There are several factors, but the nvo most significant ones seem

asion Pt. B) line extended

to be condylar growth and dentoalveolar development.62 67 The

the soft tissue pogonion ( Fig. 9-17). Total chin thickness should

role of "environmental factors" like swallowing and tongue

equal upper Lip thickness. If it is less that upper lip thickness, the mterior teeth must be uprighted further to facilitate a more hal­

meed facial profile because lip retraction follows tooth retraction.

-

THE SKELETAL COMPONENT

po ture continue to be debated. 1 5.

What does condylar growth have to do with the skeletal pattern and, ultimately, with treatment planning?

Mandibular growth and growth rotation can unfavorably impact dentoalveolar development i n both the maxilla and

13. How does one begin to analyze the skeletal

mandible.68 Bjork and Skieller69 have performed numerous

problem and its impact on a malocclusion?

studies that have shown that the most common direction of

For simplicity, the skeletal pattern analysis can be subdivided

condylar growth is vertical, \vith some anterior component.

mto three components: vertical, anteroposterior, and trans­

Patients with a pronounced short lower anterior facial height

"ef!>e.

The skeletal patterns with which the clinician must deal

.ue not only varied, they are multifactorial. Like the discussion of the "face," it is prudent to discuss the skeletal s;omponent of the treatment planning process

(F ig. 9- 1 8, A-C) generally exhibit upward and forward con­ dylar growth . These individuals generally have a deep ver­

in

tical overbite with a deep mentolabial sulcus and a strong overdosed appearance. In contrast, patients with long-face

..:ategories. Again, books have been written about the subject.

syndrome (fig. 9 - 1 8, D-F) have a more posteriorly directed

.\lany combinations of skeletal aberrations can exist.59-61 These

growth pattern of the mandibular condyle. These backward

may include, but are not limited to, the following:

growth rotators have increased anterior facial height, a more

• Maxilla : maxillary posterior alveolar excess and inferiorly or superior!)' positioned maxilla

posterior position of the chin, and, in extreme cases, a n anterior open bite may exisr.70

116

MOSBY'S ORTHODONTIC REVIEW

A

B

D

c

FIG 9-11 Profile line to nose, drawing (A) and photo (B). Z an g le, drawing (C) and photo (D).

Average normal

Soft tissue facial angle

A

B

H angle Holdway

} FIG 9-12 A, Holdway analysis. B, Steiner analysis.

Treatment Planning

•

CHAPTER 9

117

Facial esthetic line -4 mm

FIG 9-13 Ricketts analysis.

FIG 9-15 Divisions of the face.

B

A

D B

FIG 9-14 Reduction of a protrusion to improve facial

balance. A and B, Pretreatment photos. C and D, Posttreatment photos.

FIG 9-16 A, Excessive lower anterior facial height.

8, Diminished lower anterior facial height.

118

MOSBY'S ORTHODONTIC REVIEW

large adenoids, tonsils, or blocked airw·ays caused by septum deviations, large conchae, or allergies, are frequently observed in high-angle patients and may affect mandibular posture. allowing more freedom for posterior eruption. This hypoth­ esis is supported by Linder-Aronson,74 who showed closing of the mandibular plane angle and reduction in the anterior face height after removal of adenoids and tonsillectomy. Recent experimental studies have only partially clarified the situation. Current experimental data for the relationship between maloc­ clusion and mouth-breathing are derived from studies of the nasal/oral ratio in normal versus long-face children. The data

FIG 9-17 Soft-tissue thickness.

from the study show that both normal and long- face children are likely to be predominantly nasal breathers under laboraton

conditions. 75•76 isaacson et aJ.71•72 and Schudy,73 follm-ving Bjork's reports, studied jaw rotation caused by vertical condylar growth. A succinct summary of the findings of these investigators is

ln conclusion, it appears that mouth-breathing may con­

tribute to the development of orthodontic problems but I'

that forward mandibular rotation occurs when vertical con­

difficult to indict as a primary etiologic agent. Clinical!\. most orthodontists refer mouth-breathers to an otolaryn­

dylar growth exceeds the sum of the vertical growth of the

gologist for an evaluation. This problem should be evaluateJ

maxillary sutures and the maxillary/mandibular alveolar processes. A bac kward rotation occurs, and the face becomes

carefully during the diagnosis of a patient with excess vertical dimension.

longer, when alveolar process growth exceeds condylar growth. An understanding of the effect of condylar growth on mandibular position is fundamental if the clinician is to adequately and appropriately diagnose a vertical dimension abnormality.

16. What role does dentoalveolar development have in the skeletal pattern scenario? Isaacson et al.72 studied dentoalveolar development in three groups of subjects: ( 1 ) those with short anterior facial height,

SWALLOWING AND TONGUE POSTURE Many clinicians believe that if a patient has a forward resting posture of the tongue, the duration of this pressure, even it very light, could affect tooth position vertically or horizontal!\ Tongue-tip protrusion during swallowing is sometimes associ­ ated with a forward tongue posture.77 Others argue that tongue thrust swallowing simply has tOt. short a duration to have an impact on tooth position. Pre'­

(2) those with average anterior facial height, and (3} those with

sure by the tongue against the teeth during a typical swallo"

excessive anterior facial height. ln patients with long anterior facial height, the mean distance from the occlusal plane to the

lasts for approximately I second. A typical individual swallo\' 800 tin1es per day while awake but has only a few swallows per

inferior edge of the palate was 22.50 mm. This distance de­

hour while asleep. The total per day, therefore, is usually under

creased to 1 9.6 mm for the average group and 1 7. 1 mm for the group with short anterior facial height (low MP-SN angles).

a few minutes-not nearly enough time, it is argued, to affect

This difference of 5 . 1 mm of dentoalveolar development be­

the equilibrium.

I 000. One thousand seconds of pressure, of course, totals onh

tween the high-angle and low-angle groups is of no small sig­

During treatment planning for the patient with a verti­

nificance when the vertically compromised skeletal pattern is

cal dimension problem, the clinician must understand that condylar growth, sutural lowering of the maxillary complex

studied.

1 7. As one considers the skeletal problems during the treatment planning process, is the role of environmental factors clear? How should these factors be assessed?

dentoalveolar development, dental eruption, and the patient"� oral environment/habits are interrelated. There is general!' not a single causative factor that predisposes the patient to tO< much or too little vertical development of lower facial height To simplify, one might conclude as a general rule that when

The role of tongue posture, swallowing, and breathing is a

vertical condylar grO\'IIth exceeds tooth eruption (alveolar de­

subject of debate, argument, and study in orthodontics. Their

velopment), forward mandibular rotation occurs. The result

respective impact on the vertical dimension is in need of con­

is increased posterior facial height and an increase in the ratio of posterior facial height to anterior facial height. ConverselY.

tinued study and research.

MOUTH BREATHING The relationship between mouth-breathing, altered mandib­

if dentoalveolar growth and tooth eruption are greater than vertical condylar growth, the resultant mandibular change i' backward rotation. The anterior facial height/posterior facia'

clear cut as the theoretical outcome of shifting to oral respi­

height ratio decreases. Environmental factors can play a role. but the role is, at times, difficult to assess and varies from

ration might appear at first glance. Airway problems, such as

patient to patient.

ular posture, and the development of malocclusion is not as

Treatment Planning • CHAPTER 9

c

FMIA FMA IMPA SNA SN8 AN8 A0-80

occ z UL

70 20 90 82 80

2

3 mm 6 81

1 3 mm 1 6 mm 50 mm 55 mm 0.91

TC

PFH

AFH

Index

D

E

FMIA FMA IMPA SNA SN8 AN8 F A0-80 occ

z

UL

TC PFH AFH

62 30 88

79 70

9

1 2 mm 5 69 1 3 mm 1 7 mm 52 mm 73 mm

FIG 9-18 A-C, Patient with pronounced short lower anterior facial height. Facial photos (A and B) and cephalogram and numbers (C). 0-F, Patient with long-face syndrome. Facial photos (D and E) and cephalogram and numbers (F).

119

120

MOSBY'S ORTHODONTIC REVIEW

A

B

FIG 9-19 A, SNA. B, SNB.

A

B

FIG 9-20 A, ANB. B, AO-BO.

I 18.

THE ANTEROPOSTERIOR COMPO­ NENT OF THE SKELETAL PATTERN

How can anteroposterior skeletal problems be assessed?

Several cephalometric values can be used. The most common follow: SNA-This angular value gives gu idance in determining the relative horizontal position of the maxilla to cranial base. A range of 80 to 84 degrees is normal at the end of

grovvth and devclopment.78 SNB-This value expresses the horizontal relationship of t he mandible to the cranial base, and a range of 78 to 82 degrees indicates normal horizontal mandibular position.78 If the value is below 74 degrees, it might indicate that orthognathic surgery would be a valuable adju nc t to treatment. The same con ce rn should be accorded a value o f over 8 4 degrees (Fig. 9- 19 ) . ANB-The normal range is l to 5 degrees. This significant

value expresses a direct horizontal relationship of the maxilla to the mandible.79 As the Class 11 malocclusion becomes proportionally more difficult, the higher the AI': B. An ANB above l O degrees usually indicates that surgery should be a possible adjw1ct to treatment. A negat ive ANB value is perhaps even more indicative of horizontal facial disproportion. For example, an AI':B of -3 degrees

or more, if the mandible is in its true position, sho indicate careful monitori ng with the possibili� surgical assistance for Class TIT correct ion .78•79 AO/BO-The relationship will verify the horizor:t r elat ionsh ip of the maxilla to the mandible. It perhaps more sensitive to malrclationships th A N B because it is measured along the occlu plane.�0-82 Treatment becomes more difficult if · value is outside the normal range of 0 to 4 m AO/BO is affected by the steepness or flatness of � occlusal plane, since the measurement is made fr• a perpendicular t o occlusal plane from Point A o:1 Point B (Fig. 9-20).

I 1 9.

THE TRANSVERSE COMPONENT OF THE SKELETAL PATTERN

How is the transverse skeletal problem generally manifest-or more simply stated, how is it seen?

The transverse skeletal problem is most often seen when l dentition is carefully examined. A patient who has a very h _ mandibular plane angle (i.e., a hyperdivergent skeletal patt� will, ifa transverse problem exists, exhibit posterior crossbites Fi 9-2 1 , A-C). Conversely, a patient who has a very low mandibw plane angle-the hypodivergent patient-will have a bypass bnc.. commonly referred to as a "Brodie bite" (Fig. 9-21, D-F).

Treatment Planning

A

D

•

CHAPTER 9

121

c

B

F

E

FIG 9-21 A-C, Posterior crossbites are seen on these pretreatment casts. D-F, A "Brodie bite" is seen on these pretreatment casts.

THE DENTITION

How can the dentition and space for the teeth or lack thereof be evaluated carefully? most patients, a dental disharmony is manageable. To cor­ diagnose the dental problem, a careful dentition space and a study of the occlusal rel ationsh ips is essential. dentition is divided into three areas: anterior, midarch, and -..�·Pr,·nr. This division is made for two reasons: simplicity in tifying the area of space deficit or space surplus, and the pos-

Ity of arri ving at a more accurate differential diagnosis. 14·83

RIOR SPACE ANALYSIS anterior space anal ysis includes the difference in millimeters

�'Cn the space available in the mandibular arch from the distal tll.:pansion is required expander design should i ncorporate as many teeth as to minimize buccal crown torque (tipping rather than lation) and "hanging" lingual cusps. Excessive buccal torque should be avoided, since it can result in adverse odontal sequelae, relapse of the ma.x.illary constriction, an� gua1 interferences.

Treatment Tactics for Problems Related to Dentofacial Discrepancies in Three Planes of S p ace • CHAPTER 10

129

FIG 10-1 A, The Hyrax maxillary expander. B, The Haas maxillary expander. C and D, The bonded rapid palatal expander: palatal view (C) and frontal view (D). Continued

Haas expander is a fixed maxillary expander that uses pads and heavy lingual wires to apply pressure to both •o:?eth and the palatal tissue during expansion. This expander thought to result in less tipping of the buccal tooth segments �. I 0- 1 , B). The lingual wires arc soldered to bands on the first ids and the fi rst molars and extend onto the palate where are embedded i n the acrylic pads. The Haas expander as as the Hyrax expander moves the palate transversely and creases arch perimeter 0.7 nun for each millimeter of trans­ expansion. Most feel that an R.PE will move the maxilla and anteriorly as well as transversely.

BONDED RAPID PALATAL EXPANDER nded RPE. is an alternative to the banded design. It is a ed appliance that uses posterior acrylic coverage and i s rectly bonded to the teeth (Fig. 1 0- 1 , C and D). The poste­ •r bite blocks remove cuspal interferences. Headgear tubes, arch wire tubes, and reverse pull hooks for a protraction face �k can all be added as desired. This appliance is typically

used when a more rigid appliance is desired to m i n imize tipping of the b uccal segments. It is preferred in mixed den­ tition patients who do not yet have their upper first bicus­ pids, but primary molars are present. I n addition, it may be used for its bite block effect in patients with an open bite tendency.

LOWER SCHWARTZ APPLIANCE (REMOVABLE) Lower Schwarz appliance ( Fig. 10- 1 , E) is used for mml­ mal arch expansion in the mandible.4 This appliance is only activated once a week, unlike the RPEs described previously.

FIXED MANDIBULAR EXPANDER Fixed mandibular expander is used as an alternative to the removable Schwarz appliance. This fixed metal expander pro­ vides lateral expansion i n the mandibular arch (Fig. 1 0 - 1 , F). The lower fixed expander can be a good option when patient cooperation is an issue.

130

MOSBY'S ORTHODONTIC REVIEW

FIG 10-1 -cont'd E, Removable Schwartz appliance. F, Fixed mandibular expander. G, Quadhelix. H, W arch. I, Pendex appliance. J, Lip bumper appliance. (A, B, E-1, courtesy

AOA Orthodontic Appliances, Sturtevant, Wise ) .

QUAD HELIX This fixed metal expander is capable of applying forces in numerous directions depending upon how it is activated by the orthodontist ( Fig. 1 0 - 1 , G). The four helical loops (two in the first bicuspid region and two in the first molar region) can

be activated in unison or individually to achieve the desir� results. The appliance is soldered to bands on the first molar and li ngu al arms run from the bands forward to the cuspids or first bicuspids as desired. I n general, quadhelix is used if dental expansion is primarily desired.

Treatment Tactics for Problems Related to Dentofacial Discrepancies in Three Planes of Space • CHAPTER 1 0

in undesired dental movement; t herefore, the best time

W ARCH \ arch i5 similar to the quadhelLx without the four helical

ps (Fig. 1 0- 1 ,

to correct these constricted arches is usually i n the mixed

dentition.

H). This appliance will lead to more dental

pansion as opposed to skeletal expansion than a Hyrax or aas maxillary expander.

PEND EX ndex is a fixed expansion appliance that is also used to distal­ .: and derotate one or both upper first molars (Fig. 1 0- 1 , e

131

I

5. How is Class II malocclusion corrected using

fixed appliances?

I).

Pendex appliance eliminates patient compliance concerns

ANTEROPOSTERIOR AND VERTICAL DISCREPANCIES

Correction of a Class

11

malocclusion using nonextraction

m the distalization treatment objective. A Haas expansion

orthodontic treatment with fixed appliances requires the d is­

rew is usually incorporated into acrylic pads. This appliance

talization of the maxillary teeth and/or anterior movement

n be designed with bands on the bicuspids and is frequently

d in conjunction with wire rests that arc bonded to the

of the mandibular teeth . Maxillary teeth can be distalized using extra-oral forces (e.g., J-hook headgear or facebow) or

.:lusal surface of bicuspids or primary molars to provide

intra-oral forces (e.g., Class II elastics or appliances such as

ditional anchorage.

the Distal Jet or Pendulum appliance) using the lower arch

as anchorage. jp bumper ( Fig. 10- 1 , n is a large-diameter round wire

6.

What type of headgear or facebow should I use?

t extends from first molar to first molar and rests i n

Extra-oral traction can be used to achieve both tooth move­

buccal sulcus. I t also has an acrylic pad i n the anterior

ment and modification of bone growth. The type of headgear

on. It can be used in either arch to distaliz.e the first

used depends on the patient's skeletal pattern. The direction

-.J.ars and promote transverse development of the arch by

of the pull may be adjusted accordingly so that a desirable

oving the pressure of the buccal tissues on the teeth and

skeletal and/or dental effect may be achieved and any unde­

rporti ng structures.

sirable effects may be avoided. For instance, a cervical pull headgear should not be used in a patient with hyperdiver­ gent vertical growth tendency, but it is an excellent choice

�h wi res can be expanded transversely to achieve dental

in a hypodivergent patient. A hyperdivergent pattern is

or

best treated with an occipital or high-pull headgear. Also,

..,ansion in either the maxilla

mandible.

3. Which expansion appliance should I use? tors

that infl uence the selection of an expansion appli­

includc, but are not limited to, patient's age or skel­ maturity, the clinician's desire for dental versus skeletal sion, the number of teeth available for anchorage, expectation for patient complia nce, and whether the .mder

,..,iJj be used in conjunction with fixed appliances

one must decide if tipping or bodily movement of teeth i s preferred. Forces may b e arranged t o go through t h e cen ­ ter of resistance of a motar for bodily

movement. For distal

tipping, the force vector should be below the center of resis­ tance of a molar.

7. When should extra-oral traction therapy be initiated?

•ther appliances, such as a facemask.s In general, the

Extra-oral traction may be i nitiated in the mixed dentition,

re skeletally mature the patient, the n umber of teeth

especially if a skeletal effect i s desired. It may also be used

· red for adequate anchorage to minimize dental move­ increases. In addition, more rigid expansion appliances generally required in more mature patients to minimize tipping of the buccal segments.

in patients who arc not growing if only tooth movement or anchorage is the goal.

8. What are the indications and contraindications

for Class II elastics?

When should expansion be initiated? ment of crossbite with a functional shift should be

-'"'"''·"u as soon as i t is diagnosed. If no t treated, these

INDICATIONS •

Class ll molar or canine dental relationship

bites may adversely affect growth. If the mandible

•

Finishing orthodontic cases to achieve anterior coupling

to one side, growth will be asymmetric and the c h i n

•

Excessive overbite (deep bite)

deviate to t h a t side. Also, very narrow upper arch ­

•

Orthognathic facial profile

�hould be treated as early as possible. As the patient lUres, it is hard to get skeletal expansion. These narrow

CONTRAINDICATIONS

arches arc usually associated with significant crowd­

•

and are best corrected when the patient is skeletally

•

Dental open bite or skeletal open bite tendency

Expansion in skeletally mature patients may result

•

Severe mandibular retrogna thia

Class I l l skeletal discrepancy

MOSBY'S ORTHODONTIC REVIEW

132

•

Insufficient wire dimension to resist extrusion of teeth associated "''.i th the use of Class Il elastics

•

Excess lower anterior facial height

9. Under what circumstances should orthodontic extractions be considered? Orthodontic extractions should be considered if there i s excessive tooth material for the available arch length. Also, extractions will facilitate the anteroposterior tooth movements needed to attain a Class I canine and molar relationship. In

addition, patients v.'ith anterior dentoalveolar protrusion as well as patients with a skeletal open bite tendency may benefit from orthodontic extractions. Finally. extractions should be consid­ ered in noncompliant patients who refuse to wear headgear or elastics.

1 0. What are the treatment options to correct

crowding problems?

FIG 10-2 Panoramic radiograph depicting ectopic maxillary first permanent molars and early resorption of the roots of the maxillary second deciduous molars.

There are three basic ways to correct crowding problems: I . Expansion of the dental arches, including distalization of the posterior segments of the dental arch 2. Extraction of permanent tooth mass

3. Reapproximation

to reduce the mesial-distal width of

selected teeth

an asymmetric extraction pattern facil i tate the orthodontl\. mechanics? Is there an open bite tendency? If so, will extract­ i ng teeth more posteriorly help minimize the mandibular

Expansion oftl1e dental arches can be achieved ....'.it h a variety of appliances. There are a number offactors that should be consid­

plane angle? Usually, the easiest part of the orthodonti,

ered when selecting an expansion treatment tactic. For example,

the orthodontist think ahead about how a functional and

is the crowding problem caused by space loss i n the dental arch?

stable canine Class I occlusion will be achieved and ho

Or are one or more of the dental arches constricted? I f the arches

the extraction pattern will either facilitate or impede th orthodontic mechanics. Reapproximatio n is the removal of tooth structure r

are constricted, is the constriction primarily dental or skeletal? Crowding as a result of space loss is usually due to either ectopic

treatment is aligning the teeth. It is very important th.1t

eruption of the first molars or early loss of primary teeth. If space

restorative material from the mesial and distal surface� !rations (!} James A. McNamara. Jr.

In

resorption as seen in the panoramic radiograph. The major role of these wires in the late mixed dentition is to prevent the mesial migration of the first molars during the transition from the second deciduous molars to the second premolars. 1 37

138

MOSBY'S ORTHODONTIC REVIEW

In the maxilla, a transpalatal arch (TPA; Fig. l l - 1 , A) extends from one maxillary first molar along the contour of the palate to the first molar on the opposite side. This appli­ ance is capable of producing molar rotation and changes in root torque and angulation; the TPA may remain in place until the completion of the final comprehensive phase of orthodon­ tic thcrapy.1 I n the mandible, a lingual arch ( Fig. I l - l , B) that extends along the lingual contour of the mandibular dentition from first molar to first molar may be used. The lower lingual arch is used less frequently than the transpalatal arch because many patients undergoing early orthodontic treatment do not require the maintenance of the space in the mandibular second premolar region. Thus, the lower lingual arch is used only in patients in whom maximum anchorage is to be maintained. In contrast to the transpalatal arch, the lower lingual arch is usually removed as soon as the mandibular second premolars erupt fully into occlusion. 4.

How do you treat patients with crowded teeth?

Patients with developing moderate to severe tooth-size/arch­ size discrepancy problems are often treated effectively and efficiently when a patient is 8 or 9 years of age. Normally, this treatment is started after the permanent lower four incisors and the permanent upper central incisors have erupted. I n many instances, there is insufficient space to allow for the un­ impeded eruption of the maxiUary lateral incisors. Depending on the size of the pem1anenl teeth, either a serial extraction or an orthopedic ex'l'ansion protocol can be used. 5.

What is "serial extraction?"

Serial extraction refers to the sequential removal of deciduous teeth to facilitate the unimpeded eruption of the permanent teeth. Such a procedure often, but not always, results in the extraction of four first premolars. The typical serial extraction protocol is initiated about the time of the appearance of the permanent lat­ eral incisors, which erupt in rotated positions or are initially pre­ vented from eruption by the deciduous canines (Fig. 1 1 -2). In the most commonly used protocol, the first teeth to be removed arc the deciduous canines. The removal of these teeth allows for the eruption, posterior movement, and spontane· ous i mprovement in the alignment of the permanent lateral incisors. I n about 6 to 1 2 months, the removal of the fou r deciduous first molars i s undertaken, followed later by the extraction of the first premolars. It is common to observe that the adjacent teeth erupt toward the extraction sites, with the lower incisors often uprighting as well ( sometin1es too much so). As soon as the second molars near emergence, fixed appli­ ances can be used to align and detail the dentition. 6.

A

When is serial extraction indicated?

According to Graber,3 serial extraction may be indicated when it is determined "v.ion of the maxilla. Because there is no mid-mandibular the appliance produces tooth tipping rather than movement.

ss of the maxillary deciduous incisors and the eruption the permanent central incisors. This earlier i ntervention

will result in a longer period of time between the of the initial phase of treatment and the end of the com­ ve treatment phase after the permanent dentition erupted. The early treatment of Class I l l malocclusions also be characterized by more than one period of i nter­ during the mixed dentition. The most commonly used protocol for young Class 111 pa­ is the orthopedic facial mask ( F ig. 1 1 -7) combined with .-uuuVO, Javed T, et al: clinical cumparhon of the effect on the gingiva of the Prophy-Jet and the rubber cup and paste techniques. J Periodonto/ 1 986;57: I 5 1 - 1 54. 18. Barnes CM, Russell CM, Gerbo LR, et al: Effects of an air­ powder polishing system on orthodontically bracketed and banded teeth. Am 1 Orthod Den tofncinl Orthop 1 990;97:74-8 1 . 19. Ramaglia L, Sbordone L, Ciaglia R , et al: A clinical comparison of the efficacy and efficien cy of two professional prophylaxis procedures in orth odontic patients. Eur f Orthod 1999;21 : 4 23-4 28. 20. F�rsberg CM, Brattstrom V, Malm berg E, Nord CE: Ligature

. _ w1res and clastomenc nng�: Two methods of ligation, and their i association with m crobial colonization of Streptococws mutaiiS and ladobacilli. Eur J Orthod 1991; 1 7:41 7-420. 2 1 . Zachrisson BU: Bonding in orthodontics. In Graber TM, Van­ arsdall R.I. Jr, editors: Orthodontics: current principles and tech­ niques, edition 2. St Loui�: Mosby, 1994, pp 542-626. 22. Boyd RL, Baumrind S: Periodontal considerations in the usc of bonds or bands on molars i n adolescents and adults. A11gle

Orthod 1992;62: 1 17- 1 26. 23. Boyd RL, Leggott PJ, Quinn RS, et al: Periodontal im plications

24.

25.

26.

27.

of orthodontic treatment in adults with reduced or normal peri­ odontal tissues versus those of adolescents. Am f Ortl•od Dento­ facial Orthop 1989;96: J 91-199. Zachrisson BU: Periodontal chan ges during orthodontic treat­ ment. In Mc:-Jamara JA Jr. Ribbens KA, editors: Orthodontic treacment alUI the periodo11tium. Monograph I 5, Craniofacial Growth Series, Center for Human Growth and Development, Ann Arbor: The University of M ichigan, 1984, pp 43-65. Artun J, Urbyc KS: The effect of orthodontic treatment on peri­ od.'trusion. These patients will typicaUy require a second

of the dental crowding, often

phase of orthodontic treatment in adolescence, followed by or­

relative mandibular prognathism may be much improved after

with extractions. Although the

thognathic surgery and/or distraction osteogenesis, as well as

this second reconstructive procedure, it is in1portant to prepare

soft tissue augmentation (Fig. 2 1 - 1 2).

the patient and parents for its predictable return, as tl1e man­

1 2. What deformities are common in the craniosynostoses syndromes, and what orthodontic treatment may be indicated?

dible continues to complete its growth while the maxilla stays essentially unchanged. The orthodontist should monitor facial growth with yearly cephalometric films or

30-CTs and begin

the final stage of orthodontic preparation i n anticipation of the

Of the crani osynostoses (craniofacial dysostosis) syndromes,

completion of facial growth, at which time the final maxillary

Crouzon syn­

advancement wiU be performed to correct the maxillary hypo­

drome. These syndromes, because of similar defects i n the

plasia. These orthodontic procedures are typical of preparation

the most common are Apert syndrome

and

254

MOSBY'S ORTHODONTIC REVIEW

B

A

FIG 21-13 A patient with Apert syndrome. A and B, Note the midface deficiency. C, Palatal swellings, "V-"shaped arch, and severe crowding.

for orthognathic surgery, common to maxillary deficient patients, including alignment and coordination of arches.

