Evidence-Based Clinical Orthodontics

Evidence-Based Clinical Orthodontics

Edited by

Peter G. Miles, BDSc, MDS

Senior Lecturer

Department of Orthodontics

University of Queensland School of Dentistry

Brisbane, Australia

Visiting Lecturer

Graduate Program in Orthodontics

Seton Hill University Center for Orthodontics

Greensburg, Pennsylvania

Daniel J. Rinchuse, DMD, MS, MDS, PhD

Professor and Associate Director

Graduate Program in Orthodontics

Seton Hill University Center for Orthodontics

Greensburg, Pennsylvania

Donald J. Rinchuse, DMD, MS, MDS, PhD

Professor and Program Director Graduate Program in Orthodontics

Seton Hill University Center for Orthodontics

Greensburg, Pennsylvania

Library of Congress Cataloging-in-Publication Data

Evidence-based clinical orthodontics / edited by Peter G. Miles, Daniel J. Rinchuse, Donald J. Rinchuse.

     p. ; cm.

Includes bibliographical references.

ISBN 978-0-86715-564-8

I. Miles, Peter G. II. Rinchuse, Daniel J. III. Rinchuse, Donald Joseph.

[DNLM: 1. Malocclusion—therapy. 2. Dental Bonding. 3. Evidence-Based

Dentistry. 4. Orthodontics—methods. WU 440]

617.6’43—dc23

2012017471

5 4 3 2 1

© 2012 Quintessence Publishing Co Inc

Quintessence Publishing Co Inc

4350 Chandler Drive

Hanover Park, IL 60133

www.quintpub.com

All rights reserved. This book or any part thereof may not be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, or otherwise, without prior written permission of the publisher.

Editor: Leah Huffman

Design: Ted Pereda

Production: Sue Robinson

Printed in China

Dedication

This book is dedicated to our families, teachers, mentors, students, and in particular to our patients. More importantly, this book is dedicated to you, the reader, the present and future of orthodontics.

Contents

In Memoriam

Foreword

Preface

Contributors

1Introduction: Evidence-Based Clinical Practice

Nikolaos Pandis, Daniel J. Rinchuse, Donald J. Rinchuse, James Noble

2Early Intervention: The Evidence For and Against

Daniel J. Rinchuse, Peter G. Miles

3Bonding and Adhesives in Orthodontics

Peter G. Miles, Theodore Eliades, Nikolaos Pandis

4Wires Used in Orthodontic Practice

William A. Brantley

5Class II Malocclusions: Extraction and Nonextraction Treatment

Peter G. Miles, Daniel J. Rinchuse

6Treatment of Class III Malocclusions

Peter Ngan, Timothy Tremont

7Subdivisions: Treatment of Dental Midline Asymmetries

Peter G. Miles

8Evidence-Based Use of Orthodontic TSADs

James Noble

9The Effectiveness of Treatment Procedures for Displaced and Impacted Maxillary Canines

Tiziano Baccetti

10 Orthodontically Induced Inflammatory Root Resorption

M. Ali Darendeliler, Lam L. Cheng

11 Orthodontics and TMD

Donald J. Rinchuse, Sanjivan Kandasamy

12 Orthodontic Retention and Stability

Daniel J. Rinchuse, Peter G. Miles, John J. Sheridan

13 Accelerated Orthodontic Tooth Movement

Eric Liou

In Memoriam

Dr Tiziano Baccetti (1966—2011)

Chapter 9 of this book, The Effectiveness of Treatment Procedures for Displaced and Impacted Maxillary Canines, was written by Dr Tiziano Baccetti. This may well have been his last scholarly work; he completed this chapter just a few weeks before his untimely and tragic death on November 25, 2011, at the young age of 45. While posing for a photograph on a historic bridge in Prague, Czech Republic (he was the Keynote Speaker at the 9th International Orthodontic Symposium held November 24 to 26, 2011), he slipped on old stonework at the base of one of the saintly statues that decorate the bridge and fell 8 meters to the rocks below. It was the Charles Bridge—Ponte Carlo in Italian, the same name as Tizanio’s beloved father, who knows that bridge well and for whom the picture was intended.

Tiziano authored over 240 scientific articles on diverse orthodontic topics. He has been described by those who knew him best as a superman. This is supported by what he had accomplished in his short life. In 2011, Tiziano gave the Salzmann Lecture at the 111th Annual American Association of Orthodontists Session on Dentofacial Orthopedics in Five Dimensions. In concluding his presentation, he explained how his grandfather in Italy had told him as a young boy that one day he would find his America and fulfill his dreams. Tiziano said at the end of his lecture, I have found my America, fulfilled my dreams. Few, even with a long life, can say that they have fulfilled their dreams, their ambitions. We can be comforted that Tiziano did.

We feel fortunate that we can share Tiziano’s excellent chapter with our readers.

Foreword

This text can serve as a reference guide for research and studies in many difficult clinical areas where there is a lack of evidence-based information. The distinguished editors are all involved in education, research, and practice, and they have invited other well-known experts and authorities to critically evaluate the literature and topics such as early treatment, extraction and nonextraction, Class III treatment, asymmetries, temporary skeletal anchorage devices (miniscrews), impacted canines, root resorption, temporomandibular disorders, retention, stability, and accelerated orthodontic tooth movement. These are all critical areas in the full scope of clinical orthodontic practice. I am sure that every orthodontist will learn from the enormous contributions provided so clearly in this text. The first chapter introduces and defines evidence-based clinical practice. Every other chapter provides evidence for and against each controversy and concludes with a summary and points to remember.

The topics are covered in detail with extensive illustrations, cases, diagrams, and references. All discussions are based on current research findings, and when evidence is not available, it is clearly stated as such. As the editors point out, the purpose of this book is to provide the orthodontist with an evidence-based perspective on selected important orthodontic topics and to stimulate practicing orthodontists to reflect on their current treatment protocols from an evidence-based view. In the future, clinical decisions should be based ideally on evidence rather than personal opinion, and treatment strategies should be proven to be both efficacious and safe.

I am very honored and privileged to have been asked to present this foreword because this text should be the evidence-based text for EVERY orthodontist and student.

Robert L. Vanarsdall, Jr, DDS

Assistant Dean for Advancement of Dental Specialties

Professor, Department of Orthodontics

University of Pennsylvania

Preface

The specialty of orthodontics has evolved from an apprenticeship to a learned profession requiring academic training. Nevertheless, many in our profession still cling to biased beliefs and opinions rather than embracing evidence-based practice. When evidence conflicts with what experience has taught, it becomes even more difficult for such practitioners to change their views. Hence, there is complacency and resistance within the profession to adopt evidence-based treatments.

Most orthodontists experience at least enough treatment success to support a practice. Yet treatment success does not necessarily equate with treatment efficacy or even verification of an appropriate diagnosis. This success can be the biggest obstacle to change. Clinical success may be associated with a multitude of appliances, strong belief in a particular philosophy, financial motivations (even unethical ones such as inappropriate phase I treatments), the difficulties involved in switching from an experience-based practice to an evidence-based practice, and a simple lack of understanding of evidence-based clinical practice (described in chapter 1). In our profession, therefore, treatment efficacy is currently evaluated broadly in relation to benefits, costs, risks, burden, and predictability of success with various treatment options.

No longer can the role of evidence-based decision making be shunned and ignored in favor of clinical experience alone. From both ethical and legal perspectives, sound clinical judgment must be based on the best evidence available. Today a paternalistic view, whereby the doctor knows what is best