13. What deformities are common in mandibulofacial dysostosis (Treacher Collins syndrome), and what orthodontic treatment may be indicated? This syndrome, with autosomal dominant inheritance and variable expressivity, involves the derivatives of the first and second pharyngeal arch, groove, and pouch.25 The deformi­ ties are bilateral, but not necessarily symmetric, and include:: ear deformities, malar hypoplasia, and mandibular hypopla­ sia (Fig. 2 1 - 1 4). The clinical presentation is characteristic and includes malformed pinnae, often accompanied by conduc­ tive hearing loss, hypoplastic supraorbital rims and zygomas ... rith downslanting palpebral fissures and sunken cheekbones, \ and a hypoplastic mandible deficient in the ramus and body. Tn addition, the mandible exhibits a steep mandibular plane angle, a reverse curve of Spee, retrogenia, obtuse goniaI angle, and condylar cartilage of the hyaline type rather than fibrocar­ tilage.25 There is no articular eminence, limited opening, and the maxilla is often small with an anterior open bite skeletal

pattern and posterior vertical deficiency. Dental crowding can be severe, and cleft palate and palatopharyngeal incompetence are fairly common, as is macrostomia. Treatment may involve early mandibular distraction to pre­ vent tracheostomy caused by severe airway difficulties or to al­ low decannulation in those patients already tracheostornized. This should be reserved for these cases because of the significant potential morbidity of this technique at an early age.33 The goals of orthodontic treatment should be to manage the crowding and eruption problems as indicated during the mixed dentition, but comprehensive orthodontic treatment should be delayed until facial skeletal growth is nearing completion. At that time orthodontic treatment should commence, in preparation for two-jaw orthognathic and/or distraction procedures.

14. What are some other common syndromes of interest to orthodontists? Turner syndrome is a chromosomal disorder, with clas­ sically affected individuals having only a single X chro· mosomc. These patients arc phenotypically female, arc of short stature with sexual infantilism, and have variable expression of somatic abnormalities. The classic somatic

Orthodontics and Craniofacial Deformities

•

CHAPTER 21

A

255

B

FIG 21-14 A patient with mandibulofacial dysostosis. A and B, Note the downslanting palpebral fissures, hearing aids, lack of cheekbones and relatively protrusive nose, and, C, anterior open bite and crowding.

abnormalities include a webbed neck, epicanthal folds,

Another chromosomal disorder, trisomy 2 1 (Down) syn­

shield neck, cardiovascular abnormalities, abnormal ears,

drome, is the most common malformation syndrome, having

and low hairline (Fig. 2 1 - 1 5 , A and H ) .25 Dental and facial abnormalities include advanced dental age, small teeth, short roots, lateral palatal bulges, a short cranial base, and maxillary and mandibular retrognathia (Fig. 2 1 - 1 5, C).34 From an orthodontic viewpoint, this syndrome is of in­ terest because in mild form, these patients are often not diagnosed until puberty, when they fail to go through menarche. An astute orthodontist may be able to refer these patients at an earlier age, allowing an early diagnosis.

disease { purportedly caused by immune system compromises

In addition, when treating these patients, it is wise to keep

and oral respiration) and sleep apnea, fissures of the tongue,

an incidence of about 1 in 650 Jive births.25 These patients are typicaUy short, with hypotonia, upsJanting palpebral fissures, short neck, and mental retarda t ion ( Fi g. 21-16, A). O ro fa ­ cially these patients have a flat facial profile due to midfacc hypoplasia, a characteristic open mouth posture with pro­ trud i ng tongue, hypoplastic sinuses, and delayed and irregu­ lar dental eruption (Fig. 2 1 - 1 6, B). They also commonly have cardiovascular anomalies, a high incidence of periodontal

in mind the high proportion with cardiovascular anoma­

m iss i ng teeth, and anomalous teeth.35 An anterior open bite,

lies and the tendency for short roots an d root resorption.

posterior crossbite, and spaced mandibular incisors with re­

Currently most of these patients undergo growth hormone

verse overjet are often man ifest, as a result of the mid face hy­

therapy on�e diagnosed and eventually sex hormone ther­

poplasia and anterior tongue posture. Early (6 months of age,

apy as well, which can have definite effects on craniofa­

ideally) functional therapy, consisting of manual therapy, in

cial growth. For this reason it is wise to consult with t h e

conjunction with removable or fixed appliances that con tain

patient's endocrinologist regarding treatment ti mi ng and

acrylic bumps on the facial to stimulate the upper lip and an

to consider the differential effect of sex a n d gr owt h hor­

oval midline "bead" for the tongue to "play" with, has been

mones o n mandibular, versus maxillary, growth.

advocated to improve the hypotonia of the lips and tongue

256

MOSBY 'S ORTHODONTIC REVIEW

B

A

FIG 21-15 A patient with Turner syndrome. A and B, Note the low-set unusual ears, webbed neck, low hairline and retrognathia, and, C, lateral palatal bulges.

therapies. Sleep apnea therapies may be contraconducive to

and prevent some of the typical sequelae of the chronic open mouth p os ture. 36

certain orthodontic treatments (such as o ral-n asal positive

l::lecause of their constellation of facial and dental p rob­

airway pressure masks and rever e-pull h ead gear) , whereas

lems, these patients are clearly candidates for orthodontic care. A lth ough access to o rth odo n ti c care for these patients is often difficult for a variety of r eason s , in c l ud in g financial

lary expansion and maxillo-mandibular advancement) may

and transportation, orthodontists should not arbitrarily pre­

tant to identify these patients, refer them for an evaluation

clude these patients from their practice. .l7 AJthough the ba­

if sleep apnea is suspected but has not been diagnosed, and

sic treatment goals o f these pat ie nt s should not be altered,

provision of care should involve some modifications specific to t h ese individuals. Sta ged or mu ltipha se treatment is often

certain orthodontic/orthognathic therapies (such as maxil­ have a positive effect on sleep apnea. Therefore, it is impor­

co nsul t with the physician treating th em to develo p a coor­

dinated treatment plan. I n the office aU procedures should be carefully explained and demonstrated to the patient and

beneficial, as are shorter, morning appointments with limited

parent. Every effort should be made to become " friends" with

p roced u res and additional time set aside, since these p a t ie n t s

the patient first and develop a trusting relationship prior to

require extra patience on the part of th e orthodontist and a s­

instituting treatment. In addition, keep i ng appointments and

si sta n t. Pa re nts and/o r sibl i ngs can often be ver)' helpful i n

procedures "fun" and providing rewards is important. These

attaining compliance, and i t i s i mpe rative to actively involve them in home care of the appliances. The high incidence of cardiovascular problems, sl eep apnea, and periodontal dis­

patients generally have a happy, friendly demeanor once their they can be obstinate at times and easily distracted (not al­

ease must be taken into account when deciding on treatment

ways a liability).

trust is gained and can make very good patients, although

Orthodontics and Craniofacial Deformities

•

CHAPTER 21

257

A

B

FIG 21-16 A young man with Trisomy 21 (Down) syndrome. A, Note the open mouth posture and hypotonia. B, Classic anterior open bite, marginal gingivitis, and retained food.

D

c

FIG 21-17 Cleidocranial dysplasia. A, Note the midface deficiency and broad face. B, Unerupted incisors bonded with pads and gold chains. C, Fixed eruptive appliance supported by first molars and primary molars with openings for chain to pass through. Elastic thread is tied to chains to apply eruptive force. D, Chains on upper unerupted incisors with hooks bent onto the chains to allow interarch elastics to be placed.

258

MOSBY'S ORTHODONTIC REVIEW

FIG 21-18 Panoramic film of a patient with cleidocranial dysplasia. Note the failure of eruption and multiple, tightly packed supernumerary teeth.

Final ly, cleidocranial dysplasia (dysostosis) is an interesting

teeth, a l though it may still be helpful to use interarch verti­

These

cal elastics. Because of the great number of supernumerary

patients are short with a broad skull, pronounced biparietal

teeth p resent a nd cl ose p rox i m i ty of some of the teeth (Fig.

syn drome with autosomal

dominant

inheritance.

and frontal bossing, depressed nasal bridge, hypertelorism

2 1 - 1 8 ) des irable

( wide-set eyes), hypoplasia of the marilla and zygomas with

one surgical uncovering and p l acement o f traction a pp l i ­

a short cranial base, and deficie ncy of the clavicles (allowing

ances. Second molars may also benefit from uncovering and

to keep, this stage may require more than

many patients t o a pproJdmate their shoulders and resulting i n

placement of eruptive forces . Once all the permanent teeth

2 1 - 1 7, A).15 Orally t hey

arc erupted, they are aligned, the arches coordinated, and,

a drooped shoulder appearance) (Fig.

present with a high arched palate, deficient premaxilla with

for many of these patients, a maxillary Le Fort I ad vance

relative prognathism caused by normal mandibular length,

ment and inferi o r displacement will be necessary. This com­

multiple supernumerary teeth, multiple crown deformities, and lack of eruption of the permanent teeth.25

plex treatment often requires a long duration with multiple surgeries and challenges in eati ng/speech during the treat­

The primary teeth erupt normaUy but often resorb poor! y,

ment. ft is a d i sservice to the patient and families i n volved

­

and the permanent molars usually erupt, as well as occa­

not to ensure that they are comfortable with and wi l li ng to

sio na lly the incisors, but the premol a rs and canines rarely erupt.38 Eruption of the permanent teeth is not i ndu ced by

u nde rgo these c h all e n ges pri or to initiation of treatment.

simple extraction of the primary teeth. 39 Supernumerary teeth are common, espec i aUy in the maxi l l ary incisor and ca­

REFERENCES

nine regions as well as i n the mandibular p r emol a r re gio ns ,

I . World Health Organization: Available at: v.•ww.who.int/genom­

and these teeth are often dysplastic with dilaccrated and de­

2. Latham RA: Or tho pedic advancement of the cleft maxillary

formed roots (possibly caused by severe sp atial restrictions i n the alveolus).40 Assisted eruption o f the u ner up ted teeth

should be planned carefully, in stages using the remaining primary t ee th and erupted permanent teeth as anchorage, if possible .4 1 A typ i c al plan would i nvolve extraction of any remai ning primary incisors with uncovering and bonding

or t ract ion hooks o r chains to the unerupted incisors ( Fig. 2 1 - 1 7, B). Fixed app li a n ces on the rema i n i n g primary pos­ terior teeth and permanent first molars c a n be used to place eruptive archwires (Fig.

2 1 - 1 7, C). Alternatively, a recipro­

cal anchorage concept can be used with the pati en t placing elastics between the maxillary and mandibular teeth (Fig.

2 1 - 1 7, D).

Once the permanent incisors are erupted roughly

into contact, they can be bonded with fixed appliances, the prima ry molars and canines extracted, supernumerary teeth

removed, and traction hooks or chains placed on th e per­ manent premolars and canines. The permanent molars and incisors can then support the eru pt ive archwires to these

ics/anomal ies/en/. Accessed August 27, 2007.

�egment: a preliminary report. Cleft Palate J 1980; 1 7:227-233. 3. Graber TM: Craniofacial morphology in cleft palate and cleft lip deformities. Surg Gynecol Obstetr 1949;88:359-369. 4. Berkowitz S: Timing of cleft palate closu re - age should not be the sole determinan t . 1 Cranio Genet Dev Biol 1985;(Suppl 1): 69-83. 5. Mestre JC, DeJesus ) , Subtelny JD: U noperated oral cl efts at maturation. A ngle Ortlrod 1 960;30:78-85. 6. M illa rd DR, Berkowitz S, Latham RA, Wolfe SA: A discussio n of p res urgi cal orthodontics in patients with clefts. Cleft Palate j 1 988;25:403-412. 7. Huddart AG: An eval ua tion of pre surgical treatment. Hr 1 Ortl10d 1973;1 :2 1 -2 5. 8. S ubtel ny JD: Orthodontic principles in treatment of cleft Lip and palate In Bardach J, Morris HL, editors: Multidisciplinary management ofcleft lip and palate. Philadelphia: WB Sa u nders , 1 990, pp 6 1 5-636. 9. Grayso n BH, Cutting C B : Presurgical nasoalveolar orthopedic molding in p rimary correction of the nose, lip, and alveolus -

.

of infants born with unilateral and bilateral clefts. Cleft Palate

Craniofac j 2001 ;38( 3 ): 193-198.

Orthodontics and Craniofacial Deformities • CHAPTER 21 10. Moore 1{1\1: Orthodontic management of the patient with cleft lip and palate. Ear Nose Throat J 1986;65:46-58. 1 1 . El Deeb M, Messer LB, Lehnert MW, et al: Canine eruption into grafted bone in maxillary alveolar cleft defects. Cleft Palate j 1 982; 19:9-16. I 2 . Hall HD, Werther JR: Conventional alveolar cleft bone grafting. Oral Maxillofac Surg Clin North Am 199 I ;3:609-616. 13. Bergland 0, Semb G, Abyholm FE: Elimination of residual alveolar cleft by secondary hone grafting and subsequent orthodontic treatment. Cleft Palate f 1 986;23: 175-205. 14. Vig KWL, Turvey TA: Orthodontic-surgical interaction in the management of cleft lip and palate. Clin Plast Surg 1 985;12:735-748. 1 5. Boyne P): Bone grafting in the osseous reconstruction of alveolar and palatal clefts. Oral Maxi/lofac Surg Cii11 North A m

Johnston

MC: Craniofacial morphology of

monozygotic hvins discordant for clefts of the lip and/or palate.

1 7.

EP, Vargervik K, Chierici G, editors: Trea tment of hemifacial microsomia. New York: Alan R. Liss, 1 983.

27. Harvold

28. Kahan LB, Mulliken JB, Murray )E: Three-dimensional approach to analysis and treatment of hemifacial microsomia. Cleft Palate

J 1986; 1 8:90-99. 29. Kaban LB. Moses ML, Mulliken

JB: Surgical correction

of

hemifacial microsomia in the growing child. Plast Reconstr Surg

1 988;82 :9-19. 30. Vargervik K, Kaban LB: Hemifacial microsomia I. Diagnosis and

management. In Bell WH, editor: Modem praCJice in ortlwg11athic and reconstmctive surgery. volume 2. Philadelphia: WB Saunders, 1992, pp 1533- 1560. 3 1 . Kearns G. Padwa Bl, Kahan LB: Hemifacial microsomia: The disorder and its surgical management. I n Booth PW, Schendel SA, 1 l ausemen J -E, editors: Maxillofacial Stlrgery, volume 2. Philadelphia: Elsevier, 2007, pp 9 1 8-946.

1 99 1 ;3:589-597.

16. Simmons KE,

259

In preparation.

Verdon P. Utilisation raisonnee du masque orthopedique facial.

Orthodontic, Tours, 1 989. 18. Tindlw1d RS, Per Rygh, 13oe OE: protraction of the upper jaw in cleft lip and palate patients during the deciduous and mixed dentition periods in comparison with normal growth and development. Cleft Palate Craniofacial J 1993;30: I 1\2 - 194.

19. Tindlund RS, Rygh P: Maxillary protraction: different effects on facial morphology in unilateral and bilateral cleft lip and palate patients. Cleft Palate Cra.niofac f 1 993;30:208-22 1 . 20. 13uschang PH, Porter C, Genecov E, et al: Face mask therapy of preadolescents with un ilateral cleft lip and palate. Angle Orthod 1 994;64: 145-150. 2 1 . Vig KWL, Turvey TA, Fonseca RJ: Orthodontic and surgical considerations in bone grafting in the cleft maxilla and palate. In Turvey TA, Vig KWL, Fonseca RJ, editors: Facial clefts and cra­ niosynostosis: principles and management. Philadelphia: W13 Saunders, 1 996, pp 396-440. 22. Vargervik K: Growth characteristics of the premaxilla and orthodontic treatment principles in bilateral cleft lip and palate.

Cleft Palate J 1983 ;20:289-302. 23. Friede H, Pruzansky S: Longitudinal study of growth in bilateral cleft lip and palate from infancy to adolescence. Plasf Reco11str

Surg 1972;49:392-403. 24. Ross RB: Treatment variables affecting facial growth in complete un ilateral cleft lip and palate. Cleft Palate f I 987;24:3-77. 25. Gorlin RJ, Cohen MM, Hennekam RCM, editors: Syndromes of

the head and neck, edition 4 . Oxford Monographs on Medical Genetics: no. 42, New York: OxJord Universi ty Press, 200 1 .

26. Pruzansky S: Not all dwarfed mandibles are alike. Birth Defects 1 969; 1 : 120-129.

32. Posnick JC, Miihli.ng

J:

Surgical treatment of craniofacial

dysostosis syndrome and single-suture synostosis. In Booth PW,

f-E, editors: Maxillofacial surgery, 2. Philadelphia: Elsevier, 2007, pp 876-900.

Schendel SA, l lausemen volume 2 , edition

33. Koppel lJA, Moos KF: Treacher Collins syndrome. .In Booth

PW, Schendel SA, Hausemcn J-E, editors. Maxillofacial surgery,

volume 2, edition 2 . Philadelphia: Elsevier; 2007, pp 947-958.

34. Simmons KE: Growth hormone and craniofacial changes:

Prelimi11ary data from studies in Turner's syndrome. Pediatrics

1 999; I 04(Suppl ) : I 02 1- 1 024. 35. Pilcher ES: Dental care for the patient with Down syndrome.

Down Synd Res Pmct 1 991\;5 : 1 1 1 - 1 1 6. 36. Hoyer 1-1, Limbrock GJ: Orofacial regulation therapy in children with Down syndrome, using the methods and appliances of Castillo-Morales. ASDC f Dent Child 1 990;57:442-444. 37. Mmich lJR: Orthodontic intervention and patients with Down syndrome. The role of inclusion, technology and leadership.

Angle Orthod 2006;76:734-735. 38. Jensen BL, Kreiborg S: Development of the dentition i n

cleidocranial dysplasia. I Oral Pathoi 1 990; 1 9: 89 -93 . 39. Winter GR: Dental conditions in cleidocranial dysostosis. Am J Orthodont 1 943;29:61 -89.

40. Richardson A, Deussen FF: Facial and dental anomalies i n cleidocranial dysplasia: A study o f 1 7 cases. Int J Paediatr De11t 1 994;4:225-23 1 . 4 1 . Daskalogiannakis J , Piedade L , Lindholm TC, e t a l : Cleidocranial dysplasia: 2 gen erations of management. ] Can Dent Assoc 2006;72:337-342.

Tmnporo�nmbuWr Dmordem

T

emporomandibular disorders (TM Ds) involve musculo­

situation. Consider a patient experiencing left-sided mandibular

skeletal pain disorders and functional disharmony of the

pain as a result of a myocardial infarction who is treated via de­

masticatory system. TM D is one subcategory of oro fa­

livery of a maxillary splint, which provides a perfect mutually

cial pain that includes intracranial pain, headache, neuropath­

protected occlusal scheme. The infarct remains of fatal poten­

ic pain, intraoral pain, and all other pains associated with the

tial despite apparent harmony of the masticatory system.

head and neck. 1 The prelimi nary role of the dental practitioner

TMD� can be classified into several subcategories2 :

is to discern whether the patient's clinical presentation reveals

•

Masticatory disorders including protective co-contraction, persistent local muscular soreness, myofascial or trigger­

a diagnosis of pathology or dysfunction that is within the realm of dental treatment and/or if the clinical diagnosis requires al­

point pain, myospasm, chronic myositis, and fibromyalgia.

lied medical collaboration for effective management. Once

These disorders predominate in frequency and are each

the problem has been verified to be within the realm of dental

managed differently.

therapy, the clinician m ust identify the source of the problem

• Dysfunction of the joint complex itself including disc

and treat accordingly. Often the originating source and symp­

displacements, disc/condyle/fossa incompatibilities in­

tomatic site of the pain are incongruous, which differs from

cluding adhesions, and subluxation/dislocation. These

conventional dental diagnosis. Unless the primary site from

problems may require

which the pain emanates is addressed by therapy, control of the

often be anatomically documented by modern imaging

problem will remain elusive. 2 Hence, history and examination are critical to diagnosis, but also unlike most dental diagnoses,

surgical

co-therapy

and can

techniques. •

Inflammatory conditions including capsulitis, synoviti�,

the importance of the patient's history of the disorder is far

retrodiscitis, arthroses, and posttraumatic sequelae. Many

more indicative than presenting signs. Keen diagnostic skills i n

are self-resolving and require little therapeutic manage­ ment if diagnosed correctly.

t h e treatment ofTMD are t h e key to successful management, as TMD is often a combination of etiologies rather than

a

single

•

anatomical or functional disharmony. Combination of etiolo­

Hypomobility including anl,')'losis, muscle dysfunction, and anatomical impedance ranging in need from contin­

gies often complicates successful treatment and can frustrate

ued surveillance to initiation of collaborative care with

the clinician and patient.

multiple co-therapists.

Many diagnostic systems and algorithms ofTMD have been proposed since otolaryngologist James Costen first published

•

Growth disorders including congenital bone and muscle disorders.

1934. Costcn3 described a smalJ group of pa­

Accurate diagnosis and classification are critical to proper

tients w1th ear/sinu� symptoms in conjunction with functional

management to determine therapeutic modalities and to assess

his findings in

disturbance of the temporomandibular joints (TMJs) . Okeson2

the need for involvement of allied specialists. For example, as

has emphasized thd importance of determining whether the

chronicity of TMD increases, so do the number of therapists

presenting signs or symptoms arc truly emanating from the re­

needed for effective management given increasing difficulty in

gion of complaint or whether the symptoms originate from a

management. In general, dental practitioners arc most effec­

distant site by virtue of interaction of nerve fibers that coalesce

tive at managing acute muscle problems but require increased

in the upper spinal cord and brain stem. He applied the terms

collaboration to provide effective care as joint involvement and

primary pain and secondary or heterotopic pain to these two

chronicity increases.

phenomena, respectively. Successful delineation of primary

The intent of this chapter is to address the most common

and secondary pain can mean the difference between treatment

questions pertaining to TMD that arise in dental practice.

success and failure, since quality treatment can unequivocally

Hence, the approach to these questions is intended to be prac­

fail if applied to the incorrect site or misdiagnosed clin ical

tical and applicable to routine care delivery.

260

Temporomandibular Disorders • CHAPTER 22

There is also insufficient evidence to indicate that occlusal

1 . When is treatment indicated for TMD? The presence of joint sounds is insufficient reason to implement therapy. Consequently, the persistence of joint sounds alone is an inadequate criterion for success or failure of therapy. and/or

261

Pain

loss offunction are the hallmarks of need for treatment.2

adjustment is effective treatment for TMD u nless there is a sin­ gle tooth in hyperocclusion or is severely mobile.7•S, IIl Okeson2 has introduced the term

orthopedic stability to de­

scribe the simultaneous relationship between condyles tl1at are seated in a m usculoskeletally stable position as the teeth arc i n

As other weight-bearing joints of the body emit joint sounds

maximum intercuspation. I f the position o f the teeth prevents

during function, the TMJs are no exception. Thus, signs and

superior-anterior seating of the condyles and the complex is

symptoms of TMJ dysfunction are common but well tolerated

loaded by trauma or parafunction, the loading will occur in an

and are often ignored by the patient. Although statistics vary,

unstable joint relationship. This is called

60% to 70% of the popula­ tion display at least one sign of T M D and 25% display at least

The joints, muscles, or teeth arc adversely affected. Although

Dol wick and Dimitriulis4 report that

orthopedic instability.

many patients demonstrate orthopedic instability, the key fac­

one symptom. It is more often seen in females than males. Fur­

tors in the development of symptoms are loading and host

thermore, TMD is a phenomenon most commonly noted dur­

susceptibility. There arc multiple methods of loading unstable

ing the patient's reproductive years with peak frequency between

joints inclusive of trauma and parafunction. Host susceptibil­

the ages of25 and

44 years, and only 0.7% by age 65. Hence, i t is

logical to infer that signs and symptoms self-resolve without or in spite of therapy. This phenomenon has been termed

regres­

sion to the means and occurs frequently i n nature.2 Disc position is also not critically related to the success or failure of treatment. A recent study has shown that although

ity remains an elusive factor but may include gender, h istory, or emotional factors.

3. When are occlusal splints indicated in therapy, and when are alternative forms of management of TMD appropriate?

75% of those who have undergone arthroscopic

Some authors advocate the use of splints to diagnostically

surgery for difficulties in opening may have improvement

determine the position of the condyle prior to orthodontic

approximately

with significant pain reduction, subsequent MRJ imaging of

correction or prosthetic rehabil itation.1 1 - 1 4 The additional

the joints of these patients has demonstrated no true change

intent is to induce muscle relaxation to allow condylar seating

in disc position.5 Condylar position and occlusion may not be

in a physiologic position regardless of the occlusion (Figs.

highly correlated. A recent investigation has revealed that there

and

22- 1

22-2).

is a significant difference i n the occlusal position of asymp­

Okeson2 recommends occlusal splints to address symptoms

tomatic patients when comparing maximum intercuspation to

of orthopedic instability. Orthopedic instability is the lack

condylar-dictated occlusion .,...j thin the same patient.6

of simultaneous superior-anterior condylar seating with the teeth in maximum intercuspation, concurrent with relaxation

2. What is the role of occlusal disharmony in TMD?

of the dosing musculature. The intent of splint therapy is to

Multiple investigations have indicated that malocclusion and

provide a functional occlusion that is reversible or modifiable,

functional disharmony have little role i n the etiology ofTMD.

and to concurrently interrupt destructive force patterns on the

A review of the literature reveals that most studies exploring

m uscles and joints. Muscular symptoms arc more prevalent

this topic are retrospective rather than prospective, and many

than i ntracapsular disharmonies, and often surface when an

are viewpoint i n nature rather than evidence based. In a recent

unstable musculoskeletal system is loaded by parafunction re­

article involving questionnaire format and multi variate regres­

sulting from emotional stress, habitual bruxing, or deep pain

sion analyses of 4290 adults examined for TMD, there was no significant relationship to occlusal factors with respect to tem­

i nput. Multiple authors have substantiated the efficacy of splint therap)' for the reduction of muscular symptoms. 15- 1 8 Occlusal

poromandibular symptoms.7 This finding is the norm rather

spli nts may also have a role in therapy when the overwhelm­

than the exception. There has been one non- treated clinical population that

ing symptomatology and final diagnosis is that of intracapsular dysfunction without predominance of muscle symptoms.19

may have a predisposed profile for TMD. Pulli nger et al.8

The design of the splint should provide orthopedic stabil­

observed that there was a significantly high probability of

ity, albeit artificial. Efficacy of the full-coverage repositioning

nonreducing disc displacement in growing patients with

splint that reproduces a mutually protected occlusal scheme

unilateral posterior crossbitc. These authors attributed this

has been supported by evidence-based investigation. Although

tendency toward adaptation of mandibular position, which

a number of splint designs are available, the clinician should

may account for the condylar displacement. Thllander9 al o

choose the design that best suits clinical objectives. Thus, i f

recommended early correction of posterior crossbite to re­

the goal o f splint therapy is t o provide poster1or contact with

solve facial as,ymmetry, normalize m uscle activity, and avoid

anterior disclusion in excursions, the superior repositioning

disc displacement resulting from asymmetric skeletal form.

splint or stabilization splint is appropriate. Supportive therapy

A later study7 using a small subject size determined that pre­

such as physical therapy, pharmacologic management, thermal

treatment asymmetric joint spaces and asymmetric ma ndi ­

therapy, and other less conventional modalities arc also used

bles resolved by maxillary expansion, thus supporting early

effectively, but precise diagnosis is necessary for appropriate

correction of posterior crossbite.

therapeutic prescription.

262

MOSBY'S ORTHODONTIC REVIEW

FIG 22-1 A, Patient with orthopedic instability and joint pain with local muscle soreness. B, Patient after 2 months of maxillary splint wear with condyles now seated properly.

B

A

FIG 22-2 A, Patient with TMD secondary to a habitual intercuspal position that distracted condyles from the fossa. B, Patient after 6 weeks of splint therapy allowed the musculature to provide condylar seating. 4. What are the commonly used pharmacologic

( Klonopin), alp razol a m (Xanax), hydroxyzine pamoate

modalities for management of TMD? Pharmacologic intervention for the treatment of TMD can be

3.

gesi cs to enhance pain relief in conjunction with th e

categori;r,ed i n to seven broad categories: 1. Cen t ral ly acting muscle relaxants. These drugs are act u­ all y i nte rn e u ronal blocki ng agents acting at the spinal cord level and brain stem. They decrease muscular acti vity by

2.

(Vistaril), and lorazcpam (Ativan). Barbiturates. These arc often combined with anal­ anx i olytic/muscl e relaxant effect of the barbiturate. The\

are useful fo r te ns ion type headache. Barbiturates have se­ -

rious side effects including gene ra l depression, as well as

inh ibi ti ng neurotransmission and are usually administered

decreased excitability of cardiovascular, respi ratory, and

at bedtime to decrease the possibility of interference with

gast roi n testi nal systems. Sleep disturbances can occur

patient lifestyle bccau c of undesirable side effects such as

with barbiturate usc, and drug disposition tolerance can

ve rti go or drowsiness. Th ey may also be helpful in induc­

also develop as increased hepati c metabolism leads to the

ing effective stages of sleep, which is critical to management

need of increased quantity of the drug to maintain tissue

ofTMD. Examples include chlorzoxazone (Parafon Forte),

concentrations. Drug dependence, paradoxical reaction

carisoprodol (Soma), and cyclobenzaprine ( Ficxcri l ) .

(especially in the elderly), and other physical side effects

Anxiolytics. Most commonly used are ben zod ia zep i nes,

can occur. A commonly presc ribed barbiturate is butabar

which provide an antianxiety effect but are often incor­

bital, which is combined with caffeine and acetaminophen

rectly pr escribe d for muscle relaxation. They are helpful

in Fioricet. The clinician needs to be very carcfu1 in pre­

in management of insomnia associated with T M D , but

studies have shown that their effect on skeletal muscle re­

4.

­

scrib ing this class of medications for TMD.

Tricyclic antidepressants. These arc used in doses that are

laxation is no greater than that of a placebo. Hence, these

lower than those used for treatment of depression. They act

agents arc helpful as an adjunct to skeletal muscle re­

by i n h ibiti ng the reup ta ke of serotonin and norepinephrine. An example is amitriptyline ( Eiavil) administered in doses

laxation. Exa m pl es arc diazepam (Valium), clonazepam

263

Temporomandibular Disorders • CHAPTER 22 of

10 to 20 mglday at bedtime, compared with 75 to 1 SO

mg

or disc morphology.23•25 I rnaging is therefore not indicated

for depression. Side effects include drowsiness, xerostomia,

in suspected masticatory muscle disorders, nor in short- term

urinary retention, blurred vision, ventricular arrhythmias,

inflammatory disease such as synovitis, capsulitis, or retrodiscitis.

and/or postural hypotension.

5. Opiate and nonopiate analgesics.

Nonopiate analgesics

include NSAIDs and acetaminophen, the latter of which has no antii nflammatory properties and docs not affect

6. What is the role of surgery in TMD

management? According to Dolwick,4 surgery is unequivocally the therapy

platelet aggregation. An effective regimen ofNSAID dosage

of choice to address the less common TMJ disorders such as

is

600 mg of ibuprofen three times a day at mealtimes for

ankylosis, neoplasm, growlh disorders, and unmanageable

1

week. This drug carries very little abuse potential but has

dislocation. When the clinical evaluation and patient's re­

many contraindications that are often overlooked. I n the

sponse to conservative therapy (pharmacologic management,

case of NSAIDs, such contraindications include intolerance

splint therapy, physical therapy, etc.) is unsuccessful, surgery

in asthmatics. Nonopiates should be used with caution or

should be considered based on presenting levels of pain and

avoided in allergic patients; those with hepatic or renal

dysfunction. It is absolutely essential to verify that the TMJ is

dysfunction, anemia, bleeding tendencies, cardiac failure,

the primary site of pain rather than a heterotopic site as defined

pregnancy; the elderly; or t hose with GI ulceration. COX-2

previously by Okeson.2 Although open joint surgery may still

inhibitors are contraindicated in patients v,rith sulfonamide

have application i n the surgeon's armamentarium, the over­

allergies. Drug interactions include anticoagulants, alpha

whelming majority of surgery now appears to be arthrocentesis

and beta blockers, thiazide and furosemide diuretics, ACE

{joint lavage) and arthroscopy (lavage, adhesion release, and

inhibitors, fluconazole (antifungal preparations), lithium,

visualization). The latter allows tissue reduction procedures

and methotrexate.

{partial or complete diskectomy, arthrotomy, and condylecto­

6. Corticosteroids.

Used only locally via injection rather than

my) during arthroscopy if indicated. Numerous recent studies

systemically because of significant side effects. Corticoste­

have demonstrated the efficacy of arthrocentesis for conditions

roids can be destructive to joints when used repeatedly.

of closed lock and osteoarthritic joints.27·3 1 The reported suc­

7. Local anesthetics. These are applied either diagnostically or

cess rate of surgery varies, but it is well established that the suc­

therapeutically. Regional blocks are helpful to determine if

cess rate decreases as the number of previous surgeries rises.4 J t

pain is primary or secondary. Trigger point injections can

has been reported that a near zero prognosis o f successful sur­

be effective in the control of myofascial pain. Both short­

gery is expected i f the patient has undergone two or more pre­

and long-acting agents are available.

8. Botulinum toxin. Botulinum toxin A is a neurotoxin that prevents the release of acetylcholine at the motor end plates.20 The toxin is injected into muscles undergoing re­ fractory rnyospasm i n order to produce muscle paralysis o f approximately 3 months. Given the temporary nature o f

vious unsuccessful surgeries. As is true of treatment ofTMD i n general, there i s n o question that case selection i s a s important as clinical technique in TMJ surge1y.

7. What is the relationship between orthodontic therapy and TMD?

such therapy, the use o f botulinum toxin i s considered t o be

This question has been extensively investigated by an evidence­

palliative rather than definitive, but it remains a treatment

based approach as summarized in an excellent review article

option should other therapeutic measures fail.

by McNamara.32 Twen ty-one papers spanning

The clinician should thoroughly understand the pharma­

1 995 were reviewed , with sample sizes

1980

through

ranging from 22 to

462

cologic properties of prescribed/administered medications and

patients per study. In summary of the multiple articles re­

inform the patient of their possible side effects.

viewed, there is little basis that orthodontic treatment affects

5. What are the contemporary imaging modalities used in TMD diagnosis?

the prognosis ofTMD either positively or negatively, except i n t h e possible case o f unilateral posterior crossbite in the grow­ ing patient as previously mentioned in this chapter.

Many articles have been written regarding imaging protocol. In

It has been stated that an elevated host susceptibility and

patients without medical contraindication, nondynamic evalua­

orthopedic instability i n conjunction with joint loading, espe­

tion of soft tissue structures such as the disc is best accomplished

cially during parafunction, can initiate or exacerbate TMD.2

by MRJ evaluation, whereas hard stmctures such as bone and car­

Orthodontic patients with a previous history ofTM D may also

tilage are best visualized by radiographic techniques.21 Panoramic

be at higher risk for recurrence during treatment, especially i n

radiographs or conventional radiographs do not contribute to

patients undergoing active orthodontic therapy where occlusal

diagnostic accuracy beyond the diagnosis gleaned from history and

interferences emerge during the course of correction.33

physical examination alone.22 Arthrography is reserved for obser­

The presiding consensus is that orthodontic treatment is

vation of disc form, location, and joint dynamics as inferred by

not an effective primary treatment modality for patients with

observation of contrast injection into the upper and/or lower joint

TMD, nor does orthodontic therapy predispose patients to

spaces.2 New modalities of cone beam computerized technology

TMD.34 As Okeson aptly states: "The clinician who only evalu­

are effective i n assessment of size, morphology, and position of

ates the occlusion is likely missing as much as the clinician who

the condyles but are inadequate for evaluation of musculature

never evaluates the occlusion. "2

264

II

MOSBY'S ORTHODONTIC REVIEW

SUMMARY

The identification and treatment ofTMD can be as rewarding as it can be frustrating. Careful diagnosis gleaned via hi�tory and confirmed by clinical examination with imaging when in­ dicated is key to successful treatment. This approach will also indicate the need for allied specialty collaboration. Treatment should always begin conservatively and involve a clear, succinct yet informative explanation of the patient's diagnosis and treat­ ment plan to enlist involvement of the patient in his or her rehabi Htation.

ACKNOWLEDGMENT Special thanks to Dr. Jeffrey P. Okeson for his review of this manuscript as well as for h is special role in guidance and in­ struction of the principles of management ofTMD. His contri­ butions to dentistry and to the specialty of orthodontics have been invaluable. R E F E R ENCES I . Okeson )P: Diagnostic classification of orofaciaJ pa in d isorders.

In Orofacial pain: guidelines for assessment, diagnosis, and man­ agement. Chicago: Quin tessence Publishtng, 1996.

2. Okeson JP: Functional neuroanatomy and physiology of the masticatory system . In Ma11agement of temporomaudibular disor­ ders and occlt1sion. St Louis: Mosby, 2003. 3. Costen )13: Syndrome of ear and sinus symptoms dependent upon disturbed function of the temporoma ndibu lar joint. Ann Otol Rhin Laryng 1934;43: I . 4. Dolwick MF, Dimitriulis G: Is there a role for temporoma ndibu ­ lar surgery? Br I Oral Maxillofac S11rg 1 994;3:307-3 1 3. 5. Ohnuk.i T, Fukuda M, fino M, Takahashi T: Magn etic re onance evaluation of the disk before and after arthroscopic surgery for TM d isorders. Oral Su rg Oral Med Oral Path 2003;9o(Aug): 1 4 1 - 1 4!1. ti. Cord ray FE: Three-dimensional anaJysis of models articulated in the seated condylar position from a deprogram med asymptom­ at ic population: a prospective study. Part I. Am I Ortlrod Demofacia/ Orthop 2006; 1 29:6 1 9-630. 7. Tsu.kiyama Y, Baba K, Cl ark GT: An evidence-based assessment of occlw.al adjustment as a treatment for TM disorders. ) Pros Dent 200 I ;86(July) :S7-66. 8. Pul l i nger AG, Seligma n DA. Gorbein A: A multiple regression a na lysis of the risk and rel at ive odds of tem poroman di bular disorders as a function of common occlusal features. j Dent Res 1 993;72:968-979. 9. Th ila nder 13: Temporomandibular joint problems in children. I n Carlson OS, McNa mara ) A , Ribbens KA, edi tors: Developmeutal aspects of temporomandibular dsorders. i An n Arbor: Uni ver�ity of Michigan J>re�s, 1985. 10. Huang G: Occlusal adjustment for t reat in g and preventing TM d isorders. Am ) Orthod Dentofacial Ortlrop 2004; I 26(2): 138- 139. I I . Roth RI 1: Fu n c tional occlusion for the orthodontist. / Cliu Ortlrop 1 98 l ;XV;I:32-51. 12. Roth RH: Functional occlusion for the orthodontist-part ! ! . I Clin Ortlrop t 9 8 t ;XV;2 : 1 00- t 2 l . 13. Williamson EH, Evans DL, Barton WA, WiJiiams BH: The effect of bi tepl a ne use on terminal hinge axis locati on . Angle Ortlrod 1977;•17:25-33 .

14. Williamson E l l , Ste inke RM, Morse PK, Swift TR: Cen t ri c rela­ tion: a com parison of muscle determined position and operator guidance. A m / Orthod 1980;77: 1 33- 1 45.

I S. Kuttila M, Le Bell Y, Savolainen -l'\ iern i E, et al: Efficiency of occlusaJ applian ce therapy i n secondary otalgia and TM disor­ ders. Acta Odorrtol Scand 2002;60(4}:248-254. 16. Ekberg E. Vallon D, Nilner M: The efficacy of appl ia nce a therapy in patients with TM disorders of ma i nly myogen ic origi n : A ran dom ized, controlled short term trial. f Orofac Pain 2003; 17(2):133-139. 17. Roark AL, Gla ros AG, O' Mahoney M: Effects of interocclu�oal appl iances on EMG activi ty du r ing para functional tooth contact.

J Rehabi/ 2003;30:573 -577 .

1 8 . Greco PM, Vana rsda ll RI.: An evaluation of anterior tem pora lis a nd masse ter muscl e act ivi ty in appli an ce therapy. Angle Ortlrod 1 999;69: 1 4 1 - 1 46. 19. Schmitter M, Zahran M, Due }M, ct al: Conservative therapy in patients wi th a nte rior d isc displacement without reduction using 2 common splints: a randomized clinical trial. f Oral Maxillofac Surg 2005;63: 1295- 1 303. 20. Jankovic ), Brin MF: Th erapeu tic uses of botulinum toxin, N £ngl I Med 1991; 324:1 1 86- 1 194. 2 1 . Styles C, Whyte A: MRJ asses:.ment in the assessment of internal derangement of pain within the TM joint: A pictorial essay. Br I Oral Maxillofac S11rg 2002;40:220-228. 22. Epstein JB, Caldwell J, Black G: The ut ility of panoramic imaging of the TMJ i n patien ts with TM d isorders. Oral Surg Oral Med Oral Path 200 I ;92:236-239. 23. Brooks SL, Brand J'·V, Gibbs SJ, et al: I maging of the temporo­ mandibular joint: position paper of the American Academy of Oral and Ma.xillofacial Radi ol ogy. Oral S u rg Oral Med Oral Path 1997;83( 5 ) :609-6 1 8. 24. Cevidanes LHS, Styner MA, Proffit WR: I m age analysis in super­ i m posi t ion of 3-dimensional con e- beam comp u ted tomography models. Am I Orthod Derrtofacial Ortlrop 2006; 129(5):61 1 -61 8. 25. Chirani RA, Jacq JJ, Meriot P, Roux C: Tem po ro man d ib u lar joint: A meth odolOb'Y of magnet ic resonance imaging 3 D recon ­ stnrction. Oral Surg Oral Med Oral Patlr 2004;97:756-76 1 . 26. Kawamata A, Fujishita M, Kuniteru , et al: Th ree d im ensional com puted tomography of postsurgical condyla r displacement after mandib ular osteotomy. Oral Surg Oral Med Oral Patlr 1 998;85:37 1 -376. 27. Nitzan OW, P rice A: The use of arthrocentesis for the treatment of osteoarthriti c TM)'s. f Oral Maxillofac Surg 200 I ;59( I 0}: 1 1 54- 1 1 59. 28. Yura S, Totsuka Y, Yoshikawa T, I nou e N: Can arthrocentesis release in t racapsul a r adhesions? Arthroscopic Findi ngs before and after irrigation under sufficient hyd rau lic pressure. I Oral

Maxillofac Surg 2003;61: 1 253- 1 256. 29. Nitzan OW: TMJ "open lock" versus con dylar dislocation: signs and symptoms, imaging t rea t ment and pathogenesis. J Oral Maxillofac Surg 2002;60( May):S0ti-51 1 . 30. Emsboff R, Rudisch A , Bosch R, Strobi l i: Progn ostic indicator� of the outcome of arthrocentesis; a short term follow-up study. Oral Surg Oral Med Oral Path 2003;96(} uly): 1 2- 1 8. 3 1 . Gesch D, Bernh ardt 0, Mack F, et al: Association of malocclu­ sion an d function al occlusion w it h su bjec tive �ymptoms ofTMD in adult: Results of the study of health in Pomeran i a (SHIP). Angle Orthod 2005;75(2) : 1 83- 190. 32. Mc i'Jamara J: Orthodontic treatment and temporomandibular d borders. Oral Surg Oral Med Om/ Path 1 997;83( 1 ) : ! 07- 1 1 7. 33. Lc Bell Y, . iemi PM, Jamsa T, et al: Su bjective reactions to int er­ vention with artificial i nterferences in subject� with and without a history of temporomandibular d iso rders. Acta Odontol Scaud 2006;64( 1 ):59-63.

34. Cont i A, Freitas M, Conti P, et al: Relationship between �igm and symptoms ofTM d isorders and orthodontic treatment: a cross sectional study. Angle Orr/rod 2003;73(4) :4 1 1 -4 1 7.

Retention in Orthodontics

Jeryl 0 . English

C

omprehensive orthodontic therapy requires that treat­

•

Hltesh Kapadia

an Objective G rad i ng System to evaluate the final dental casts

ment goals be established during the time of treatment

and panoramic radiographs.10 The Directors of the ABO de­

planning. Begin treatment with the end in mind. These

veloped this grading system for assessing occlusal and radio­

goals should include patient esthetics, i mproved occlusal func­

graphic results of orthodontic treatment. Using this system,

way to ensure continued satisfactory alignment after treatment

arc producing excellent clinical results.

tion, and long-term retention. Litde et al. 1 states that the only is by the usc of fixed or removable retention for life. Therefore, instability or a tendency toward relapse should be anticipated.

orthodontists can grade their treated cases to determine if they

1 . What is retention?

Patients should be advised of the potential for relapse prior to

Retention is the last phase of orthodontic treatment and one

treaunent and of the need to stay in long-term retention.

of the most important, where teeth are held in an esthetic and

Orthodontists should work to produce an occlusion that is

functional position. 1 1 • 1 2 Retention of the corrected malocclu­

functionally efficient, esthetic, and healthy. Long-term reten­

sion is just as important as the diagnosis, treatment plan, and

tion helps to ensure stability of the dentition. Interdigitation of

actual orthodontic treatment to correct the patient's maloc­

the posterior occlusion plays a significant role in the control of

clusion. Planning for retention should be done prior to any

anteroposterior and vertical facial growth and is an important

orthodontic treatment for each individual case. The type of

factor in jaw relationships.2 Numerous authors have stated that

retention should be determined at the begilll1ing of treatment

good intercuspation and occlusal contacts may be the key to a

as well as any procedures to help retain the final functional and

stable orthodontic result.3·8

esthetic occlusion.

Many of the current concepts in occlusion are derived from a benchmark study by Andrews9 to determine the keys to nor­ mal occlusion. Criteria for inclusion of these nonorthodontic

2. Why is retention necessary? The need for retention is important to maintain the stability of

patients in the study were a pleasing appearance, straight teeth,

the occlusion achieved by the orthodontist and patient . 1 3 With­

and a good bite that would not benefit from orthodontic treat­

out stability, the esthetic and functional resulL may relapse. The

ment. I n these individuals, Andrews found six: keys in their

i mprovements achieved from long and painstaking treatment

normal occlusions:

may be lost because of relapse after the orthodontic appliances

1 . Molar relationships

arc removed. Teeth that have been moved orthodontically have

2. Crown angulation

an inherent tendency to return to their original malocclusion

3. Crown inclination

positions.

4. No rotations

5. No spaces 6. Flat occlusal plane It has long been the goal of orthodontists to treat their

3. What are the general factors affecting stability? Throughout the orthodontic literature, many factors have been discussed concerning stability of the orthodontic treatment

patients using these six keys as guides for establishing a normal

result. 1 4•l5 Three factors are consistently mentioned as to why

occlusion that is esthetic and with good occlusal function.

retention is necessary to maintain the orthodontic correction:

Many of thes,t keys were included in the Objective Grading System developed by the American Board of Orthodontics (ABO) in the mid-'90s. In an effort to enhance the reliability of the ABO examiners and provide the candidates with a tool to assess the adequacy of their finished orthodontic results, the Board has established

1 . The time needed for the gingival and periodontal liga­

ment fibers to reorganize.

2. Growth, especiaiJy mandibular growth, may alter the

orthodontic correction.

3. Soft-tissue pressure from the oral musculature may lead

to a relapse tendency.

265

266

MOSBY'S ORTHODONTIC REVIEW

4. Why is growth a consideration in retention? The nature and duration of retention depends on the patient's

since the mandibular plane angle and anterior facial length will increase. Retaining the correction can be frustrating because of continued mandibular growth, which is difficult to control.

maturational status and on anticipated future growth.16 Growth

Correction of true Class III malocclusions in adults caused by

produces occlusal changes in all three skeletal dimensions. The

maxillary hypoplasia, mandibular prognathism,

transverse dimension is completed first and has a lesser effect

tion of the two most often requires orthognathic surgical cor­

or

a combina­

on the occlusion than the vertical and anteroposterior dimen­

rection. A gnathologic positioner is a useful retainer in mild

sions. However, i f a patient has had transverse expansion, there

Class III malocclusions. Use of chin caps to restrict mandibular

is a degree of rebow1d even in the transverse dimension. Ide­

growth is not very effective.

ally, an adolescent patient should wear orthodontic retainers indefinitely; however, at a minimum, the retainers must be worn until growth is completed in adulthood. Even adults

8. What are retention considerations in open bite

cases?

show some craniofacial remodeling that can cause alteration

An open bite malocclusion may be dental or skeletal in nature.

of the occlusion. ln orthodontics, we arc dealing with a living,

A dental open bite may be caused by depression of the incisors

dynamic system of growth. Throughout our life, orthodontic

because of a habit such as thumb· or finger-sucking or poor

retention will help to minimize the changes in our occlusion.

tongue posture. A good cephalometric value to differentiate

Therefore, retention should be considered for life if the occlu­

between a dental and skeletal open bite is incision-stomion;

sal alignment is to be maintained.

dental open bites have intruded maxillary incisors whereas

5. What are retention considerations in extraction and nonextraction cases?

skeletal open bites have a normal incisor position. The open bite must be accurately djagnosed and treated if relapse is to be prevented.

There is not a specific retention philosophy for extraction cases

In skeletal open bite, incisors are in a normal position, but

and another for nonextraction cases. The orthodontist decides

the posterior teeth have elongated. Controlling the eruption of

on the individual's retention plan at the beginning of treatment

the maxillary molar with high- pull headgears and a transpalatal

when the diagnostic records are used to establish the patient's

bar with a midline acrylic palatal button 4 mm off of the palate

will be possible to

is useful to control extrusion. If correction of severe open bite

treatment plan. By following this plan, it

achieve an esthetic and functional occlusion.

is not started in the mixed dentitjon, it will most likely require

Edwards16 has shown that in extraction cases, excess gin­

orthognathic surgery in late adolescence or adulthood. The

gival tissue forms as the adjacent teeth are moved toward one

skeletal open bite phenotype is easily diagnosed in the early

another in closing the extraction site. This excess gingival tissue

mixed dentition.

should be surgically removed to prevent relapse.

6. What are retention considerations in Class I I cases?

9. What are the considerations in deep bite cases? Deep bites are common in certain malocclusions such as Class IT division

2 and are caused by overeruption of the maxil·

Skeletal Class II malocclusions are corrected in two ways: re­

lary incisors, mandibular incisors, or both. Once the deep bite

stricting maxillary growth with headgear appliances, or using

is corrected, it must be controlled in retention or it is likely

a functional appliance such as a Herbst or Twin Block. Class II

to relapse.19•20 Retention is accomplished with a maxillary re­

elastics are also used, but this may cause proclining and flaring

movable retainer with a bite plate, which the lower incisors

of the lower incisors. If proclined, the lower incisor will upright

and cuspids will contact if the bite- begins to deepen. The ap­

and crowd because of lip pressure once retention is removed.

pliance should not cause the posterior teeth to djsocclude. This

To overcome these relapse tendencies, discontinue Class II elastics at least

2

months prior to debonding. Overcorrection

of the Class II treatment is recommended due to differential jaw growth resulting in long-term relapse. This relapse tendency can be controlled by continuing t o

retainer should be worn at night until the late teens or early 20s to maintain occlusal stability.

1 0. What are the indications for bonded lingual retainers?

wear a headgear a t night o r using a functional appliance such as

Fixed orthodontic retainers are usually wires bonded to the lin­

a Bionator to hold the occlusal relationship.l5 Obviously, this

gual surface of the mandible anterior teeth

type of retention is for the patient with a more severe skeletal

prolonged retention.2 1•22 These may be fabricated directly in the

problem initially.

mouth or indirectly from an accurate stone model. The bonded

7. What are retention considerations in Class Ill cases? Early correction of skeletal Class III malocclusions in the

for esthetics and

retainer is placed in the patient's mouth and secured with a light

cured composite resin. The fixed retainer is useful to retain the mandibular canine-to-canine region, and a bonded retainer is more esthetic than a banded retainer. The fixed bonded retainer

mixed dentition using a palatal expander and protraction

is also used to maintain corrected midline diastema and to main·

facemask is useful for altering the skeletal components.17•18 It

tain pontic or implant space. It is also useful for maintaining the

is more successful in deep bite cases than in open bite cases,

vertical position of teeth extruded into the arch such as palatally

Retention in Orthodontics

•

CHAPTER 23

267

A

FIG 23-2 Orthodontic

B

Maxi ll ary Hawley retainer. (Courtesy of AOA Appliances, Sturtevant, WI.)

FIG 23-1 Mandibular bonded retainer. A, Cuspid to cuspid. B, Bonded to every tooth.

impacted cuspids In most instances the retainer wire is bonded to the terminal teeth (canines) of the retainers ( Fig. 23- I , A) and not bonded to every tooth. Fixed retainers make interproximal hy­ giene procedures more difficult. However, with good flossing pro­ cedures, these fixed bonded retainers could be left in place until adulthood or indefinitely if needed. It is important that the general dentist not remove the bonded lingual retainer \\r\thout consul­ tation with the orthodontist, since the teeth may relapse. Today more orthodontists are bonding a 0.0 1 95 twisted wire to every tooth from cuspid to cuspid (Fig. 23-1, B). This increases stability and is possible due to improvements in the composite material. .

-

1 1 . What are the indications for removable retainers? Removable retainers are effective for retention against intra­ arch re lapse. These retainers are made of stainless-steel wire and acryl ic (Fig. 23-2 ). The four basic components are the clasps, the anterior re­ tainer wire, the acrylic body, and any auxiliaries added to the retainer. They should be fabricated from an accu ra te stone cast. The labial bow provides the orthodontist the ability to control the anterior teeth. Retention clasps are necessary for the retainer to stay firmly in place. The Hawley retainer is the most common removable retainer and the type of retainer used to control a deep bite, as a bite plane is easily added. A lower Hawley retainer is much more difficult to insert because of unde rcuts in the premolar and molar region. A bonded lingual retainer is more suitable for the mandibular arch. A second majo r removable retainer is the wrap-around re­ tainer (Fig. 23-3 ). It fi rmly holds each tooth in position and is

FIG 23-3 Orthodontic

Maxillary wrap-around retainer. (Courtesy o1 AOA Appliances, Sturtevant, WI.)

excellent for mai n ta i nin g space closure after extractions. There no wires across the occlusion so there are no occlusal in­ terferences. Wrap-around retainers are more diffic ult to fab­ ricate and are therefore more expensive than regular Hawley retainers. are

,

1 2 . What are the indications for vacuum-formed retainers? Wiith the development of clear, thin thermoplastic materi­ als, vacuum-formed retainers have become very popular with many orthodontists in the last few years.23 Vacuum-formed re­ tainers have many advantages over wire and acryl ic for many orthodontic patien ts requiring removable retainers. These re­ tainers are fabricated on a dental st udy cast i n app roxjmately

268

MOSBY'S ORTHODONTIC REVIEW

30 m inutes with a relat ively i nexpensive material. The retainers are comfortable and rarely

interfere with speech, they require

no adjustme nts, and they are esthetic because of their almost­ invisible appearance. The retainer is

typi cal ly inserted on the

day the braces are removed. These retainers are easily cleaned and p rovide good stabil it y of the occlusion, especially in the maxillary arch. P ossible disadvantages are t h at they do not al­ low the sett ling of th e occlusion, and since they cover the oc­ clusal surfaces, masticatory forces can cause

wear and requi re

the retainer to be remade . Some have advocated using a sec­ tional vacuum-formed retainer from cusp id to cuspid. Unfor­ t unately, this type of retention over the long term would allow

at least until early adulthood. Removal of this retainer should be done only after the orthodontist is consulted. Some retain­

ers may stay for a lifetime. The answer to the question of long­ term stability is long- term retention .

15. When are positioners used as retainers? A tooth positioner is an excellent retainer in

certain malocclu­ sions, although it is more commonly used as a fin ish ing appli­ ance.25·26 ( Fig. 23-4 ) . It has the advantages of massaging the gingival tissues, and it is not subject to breaka ge as ac ryl ic retainers are. lt is bulky and typ i cal ly is worn 2 to 4 hours per day. Positioners do not

extrusion of the pre molars and molars, potentially opening the

retain rotations or in cisor irregularities as well as standard re­

bite. This retainer is simple, esthetic, and comfortable, and it

tainers. Positioners maintain the occlusal relationship as

has received an enthusiastic reception from both patients and

as the i ntra-arch tooth p osit ions. They are excellen t retainer

add i t io n, the vacuum-forced retainer offers a perfect vehicle for transporting bleach to patients' teeth after completion of orthodont ic treatment.

for Class II and Class III maloccl usions as well as for open bite

orthodontists. Jn

13. Are there indications for combining removable and fixed retainers?

well

malocclusions. The optimum positioner is one that has an ar­ ticulator mounting that records the pat ient's

h inge axi s. This

gnat hologic positi oner is more expensive, but it will prevent the posterior open bite that results when a positioner

is made

to an incorrect h i nge axis. A tooth posi t i oner is not appropriate

In adult cases with general iud spacing , a palatal bonded retainer

for every orthodontic pati en t, but for selected patients, it can

may be necessary to avoid re-opening of spaces. In cases with

be an excellent fi nishing appliance and retainer.

large diastemata, a bonded palatal retainer may be required to maintain the closure. In cases with a palatally impacted canine, a bonded retainer may be necessary to prevent vertical relapse .

16. Are spring retainers useful for retreatment of mandibular incisor crowding?

In each of the three examples, a vacu u m- forced retainer could

Recrowd i n g of mandibular

be used over the bonded retainer to

spring a l igner to correct incisor position. If late mandibular

help prevent breakage of

incisors is the indicat io n for

a

is t he cause of the c rowd i ng, it may be necessary to re­

the bonded retainer caused by occlusal interference or contact

growth

during biting. It is important for the orthodontist to evalu­

duce the i n terproximal width of the i ncisors . The interproxi­

ate the patient's overbite and overjet and to place the bonded

mal enamel can be removed with thin discs i n a h an dp i ece

retainer as gi ngival as possibl e to avoid i nterference with bite

called air rotor str ippi ng (ARS) or with abrasive strips. This

closure. When a properly placed Lingual - bond retainer is com­ bined with a vacmun-forced retainer, the bonded retainer

can

remain in place for a long 6me.

enamel reduction must be performed cautiously to re move only 0.25 mm per side on the incisors. Tf t he recrowding i on ly 2 to

3

mm, this can be co rrected with the spring retai ner.

First, the i nterproximal reduction is comp leted followed

by

14. What are the long-term retention considerations?

top ical fluoride, and then an impression is taken for a s t ud}

Orthodontic retention should be continued until craniofacial

alignment. The spring aligner

grow t h

pat ien t 's mouth. Once the teeth move into a li gnment, the

is essenti ally completed in the early 20s.24 Late man­ dibular growth is the greatest contributor to mandibular inci­ sor c rowdi n g; therefore, retention is certainly a requirement for all orthodontic patients. It is commonly recommended that all patients have a retenti on mainten a nce p hase for at least 1 year. After that, the patient will be seen only if there are dif­ ficulties wit h th e retainer ( e.g., i f i t i s broken, bent, o r lost). It is importa n t that the orthodontist establish a retention proto­

cast. The anterior teeth are sectioned and reset into proper

is fab ricated and seated in the

"active" spring retainer now become s a passive retainer. Most orthodontists find that it

is actually much faster and easi e r to

replace brackets on the anterior teeth and rea lign ra ther t han

u sing a spri ng re ta iner . 17. What are the indications for circumferential supracrestal fibrotomy (CSF)?

col for each patient during the ini ti al diagnosis and treat men t

CSF is a surgical excision of the free gingival fibers and t rans­

planning phase. Most orthodontists use a removable retainer

septal fibers to reduce rotat ional rela pse. Surgery to cut the su­

in the maxillary arch. As most of the relapse occurs in th e first

pracresta1 e1astic fibers is necessary because rotational rel apse

6 months followi ng bracket removal, the maxillary retainer is

is caused by t he network of elastic supracrestal gingival fibers

worn full time for 6 m onths. After the first 6 months, the patien t

ret urning to their original posit ion. Th is surgical tech nique

wea r only a n d gradually reduce this i f n o pres­ sure areas are noted when seating the retainer. Event ually, t h e ma x illary retainer may not be needed. The lower retainer is usually a bonded - Lingual retainer, which should be left in place

was developed by Edwards and includes infiltration with a local

can go t o night

anesthetic followed by a circumferential incision around the tooth to the crest

of alveolar bone. 27·31 These surgical cuts are

made after a previ ously rotated tooth is orthodontically moved

Retention in Orthodontics

•

CHAPTER 23

269

FIG 23-4 Silicone tooth posi tioner. (Courtesy of AOA Orthodontic Appliances, Sturtevant WI.) ,

to its ideal position within the arch. There is minor discomfort after the procedure, but no periodontal pack is necessary. In most cases, it is done by the orthodontist near the end of the finishing phase of treatment. The most important consider­ ation is to retain the tooth in its ideal position while gingival healing occurs. Some orthodontists prefer to perform the CSF after the braces have been removed, but retainers must be in­ serted immediately to prevent the tooth from rotating back to its original position. This procedure is indicated for a severely rotated tooth, and it is not appropriate for crowding of teeth without rotations.

1 8. What are the indications for a frenectomy? A

frenectomy is the surgical removal or repositioning of a frenum and is performed to enhance the stability of a corrected diastema.32 A maxillary midline diastema is caused by insertion of the labial frenum, which is a band of heavy fibrous tissues between the central incisors. When the cause of the diastema is a prominent labial frenum, the frenectomy should be performed after orthodontic alignment and space closure, but prior to the removal of the orthodontic appliances. The major point in a frenectomy being successful is removal of the interdental fibrous tissue. It is not necessary to remove a large portion of the frenum itself. The scar tissue will stabilize the teeth and help to prevent the diastema from returning. This procedure should not be performed until the diastema is closed or the scar tissue will prevent closure. It is difficult to maintain space closure 11fter correcting a diastema, so a lingual-bonded retainer is indicated to keep the space closed. In addition, many children in middle to late mixed dentition demonstrate diastemas of approximately 2 mm. This diastema will normally close with the eruption of the maxillary canines and does not require a frenectomy.

1 9. What is relapse?

Relapse is the change in tooth position toward the former location following active orthodontic treatment. Teeth are in a stable position because of the equilibrium of forces of chewing, swallowing, tongue, and cheek movements. There is a balance between the internal and external oral m uscu­ lature. Tf a tooth is moved, this equilibrium is altered and it must be reestablished to prevent relapse. New fiber and hard tissue formation is dependent on retention. The gingi­ val fiber networks must reorganize to accommodate rhe new tooth positions. Immediately after orthodontic appliances are removed, the teeth arc unstable to occlusal and soft tis­ sue pressures. 1 3 This is the reason every patient must be placed in orthodontic retainers for a minimum of 6 months to reestablish the equilibrium. Very few cases require mini­ mal or no retention. If the posttreatment dentition starts developing mandibular incisor irregularities, reduction of the incisor width by slenderizing can certainly help. Usually, only minimal tooth structure has to be removed if the i nci­ sor root apices have been adequately spaced. Routine cases require retention appliances until the decision to extract or retain the third molars is determined, and the growth pro­ cess is nearly completed in the early 20s. 20. What is the role of the third molars and

relapse?

It is unclear what role the third molars play i n the severity of late mandibular crowding. The etiology of late crowding of the mandibular arch is multifactorial and is associated with the amount and direction of late mandibular growth. There is a controversy of the relative merits of extraction of third molars to alleviate mandibular anterior crowding.33·34 Most authors

270

MOSBY'S ORTHODONTIC REVIEW

feel that the extraction of third molars for the purpose of

5. Overjet: Overjet is used to assess the relative transverse

preventing mandibular anterior relapse is not j ustified.

21. What is the Objective Grading System used by the American Board of Orthodontics (ABO)?

relationship of the posterior teeth and the anteroposterior relationship of the anterior teeth.

6. Interproximal Contacts: Interproximal contacts are used to determine if all spaces within the dental arch have been

In the mid 1 990s, the American Board of Orthodontics began

closed. Persistent spaces between teeth after orthodontic

investigating methods of making the clinical examination more

therapy are not only unesthetic, but can lead to food impac­

objective. Because a major emphasis has always been placed on the final occlusion, the first efforts were directed at developing

tion.

7. Root anguJation: Root angulation is used to assess how \veil

an objective method of evaluating the dental casts and intra­

the roots of the teeth have been positioned relative to one

oral radiographs. At the 1995 ABO Clinical Examination, 100

another. Although the panoramic radiograph is not the per­

cases were evaluated. A series of 1 5 criteria were measured on

fect record for evaluating root angulation, it is probably the

each of the final dental casts and panoramic radiographs. The

best means possible for making this assessment.

data showed that the majority of the inadequacies in the final

The Directors of the ABO spent countless hours develop­

results occurred in 7 of the 1 5 criteria (alignment, marginal

ing this system for assessing the occlusal and radiographic re­

ridges, buccolingual inclination, overjet, occlusal relationships,

sults of orthodontic treatment. The usefulness of this system

occlusal contacts, and root angulation) . The following year in

depends not only on its objectivity, but more importantly

another field test, 300 sets of final dental casts and panoramic

on the validity and reliability of the measurements. After re­

radiographs were evaluated by a subcommittee offour directors.

peated comparison of both objective and subjective systems,

Again, the majority of the inadequacies in the final results oc­

the Directors are confident that the "cut-off' score to pass this

curred in the same seven categories, but the committee had diffi­

portion of the clinical examination is valid. Today, candidates

culty establishing adequate intcrcxaminer reliability. Therefore,

must grade their own results before the clinical examination.

the subcommittee recommended that a measuring instrument

Candidates will know if their results will pass the CCRE por­

be developed to make the measuring process more reliable. In

tion of the clinical examination. Furthermore, diplomates may

1 997, a third field test was performed with the modified scoring

use this scoring system at anytime in their orthodontic career

system and the addition of an instrument to measure the various

to determine if they are producing "Board quality" results. The

criteria more accurately. Based on the collective and cumulative

Board hopes that this method of self-evaluation will help to

results of extensive field tests, the Board decided to officially ini­

improve the quality of orthodontic care in the future.

tiate the usc of this Objective Grading System for candidates for the Clinical Examination. 10 The seven criteria are: 1.

Alignment: In th e anterior region, the incisal edges and

lingual surfaces of the axillary anterior teeth and the incisal

REFERENCES I . Linle RM, Riedel RA, Artun J : An evaluation o f changes in man­

edges and labial-incisal surfaces of the mandibular anterior teeth were chosen as the guide to assess anterior alignment. In the maxillary posterior region, the mesiodistal central

2.

groove of the premolars and molars is used to assess ade­ 2.

quacy of alignment.

Marginal Ridges: Marginal ridges are used to assess proper vertical positioning of the posterior teeth. Based on the four field tests, the most common mistakes in marginal ridge alignment occurred between the maxillary first and second molars. The second most common problem area was be­

3.

tween the mandibular first and second molars.

4. 5. 6.

Buccolingual Inclination: In order to establish proper oc­ clusion in maximum intercuspation and avoid balancing interferences, there should not be a significant difference between the heights of the buccal and lingual cusps of the

4.

3.

maxillary and mandibular molars and premolars.

7.

8.

Occlusal Relationship: Occlusal contacts are measured to assess the adequacy of the posterior occlusion. Again, a major objective of orthodontic treatment is to establish maximum intercuspation of opposing teeth. Therefore, the fw1ctioning cusps are used to assess the adequacy of this cri­

9. 10.

terion (i.e., the buccal cusps of the mandibular molars and premolars and the lingual cusps of the maxillary molars and premolars).

II.

dibular anterior alignment from 10 to 20 years postretention. A m ] Orthod Dentofacial Orthop 1 988;93:423. Ostyn JM, Maltha JC, van't I-Iof MA, van der Linden FP: The role of interdigitation in the sagittal growth of the maxillo­ mandibular complex of Macaca fascicularis. A m ] Orthod Dentofacial Orthop 1996; 1 09: 7 1 - 78 . Tweed CS: Indications for the extraction of teeth in orthodontic procedures. A m ] Orthod 1944;30:405-428. Huckaba GW: The physiologc i vasis of relapse. Am I Orthod 1952;38:335-350. Schudy GF: Posttreatment craniofacial growth: its implications in orthodon tic treatment. Am I Orthod 1 974;65:39-57. Fotis 13, Melsen B, Williams S: Posttreatment changes of skeletal morphology following treatment aimed at restriction of maxil­ lary growth. Am I Orthod 1985;88:288- 296. Harris EF, Vaden JL, Dunn KL, Behrents RG: Effects of patient age on postorthodontic stability of the mandibular arch. Bur ] Orthod 1994;105:25-34. Parkinson CE, Buschang PH, Behrents RG. et al: A new method of evaluating posterior occlusion and relation to posttreatment occlusal changes. Am I Orthod Dentofacial Orthop 200 I ; 120: 503 - 5 12 . Andrews LF: The six keys to normal occlusion. Am I Orthod 1972;62:296-309. Casko JF, et al: Objec tive grading system for dental casts and panoramic radiograph. Am I Orthod Dentofacial Orthop 1 998; 1 14:590-599. Blake M, Bibby K: Retention and stability: a review of the litera­ ture. Am I Orthod Den tofacia/ Orthop 1998;1 14:299-306.

r. Retention in Orthodontics • CHAPTER 23 12. Kaplan H: The logic of modern retention appliances. Am J Orthod Dentofacial Orthop 1988;93 : 325-337. 13. Sandowsky C: Long-term stability following orthodontic the rapy. In Burstone C), Nanda R, editors. Retention and stabili­ ty in orthodontics. Philadelphia: WB Saunders, 1993, pp I 07- 1 1 3. 14. Reitan K: Principles of retention and avoidance of treatment

rela pse. Am J Orthod 1969;55:776-790. 1 5 . Nanda RS, Nanda SK: Considerations of den to facial growth in long-term retention and stability: is active retention needed? Am

f Orthod Dentofacial Orthop 1 992; l 0 I :297-302. 1 6. Edwards ) : Th e prevention of relapse in extraction cases. A m

] Orthod 1 97 1 ; 160: 128- 140. 17. McNamara JA: An orthopedic approach to the treatment of Class III malocclusion in young p atien ts.

I Clin Orthod

1 987;2 1 :598-608. 18. Kulbersh VP, Berger J, K ersten G: Effects of protraction mechanics on the mid face. Am J Orthod Dentofacia/ Orthop 1998;1 14:484-491 . 19. Lewis P: Correction of deep overbite: A report of three cases. A m 1 Ortlwd 1987;91:342-345. 20. Kim TW, Little RM: Postrctention assessment of deep overbite correction in Class II division 2 malocclusion. Angle Orthod 1 999;69(2): 1 75- 186. 2 1 . Espen HD, Zachrisson BU: Long- term experience with direct bonded lingual retainers. f Clh1 Orthod 199 1 ; 1 0:6 19-630. 22. Orchin )D: Permanen t lingual bonded retainer. ] Clin Orthod 1 99 1 ;24:229-2 3 1 .

271

23. Sheridan )J, LeDoux W, McMinn R: Essi x retainers: fabrication and supervision for permanent retention. I Clin Orthod

1 993; 27:37-45. 24. Zachrisson BU: Important aspects of long- term stability. ] Clin Ort hod 1 9 7 1 ;9:563-583. 25. Kesling HD: The philosophy of the tooth positio ni ng ap pli an ce . Am f Orthod 1945;31 :297-304. 26. Caran o A, Bowman SJ: Short-term intensive use of the tooth positioner in case finishing. f Clin Orthod 2002;36(4) :216-2 19. 27. Edwards }: A surgical procedure to eliminate rotational relapse. A m 1 Orthod 1970;57: 35-40. 28. Edward J: A long- term prospective evaluation of the circumfer­ ential supracrestal fiberotomy alleviattng orthodontic relapse.

Am f Orthod 1 988;93:380-387. 29. Edwards

j: The prevention o f t relapse in extraction cases. Am

J Orthod 1 9 70;60: 128-1 40.

30. Boose L: Fiberotomy and reproximation without lower reten­ tion, nine years in retrospect: Part l. Angle Orthod 1 980;50:88-97.

3 1 . Boose L: Fiberotomy and reproximation without lower retention, nine years in retrospect: Part ll. Angle Orthod 1980;50: 169-178.

32. Edwards JC: Th e diastema, the frenum, the frenectomy: a clinical study . Am I Orthod 1977;7 1:489-508. 33. Richardson ME: The role of the third molar in the cause of lower arch crowding: a review. Am J Orthod Dentofacial Orthop 1989;95( l ): 79-83. 34. Adcs A, J oo ndeph D: A long-term study of the relationship of th ird molars to mandibular dental arch changes. Am 1 Ortfrod Dentofacial Orthop 1990;97:32 3-335.

Soft-Tissue Diode Laser Surgery in Orthodontics

C

ontemporary orthodontics continues to merge with

improving tooth proportionality, and improving a gummy

modern-day technology and the growing focus on

smile can greatly enhance the esthetic treatment outcome.

dental esthetics in today's culture. One of the main

Gingival recontouring is also indicated in patients with poor hygiene where inflamed gingiva, pseudopockets, and difficulty

treatment goals of orthodontics has been the ability to produce an esthetic smile in a timely manner. In previous years, ortho­ dontists have been limited in what they could do to in1prove

brushing and flossing are present.3•4 Excessive gingival tissue

treatment outcom es by the lack of t echnol ogy and knowl­

can often prevent the orthodontist from placing brackets in an ideal position. The removal of th is gingival tissue permits the

edge. Tn recent years, the advent of the soft-tissue diode laser has made several soft tissue procedures easily accessible and

orthodontist to bond a bracket to the tooth i n the desired posi­ tion in a timely manner. 3.4

doa ble for orthodontists. Several adva ntages of the diode la­

Aphthous ulcers can be very uncomfortable and painful for

ser include: ease of use, the ability to maintain a hemostatic environment, minimal discomfort for the patient, ability to

the patient (Fig. 2 4 - 1 ) . Traditionally, salt water rinses, topical anesthetic, and tetracycline would be prescribed to alleviate the

cut only soft tissues (not hard tissues), and sutures being un­

symptoms.3 The orthodontist now has the ability to lase the aph­

necessary for proper wound healing. These advantages have

thous ulcer, thus relieving the patient of pain almost immediately.

encouraged several orthodontists to perform their own minor soft-tissue procedures, allowing the orthodontist to finish

The laser is activated for 30 secon ds at a very low wattage and

cases much more efficiently and to a higher esthetic standard. Slowly erupting teeth and gingival overgrowth that have previ­

ulcers generally take up to 14 days to heal, but with laser surgery, the ulcers can heal within 1 day after treatment. The laser wound

ously lengthened treatment time can now be readily handled

that replaces the ulcer is nonpainful and allows the patient to

by th e orthodontist with the usc of a diode laser. Unaesthetic gingival contours and margins can now be routinely managed

have a faster and more com fortable recovery.3•4

along with incisal recontouring in order to produce a most esthetic treatment result. Several soft-tissue procedures along with their indications and methods will be addressed in this chapter.

1 . What soft-tissue procedures using a laser should an orthodontist consider?

kept at a distance of 1 to 2 mm away from the lesion.3·4 Aphthous

Soft tissues can sometin1es cover a tooth and impede its eruption into the arch. The soft tissue laser can be used to rem ove overlying tissue so tha t the orthodontist can bond a bracket and begin moving the tooth i mmediately.3.4 Orthodontists sometimes find themselves waiting to band second mo)ars when an operculum is present. The soft tissue laser can remove opercula so that the orthodontist can band the second molars and keep treatment on track.4 a

Orthodontists continually strive to find methods to enhance

Patients who present with a large diastema often have

treatment results and reduce treatment time. The advent of soft tissue lasers allows the orthodontist to have more control

low fren u m that contributes to the excessive spaci ng. After orthodontically closing the space, it is often recommended to

over factors that previously could impede treatment time and

perform a frenectomy to help stabilize the space closure. The

co m pro m ise treatment results. Several clinical instances ex­

soft-tissue laser makes frenectomy procedures easier to man­

ist where the use of a soft-tissue laser would be beneficial to

age, minimal in discomfort, and hemostatic.

both the orthodontist and the patient: gingival recontouring, aphthous ulcer management, expedi tion of tooth eruption, re­ moval of operculae, and frenect om ies. 1 •4 Removal of soft tissue with the laser is useful for gingival recontouring in orthodontics for esthetic, health, and time reasons. Gingival reshaping for uneven gi ngi val m argins,

272

2. What type of laser should be used in orthodontics? A lase r is made up of a monochromatic light that travels th rough a tube that collimates the light energy. A protective shield encircles the light, allowing the laser to be released only

273

Soft-Tissue Diode Laser Surgery in Orthodontics • CHAPTER 24

A

B

FIG 24-1 Aphthous ulcer (before and after). A,. Aphthous ulcer before laser surgery.

B, Aphthous ulcer immediately after laser surgery. C, Aphthous ulcer 1 week after laser surgery.

at the tip and not through the sides.2 This exposed energy can be controlled by the operator through the power adjustment. The laser cuts the tissue through ablation, where the energy is absorbed in the cells and is immediately subjected to heating, welding, coagulation, protein denaturization, drying vapor­ ization, and carbonization.2 It is recommended that the laser deliver its energy in a pulsed mode, which allows intermittent cooling, less tissue damage, and less discomfort.2 Three main types of lasers are used i n dentistry: the C02 , erbium, and diode laser. The C02 laser can be difficult to use because the tip does not directly contact the surgical site; instead, it must be used at a slight distance and a delay is present from when the incision is made to when it can be seen.2 The erbium laser has a very high wavelength and is effective i n soft tissue removal; however, it does not control bleeding welJ.2 The last type of laser is the diode laser, where the light energy is absorbed by the melanin of the cells2 (Fig. 24-2) . This allows the diode laser to control bleeding exceptionally well at the s u rgical site. The laser tip gently contacts the surgical site, allowing the operator to have tactile feedback.2 Other advantages of the diode include its manageable size, its ability to cut only soft tissues and not hard tissues, low cost, and the fact that these procedures typically require only a topical anesthetic. 2 The laser cau­ terizes the surgical site while cutting so that a periodontal dressing is not necessary for healing.

3. What is the indication and technique for soft­ tissue laser surgery for gingival recontouring? -

-

-

The principles of cosmetic dentistry must be incorporated into orthodontic treatment in order to optimize the esthetic results.1 Orthodontists routinely evaluate the smile line, smile arc, and tooth and gingival proportions. The ortho­ dontist should understa nd the esthetic concepts of tooth proportionality, contacts, embrasures, and gingival char­ acteristics before using laser surgery for gingival removal. The ideal maxillary central incisor should be approximately 66% to 80% width compared with height.1 It is important to assess if a tooth disproportion is due to a short clinical crown height, gingival overgrowth, or delayed passive erup­ tion . ' Depending on the cause of disproportion, waiting for eruption, gingival recontouring, or dental restorations may be the optimal solutio n . 1 Other important esthetic concepts include the placement of contact points and embrasures. As teeth move from the midline to posterior, contact points should progress apically and embrasures should become larger.1 Gingival esthetics also plays an important role in the success of a treatment outcome. The gingival shape (the curvature of the gingival margin of the tooth) of the man­ dibular incisors and maxillary laterals should have a sym­ metrical half-oval or half-circular shape; therefore, their gingival zenith should be located within their longitudinal

274

MOSBY'S ORTHODONTIC REVIEW

axis.1 The gingival shape of the maxillary centrals and

often find that they are unable to ideally place a bracket

canines is elliptical, resulting in a gingival zenith that is dis­

because of gingival overgrowth or delayed passive eruption. In

tal to the longitudinal axis.1

these instances, it would be very helpful for the orthodontist to

The orthodontist can find numerous occasions to use gingi­

be able to remove any excess gingival tissue in order to place

val recontouring to improve treatment results. When initially

the brackets in an ideal position rather than waitiag for erup­

evaluating a patient for orthodontic care, the orthodontist care­

tion or referring the patient to a periodonti st to have the teeth

fully evaluates the casts and patient to determine ideal bracket

uncovered.M

placement. Most orthodontists will use the incisal edge of the

G ingival recontouring can also be very helpful in aiding

teeth to determine bracket placement height. Orthodontists

patients with poor oral hygiene. Patients often have mar­ ginal to poor oral hygiene that can cause inflammation and pseudopockct formation of the gingiva. These pseudopock­ ets can exacerbate the inflammatory process by impeding the patient's ability to thoroughly brush and floss around the teeth and gingiva.3·4 Gingival recontouring can help to reduce this inflammation and thus allow the patient to ac­ cess more areas to keep the gingivitis under control. Closing large extraction spaces can also cause redundant tissue to appear, especially in conjunction with poor oral hygiene.3 Removal of this tissue allows the patient to keep these areas under hygienic control. As orthodontists begin to in corporate more cosmetic den­ tistry into their treatment plans, gingival recontouring proves

to be extremely useful in finishing a case to a better esthetic

FIG 24-2 Diode laser (ZAP Softlase).

outcome ( F ig.

24-3). Patients may have uneven gingival

A

B

c

D

FIG 24-3 Crown lengthening (before and after). A, Preorthodontic treatment. B, Prelaser surgery. C, Immediately postlaser crown lengthening surgery. 0, Two weeks after surgery. E, Postorthodontic treatment.

Soft-Tissue Diode Laser Surgery in Orthodontics • CHAPTER 24 margins,

gingival

to-height ratio rc�ult. The

inflammation,

or

poor crown

275

width­

that result in a less-than-optimal treatment

oft-tissue Ia cr allows orthodontists to improve

tooth proportionality and gingival shape and contour in ac­ cordance to the smile arc and smile line of the individual patient.1•2•4

A

When performing a gingivectomy, apply topical anesthetic and use a probe to mark height guides, leaving I mm of sulcus when finished. Hold the laser tip perpendicular to the tissue at the gingival margin and use a continuous wave stroke to re­ move the tissue surface one layer at a time. After the ideal con­ tour arc achieved, clean the area with a microbrush or cotton ball with 3% hydrogen peroxide.5

4. What is the indication and technique for soft-tissue laser surgery for a frenectomy?

B

Patients who present with a large diastema often have a low frenum that can contribute to the excessive spacing. Ortho­ dontists will treat the diastema by closing the space and then stabilizing it with fixed or removable retention i n addition to a frenectomy. The soft-tissue laser make performing a frenectomy much more comfortable for the patient. The healing process is less painful, no sutures or dressings are needed, and bleeding is highly controlled. As the frenum heals in it new position, the sca r tissue c a n h e l p to maintain

c

the space closure ( Fig. 24- 4 ) . The technique for performing a frenectomy includes first placing topical anesthetic at the surgical site. Hold the upper lip and lightly pull the lip forward until the frenum is taut. Lase the frenum horizontally approximately 3 mm from the frenum base and use light, continuous waves until the lip

is released, leaving a V-shaped crater approximately I inch wide. Continue to lase deep enough to prevent reattachment and then smooth the remaining tissue at the base of the fre­

num. Clean the surgical site with 3% hydrogen peroxide on

D

a cotton ball.5 Another technique, the diamond-release fre­

nectomy, involve� pulling the upper lip taut, lasing the sides of the V -shaped frenum, and then lasing the base of the frenum, which creates a "diamond" -shaped :.urgical site.

5. What is the indication and procedure used with a soft-tissue laser to uncover impacted teeth? Orthodontic treatment can sometimes be slowed drastically

FIG 24-4 Frenectomy (before and after). A, Initial

malocclusion with diastema. B, Postorthodontic treatment and prelaser surg e ry. C, Immediately after laser frenectomy surgery. D, One month after surgery.

by waiting on an impacted tooth to erupt through soft tis­ sue. 3 Traditionally, patients would be referred to a perio­ dontist so that the tooth could be exposed and a bond and chain could be placed for orthodontic traction; however,

an attachment to the tooth and begin moving it into the arch immediately ( Fig. 24-5).3

thick tissue covering the tooth can still impede the tooth

When lasing tissue overlying a tooth, the operator must ad­

from finally erupting into the arch, especially palatal tis­

just the power as needed according to the tissue th ickness. After

sue. The oft-tissue laser can be used to remove thick tissue

applying topical anesthetic, probe the surgical site to locate the

so that th.c tooth can continue to be moved into the arch

tooth and mark the attached tissue. Carefully remove the tis­

without hindrance. Sometimes the impacted tooth is nearly

sue with light, continuous waves until the underlying tooth is

erupted into the mouth; however, a thin layer of tissue still

exposed. After exposure, wipe the area with 3% hydrogen per­

covers its su rface.3 In these cases the laser can be used to re­

oxide with a microbrush or cotton roll. A bond can be placed

move the overlying tissue so that the orthodontist can bond

immediately after tissue removaLS

276

MOSBY'S ORTHODONTIC REVIEW

A B

FIG 24-5 Uncovering of an impacted canine. A, Impacted canine before laser surgery. B, Canine immediately after laser surgery. C, Postsurgery orthodontic activation.

REFERENCES 1 . Sarver OM: Principles of cosmetic dentistry in orthodontics.

I . Shape and proportionality of anterior teeth. Am j Orthod

Dentofacial Orthop 2004;126:749-753.

2. Sarver OM, Yanosky MR: Principles of cosmetic dentistry in orthodontics. 2. Soft tissue laser technology and cosmetic gingi­ val contouring. Am f Orthod Dentofacial Orthop 2005; 1 27:85-90.

3. Sarver DM, Yanosky MR: Principles of cosmetic dentistry i n orthodontics: Part 3 . Laser treatments for tooth eruption and soft tissue problems. Am ] Orthod Dentofacial Ortlrop 2005; 1 27: 262-264. 4. Yanosky MR: The soft-tissue las er: managing treatment and enhancing aesthetics. Available at: OrthodonticProductsOnline. com, August 2006. 5. ZAP lasers.Orthodontic laser procedures guide. Available at: www.zaplasers.com.

Secrets in Computer-Aided Surgical Simulation for Complex Cranio-Maxillofacial Surgery

C

ranio-maxillofacial (CMF) surgery is an encompassing term that involves the treatment of diseases, injuries,

2. What are the current planning methods for CMF surgery?

and deformities of the skull and face. CMF deformi­

CMF surgery requires extensive presurgical planning because

ties can be either congenital or acquired and include dento­

of the complex nature of 3D anatomy of the skull and face. The

facial deformities, congenital deformities, defects after tumor

current methods used to plan CMF surgery vary according to

ablation, posttraumatic defects, and deformities of the tem­

the type of surgery being planned but are not much different

poromandibular joint (TMJ). CMF surgery requires extensive

from the methods that are used to plan simple orthognathic

presurgical planning because of the complex nature of three­

surgery.

dimensional (3D) anatomy of the skull and face.

1 . How many patients with CMF deformities are in the United States?

I n general, current surgical planning methods for complex CM F deformities involve the following steps. The first step is to gather data and quantify the deformity from ma11y different sources, including physical examination and anthropometric

I n the United States, it is estimated that 1 7 million indi­

measurement, medical photographs, medical imaging studies

viduals aged 1 2 to 50 years ( 1 8% of this population) have

(cephalometric radiographs and analysis, computed tomog­

malocclusions that are severe enough to warrant surgical

raphy [CT], etc.), and plaster dental models when the surgery

correction.1•4 In addition, congenital anomalies of the CMF

involves the jaws. The second step is to simulate the surgery,

skeleton affect a large number of children. The most com­

including prediction tracings, plaster dental mudd surgery, or

mon congenital anomalies include cleft lip and palate (over

CT-based physical model surgery. The last step in surgical plan­

(343-476 per I

ning is to create a way of transferring the surgical plan to the

million live births6), and hemifacial microsomia ( l per 5600

patient at the time of the surgery. This is usually done by creat­

3.6 in

1 000 live births5), craniosynostosis

live births5). A majority of these patients will require surgery.

ing surgical splints, templates, measurements of the bone move­

Additional CMF deformities also occur after tumor ablation

ments, or visual "clues."

and trauma. Treatment for head and neck tumors often re­ sult in significant deformities that require reconstruction.7•11 The incidence of head and neck cancer is 9.7 per 100,000 Americans. This translates into 28,000 new patients every year, which does not include patients with benign tumors who also may require surgcry.9 It is reported that nonfatal injuries from trauma affect 28 million Americans ( 10% of

3. Why are the current planning methods often not adequate for planning complex

CMF surgery?

ISSUES WITH TWO-DIMENSIONAL PREDICTION TRACINGS

the population) annually, IO ·with 37% suffering injuries in­

The CMF surgery is usually simulated using prediction tracings.

volving the head and face . 1 1 A significant number of these

The tracings are made from the cephalometric radiograph by

patients will also require surgical treatment. Finally, 5% to

outlining the bones and soft tissues onto an acetate paper.LS,I6

1 5% of the population is reported to have symptoms ofTMJ

The outlines of the bones to be moved arc drawn on additional

disorders, with peak prevalence i n young adults ( 20-40 years

sheets of acetate paper. The surgical simulation is completed by

of age).12·�3 Although the majority of these patients do not

moving the bone tracings to the desired position. The predic­

need surgical treatment, patients with TMJ ankylosis, severe

tion tracings can also be completed by computerized software.

rheumatoid arthritis, or osteoarthritis may require TMJ re­

A significant drawback of prediction tracing is that it is two­

construction. I t is estimated that about 3000 prosthet ic joint

dimensional (2D). 1 7•20 Patients' 3D anatomic structures are

replacements are performed each year, 14 as well as a similar

compressed at the mid-sagittal plane to a 2D cephalometr ic

number of autogenous reconstructions.

radiograph. It also creates a significant overlap of right and left

278

MOSBY'S ORTHODONTIC REVIEW

structures. Prediction tracings may be clinically acceptable if the patient has only anteroposterior (AP) or vertical deformity. However, with this technique, it is impossible to simulate sur­ gery in the three di mensions, which is essential in patients with 3D problems (i.e., asymmctries) . 21 •22 Another problem with prediction tracings is that they portray the dentition as a 2D image.21•23 For this reason, surgeries that involve the dentition should also be simulated on plaster dental models that have been mounted on an articulator. IS. Io,24

because the CT image data, from which the models are built, are unable to accurately render the teeth and are also subject to artifacts. A11 additional plaster dental model surgery is still necessary to establish a new dental occlusion and to fabricate surgical splints. Another disadvantage is that it is il)1possible to simulate different surgeries on a single model. Once the model is cut, it is impossible to undo the cut.

ISSUES WITH CT MODELS

Surgeries that involve the teeth are also simulated on plaster den­ tal modcls.15·16•24 The purpose of tJ1is step is to establish a new dental occlusion and to fabri01te surgical splints. The splint helps the surgeon establish the desired relationship between maxilla and mandible. A drawback of plaster dental models is that they do not depict the surrounding bony structures.23•26 Therefore, it is impossible for the surgeon to visualize tJ1e skeletal changes that occur during model surgery, which is criti01l in the treat­

Three-dimensional CT scans have been successfully used to visualize and quantif)' the patient's condition. However, they have not been successfully used for surgical simulation because of two major reasons. First, the CT docs not render the teeth with the accuracy that is necessary for surgical simulation.2I .23 Also, raw CT data are presented by a sequence of2D cross-sec­ tional images of the vol um e-of-interest, layer by layer. During the 30 reconstruction, the missing data between adjacent lay­ ers are reconstructed by mathematical algorithms (e.g., March­ ing Cubes25). Currently, the most precise 3D CT scanners scan at a minimum slice thickness of 0.625 nun. At this thickness, although they are adequate for bony structures, they arc not capable of accurately reproducing the teeth to the degree that is necessary for surgical planning. The occlusion between maxil­ lary and mandibular teeth requires a high degree of precision. Even a 0.5 mm error may cause malocclusion. Furthermore, it is very difficult, if not impossible, to remove artifacts, which is the scattering caused by orthodontic brackets or dental metallic re storations . Because of these limitations, smger ies that involve the teeth are still simulated on plaster dental models.t5.l6•24 With the fast development of cone-beam CT technology, the scanning slice thickness is reduced to 0.2 mm. lt also has a bet­ ter control on tJ1e artifacts. Radiation exposure to the patient� has been significantly reduced. The cone-beam CT scanner has become a favorite gadget for orthodontists and dentists. How­ ever, in the treatment of com plcx CM F deformity, the surgeons want to see the "true" replica of CM F bones. The images from cone-beam CT have relatively lower contrast compared with regular medical CT images. This makes the segmentation pro­ cess (to separate the bones from soft tissue on the CT image) rather diflicult. After 3D reconstruction, it is common to ob­ serve that the anterior walls of the maxillary sinus or orbital floors are "mystically" missing on the 3D model. Although the artifacts produced by cone-beam CT are minimal, the rendi­ tion of the teeth is still inappropriate for simulating the final occlusion or for making the surgical splints.

ISSUES WITH CT-BASED PHYSICAL MODELS Another means of simulating surgery is to use CT-based physi­ cal models produced by rapid prototyping techniques (e.g., stereolithography apparatus [ SLA] models). Even though these models are useful, they have a number of disadvantages. One disadvantage is that in cases involving the occlusion, the teeth are not accurate enough for precise surgical simulation. This is

--

ISSUES WITH PLASTER DENTAL MODEL SURGERY

ment of complex CMF deformities. Finally, there are t-.vo major

issues regarding the usc of plaster dental model surgery. Issues with Face-Bow Transfer The ability of the surgeon to transfer the desired surgical plan to the patient during orthognathic surgery depends mainly on the accuracy of the surgical plint. The fabrication of an accu­ rate splint requires that the models be mounted to replicate the position of the patient's dentition. However, Ellis et al.24 dem­ onstrated a significant difference between the inclination of the occlusal plane on the mounted models and the actual occlusal plane as measured on the cephalograms. Another study27 shows

that tJ1e average occlusal plane inclination using the SAM Ana­ tomical Face-Bow was 7.8 ± 4.2 degrees, statistically significant greater than the actual. The mean occlusal plane inclination of the models obtained using the Erickson Surgical Face-Bow was 4.4 ± 2.2 degrees statistically significant greater than the actual. The advantage of using models that are accurately oriented to Frankfort horizontal becomes evident once the implications of using inaccurately mounted models are understood. fig. 25-l illustrates the results of using inaccurate models to fabricate an intermediate splint. Fig. 25- 1 , A, depicts tJ1e cephalometric tracing of a hypothetical patient with mandibular prognathism and maxillary hypoplasia. The surgical plan for this patient calls for a 10 mm maxillary advancement and a 4 mm man­ dibular setback. In this case, the axis-orbital plane (face-bow) is 1 2 degrees off the Frankfort horizontal. Fig. 25- l , A, depicts the articulator on which the models have been mounted using the conventional system. The occlusal plane inclination of the mounted models (Fig. 25-1, B) is 12 degrees greater than that on the cephalometric tracing (see Fig. 25- 1 , A). ln Fig. 25- 1 , C, the maxillary model has been advanced 1 0 mm forward, and the intermediate splint has been fabricated. Fig. 25- l , D, de­ picts the ptanned position for the maxilla and the actual posi­ tion of the maxilla at the time of surgery. In this hypotJ1etical case, the position of the maxilla at surgery is 1.5 rnm behind the planned position, producing a maxillary advancement of only 8.5 mm, or 15% less than desired.

--- ----

Secrets in Computer-Aided Surgical Simulation for CompJex Cranio-Maxillofacial Surgery • CHAPTER 25

A

B

c

D

279

FIG 25-1 Face-bow transfer in a hypothetical patient. A, Prediction tracing in a hypothetical patient. The horizontal line in black is Frankfort horizontal. The red line is the axis-orbital plane, which is 1 2 degrees off Frankfort horizontal. The plan calls for a 1 0 mm maxillary advancement (blue line). B, The models mounted on an articulator. Note that the occlusal plane inclination of the mounted models is 1 2 degrees steeper than the actual occlusal plane. C, Model surgery. The maxillary model has been advanced 10 mm, and the intermediate splint (red) has been fabricated. D, The maxillary position at surgery. The blue outline represents the desired position for the maxilla. The red outline represents the actual position at surgery. Note that the actual position is 1 .5 mm behind the desired position.

In order to solve this problem, researchers and clinicians have developed various techniques. Ellis et al.24 developed a modified mounting technique used with Hanau articular. Gateno et aL27 also developed face-bow transferring technique used ·with SAM articulator that takes the individual anatomic variations among subjects into consideration. Issues with Mandibular Autorotation

Predictable outcomes in double-jaw surgery depend on pre­ cisely positioning the maxilla. This is important, not only be­ cause an ideal maxillary po ilion is necessary to achieve good mid-faci<Jl aesthetics, but also because the ultimate position for the mandible depends on ir. The first step in double-jaw surgery is to place an exter­ nal reference marker (e.g., a K-wire or a screw) in the na­ sal bones. The vertical distance between this marker and the edges of the maxillary incisors is recorded. This measurement

will help establish the correct vertical position for the maxilla. In double-jaw surgery, the maxilla is usually cut first. l n order to position the maxilla at the time of the surgery, surgeon� use an intermediate surgical splint that determines the AP and transverse position of the maxilla as well as any desired rota­ tions in space. The intermediate splint is temporarily placed between the ostcotomized maxilla and the mandible, and the teeth arc wired in this position. The vertical position of the maxilla is then determined by autorotating the maxillo­ mandibular complex to a predetermined vertical position, using the pre-determined distance between nasal marker and inci or edges as reference. Once the maxilla is in place, the dental fixation is released and the mandible is osteotomized and positioned according to the position of the maxilla. The splint is fabricated prior to surgery using plaster dental mod­ els, which have been mounted on an articulator. Articula­ tors arc mechanical devices that simulate the movement of

280

MOSBY'S ORTHODONTIC REVIEW

the mandible. They are based on the principle that during

in simple orthognathic surgery cases because of limited surgical

opening and closing of the mandible in its most retruded po­

movement, this unplanned displacement can be significant in

sition (centric relation), the condyles rotate around a hinge axis (hinge axis theory). 28•32 However, recent studies show

complex and asymmetric deformities. In patients with hemifacial

that during mandibular opening, translation and rotation are

(occlusal cant) is commonly encountered. Fig. 25-2.,

always continuous and combined.33-35 Even for the first mil­

the cephalometric tracing of a hypothetical patient with hem ifa­

microsomia, a discrepancy of 5 to

10

mm in the occlusal plane

A, depicts

limeter of mouth opening, the condyles actually follow a path

cial microsomia. To correct a 6 mrn occlusal cant, the interme­

(combined rotation and translation), rather than rotating

diate surgical spl int can often be thicker tl1an

around a single poi nt.30•36•37 Because the mandible also slides

in at least

forward during autorotation, the maxillo-mandibular com­

In this case, tlle actual maxillary position after surgery is anteri­

plex will also move forward accordingly. Unfortunately, cur­

orly displaced

rent dental articulators are unable to simulate these complex movements. Therefore, traditional surgical planning, which uses semiadjustable articulators to simulate surgery and fab­ ricate the intermediate surgical splint, frequently results in unplanned displacement of the maxilla in the AP dimension.

20

20 mm and result

mm of mandibular autorotation ( Fig.

5 mm

in tlle AP direction (Fig.

25-2, B).

25-2, C).

Issues with the Transfer of the Surgical Plan to the Patient at the Time of the Surgery The last step in surgical planning is to transfer the surgical plan

Clinically, the authors have noted that although the amount

t.o the operating room. In cases involvi ng the jaws, this i s done

of unplanned maxillary AP displacement can be relatively small

using dental splints.15•16 These splints help the surgeon place

:vertical

8

c

FIG 25-2 A hypothetical pat ient with hemifacial m icrosomia. A, Cephalometric tracing of a hemifacial microsomia case. B, Autorotate the mandible in order to co rrect the cant and make an intermediate splint. C, Unplanned 5 mm maxillary and mandibular advancement. The solid black line represents the desired maxillary position; the red dotted line represents the actual outcome with unplanned 5 mm anterior displacement.

Secrets i n Computer-Aided Surgical Simulation for Complex Cranio-Maxillofacial Surgery

•

281

CHAPTER 25

the jaws in the desired position. However, for the craniofacial

measurements. The third step is to simulate the surgery in the

cases that do not involve dentitions (e.g., orbital osteotomies,

computer. The final step of the CASS is to transfer the com­

cranial vault reshaping), surgeons currently do not have an ac­

puter surgical plan to the patient.

curate method of transferring the plan to the operating room. Certain measurements taken during the planning process can be used to guide surgery, but most commonly the placement of the bones in the desired position is more an art than a science.

5. How do you create a computer model that is adequate for planning a CMF surgery? If the surgery does not involve teetll, the conventional 3D CT model can be used for surgical planning. However, if the sur­

HOW TO SOLVE THESE ISSUES?

gery involves teeth, as mentioned previ ously, tile conventional

The success of CMF surgery depends not only on the surgical

CT model does not present the teeth accurately to the degree

techniques, but also upon an accurate surgical plan. Because of

that is necessary for surgical planning. Therefore, a compos­

the problems mentioned previously, it is evident that the cur­

ite skull model17•2 1.51 is required. This model simultaneously

rent methods used to plan CMF surgery are often inadequate.

displays an accurate rendition of botll the bony structures and

In addition, in many cases these methods are known to produce

the teeth.

unwanted outcomes. Moreover, the whole planning process is

In order to create a composite skull model, a bite-jig is first

tin1e consuming.38 An experienced surgeon frequently spends

created (Fig.

4 to 6 hours to complete the surgical plan and to fabricate the

dental casts to each oilier and to support a set of fiducial mark­

25-3, A). It is used to relate the upper and lower

splints. Finally, the cost of planning a complex case, both in

ers, which are used to register the digital dental models to the

time and in resources, can be fairly high.38

3D CT skull model. To facilitate the fabrication of the jig, self­

The need to improve the current surgical planning methods

curing mctllyl methacrylate material is directly placed between

has led researchers to develop a more sophisticated planning

the maxillary and mandibular teeth to create a bite registration

method for CMF surgery (i.e., computer-aided surgical simu­

in centric relation. Each jig incorporates four fiducial marker

lation [ CASS] ). CASS has wide applications in maxillofacial I9 39 44 surgery, . · craniofacial surgery,20.45 trauma, and distrac­

second premolars. The supporters are arranged in various

tion osteogenesis.20•46·50 Using CASS, surgeons can perform " "virtual surgery and create a 3D prediction of the patient's

set of CT-compatible fiducial markers is inserted into the sup­

supporters, which are placed buccal to the lateral incisors and planes in order to maximize the accuracy of the registration.

A

surgical outcomes as if they are performing surgery in the op­

porters at the time of tile CT scanning so they can be captured

erating room.

without scattering by the CT scanner (see Fig. 25-3,

4. What are the basic steps of CASS to plan a CMF

surgery? CASS is to create

skeleton is obtained while the patient is biting on the bite-jig (Fig.

There are four major steps in the CASS. The first step

of ilie

3D computer models of volume-of-interest. 3D and 2D

The second step is to quantify the deformity using

A ) . After

the bite-jig is created, a CT scan o f the patient's craniofacial

25-3, B and C). Thereafter, the digital dental models are

created by scanning the plaster dental models in a very high resolution scanner and

E).

(0. 1 5

mm or more accurate) (Fig.

Using the fiducial markers, the "bad" teeth

FIG 25-3 The creation of the computerized composite skull model. A, Bite-jig was created with fiducial CT/MRI-compatible fiducial markers. B, The patient was biting on the bite-jig with fiducial markers during CT scan. C, Three separate but correlated computer models were reconstructed: a midface model, a mandibular model, and a four-fiducial­ marker model. D, The bite-jig with fiducial markers was placed between the upper and lower plaster dental models during the scanning process. E, Three separate but correlated computer models were also reconstructed: an upper digital dental model, a lower digital dental model, and a four-fiducial-marker model. F, The computerized composite skull model simultaneously displayed an accurate rendition of both the bony structures and the teeth. (From Gateno J, Xia JJ. Teichgraeber JF, et al: J Oral Maxillofac Surg 2007;65(4):728-734.)

on

25-3, D the CT

282

MOSBY'S ORTHODONTIC REVIEW

skull model are removed and replaced by the "good" teeth from the digital models. This results in a computerized composite skull model that simultaneously displays an accurate rendition of both the bony structures and the teeth (Fig. 25-3, F). 6. How do you plan the surgery using CASS techniques?

The composite skull model is initially prepared (pre-cut) to simulate various osteotomies. As an example, they may include a Le Fort l osteotomy, a sagittal spli t osteotomy, an inverted "L" osteotomy, or a genioplasty. After the model is prepared, the surgeon is able to move the bony segments to the desired position and rotate each bony segment around a pivot point according to quantitative guidance and the surgeon's visual judgment. Once the bony segments are i n the desired location, the simulated outcomes and surgical movements are recorded. Usi ng CASS, the surgeon is able to sim ul at e a number of diffe r­ ent surgical treatments in order to create the most appropriate surgical plan. 7. How do you transfer the computerized surgical

plan to the patient at the time of the surgery? �

----

-

-

The final step of the CASS is to transfer the computer surgi­ cal plan to the patient. In order to accomplish this, surgical dental splints and templates are created using computer-aided

A

B

designing/computer-aided manufacturing techniques.1 7,5l ,S2 Jn surgeries that involve the teeth, surgical dental splints arc created by a computational process after inserting a digital wa­ fer between the maxillary and mandibular dental arches (see Fig. 25-4, A). l n surgeries that do not involve the t�cth, digital templates can be created (Fig. 25-4, B). They arc used during surgery to help the surgeons achieve the desired results. The templates record the 30 surface geometry of the area of inter­ est so that the template fits on the bone in a unique position. The digital splints and templates are then sent to a rapid proto­ typing machine to fabricate physical splints and templates (see Fig. 25-4, C and D) . They can then be sterilized and used at the time of the surgery (Fig. 25-4, E and F). In surgeries that involve bone graft, the computerized mir­ ror-imaging technique is used to mirror image the geometry from the healthy side to the defect side. The mirrored image f1om the healthy side is then superimposed over the defect side (Fig. 25-5, A ) . The difference of geometries between the two sides is computed, resulting in a digital bone graft template (Fig. 25-4, B). Using rapid prototyping machines, the digital templates are fabricated to physical templates (Fig. 25-5, C) that are used during surgery to sculpt autogenous bone (Fig. 25-5, D) to precisely replace the m issing bone (Fig. 25-5, E). If desired, the d igital templates can also be used to directly fabri­ cate implantable implants.

c

D

F

FIG 25-4 Surgical dental splints and templates are created using computer-aided designing/ computer-aided manufacturing technique. A, Digital surgical S£1int . B, Digital chin template. C, Physical surgical splint. D, Physical chin template. E, The use of physical surgical splint at the time of the surgery. F, The use of physical chin template at the time of the surgery. (From Gateno J, Xia JJ, Teichgraeber JF, et al: J Oral Maxillofac Surg 2007;65{4):728-734.)

Secrets in Computer-Aided Surgical Simulation for Complex Cranio-Maxillofacial Surgery • CHAPTER 25

283

A

c

E

D

FIG 25-5 Surg1cal planning of onlay bone grafting. A, A mirror image of the unaffected side was created. It was superimposed over the affected side. B, A digital template that depicted the differences between the mirror image and the affected side was created. C, A physical form of the same template was fabricated. D, Autogenous bone was harvested and sculpted according to the shape of the template. E. The sculpted autogenous bone graft precisely replaced the missing bone. (From Gateno J, Xia JJ, Teichgraeber JF, et al: J Oral Maxillofac Surg 2007;65{4):728-734.) Finally, a physical model with the planned outcome can be

preoperative,

fabricated for pre-bending the bone plates that are used in the

shown i n Fig.

planned,

and

postoperative outcomes are

25-7.

25-6). This wlll not only improve the accuracy of

The ideal surgical plan is the one that can be reproduced

the operation, but also reduce the total operative time by elimi­

accurately i n the operating room. A recent published study

nating the need to bend these plates at the time of the surgery.

evaluated the accuracy of CASS i n the treatment of patients

surgery (Fig.

8. What is the accuracy of using the CASS method in complex CMF surgery? Fig.

25-7

the planned and the actual postoperative outcomes was within

ill ustrates a typical patient that is best treated using

CASS. The patient suffered TMJ ankylosi s caused by a left ear infection at the age of

with complex CMF deformities.s3 This pilot study showed, with CASS planning, that the largest linear difference betvveen

5. He was treated by arthroplasty and

costochondral graft . Although the arthroplasty was success­ ful, the costochondral graft and the left face failed to grow. The practitioner used the CASS planning method. The com­ puter-generated surgical splints and templates were used to transfer the computerized surgical plan to the patient at the

1 .99 m m and the largest median of the linear difference was 0.85 mm. The largest angular difference between the planned and the actual postoperative outcomes was limited \-vith i n 3.48 degrees and the largest median of the angular difference was I . 70 degrees. 9. What is the cost-effectiveness for using the CASS?

of the su rgery. The osteotomized maxilla was positioned

A recent published study compared the costs and benefits be­

using the computer-generated i ntermediate splint. The man­

tween using CASS and the current surgical planning meth­

fix­

ods for complex CMF surgery.38 The comparison of methods

time

dible and chin were then osteotomized, repositioned, and

ated by m i n i-plates. Bone grafts were harvested and carved

applies to all CMF surgeries where the patient's condition is

according to the planned size and shape. Six-week postop­

severe enough to undergo a CT scan and an SLA model is nec­

erative CT scans showed the surgical plans were precisely

essary for the surgical planning process. The study showed that

reproduced in the operating room and the deformities were

CASS has lower costs in terms of surgeon time, patient time,

corrected as planned. The comparison chart of the patient's

and material costs. Specifically, total surgeon hours spent in

284

MOSBY'S ORTHODONTIC REVIEW

FIG 25-6 A physical model of the planned outcome is fabricated and used to pre-bend the bone plates that will be used in the surgery. A, Pre-bend the bone plates based on a physical model of planned outcome and bone graft. B, Adopt the pre-bent bone plates at the time of the surgery. (From Gateno J , Xia JJ, Teichgraeber JF, et al: J Oral Maxillofac Surg 2007;65(4):728-734.)

Pre-OP

Post-OP

Pre-OP

Planned

Actual Post-OP

FIG 25-7 Comparison chart of a patient's preoperative, planned, and postoperative outcomes. (From Gateno J, Xia JJ, Teichgraeber JF, et al: J Oral MaxHiofac Surg 2007;65(4):728-734.)

planning arc 5.25 hours compared with 9.75 hours for cur­ rent standard methods. Material and scanning costs are $ 1 900 for CASS compared with about $35 1 0 for standard methods. Patient time for planning is reduced from 4.75 hours to 2.25 hours with CASS. The reduction in both time and other costs remains when the up front costs of CASS are added to the vari­ able costs. Amortized across the 600 patients per year ( 1 800 for the assumed 3-yea.r life of the training and software), this adds only a few dollars and a fraction of an hour per surgery. Even in the case of a small clinic when the cost is amortized for 6

patients per year ( 1 8 patients for the assumed 3-year life of the training and software), the per-surgical costs (9.65 hours and $2456) will still favor CASS. 10. What other method can be used to transfer the computerized plan to the patient at the time of the surgery? Surgical navigation is an alternative tool to transfer the com­ puterized surgical plan to the patient at the time of the surgery. The navigation system is similar to a car global positioning

Secrets in Computer-Aided Surgical Simulation for Complex Cranio-Maxillofacial Surgery • CHAPTER 25

285

FIG 25-8 Navigation emitters consist of patient tracker (A), navigation pointer (B), instrument tracker (C), and, calibration station (D).

Detector

FIG 25-9 A unique link is generated between the detector and the emitters after the registration process.

system (GPS). It consists of a computer, a monitor, a set of cameras (like the satellites), and a series of navigated instru­ ments (like the GPS handheld). The navigated instruments in­ clude a patient tracker (Fig. 25-8, A), a navigation pointer (Fig. 25-8, B), an instrument tracker (Fig. 25-8, C) and a calibration station (Fig. 25-8, D). The navigated instrument (i.e., a patient tracker mounted on the patient's skull) emits infrared signal of the x, y, and z coordinates to the cameras (Fig. 25-9). Once the cameras receive these signals and send them to the computer, a unique link is established between the camera and the instru­ ment (see Fig. 25-9). Therefore, the position ofthe patient's head can be tracl<ed down by the patient tracker. Equally, the posi­ tion of both surgical instrument and pointer can be tracked by the instrument tracker. The calibration station (see Fig. 25-8, D) is a special type of the emitter. It calibrates the position of the instrument's tip to the instrument tracker. Virtually any kind of surgi cal instrument can be calibrated by the calibration

station and instrument tracker. Finally, the monitor displays the sagittal, coronal, axial, and 3D views of the CT image, as well as the location of the navigated surgical instruments (Fig. 25- 10). This technology has been proven accurate, with a precision ranging from 0.2 to 1.1 mm.47•54·56 Surgical navigation also of­ fers an improved spatial representation of complex surgical environments, helping the surgeon to respect vessels, nerves, external and middle ear or middle cranial fossa.48·57•58 However, navigation technology requires the installation of cameras and sensors followed by registration. This extra step may prolong the surgery in comparison to the use of surgical splints and templates. Another disadvantage is the cost of the navigation system. An additional staff member is also required during the surgery for the manipulation of the computer. Therefore, the indication of using surgical navigation technology is crucial. The authors reserve this technology to the surgery in which the

286

MOSBY'S ORTHODONTIC REVIEW

�IG 25-10

The navigation monitor displays the sagittal, coronal, axial, and 3D views of the CT 1mag�, as well as the location and trajectory of the navigated surgical instruments. The resection marg1ns have also recorded in the navigation computer, forming a computerized surgical plan.

use of surgical spl ints and tem plates is general ly not feasible.

7.

These surgeries usually involve the area that has less significant s ur face geometry or li m ited s ur gical exposure (i.e., reconstruc­ tion of complex post-traumatic deformities of the midface45 or

TMJ ankylosis. 17·59,60

8.

REFERENCES l . Nationa l Center for Health Statistics, Third National Health and Nutrition Examination Survey (N HANES Ill, 1988-1994). H ya ll�vWe, MD: :-Jational Center for Health Statistics, 1 996. 2. Proffit \VR, Fields HW Jr, Ackerman JL, et al: Contemporary

9.

orthodontics, edi tion 3. St Louis: Mosby, 2000. 3. Proffit WR, Phillips � Dann CT: Who seeks surgical-orthodon­ tic treatment? lnt 1 Atlt1l1 Orthod Orthognath Surg 1 990;5: !53.

10.

dentofacial deformities population at the University of North Carolina. lnt 1 Adult Orthod Ort110gnath Sr1rg 1997; 1 2: 1 7 1 . 5. Gorlin RJ, Cohen MM, Hennekam RCM, editors: Syndromes of the heJld a11d neck, edi tion 4. New York: Oxford Uni versi ty Press, 200 1 . 6. Cohen MM, MacLean RE: Craniosynostosis: Dingr10sis, evnlrln­ tion, ar1d management, edition 2. New York: Oxford Unjversity Press, 2002.

12.

4. Severt TR, Proffit WR: The prevalence of facial

asymmetry in the

I I.

13.

ational Center for Health Statistics, ational Hospital Dis­ charge Survey: Annual Summary with Detailed Diagnosis and Procedure Data. Vital and Health Statistics series 13, no 1 5 1 . DHHS publication No.(PHS)200 1 - 1 722, Hyattsville, MD: ational Center for Health Statistics, 1 999. American Sociery of Plastic Surgeons, National Plastic Sur­ gery Statistics: Cosmet ic and Reconstructive Patient Trends (2000/200 I /2002). American Society of Plast ic S urgeons, 2000/200 1 /2002. Cancer Statistics Branch, SurveiUance Re�earch Program, _ Nat1onal Cancer Institute SEER"Stat Software (www.scer.cancer. gov/seerstat), version 5.0.20. Bethesda, MD: 1\:ational Cancer Institute, April, 2003. WISQARS: OveraU injury causes: nonfatal injuries and rates per 1 00,000 (2001 -2002, United States). Atlanta: Natjonal Center for Injury Prevention and Control, 2003. T icknon L: Trauma Statistics. M inneapolis, MN: Trauma Regis­ try, Hennepin Coun ty Medical Center, 2003. I'\ II I Office of Medical Application of Research: :-Jational Insti­ tutes of Health Technology A��es�ment Conference on Manage­ ment ofTemporomandibular Disorders, Bcthe�da, Maryland, April 29-May I , 1 996. Proceedi ng�. Oral Surg Oral Med Oral Pathoi Oral Radio/ Endod 1 997;83:49. :-Jational lnstitutes of Health: Management of temporomaJldibular disorders. National Institutes of Health Technology Assessment Conference Statement. 1 Am Dent Assoc 1 996; 1 27: 1595.

Secrets in Computer-Aided Surgical Simulation for Complex Cranio-Maxillofacial Surgery • CHAPTER 25 14. Cowley T: Numbers of p atient undergo TMJ reconstruction

annually. Personal communication, 2003. 15. Bell WH, edit or: Surgical correction ofden tofacial deformities. Phi ladel ph ia : WB Saunders, 1 980 . 16. Bell \.VI !, editor: Modem practice i n orthognathic and reconstruc­ tive surgery. Ph iladel phia : WB Saunders, 1992. 17. Xia JJ, Gateno }, Teichgraeber JF: Three-dimensional com p uter­ ai ded su rgica l simulation for maxillofacial surgery. Atlas Oral Maxillofac Surg Clin North Am 2005;13:25. 18. Papadopoulos MA, Ch ristou PK, Athanasiou AE, et al : Three­

39. Altobelli DE, Kikinis R, Mulliken )B, et al: Com puter-ass i sted

t hree-dimensional pl ann ing in cran i ofacial surgery. Plast Recon ­

str Surg 1 993;92 : 5 76.

40. Vannier MW, Marsh JL, Warren ]0: Three dimensional CT re­

constr uc tion i mages for craniofacial surgical pl ann i11g and evalu­ ation. Radiology 1 984;150: 1 79.

4 1 . M arsh JL, Vannier MW: The "third" dimension in craniofacial

surgery. Plast Reconstr Surg 1983;71 :759.

42. Xia ), Samman N, Yeung RW, et al: Three-dimensional virtual

dimensional craniofacial reconstruction imaging. Oral Surg Oral Med Oral Pat/wl Oral Radio/ Endod 2002;93:382.

19. Xia j, 1p HH, Samman N, et al: Com puter-assisted three-dimen­

43.

sional s urgical plann in g and sim ula tion: 3D virtual osteotomy. Tnt J Oral Maxillofac Surg 2000;29: 1 1 .

44.

j Craniofac Surg 2003; 1 4:833.

45.

20. Gateno J , Teichgraeber JF, Xia JJ: Three-dimensional s urgical planning for maxillary and mid face distraction osteogenesis. 2 1 . Gateno J , Xia ), Teichgraeber JF, et al: A new technique for the

creation of a comp ute rized composite skull model. I Oral Maxil­

lofac Surg 2003;6 1 :222.

22. Santier G: 3-0 COSMOS: a new 3-D mod el based computerised ope ration simu.lation and navigation system. / Maxillofac Surg 2000;28:287.

23. San tier G: The Graz hem isphere spl in t: a new preci se , non-inva­ sive method of replacing the dental arch of 3D-models by plaster models. J Craniomaxillofac Surg 1 998;26: 1 69. 24. Ellis E 3rd, Tharanon W, Gambrell K: Accu racy of face-bow transfer: effect on su rgical predi ction and postsurgical result. J Oral Maxillofac Surg 1992;50:562. 25. Lorensen WE, Cline liE:

M archi ng cubes: a high resolution 3D

surface construction algor it hm. Comput Graph 1987;21 : 1 63.

26. La mbrech t

JT: 30 Modeling techrrology in oral and maxillofacial

surgery. Chicago: Quintessence, 1995, p p 6 1 .

27. Gateno ) , Forrest KK, Camp B: A comparison of 3 methods of

face-bow transfer recording: i mp licat ions for orthognathic sur­ gery. j Oral Maxillofac Surg 200 I ;59:635. 28. G ran t PG: Biomechanical sign i fican ce of the instantaneous cen­ ter of rotation: the huma n temporo ma ndibu la r joint. J Biomech 1 973;6: I 09.

29. Ru benstein LK, S tra uss RA, I saac son R), et al: Quantitation of

rotationa.l movements associa ted with surgical mandibular ad­

vancement. A ngle Ortlwd 1991 ;6 1 : 1 67.

30. Rekow ED, Speidel TM, Koenig RA: Location of the mandibular center of autorotation in maxillary im pact ion surgery. Am J Or­

thad Dentofacial Orthop 1 993; 1 03:530. 3 1 . Sheppard I M : The effect of the h in ge axis clutches on condyle posi tion. j Prosthet Dent 1958;8:260. 32. Sperry TP, Stei nberg MJ, Gans B): Mandibular movement dur­ ing aut orotat ion as a result of maxillary impaction surgery. Am J Ortlrod 1982;8 1 : 1 1 6. 33. Nager! H, Kubein-M eese nb urg 0, Fanghanel j , et al: Elements of a general theory of jo in ts. 6. General kinematical structure of mandibular movements. A nat Anz 1 99 1 ; 1 73:249.

34.

McMillan DR, McMillan AS: A compa rison of hab itual jaw move­ ments and articulator function. Acta Odonto/ Scand 1986;44:291 .

35. McMillan AS, McMillan DR, Darvell BW: Ce nters of rotation

d uring jaw movements. Acta Odontol Scand 1 989;47:323.

36. Ferrario VF, Sforza C, Miani A )r, et a.l: Open- close movements

in t he hu ma n tem porom andibular joint: does a pure rotation argund th e i ntercondyla r hinge axis exist? f Oral Rehabil 1 996;23:40 I .

37. Hellsing G , Hellsing E, Eliasson S : The h inge axis concept: a ra­

diographic study of its relevance. 1 Prosthet Dent 1995;73:60.

38. Xia JJ, Ph ill i ps CV, Gateno J, et al: Cost-effectiveness ana lysis for

computer-ai ded surgi cal simulation in co mplex cranio-maxil­ lofacia1 surgery. 1 Oral Maxillofac S11rg 2006;64: 1 71!0.

287

46.

real ity surgical plan ni ng and simulat io n workbench for orthog­ nathic surgery. lnt I Adult Orthod Orthognath Surg 2000; 15:265. Xia j, Samman N, Yeung ltW, et al: Com puter-assi sted three- di­ mension al surgi cal plan ing and sim ulation. 3D soft tissu e plan­ ning and p redi ction. lnt j Oral Maxiilofac Surf{ 2000;29:250. Xia J , Tp rrr T, Sam man ;-.r, et al: Three-dimensional virtual-real­ ity surgical pl anning and soft-t issue predi ct ion for orthognathic surgery. IEEE Tratrs TnfTeclmol Biomed 2001 ;5:97. WestendorffC, Gulicher D, Dammann F, et al: Compu ter­ assisted su rgica.l treatment of orbitozygomatic fractures. I Cra­ niofac Surg 2006; 1 7:837. Schicho K, Fi g! M , See mann R, et a l: Accuracy of treatment p lan ­ nin g based on stereo lithograph y in comp ut er a�sisted surgery. Med Plrys 2006;33:3401!.

47. Klug C, Sch icho K, Ploder 0, et al: Poi n t - to-po i nt com p u te r­ assisted na viga tio n for precise transfer of planned zygoma osteotomies from the ste reolithographic model into reality. J Oral Maxillofac Surg 2006;64:550. 48. Heiland M, H aberma n n CR, Sch mel zle R: I ndication s and limi­ tations of intraoperative navigation in maxillofacial surgery. j Oral Maxillofac Surg 2004;62:1059. 49. Gateno J. Teichgraeber JF, Aguilar E: Computer p lan n ing for a st Reconstr Surg 2000; 1 05 : 873 . distraction osteogenesis. Pl 50. Gateno }, A llen ME, Teichgraeber JF, et al: An in vitro study of the accuracy of a new protocol for p la nning distraction osteo­ genesis of the mandible. J Oral Maxillofac Surg 2000;58:985. 5 1 . Gateno j, Teich graeber JF, Xia j: M ethod and apparatus for fab­ ricatin g ort hognat hic surgica l sp li nts (US Pat ent 6,671 ,539). In US PTO Patent Full- Text and I mage Database. U.S. Patent and

Trademark Office, USA, Dec. 30, 2003. Gaten o ] , Xia ], Tcich gracb er ]�, et al: The preci sion of comput­ er-generated surgical spl ints. j Oral Maxillofac Su,-g 2003;61 : 8 1 4 . 53. Xia ]), Gateno ), Teichgraeber JF, et a.l: Accuracy of the com­ p ute r- a ided surgica l simu.lation (CASS) system in the treatment of patien ts with com plex craniomaxi Uo facia J de fo rmity: A pilot 52.

st udy. f Oral Maxillofac Surg 2007;65:248. Hilbert M, Niederdellmann H: Inherent precision of mechanical, infrared and l ase r- guided navigation systems for co mpu ter- assisted surgery. 1 Craniomaxillofac Surg 1 997;25: 192. H assfeld S, Muh.ling J: Navigation in maxillofacial and craniofa­

54. Marmu.lla R,

55.

cial surgery. Compr1t Aided Surg 1998;3: 183.

56. Husstedt II, H ee rm an n R, Recker TT: Con t ribu tio n of l ow-dose CT-scan p rotocol s to the total p osi t i on i ng error in com pu ter­ assisted surgery. Comput Aided Surg 1 999;4:275.

57. Gellrich NC, Schramm A, Hammer B, et al: Computer-assisted

second ary reconstruction of unilateral posttraumatic orbital de­

formity. Plast Reconstr Surg 2002; 1 1 0: 1 4 1 7. 58. Smith JA, Sand.ler NA, Ozaki WH, et al: Subjective and objec­ tive assessment of the temporalis myofascial flap in previousl y operated temporomandibular joints. / Oral Maxillofac Surg 1999;57: 1058.

59. Bau mann A, Schich o K, Kiug C. et al: Computer-assi sted naviga­

tional surgery in oral and maxillofacial surgery. Atlas Oral Maxil­

lofac Surg Clin North Am 2005; 1 3:4 1 .

60. M a lis 0, Xia J j , Gate no J , et al: New p rotocol for 1 -stage treat­

ment ofTMJ ankylosis u si ng su rgical navigation. j Oral Maxil­

lofac Surg 2007;65(9): I 843 .

\

A Aberrant condylar proce>s, 253 Achondroplasia, 25 t

Adults (Contirwed) illustration, 207f

Acrofacial dyostosis, 251

initiation, 206

Acrylic blocks, trimming, 143f

retention considerations, 2 1 1

Acrylic body, 267

sequence, 201l

Acrylic chin cup, head strap attachment, t43f

orthognathic surgery, consideration

Acrylic splint 1\.'vtE appliance, 140f

periodontal disease, presence, 206

Activation force (enhancement), steel ligature (usage), 88£

treatment

Acrylic maintenance plate, occlusal view, !44f

(timing), 2 1 1

adolescent treatment, contra�!, 206

Active clip, activation, 92f Active molar uprighting, 194 Active self-ligating bracket, definition, 87 Active springclip forces wire, 88f Acute nasolabial angle, 42f Adolescence AP maxillomandibular relation�hips, change (expectation). See Caucasians 7

bony chin, remodeling (extent), 8 condylion, growth/remodeling (expectation), 8

entry, age. See Children 2

facial heights, sex differences, 6 gonion, growth/remodeling (cxpcctation), l:l growth spurt, initiation, 2 lip length/thiclmess, change (extent), 9 ma11dibular arch depths, change, 5 mandibular incisor eruption, extent, 4 mandibular size/position, sex differences, 7 maxillary arch depths, change, 5 nose (shape), change (process), 9

soft-tissue facial profile, change. Sef' 9

untreated mandibular intermolar widths, change, 4 untreated maxillary intermolar widths, change, 4 Adolescents

Class II dental malocclusion, prevalence, 3

options, 208 Advancement genioplasty, 213-214f

soft-ti•suc proftle, change (process), 10 upper lip length, occurrence, J O Adults Class

Jt dental malocclusion, prevalence. See Young adults 3

Class I l l patients (treatment), extraction patterns (consideration), 202

Class IT patient (treatment), extraction patterns (consideration), 201

comprehensive orthodontic treatment, indication, 2 1 0 compromised maxillary/mandibular dentition, teeth loss (impact), 222f growth patterns, 1 muhidiscipliilary treatment, 204 orthodontic tooth movement (initiation), periodontal therapy (usage), 207

orthodontic treatment, t 97 comraindication�. 206

dentist, involvement, 204 goals, 206

composite initial photographs, 76-77f definition/significance. See Teeth 19 final cephalometric tracing, 76 77( final panoramic radiograph, 76-77f initial cephalometric tracing, 76-77f initial panoramic radiograph, 76-77f

Air-powder polishing system, comparison, 240

Air rotor stripping (ARS), 268 Airway analysis, 48 Alcohol embryopathy, 251

Aligners, elements (weaknesses), 150 Alignment, clinical examination criterion, 270 Alprazolam (Xanax), 262-263 Alveolar bone heights/volume, assessment, 48

Alveolar crest, distance. See Permanent teeth 23

Alveolar process, dental CT, 233

Alveolar ridge bone grafting, 248f

Anterior CO/CR shift, presence, 58 Anterior crossbite, 58 existence, 192

Anterior deepbite, existence. 59 Anterior dental crossbite correction, 1 79f finger spring>, 179f fixed lingual arch, 179f Anterior discrepancy, 1 2 1

Anterior facial height, compMison. See Posterior facial height 59 Anterior maxillary region, impactions

Alveolus, involvement, 244

(assessment), 49f

Amelogenesis imperfecta, 3 1 f

Anterior nasal spine (ANS), 36

American Association o f Orthodontists Council

Anterior open bites

on Scientific Affairs, 200

American Board of Orthodontics (ABO) Clinical Examination, 270

American Board of Orthodontics (ABO), usage.

correction, 193

digital sucking, impact, 23 existence, 59 ilh1•tration, 255f

See IJiscrepancy index 60; Objective

Anterior retainer wire, 267

Grading System 270

Anterior space

American Dental Association (ADA), gingivitis treatment products, 239 ANB. See A-point, nasion, and B-point 36

mandible rotation, process, 9

l9f; Primary molars 34 case example, 75 composite final photographs, 76-77f

photographs, 76-77f

dentition 4 orthodontic treatment, I

nose, changes, I 0

Ankylosis. See Lower primary second molars

Air powder polishing (APP) system, 240

Analyses, data areas (usage), 27b

treatment, contrast. See Adults I

3D-3T diagnostic summary, 78t treatment, 75

Agenesi.>. See Teeth 35f

compromised maxillary/mandibular

Adulthood

Ankylosed tooth

Anatomic planes, 37

Anchorage. See Direct anchorage; Indirect anchorage 236f control, 62-63

devices, usage. See Mini-screws; Palatal implants 236

analysis, 1 2 1

illustration, t 22f

availability (measurement), 122f requirement, measurement, J22f Anterior tooth arch surplus/deficit, sum, 121 Anteroinferior angle, 38 Anteroposterior (AP), 54 cephalogram, diagnostic tool, 66 discrepancies, 1 3 1 facial proportions, judgment, 198

loosing, 226f

growth, control, I

requirements, 63

maxillomandibular relationships, change (expectation). See Caucasians 7

Andrews, Larry F., 92-93 Angle, Edward Hartley, 52, 83, 83-ll4 Tweed, student, 85 Angle pin/tube appliance, 84f Angle's classification

definition. See Occlusion 1 5

publication, 3 3 Angle's dental classification, basis (repreo;entation), 33

Angle's Dental Cla5!> 1!, divisJOn I malocclusion, 33f Angle's Dental Class 11, division 2 malocclusion, 33f Angle's Dental Class I l l malocclusion, 33f

Angle's Dental Class 1 malocclusion, 33f Angle's Ribbon Arch Appliance, 84f

orthodontic problems, 57

problems, assessment process, 120 skeletal measurements, 37 Anx:iolytics, usage, 262-263 A0-1:10 illustration, 120f value, 120

Apert syndrome, lSI illustration, 254f

Aphthous ulcers discomfort, 272 lasers, usage, 273f A-point, nasion, and B-point (ANB) angle, 37-38 indication, 57-58

Angle System, 84f

illustration, l20f

Angulation problems, 222[, 223f

value, 120

Page numbers followed by a b, indicate boxes; f, figures; t, tables.

289

290

I N DEX Bionator (Corlliuued)

A point (mbspinale), 36 APP. See Air powder poli�hing 240 A-P plane. Set Sagittal plane 58

Appliance M!lection, 1 2 8 Arche> circumference discrepancy, 32 fonn�. 32f 3D control, 91 f length availability, analysis, 19!!

perimeter>. See Mandibular arch perimeters; .Maxillary arch perimeters 4f change. Su Late primary dentition; Permanent dentition 4 problems, 193 shape, appreciation, 32 spacing, isolated tooth movements (relatiomhip), 194 stabilization, palatal implant (usage), 227f widths, differences. See Class 1'\ormal occlusion 5

I!

malocclusion 5;

Art.h wire friction. See Bracket 89 placement process. See Edgewise appliance 85 role. See Orthodontic tooth movement 89 ;ecuring methocb, Uf Archwire wbcs, soldering, 165

ARS. Sel' Air rotor stripping 268 Arthroplasty, 283

Articulare, 36-37 Articukttor, orthodontic casts (mounting, indications) , 34 A>ymmetric extraction, 1 49f A')'Til metric extract inn pattern�. 134 Asymmetric mandibular setback, 1 87- 1 88f Asymmetric occlusal relationships, das:.iftcation proce;s, 34 A>ymmetry, po>teroanterior cephalometric film, 36f Atrophic ridges, 223f Autogenou� bone, harvestingl�culpting, 283f Auxiliaries, addition, 267 Axillary slot, flexible wire (usage), 85 Average faces, superimposition, 45 Average mandibular alignment scores, 3f

8 Barbiturate�. usage, 262-263 Bcdcwith-WicdematUl syndrome, 251 Begg, Raymond, 84 Begg Appliance, 85f Beta-titanium (TMA) steel wires, difference, 92

/

Bicuspid distali7ation, 160·1 62f Bicuspid extraction, allowance, 134 Bilateral bite blocks, location, 143f Bilateral cleft lip/palate, 244 features, 249 repair, 247f Bilateral landmarks, 36 Bilateral lower molar uprighting, 2 1 Of pomreatment intraoral photographs, 21 Of pretreatment intraoral photographs, 210f

Bimaxillary crowding. See Cla�s II di\��ion I malocclusion 60·63 Bimaxiilary protrusion, 60-63 Riocompatible materials, usage, 83 Biocompatible TAOs, 232f Biocl)l, usage, 140f Biulngical o :..seointegration, 232 flinmechanics, definition, 96 Bionatur appliance, 135f illuwation, 162f intraoral u!>llge, 166-168f usage, 163

onhodontic results. See Post-Bionator re�ult; 166- 1 6!!f results. See Post-Bionator rc�ults 166- 168f treatment. See nlso Close bite 169- 1 73f headgear, usage, 169- 173f u.age. Sl'e Early treatment 24 wax bite registrations, 164 Bite-jig, creation, 281 f Bite �plinL�. 'ub;titute, 150 Black triangle, prc;cncc, 2 12-2 14 Bolton analysis, definition, 33 Bolton ratios, study, 33 Bolton's discrepancy, 150

Bondable adhe>ives, 220 Bonded acrylic splint expander, 140 Bonded expander, 1 4 1 f Bonded fan appliance, 248f Bonded lingual retainer>, retention (considerations), 266 Bonded raptd palatal expander (bonded RPE), 129 frontal 'ie''• 129 130f palatal view, 129-130f Bonding problem>, avoidance, ISO Bonding proce\S, evolvement, 118-89 Bone deposition, creation, 234f Bone graft, surgical involvement, 282 Bone graftmg procedure>, u.age, 207-208 Bone plate,, pre-bending, 284f Bone specimens, histologic examination, 235 Bony chin remodeling, extent. See Adule>cence !!; Childhood 8 �oft tissue covering, 39 Bony defect, observation, 2 1 2 f Boy> craniofacial mea>ure>, relative size, 6f PHV frequency distribution, 2f stature, relative size, 6f B point (supramentale), 36 Brachyfacial photographs, 40-41 f Bradcet arch wire, friction, 89 ba* contammation, impact. See Enamel bonding 93 design�. SEM images, 90f body, wings, pre�ence, llllf construction process, 90. See nlso Direct bonded bracket 89 definition. Sec Double-tube bracket; Single-tube bracket; Spring-wing bracket; Triple-tube bracket !!8 designs, 83 placement, 146 power arm, attachment, 93 prescription, meaning, 87 slot dimension, indication, 89

systems, contra:.\. See full banded btatkel

systems 86 width, defmition. See Inter-bracket width 88 wire interaction, result, I OOf Branchial arch, 251 Bn\nemark, P.l., 220 Broadbent, B. l loUy, 1 2 1 Brodie bite (scissor bite), 59 observation. See Pretreatment 1 2 1 f Bruxism, 150 Buccal corridor�. 40-41 f evaluation, 39 spaces, 55 Buccal crossbi te, 60

Buccolingual inclination, clinical eXJmination criterion, 270 Buccoversion, 42f

c CAD/CAM technology, 146 Calibration station, 2115f Camouflaged Class Ill trt-atment, 184 Canine tipping ( minimization), T attachment (impact), l 49f Canine-to-canine lingual arch, 194 C..ant of the occlusal plane. See Ocdu>al plane 59 Carbon dioxide (C02) laser, 273 Cardio-facio-cutaneou.�syndrome (CFC syndrome), 251 Carpenter syndrome, 251

Case history, usage, 53

CASS. See Computer-aided surgical

simulation 281

Cast. See Posttreatment; Pretreatment l07-109f; Relapse l l l f analysis, areas (significance), 32 occlusals, I 05- 1 06f Cauca,ians (adolescence), AP maxillomandibular relationships (change, expectation), 7 CBCT. See Cone Beam CT 46t Cementoenamel junction (CEJ), constriction, 29-30

Central incisor, mcsioversion. See :Maxilla!)' right central incisor 30f Centrally acting muscle relaxants, 262 Centric occlu>ion (CO), functional shift, 28

Centric relation (CR), functional shifts, 28 Centroid, 262-263 Cephalogram, I 05- 1 06f. Seenlso Posttreatment; Pretreatment; Progress I IOf usage, 208 Cephalometric analysis essentials, 37 hard/soft ti,,ue points, 36 strategy, usage, 58-59 usage, 53 Cephalometric discrepancy, 1 2 1 Cephalometric findings, 66 Cephalometric radiographs applications. See Lateral cephalometric radiograph 36 diagnostic reference

plane;/mea>uremenL�. 37f usage. See Landmarks 36f Cephalometries, usage, 1 5 2 Cephalometric tracing. See Final cephalometric tracing; Initial cephalometric

tracing 6 1-62f Ceramic bracket, definition, 93 Ceramic In-Ovation, usage, 95f Cervical facebow, 140 CFC �yndrome. ee Cardio-facio-cutaneous >yndrome 251 Chair time, reduction, 244 Cheekbones, ab-ence, 255f Childhood bony chin, remodeling (extent), 8 condylion, growth/remodeling (expectation), 8 facial heights, sex differences, 6 gonion, growth/remodeling (expectation), 8 lip length/thicknes , change (extent), 9 mandibular arch depths, cllange, 5 mandibular size/position, >ex differences, 7 maxillary arch depths, change, 5 nose (shape), change (process), 9 soft-tissue facial proftlc, change, 9

INDEX Childhood (Continued)

untreated mandibular intermolar widths,

change, 4

untreated maxiUary intermolar widt hs, change, 4 Children adolescence, entry ( age}, I distal step, !Sf face, asymmetrical growth, 46f Ou;h t�rrrunal pl.me, !Sf growth patterns, I me,ia l >tep, I Sf Chin cup, treatment force magnitude/direction,

recommendation, 184 indication, 1!13 treatment timing/durat ion, 184 Chromo>mal disorder, 255-256 Circadian rhythm, 1 3 Circumferential supracrcstal fibrotomy (CSF}, indications, 268 Circummaxillary sutures im•olvement. Su Maxillary protraction 183f mobilization, 128

Clasps, 267 nece,si ty. See Reten ti on 267 Cia· .. � I adolescen t patient, mand ibul ar anterior crowding, 1 98 Cl.1ss I crowded patients, interproximal reducti on ( usage}, 198 Class I dental relation>hip, 182-183 Class 11 buccal segment relationship, 123 Class II camouflage treatment, 170 Class 11 ca>e>, retent ion (considerations), 266 Cla.�s 11 dental maloccl usion, prevalence .

See Adolescents 3; Young adults 3 Clao;s II dental relationship, 182-183 Cia._. II discrepancy, correction, 133 Class I I division I malocclusion bimaxillary crowding, 60-63 cephalomet ric radiograph, 157-158f deep bite.\, 266 facial swcUmg, changes, 48f headgear treatment, 157- 1 58f Class II early treatment (Univer ity of Florida}, 24 Class II clastics

contraindications, 131, 131 indications, 1 3 1 , 1 3 1 Class II hori10ntal types, 1 53t Moyers' differential d iagnosis, usage (process}, 1 52 Class Ill anteroposterior di screpancy

(correction), orthodomic c>.:tracrions (consideralion), 134 Class Ill buccal segmenl relationship, 123 Class lll ca>es, retention (considerations), 266 Class Ill correctors, treatment results, 183

Class Ill early tream1ent, initiation (decision ), 25 Class Ill malocclus i o n . See Pseudo Class Ill malocclusion 178 diagnosis, 33-34 early treatment, necessity, 140 facial �welling changes, 48f U i uslration, 181- 182f occurrence, 15 posttreatment photographs, 181- 182, 185-186 retainer>, 268 treatment, 185f chin cup, usage, 1 84f Clas; l11 molar malocclusion (treatment), orthodorllic clastics (usage), 202 Class III molar relationships. 133 explanation, 20 I

Class Ill patient> high-pull chi n-cup, impact, 201

lower jaw, �trength, 202 reverse-pull face mask, impact, 20 I treatment, extraction patterns (consideration ) . See Adults 202

underbite, 202

Class I l l skeletal malocclusion, 57 Cia" 11 malocclusion arch widlh�. differences, 5 components, 152 correction, 1 33 distalizing protocol, 159 fixed appliances, u>agc, 131 treatmem protocols , 155 definition, 33 early treatment

eiTcclivcncss, 24 necessity, 1 4 1 etiol ogy, 152 Herbst appliance, usage, 142 intraoral photo, 157-ISBf local/environmental factors, 153- 155 prevalence, 152

retainers, 268 >pontaneou> correctron. explanation. 142

strong ch in, 1 13f

treatment, orthopedic approach (con�ideration), 200 Class 11 measurement, 125f Class 11 molar malocclusion facto rs, treatment decisions, 199 molar di,taliLing non- com pliance appliances, usage, 200 presentation, 199 treatment, orthodontic da�tics (usage process), 200 Class 11 molar relationships, 1 3 3 correction, headgear (impact), 200 exp lanation, 199 Class 11 occlusion, occurrence, I S Class 1 1 patients convex profile, 201

overjet, excess, 20 I rerrusi,•e lower jaw, 20 I treatment. See Early mixed dentition 142 extraction pattern>, con>ideration .

Sce Adults 20 I similarities, 1 4 1 Class II problem, approach ( usage) . See Maxilla 142

Class II skeletal malocclusion, 57 Class 11 treatmen\. Sfr S u rgical Class I f t rea tment 1 70 Class . II vertical types, 1 54t Moyers' differential di agnosis, usage (prnce»), 152

Class I molar relationship, 63 explanation, 198 Class I occlusion, keys, 93f Class I patien t, permJnent teelh extraction (factors), 199 Cla.s I ;keletal malocclusion, 57 Clcft-affeCied orthognathic surgery patient� maxillary relapse (risk), 2 5 1 Cleft-affected patient> di git-sucking appliance, 247f expansion appliances, example>, 248f orthodontic/orthopedic treatment, timing, 244 orthodontic treatment, indication. See Primary de ntit ion 245 skeletal discrepancies, orthodontic treatment (indication}, 250

291

Cleft alveoli, posterior crossbitelmalaligned maxillary i nci�ors, 245-247 Clefting, syndromes, 251 Cleft lip, 244, 277 Cleft palate, 244, 277 Cleft patients orthodontic treatment, indication. See Mixed dentition 245 permanent dentition, orthodontic treatment, 250 Cleft region, dc,•i,l!ion (nhlgnitude), 47f Clei docranial dysplasi,1, 251 auto,nmal dominant inherilance, 258 illustration, 257( panoramic film, 25!1f ClinCheck, d iagnostic tool, 150 Clinical �xamination, 27 aspects, coverage, 28

usage, 53 Clinical EMrmination, cnteria, 270 Clonazepam ( Kionopin), 262-263 Clo.e bit�. 13ionator treatment, l69- 1 73f posto rthodo ntic results, 169f CMF. See Cranio-maxillofacial 277 CO. See Centric occlusion 28 CO� laser. See Carbon dioxide IJ�er 273 CO-CR di\Crcpancies, presence, 210 Coinc ident midlines, 40-41 f Cold-cure acrylic, usage, 140f Complex CMF su rgery, CASS method usage (accuracy), 283 Composi1e final photographs, 6 1 -62f, M-65f, 67-61!f Compo�ite initial photographs, 61 -62f, 64-6 5f, 67-68f Comprehemive orthodonti c trealmenl, indicalion. See Aduh� 2 1 0 Com puted 10mographic-bascd (CT-based) physical models, i�sues, 27!1 Computed lomogrJphic (CT) image�. analy,i>, 233 Compu ted tomographi c (Cr) models, issues, 278 Computer-aided surgical simulation (CASS), 281 co;t-effectivcncss, 283 method, usage (accuracy). See Complex CM F surgery 283 step>, 28 1

Computer-based stati�tical evaluation, usage, 152 Computerized composite skull model, creation, 281f Computerized 'urgicaJ plan, lransfcr methods, alternatives, 284

proce�s, 282 Computer software tools, usage, 45

Concave photograph ic analysis, 40-41 f Concave proft!e, 58 Concrescent teeth, 30 Concurrent forces, calculation method.�. 97 Condylar growth, 1 59 impact. Ser Skeletal pattern 1 1 5 Condylion, growth/remodeling (expectation). See Adolescence; Childhood 8 Cone Beam CT (CI3CT), 461 machines, us.�ge. Sec Temporomandibular joint 49 soft ti;suc images, SO tech nology introduction, 49 usage, 48 usage, 4!1 Cone Beam Image, 3D views, 48f

INDEX

292

Cone-beam C I technology, development, 278

Crowd ing, 222f. See also Late crowdin g 1 8; M ild

crowding 54b; Primary dentition 15f; Secondary crowdin g 18

Congenitally missing maxillary lateral incisors, 35f

determination, third molars (role), 3

presentation, 72 Congenital missing lower second permanent

Dental maxillary transverse discrepancy, dental origin (treatment), 66-69

Dental midlines. See Mandibular dental midlines 59; Maxillary dental midlines 59

elimination, 1 3 1

Dental open bite, p resence, 1 33

horizontal mandibular growth, impact, 3

Dental posterior crossbites, correction, 128

Controlled tipping

l i lmtration, 255f

Dental problems, 256

definition, 98

in1pact, 160- 1 6 1

Dentistry, i mplants (history), 220

prevalence. See Incisor crowding 3 problems. treatment options, 132

Dentition, 121

Conventional fixed appliances, 1 3 1 Con ven tional late orthodontic treatment, 2 2

treatment, 185- 186£

premolars, 19f

movement.

See Rotation 98f

Convertible tube, definition, 9 1

Convex photographic analysis, 40-4 1 f

illustration, I 09f

vertical mandibular growth, impact, 3 wisdom teeth, role. See Lower anterior

Cortical bone, entry location, 233f Crown

Corticosteroids, usage, 262-263 plans, incorporation, 274-275

flexible initial "�re, usage. See Crowded dentition 9 l f la teral limit, 108

surgery. See Postlaser crown lengthening

Costen,

James, 260 Costochondral graft, 283

surgery 274f

Counter oscillation. See Toothbrushes 240

position , compensation , 199

preparation, facilitation, 2 10f

posterio r limit, 107

CSF.

definition, 99

illustration, I I If mutilation, 2 1 0

Crown-root alignmen t, 9 l f

Couple

See Permanent teeth 18

final orthodontic alignment, 225f

angulation, 265 inclination, 265 lengthening, 274f

principles, incorporation, 273-274

movement 195 changes, occurrence.

evaluation process, 1 2 1

crowding IS

Cosmetic dentistry

anterior limit, 107 anterior trauma, impact. See Isolated tooth

timing, 24

Convex profile, 58

•

vertical growth, palatal implan ts

definition, 99

See Ci.rcumferential supracrcstal fibrot omy 268 CT. See Computed tomographic 233

determination, 99

Curve ofSpee, depth (measurement), 124f

vertical limit, I 08

increase, I O i f

Cuspid

moment

role. See Translational movement 99 moment, depiction IOOf production, example, lOOf CR. See Centric relation 28 Cranial sutures, release, 253-254

Craniofacial deformity, 244 treatment, 251 Craniofacial dysostosis syndromes, 25 I Craniofacial

growth

impaction, case example.

mid-growth spurt, impact, 2

cuspid 69

(timing), 9

Desires, consistency. See Evidence 104

0

Development (measures), WHO determination. I

Damon brackets, usage, 86

Diagnosis, definitiveness, 52

Detector, emitters (link), 285f

Dark buccal corridors, 40-4 1 f

See also Lower

canines 139f

early treatment, effectiveness, 142

Craniofacial sutures, closing age (expectation), 8 Cranio-maxillofacial (CMF) bones, true rep l ica, 278

deformities,

patients ( U.S. number) , 277

Cranio-maxillofacial (CMF) surgery, 277 comparison chart, 284f

Deep bites. See Impinging deep bites 133 dental malocclusions, 59 Deep impinging bite, 160- 161

Delaire facemask, I 78

planning methods, 277

development 1 7

correction. See Dental posterior crossbites; Skeletal posterior crossbites 128 malocclusions, I 90 treatmen t, problems, 193

results. See Teeth 192

o rder. See Teeth, movement 192

See Patient 27

disadvantages, 223, 223

similarity, 253 Crowded Class I pat ient, second molars

(extraction), 199

Crowded dentition, flexible initial wire (usage), 91 f 138

See Cleft-a ffected

patients 247f Dilacerations, 81-82 Diode laser, 273

Direct bonded appliance, securing (mechanism) I 99-200

advantages, 223

Crouzon syndrome, 251

Crowded teeth, treatment process,

D en tal Class II di visio n I, 54b

Dental implants, 223

treatment, initiation, 1 3 1

Di gi t-sucking appliance.

iUustration, 274£ Direct anchorage, 236f

development 1 8 Dental casts, obtaining, 32

Dental history.

problem, 192

(occurrence). See Occlusal

Dental compensations, placement, Dental Contou r Appliance , 1 46

Digital habits, 23

presentation. See Teeth 81-82

size, problems, 139 width , changes

D igital chin template, 282f

Digits, fusion, 253

length, changes (occurrence). See Occlusal

Crossbites, 202

(Valium). 262-263

Differential diagn osis, 52

Digital surgical splint, 282f

openbites (contrast). 202 expansion , 132

deformities, 253 Craniosynostosis, 277

Diagnostic set - up, useful ness , 34 Diagnostic wax-up. See Fi na l occlusion 204

correction, 269

Dental arches

inadequacy, reasons, 277 Cran iosynostoses S}1ldromes, 251

Cephalometric radiographs 37f Diagnostic setup, 1 3 5 f

Diazepam

talon cusp. inclusion, 31 f

Dental anterior openbites, skeletal anterior

computer model, creation process, 281

Diagnostic reference planes, 37. See also

closure, discussion. See Midlines 195

characterization, 30

radiographs ( screenin g tool), 35

planning, 28 1

comprising, 53

Diagnostic grid, definition. See 3D- 3T diagn ostic

Diastema, 223f

Dens evaginatus (dens in dente)

Dental abnormalities (detection), pan oramic

issues, resolution process. 281

Diagnostic arch, 32

Diagnostic database, 53

grid 55

cases, retention (considerations). 266

maturity level, expectation, 6

tbognathic surgical treatment, 213-214f

C-,qjre, usage, 92f

Deep bite

relative growth, expectation , 6

role. See Skeletal

pattern 1 1 8 Dentoskeletal Class II malocclusion (severity), o r-

deciduous canines; Upper deciduous

Craniofacial structures

nontrcauncnt

See Impacted

Cusp ofCarabelli. See Maxillary first molars 31f

Craniofacial skeleton, growth cessation

Cranio-maxillofacial (CMF)

illustration, 112f

Decid uous canines, removal, I 38.

absence, 206

(impact ), 234

Dentoalveolar developmen t,

arch"�re retraction , 99

,

illustration, IJOf

See Teeth 88

Di rect bonded bracket components, 87 construction process, 87

Discrepancy index (definition ) , ABO

illustration, 225f

Disk position, importance, 261

placement. See Retrom olar area 226f

Distal Jet, appliance, 200

surgical process. involvement, 223 usage, concept, 223 Dental malocclusions.

See Open bite 59

usage, 60

Di�ease control. initiation. 204

Distal step. See Children 1 sf Distoversion. 42f. See also Maxillary right lateral incisor 30f

.

I N DEX

Dog (skull), orthodontic appliance

Equilibrium

(Vitallium screw anchorage),

example. See Orthodontic appliance 1 0 1 law, application process. See Orthodontic

23lf Dolichofacial photographs, 40-4 1 f

appliance I 00

theory. See Teeth 2

Double-jaw surgery, �teps, 279-280

Double-tube bracket, definition, 88

Downslanting palpebral fissures, 254

Erbium laser, 273 Eruption

illustration, 255£

stages. See Teeth, eruption 1 3

Down syndrome. See Trisomy 2 1 255-256

pattern, 1 8

Drugs, dependence, 262-263 Dual-dimension wire, usage. See SPEED Hills wire 92f Dysplastic/displaced car, observation, 252f

Dysplastic ramus/condyle, 252f

problems. See Second permanent molars 20; Upper permanent canines 1 9

Esthetic line ( E plane), 39. See also Ricketts' E-line 58

Esthetic requirements, 93 Esthetic restoration, 217f

Ethmomaxillary suture, 183f

E

Evaluation, zonal method, 47f

E arch. See Expamion arch 113-114

Evidence-based recommendations. See White spot lesions 239

Early mandibular distraction, treatment, 254

Evidence-based treatment, delivery, 23

Early mixed dentition, Class U patient

Evidence (scientific body), desires

Early permanent dentition, Hyrax-type

Ex40 (aligner material), impact. Set Teeth,

exp.mdcr (usage), 1 4 1 f Early treatment

Exomphalos-macroglo �ia-giganti'm

treatment, 142

advantages. See Orthodontic treatment 22 bionator, usage, 24 contraindications, 137

definition/in,•olvement. See Orthodontic treatment22

delay, risks, 144 disadvantages. See Orthodontic treatment 23

effectiveness. See Class I I malocclusion 24 headgears, w.age, 24

Ectodermal dyspla�ias, 251

Ectopic eruption. See Upper first molars 19f

(consistency), 104

movement 147

syndrome, 251 Expansion, initiation (timing), 1 3 1 Expansion appliance

selection, factors, 1 3 1 usage, decis1on, 1 3 1 Expansion arch ( E arch), 83-84 Expansion orthodontic treatment, 104 External root resorption existence, 133 history, 1 3 3 Extraction case example, 64-65f

non-extraction, contrast (case example), 63

defmition, 19

retention, considerations, 266

Ectopic maxillary first permanent molars, panoramic radiograph, 132f Ectopic permanent first molar, correction, 193-194 Edentulous site, availability (absence), 223 Edentulous space, dental shifting, 2 1 2 Edgewise appliance

sites, teeth (tipping), 139£ 3D-3T diagnostic summary, 66t Extraoral elastic traction band, placement, 246f Extraoral forces, visibi l ity, 231 Extraoral protraction force, 249 Extraoral traction definition, ISS

appliance, preceding, 83-84 arch wire, placement process, 85 evolution, process, 8S introduction, 83

therapy, initiation (timing), 1 3 1 Extreme makeover edition, 222 Extrusion to extraction meaning, 203

o· ring tics, usage, 91 f

procedure, 203

Edgewise bracket arch wire slot, diagonally opposed corners (removal), 85f

difference. ee Pin and tube vertical bracket 8S horizontal tunnel, addition, 85f

wedge removal, 84-85

Edgewise specialty practice, initiator, 85

Edgewi se twin bracket, Kobaya�hi tie hooks (usage), 90f

Ehlers·Danlos syndrome, 251 Elbow tubes, >oldering, 165 ELITE,46t Embryopathies, 251 Enamel bonding, bracket base contamination

(impact), 93 Endosseous implant, placement, 234 Entropy

law. See Thermodynamics 55

production, law. See Maximum entropy production 52

Epithelium, enamel organ, 13

E plane. Sec Esthetic line 29

293

Faces (Continued)

prerequisites. See Good face 1 1 2

superimposition. Su Average faces 45 under�tanding. See Ideal face 1 1 4

Facial asymmetry, mandibular lateral displa(.ement (impact), 59

Facial balance

improvement, protrusion (reduction), 1 1 7f posttreatment photographs, 1 1 7f pretreatment photographs, l 1 7f

skeletal pattern, relationship, I 1 4 soft tissue maldi�ment, 59 Facial thirds, proportion, 59 Fan appliance, 247

FAS. See Fetal alcohol syndrome 251 FASTSCAN, 46t

Fetal alcohol syndrome (FAS), 2 S I Final cephalometric tracing, 61-62f, 64-6Sf Final occlusal adjustment, 208 Final occlusion, diagnostic wax-up, 204 Final panoramic radiograph, 61 ·62f, 64-65[ Financial cost, increase, 23 Finger spring�. See Anterior dental crossbite 1 79f

F

First law of motion, 96

Facebow. See Cervical facebow 143f usage, decision, 1 3 1 Face-bow transfer illustration, 279f issues, 278

Facemask. See Dclaire facemask 178

therapy. See Protraction faccmask therapy 25 indication, timing, 178 treatment timing. 180

Facemask treatment clinical response, variations, 183 efTects, expectation, 180 retention, necessity, 183

Faces

divisions, I 17f evaluation, consideration, I l l hypcrdivergency, 123 hypodivergency, 123

orientation, relationship. See Isolated tooth movement 193

First premolar removal, 139f transposition, 30f First/second pharyngeal arch/groove/pouch, derivatives (involvement), 254 Fixation screws, 232 Fixed appliance. See Conventional fixed appliances 1 3 1 brackets, parts, 87f lnvisalign System, comparison, 150

tooth movement, occurrence (process), 87 usage. See Class II malocclusion 1 3 1 Fixed appliance, development, 83 Fixed-expansion appli.lllce, 248·249 Fixed jackscrew devices, 247·248 Fixed lingual arch, expansion (maintenance), 249f Fixed lower lingual arch, usage, 138f Fixed mandibular expander, 129 illustration, 129f

294

I N DEX

Functional jaw orthopedics (F)O), 159

Fixed orthodontic appliance characteristics, 83 ddinition, 1!3 Fixed orthodontic brackets, characteri.�l plane, I 52 Functional shift, 34f Functional treatment, stability, 169

G Gemination, 29-30. See also Mandibular central incisors; Ma n d ibular lateral

incisors 31 f

Gender-specific growth curves, child

classification, 29 Gingival display, excess, 218f

Gingival grafti ng, usage, 207-208 Gingival ligament fibers, reorganization, 265 Gingival margin, placement ( problem), 147-148f

Gi.ngi\�11 markings, 2ll!f G i ngiv.1 l overgrowth causes, 241 predisposition, treatment, 241 Gingival recession, 241 orthodontic treatment, risk factor, 24 1 Gi ngi val recontouring soft-tissue laser surgery,

unit of moment, definition, 'J9

vector, 97f vertical component, 97f Force, physics definition, 98

Fo rced eruption, 209 accomplishment, process, 209 restorative dentistry, 195 Fo�sa displacement/growth/adaptation, 159 Four- fiducial-marker model, reconstruction, 281 f Frankel appliances, 135f usage, 24 frankcl ll appliance, 159 i llu,tration, 162f frankel Ill Regulator, usage. See Ret Frankfort horiwntal (FH), 37

�on 183f

hnri70nlal lioe, 279f

orientation, models (usage), 278 reference, 37 �rankfort mandtbular m'i>or angle (FMIA}, 1 2 1 Free gingival graft. recommendation, 207 Frenectomy deci�ion, 195

indication, PHV frequency distribution, 2f Glabella (G), 37, 59 Glenoid fossa, position (change) . See Postnatal growth 8 Gnathion, 36 Goldenhar 'yndrnme, 251 di;order�. 25 1 Gonia! angle, clo;ure, 184 Gonion. 36-37 growth/remodeling, expectation. See Adolescence; Childhood 8 Good face prerequisites, 1 12 quantification/measurement, 1 1 3 Growth

deficiencies, 25 disorders, 260 dynamics, predict..1bility, 23 me"'ures, WHO determinati on , I modification treatment, availability (absence), 2 1 1·2 1 2 GTR. See Guided tissue regeneration 241 Guided ti;.,ue regenerat ion (GTR), 241

Friction-free appliance, advantage, 90

Gummy •mile, improvement, 2 1 8 f

Frontal facial photographs, 40-41 f

H

frontal anai)'Sis, inclusion. 54

Frontal photographs (diagnosis), aspects ( notation), 38 Frontornaxillary suture, 1 113f Full banded bracket ;ysterns, full direct bonded bracket systems (contrast), 36 l�ull bands, direct bonding, 86f Full moth periapical survey 152

illustration, 227f surgical proce�), in"olvement, 226 usage, 228(

Mini-plates. See L-shaped mini-plates 232-233 2\.tini-�crew\, 232

�IP. See Mandibular plane 37 �1PA. See Mandibular plane angle 59 MPD. See Myofasdal pain dysfunction 28 MRI. See Magnetic resona nce imaging 50 Mucosa, cleaning, 235

anchorage device�. usage, 231 clinical procedure, 235

Muscle relaxants. See Centrally acting muscle relaxants 262-263

insertion, imaging measures (necessity), 233

Myofascial pain dysfunction {MPD), 28

impact. See Root injury 235

loading

N

time schedule, 235

Nager acrofacial dysostosis, 251

stability, orthodontic loading (impact),

236

Minor mandibular crowding, 105- 106f Minor tooth movement

aswciation. See lnterceptive orthodontics 190 compari�on. Su Major tooth movement 190

Missing maxillary laterals

Nager syndrome, 251

Naage,

initiation, timing, 240

properties, 92 Orthodontic care, age comideration, 29

Orthodontic database, necessity. See Isolated tooth movement 193

Orthodontic elastic:., u�age. Set Class I l l molar

mini-�crew,, u'.1ge (clinical procedure), 236 palatal im plant• (u�age), clinical procedure

considerations, 2 1 2

Orthognathic profile, 1 14f ca.-.es,

proces�. See Cia� II molar malocclusion 200

diagnO\tic pnKe:» (predictive analysis}, 39

comideration, tinting. See Adults timing,

dental hi>tory, point clarification,

27

desire�

Orthognathic surgery

Orthodontic extractions, comideration, 132.

27-21!

cooperation, anticipation, 133 dental esthetics, orthodontic

(explanation}, 236

malocclusiOn 202

27

biting, centric occlusion, 34f

goal, 197

appliance 83 law of equilibrium, application process, 100

Parallelob'l'am method, 97 Parental burnout, 137

early treatment

239

Parallax technique, 47-41!

173

21 J

consistency. See [vidence I 04 desires, consideration, 104 medical hi'>tory, point clarification, 27 periodontaUy compromised situation, 133

See alw Class Ill anteroposterior

Orthognathic �urgel"), timing, 25

range of motion (ROM}, recordation, 28

discrepancy 134

Orthopedic facial ma;k, hook attachment, 141 f

retreatrnent,

Orthopedic treatment, goal, 139

-.elf-e;.teem, improvement, 22

ab..ence, 133 Orthodontic force

horizontal/vertical componenb, 96 system, 97 definition. See One couple orthodontic

Osseointegrated orthodontic implant surface, h.istological section, o�seointegration, 220

force system 10 I; Two-couple

Orthodontic implant anchors ( 01;\s) , 220

Orthodontic loading

treatment planning, 1 1 8

defining, 235

vertical problems, early trcauncnt

232

Osseom ;urgical procedures, necessity, 203

Overbite, 59. Sec also Negative overbites 133 clinical examination criterion, 270

implant, 236

Ovoid arch form, 32f

p.llatal implant�. �tahility, 235

Orthodontic matt:rials, development, 93

p

Orthodontic models,

Pacifier habits, 23

27

Orthodontic patient rccord3D-3T (importance), 55 Orthodontic photogntphs, 39

creation,

55

palatal ex:pamion appliance 183f

case examples. 60

referral, necessity, 197 Orthodontic record�. neces,ity, Orthodontics art/science.

208

discipline, 83 future, 228

Periodontal ligament fibers, reorganization, 265

234

development, illustration, 229f illustration,

226f

benefits, 221

222

history, 220

;,kdctal anchorage, usage, 204 Orthodontic space closure. decision, 195

procedures 24 1

Orthodontic treatment,

22

application selection/utilization, Importance, 12R

documentation, 28

(impact), 207 Periodontal treatment, completion, 208

loading time >hip. See Periodontal regeneration

orthodontic tooth movement

loading

Palatal plane (PP}, 37, 152

Orthodontic tooth movement arch wire, role, 89

Periodontal regeneration procedures,

Periodontal therapy, mage. See Adulb 207

Orthodontic therapy, relationship.

Sa Temporomandibular disorders 263

240

instaUation, 233f

timing, 234

benefits, explanation,

Periodontal care, continuation, 208

anchorage devices, usage, 231

proces s.

implants

200

Periodontal attachment, loss, 240 Periodontal complications, pre\ention, 240

(recommendation), 233

22!1

Pendulum appliance, 159.

Periodontal di case, treatment,

insertion, imaging measures

52

developments,

distali1ing treatment, 160- 1 6 1 f

advantagesldisad,"antages, 224 clinical procedure,

Orthodontic radiographs, 35

2

Pende>.. appliance o f l lilgers, 143f

Palatal implants, 224

Orthodontic problems

skeletal ind icJ tors , Jssociation, Pendex, 1 3 1

placement. 160- 1 6 l f

Palatal expansion appliance, u�ge. See Rapid

example, 54, 54

2

arm, cut, 160-161(

Pain

Palatal acrylic, 140f

component�. 54b

attainment, timing,

frequency distribution. See l.loys; Girls 2f

illustration, 129 130[

•mportance, 261

Orthodontic problem list

(effectiveness), 142 Peak height velocity (PHV), I

appliance, 159

emergency relief, usage, 208

views, capture, 39

orthodontic tooth movement 195 specialist, referral, 199

Overjet, 58

impact. See M ini->crew> 236

;keletal pattern, impact. See Isolated

creation, 234f usage,

orthodontic force sy�tem 103

static equilibrium, tO I f

225f

107-108f

tilting, minimi7.ation, 1 1!0f Palate (clefts), repair (ab�nce), 245f

Panoramic radiograph. See Final panoramic radiograph; Initial panoramic radiograph 6 1 -62f

3dvantagi'S. See Intraoral periapical rndiogxaphs 35 analysis, 233

screening tool. See Dental abnormalities 35

usage, 149f See also Teeth 35f Panoramic x-rayo, us.1ge, 208

Perioral soft tissue, thicknes.s, 133 Permanent canines, isolated orthodomic tooth movement (comideration), 194 Permanent dentition mixed dentition, transition,

131!f

untreated arch perimeter, change, 4 Permanent first molar, ectopic eruption, 193 Permanent incisors crossbites, correction (problem}, 192 eruption anterior space, commonness, 1 7 rotated position, treatment dt!ci�ion, 195 natural realignment, 193

space deficit solution, process. See Primary incisors/permanent incisors 1 7

Permanent incisors, initial location/size

(comparison}. See Primary teeth

17

I N DEX Permanent molar mesiolingual cusp, emergence. See Lower

right first permanent molar 1 4f relationships (p rediction), terminal plane relat ionship, 14 Permanen t second molar, mesial angul ation tipping (treatmen t process), 194

Permanent teeth

Pnsterior crossbite (Co11ti11 ued) treatment, location. I 9 1 types, I \I I Posterior dental crossbite, skeletal crossbite (contrast), 202 Posterior dentition. space requirement, 125f

Pretreatment (Cmrtinued) progress photos, 105- 106f tracing/numbers, 105- 106f, 107- 108(

Primary canine, removal, I 92 Primary dentition

deft-affected patients, orthodontic trcauncnt (indication), 245

Posterior facial height, anterior facial height (comparison), 59

crowding, I Sf absence, 1 9 1

alveolar crest, distance, 23

Posterio r nasal spine (PI\S), 36

average eruption timing/sequence, 16t

Posterior occlusal coverage, usage, 248f

eruption denti tion, changes (occurrence). 18

Posterior occlusion, 147-148(

features. 1 4 spacing, !Sf

Posterior segments

terminal plane, 14

arch collapse, 247f expansion, 246f Posterior space

treatment, problems, 23

stages, 15- 16 eruption timing/sequence, IS extraction factors. See Class I patien t 199

treatment plan. See Isolated tooth movement 1 94

mass, extraction, 132 mineralization, occurrence, 16 transitional periods, 16

Peut7.-) eghcrs sy nd rome, 251

Pfeiffer syndrome, 251

Pha;,e II trt!a lment, 137. See also Pre-Phase II treatment 144

occurrence, 144 Phase ! treatment, 137

duration, 143

interim period, 144

analysis, 123

ill ustration, 1 25f

availability, 1 2 Sf

Posterior teeth, axial inclinations (correction), 128 Posterior vertical development, 143f Posteroanterior cephalometric film. See Asym met ry 36f

299

relationsnips, 14 Primary inci;,ors/pennanent incisors, space deficit solution (process), 1 7 Primary molars, an kyl osis, 34 Prima ry second molars

term i nal plane relationship, 1 4 width, 198

Primary stability, changeover, 234f Primary tcctl1 average eruption timing/sequence, 1 4t

Post-Herb�t treatment, 1 74f

eruption, 258. See also Lower central

orthodontic results, 174f

incisors 14

Postimplam placement results, 216f Postla..<er crown lengthening surgery, 274f

eruption timing/sequence, 14

Postnatal growth, glenoid fossa position

permanent incisors, initial location/sue

Postnatal ctaniofacial growth, I

extraction/disciog. 190

( change) , l5

(comparison),

17

Phenytoin (Dilantin), usage, 241

Postorthodontic occlusion, 2 1 5-216f

Prioritized problem list, definition, 54

Photo-grammetry, 46t

Postorthodontic preparation, 2 1 6f

Problem-oriented app roach. See Treatment 197

Postsurgcry orthodontic activation, 276f

Profile, line to nose, 1 16f

Photographic analysi s, 53 PHV. See Peak height velocity I Physical chin template, 282f

Postsurgical splint, progressive reduction, 253

Profile analysis, 42f

Phy;,ical growth, assessment methods, 29

casts, 107-1 08(, I I I f

goals. Sec Facial profile analysis 42 Profile photographic analy�i>, 40-41 f

P hysinlogical tooth amition, simulation, ISO

cephalogram, llOf

Profile view, inclu;ion, 55

Pin and tube appliance

dentition, mandibular inci;.or irregularities

Progress

Angle development, reasons, 84 appliance, Angle replaceme nt, 84

Pin and I ube vertical bracket, edgewise bmcket (differences), 85 Pin-retained jackscrew, 244-245 Plane of space, problems. See Vertical plane of space 51\ Pla, 39-42

Skeletal aberrations, exist�ncc, 1 15

illustration, 42f Rule of'J"hirds, 39 illu�tration, 42f

appliance, 248f R�movabl� retaineN> componen L.,, 2 67

fixed rct�oncro, combination (indications), 268

indications, 267 Removable Schwam appliance, ll9-130f Re>ection margins, recordation, 286f Resistance, center, 94f definition, 97

Restorative prosthetic dentistry, 208

Result�, delivery, I0'1

Retained left dcciduou> cuspid, 3 1 f Retai11ers, positioncrs (u�age), 268 Retention

dasps, n�cssity, 167 considerations. St>e Ciao> II ca>e>; ClaS!. Ill Ca>C>; Deep bite; Extraction;

s

1-rankel lll Regulator, u>age, 1 83f growth, con>ideration, 266

Saethre-Chollcn syndrome, 251 Sagi ttal (A-P) plane dental t issue, 58

>keletal ti;.;.ue, 57

prutocul. SeE' Molars 209

Retrcm, 57-511

Retromolar area, dental implants (placement), 226f

Retru;,ive chin. See Facial convexity 57 Retrusive lower jaw. See Class II patients 201 Rl·versc-pull face m�k. impact. SeE' Class III patients 201

Ribbon Arch appliance, appliance (basis), 84 Ricketts analysis. I 17f Ricketts' E-hne, 58 Right unilateral cleft lip/palate, 47f Rigid rectangular stainleS!. steel ''�re, usage, 9 1 f

HM E. '>ce Rapid maxillary expansion 139

Root angulation, clinical examinauon criterion, 270 Root apex, movement, 99f Rnm development, 23 Root formation, 13

Root injury, mini-�crews ( impact), 235

Root morphology, presence. See Short blunted root morphology 133

classification proce;s, 232 .,ystems, evolution, 232

usage. Su Orthodontics 204 anterior openbite> 202

Skeletal changes, result, 25 Skeletal Class Ill malocclusion, 183 treatment, surgical maxillary advancement ( usage), l87- 1 88f

soft tissue, 58 Sagi ttal ( A- P) plane of space, problems, 57

Skeletal Class Ill mandib ular as>•mmctry,

SA."-.1 articulator, 279 SAR.Pt. 51'1' Surgical ly .1�isted rapid palatal

Skeletal Class l l malocclu!>ion, 54b

SAM Analytical Face-Bow, 278

expansion 69

ourgical maxillary advancement (mage), 1!!7- l !!!lf correction, 57

Scalar, contrast. See Vector 96

Skeletal Class II problems, 170- 173

Scanning electron m1cro�cope (SEM), �ge.

Skeletal convexity, 1 14f

Scaling, u�age, 207-208

See Implant; Macro roughness; Micro roughness; Surface 1mplant 22 1 f

Schwartz applia nce. See Iower SchwartL.

appliance 129; Remo,·able Schwartz

naturefduration, 266 neces.�ity, reason�. 265

Skeletal anchorage, 204

Skeletal anterior openbites, contrast. See Dental

Nonextraction; Open bite 266 definition, 265

research articles, 22

Rubber cup/pumic� technique, comparison, 240

hwarv appliance, 1 4 1 f

Removable maxillary expan>tOn

Single phase treatmen�. evidence-based

appliance 129-130f

Sci.>or bite. Sel' Brocli� bite 59 Sc rew-retained jachcrew, 244-245 Secondary crowding, 18 Secondary stabil ity, changeover, 234f Second low of motion, 96

Second molar�

d istal ization, pahllal implant (usage), 227f

Second molars, extraction. See Crowded Class I patient 199 Second permdnent molar\, eruption problem, 20 Segmental orthodontic treatment mechanic�differential forces, usage ( con�ideration ), 206 Self-ligating brackets, 86f, 95f

definition, 87. See also Acthe self-ligating bracket 87 function, 1!6 impact, 89 usage, 83

Self-ligating SPEED appliance, usage, 9lf Sella,36 Sella-na;ion (SN), 37 Sella-nasion (SN) cranial ba;.e plane, 152 Sella-Na,ion-Sub;pinale (SI'\A) angle, 37-38 Sella-Na�ion-Supramcntalc (SNB) angle, 37-38

Skeletal components, 1 1 5

problem, existence, 1 1 2- 1 13 Skeletal cru;,;.bite, contrast. See Posterior dental cro;,sbite 202

Skeletal deformity, camounage, I SO keletal discrepancie,, orthoclontic treatment (indication). See Cleft-affected patJents 250

Skeletal growth, modification (ability), 22 Skeletal imbalance, pretreatment facial photographs, 207f

Skeletal indic.1tors, association. See Peak height velocity 2 Skeletal malocclusion, camounage, 185-186( Skeletal open bite, 266 prc;,cnc�. 133

Skeletal open- bite patients. See Hyperdivergent patients 7

Skeletal pattern, 1 1 3 anteropmterior component, 120 condylar growth, impact, I I 5 hyperdiv�rgency, 123 hypodivergcncy, 123 imbalance, 133 relationsh ip. Sec Facial balance 1 1 4 scenario, dentoalveolar de"elopment (role), 118 tranwer-.e component, 120 vertical compunent, 1 15 vertical plane, factors, l iS

Skeletal po>terior croS!.bites, correction, 128 Skeletal problem analysi�. I I S

comideration, I I ll

INDEX Skeletal protraction, facilitation, 128 SLA. See Stereolithography 146-147 Sliding mechanics, definition, 9 1 Smile line, 55 Smiling photograph.�. 107-109f SN. See Sella-nasion 37 Sn. See Subnasale 37 SNA illustration, 120f value, 120 SNB illustration, 120f value, 120 SN-GoGn, 38 angle, 60 Soit tissue chin, positioning. See Facial profile 1 1 2- 1 13 comiderations, 63-66 covering. See Bony chin 39

facial profile, change. See Adolescence 9; Childhood 9 landmarks, 37 laser surgery, indication/technique. See Frenectomy 275; Gingival recontouring 273; Impacted teeth 275 lesions, treatment, 206 maldi5tribution, impact. See Facial balance 1 1 4 measurement�. 311 overlay, 1 1 3 i mpact. See Facial balance 1 1 4 pressure, 265 procedure�. la�er usage (consideration), 272 profile change, process. See Adulthood I 0 impact. See bolated tooth movement 196 removal, 272 t hickness, l l l!f Space absence, 265 analysis. See Anteriur ;pace 1 2 1 ; Midarch space 1 2 1 ; Posterior space 123 deficit solution, process. See Primary incisors/ permanent incisors 17 evaluation process, 121 gaining, average, 137 lo,s, undermining, 19f maintenance, purpose, 137 managemcm, 23

problems. See Sagittal plane of;pace 57 providing, goal, 201 redistribution, facilitation (orthodontic treatment), 217f

Space-age materials, usage, 83 Spee, curve. See Curve ofSpee l24f Speech articulation distortion, 193 SPEED appliance, 91 u>age. See Self-ligating SPF.ED appliance 9 1 f SPEED brackets clip, uniqueness, 89 construction example, ll7 multi - piece construction, 86f appliance parts, 87f usage, 86

Square arch form, 32f Stability, factors, 265 Stainless steel ligatures, usage. See Siam� brackets; Twill brackets 86f Stainless steel staples, u�ge, 246f Stainless steel wires, difference, 92 Standard deviation faces, 45-46 Static equilibrium. See Orthodontic force IOif defmit ion, I()() Steel ligature, usage. See Activation force 88( S teel ring, clastic o-rir1g (contrast), 88f Steep mandibular plane angle, 105- 106[ Steiner analy;b, illustra t io n, l l6f Steiner's analysis, 57-58 usage, 59 Stereolithography (SI.A} apparatus model�. 278

process, 14n-147 Stereo-photogrammetry, 46t Stomion,37

Straight photographic analysis, 40-4lf

Stripping. See Air rotor >tripping 268;

Interproximal reduction 198

Strong chin. See Class II malocclusion 1 13f

Structure, relative growth (knowledge), I Structured light, 46t Study ca5l analysis, usage, 53 Srurge-Weber syndrome, 251 Sub-masseteric region, swelling process, 48f Submental x-ray tomograms, usage, 208 Subna�le (Sn), 37 extension, 59 Subspinale. See A point 36 Sunday bite, 28 Supereruption, 222f Superimpositions tracing, 1 1 2f u�ge, 39 SuperMesh, 90f Supernumerary teeth, 35f location. See Upper jaw 2 1 f Supplemental intraoral periapical films, indication, 35 Supramentale. See 13 point 36 Surface imaging, 45 technology, 50 Surface implant, SEM (u>age), 2 2 1 f Surgical Class l 1 l treatment, 184 Surgical Class II treatment, 170 Surgical dental splints/templates, creation,

2R2f

Surgical evaluations, 46 Surgically as;isted rapid palatal expansion (SARPE) appliance, 69 Surgical plans approval, 251 transfer, is�ues, 280 Surgical plates, 227

advantage>/disadvantuges, 227 surgical process. involvement, 228 usage, 227 Surgical procedure, mrnor procedure, 221

SPFED Hills wire, dual-dimension wire

Sutural clo>ure, initiation (estimated age;), 9t Swallowing, I 18

(usage), 92f SPEED hoolu., 94f

T

Splints

design, Uti recommendation. See Occlusal splints 261 Spontaneou• correction, explanation. See Class I I malocclusion 142 Spring retainers, u�fulness. See Ma ndibular inci�ors 268

Spring-wing bracket, definition, 88

TAD. See Temporary a nchorage device 232 Talon cusp, inclusion. Sec Den> cc Tramlational tooth movement 98 3D control, 83 ch anges, I 0 I f crossbites, order, 192 improvement, l::x40 aUgner material ( i mpact), 147

occurrence, process. See Fixed appliance 117 treatment, impact. Sec Limited tooth movement treatment 2011 types, change (depiction), I O i f

INDEX

302

Temporary anchorage implan� locationlusage, 232 mini-�rew�. placement, 232

Temporary anchorage device (TAD), 232

See also Biowmpatible TADs 232f

defmition, 232 Temporo mand ibular di�rdcr> (TMDs) cJa.,si!ication ,

260

diagno>is, imaging applications (usage), 263 increase, 28

Thl}. See Temporomandibular joint 28; Transmandibular junction I 52- I 53 Tongue po'ture, I I !I

Tripl�-tube bratket, definition, 88

Tongue-thrmting habit, impact.

Trisomy 21 (Down syndrome), 255-256

Trichion (Tr), 59 Tricyclic antidepressants, mage, 262-263

illustration, 257f

Su Malocclusion 28f Tooth borne appliance, 159

Trombone-style appliance, ela;tic chain (usage), 248f

Toothbrushe;

circular motion, 240

compari�on, clinical trials. See Manual

Turner ;yndrome, 251 chromo;omal disorder, 254-255

toothbrushes 240

invoh•ement, 260

contrast. See Oral hygiene 239

management

counter o,cillation, 240

Tweed, Charles II., 85, 1 2 1

rotation oscillation, 240

Twin Block

ph;umacologic modalities, usage, 262

illustration, 256f

;ide-to-side action, 240

surgery, role, 263 occlu;al disharmony, role, 261

Torque control, 92f

illustration, 162f

orthodontic therapy, relationship, 263

TPA. See Trampalatal arch 138

usage. 161

therapy, occlu>al ;,plints (indication), 261

Tracker, navigation emitters, 285f

treatment, indication, 261

Tran>lational movement (creation), moment of

Temporomandibular joint (TMJ ) anai)'Si�. rypcs (availability), 49

disorders, 28

prevalence/incidence, increase, 206

disturbance, 260 function, e-xamination, 28 images (quality), CBCT machines (usage), 49 impaCI, 252f morphology, 49 illustration, SOf panoramic radiograph, usage, 35 tomograms, usage. 208

Thermodynamics, second law (law of entropy), 52

Third law of motion, 96, 222

'I hird molars disposition, consideration, 209 role, 269. See also Crowding 3

Th i rd- t>rder movements, 89 3D-3T diagnostic grid

common findings, 56t

appliance;, 57

placement, 163- 164f tootlt borne, consideration, 159

couple (role), 99

Translational tooth movement

points, equal movement, 99f

'

Tumor ablation, 277

treat men t, 163-164f usage, 163

Twin brackets, stainless steel ligatures (usage), 86f

Tramlational tooth movement, definition, 98

Twirming, 30

Transmandibular junction (TMJ),

Two-couple orthodontic force system definition, 103

trauma, I 52- 1 53

Transpalatal arch (TPA) , 138

mage 235. See Leeway space 138f

Transpo>ed Leeth, 3D-3T diagnostic summary, B i t Transposition ca'e example, 78 ca.o.e;, treatment, 78 compo,ite final photographs, 79-80f composite initial photograph�. 79-80f correction, decision, 78 ectopic eruption.

See Teeth 78

final cephalometric tracing, 79-80f final panoramic radiograph, 79-!!0f initial cephalometric tracing, 79-SOf

creation, 55

initial panoramic radiograph, 79-80f

definition, 55

photograph>, 79-I!Of

example, 102f Two-dimensional prcdicuon tracings, issues, 277

u

UI - L l . See l n terincisal angl� 38 U 1-SN angle, 60

UDML See Maxillary dental midlines 59 left shift, 40-41 f

right shift, 40 41 f Ultrasonic cleaning, HO Uncontrolled tipping definition, 98 movement, 98f

Uneru pted incisors, bonding, 257f Unilateral clef-affected patients, 247 Unilateral cleft lip/palate, 244

information, 56

Transverse dbcrepancie,, 128

list,60t

Tr.mwerse maxillary growth (midpalatal

amount, 280 UnplallJ\ed maxillary/mandibular

Transverse plane of space, problem�. 59

Untr�ated arch perimeter, change. See Late

method, steps, 55 treatment objectives, 56

�ge, advantages. Set' "I reatment planning 55

Three-dimensional CT scans, visualization/ quantification succe��. 278

Three-dimensional image, meaning/obtaining, 45 Three-dimensional imaging, 45 costs, involvement, 50

devico:s

�uture), palawl irnpldnl> (impact), 233 Transverse plane, passage, 54 Transverse proportions, judgment, 53 Transverse �kcletal problem manifestation process, 120 observation, 120 Traumatic occlu;.ion, elimination, 247 Treacher Collins syndrome, 251 Treatment

clinical setting, 50

goals, making, 56

medico-legal issues, 50

mechanics, comitlemtions, 221

future, 50 systems, limitation, 50 technique�. impact, 47 Thumbsucking habit, impact. See Ma.ociUa JS6f; Open bite 28f Tie-"�ngs

definition, 1:19 u'age. See Ligatures 86f

Time brJckets, �ge, 86 Tip-Edge bracket

probl�m-orientcd approach, 197

progres•. photographs, I 05-106f

timing, summary, 2St

Treatment objectives, 1 46. Sec also 3D-3T diagno\tic grid 56

lbting, 55 Treatment plan development, 104 concept, 107 formation, 55

creation, 85f

demonstration, 57

definition, H4

process, 57

Tipping

definition. See Con trol led tipping; Uncontrolled tipping 98

movement. See Rotation 98f

goal, 104 proce;.;, error (room), 104 Treatment planning 3D-3T diagno>tic grid, usage (advantages), 55

Ti�ue, lasing, 275

co mplexity, 125

Titanium implants, 224

comideration, 250

TMA. See Beta-titanium 92

TM D�. See Tcm))Oromandibular disorders 28

process, simplification process, I I I Treat software, 147

Unplanned maxillary AP displacement,

advancement, 21:\0f

primary dentition 4: Permanent dentition 4 Untreated mandibular intercanine widths, change (proc�ss), 5 Untreated mallllary i ntcrcanine widths, change (process), 5 Upper deciduow cani nes, removal, 139f Upper elbows, shimming, 165 Upper first molars ectopic eruption, 19f eruption, tran�itional period, 16f Upper incisors alignment, improvement, 139f intru.,ion, comprehensive orthodontic treatment, 2 1 5-216f

Upper incisor to NA ( U l -NA) measurement, 38 Upper incisor to Sn (UI-SN) measurements, 38 Upper jaw, supernumerary teeth � location), 2 1 f Upper lateral inci�ors, implant replacement (orthodontic preparation), 216f Upper left lateral, forced eruption, 2 12f

Upper lip length, occurrence. See Adulthood 10 Upper lip thickness, I 15f

Upper/lower econd primary molars, di;.tal surfaces (anteroposterior relationship), 14 illustration, I Sf Upper permanent canines, eruption problems, \9

I NDEX IJppcr right central, forced eruption, 2 1 1 f

IJpper right central incisor. decay, 217f

Upper �econd primary molars, exfoliation, 19[

Uprighting. See Molars 194

Vertical pla ne passage, 54

relationship. See Isolated tooth movement 193

Vertical plane of space

spri ngs, tooth inclination, 85f

problems, 58

v

skeletal tiS.\UC, 58

.>Oft JjS>ur, 59

Vacuum-formed retainer., indications, 267

Vector. See Force 97f

physics definition, 96

scalar, contra�t. 96

Vertical bone level. See l iard palate 233 Vertical bony defect, elimination, 2 1 2 f

Vertical Cia)> I! type>, 1 54- J SSt

Vertical correction, improvement, ISO Vertical dimension, control, 53 Vertical discrepancies, 1 3 1

Vertical facial proportions, judgment, 198 Vertical growth, control, 1

Vertical mandibular growth, impact. See Crowding 3 Verucal maxillary excess, indication, 55

Vertical problem' early treatment, effectiveness, 142

skeletal component, chatlenge, 142-143

Vertical-pull chin cup, lateral view, 144f

Vertical pull headgears/vertical pull chin cups, 69

Vertical ,keletal measurements, 38 Video-i maging r.tdiation >OUrccs, 46t Vitallium screws

anchorage. Sec Dog 23 1

placement, 231 -232

w

W arch, 131. See nlso I Modified W arch 249f illustration, 129-130f

quadhelix, similarity, 131 radiograph, 248f

Wax bite regi�trations, 164

Webbed neck, illustration, 256f Wedge, 107 White spot lesions. evidence-based recommendations, 239 Wire bracket interaction, I 02f Wire deflection, impact,

I() I f

Wire hook, adju.,tmenl, 90f

Wire stiffness, increase, I O l f Wisdom teeth, role. See I ower anterior crowding 1 8

y

Y-ax.is ( S-Gn), 37. Seen/so SGn-FH 31l Young adults, Class II malocclusion ( pre,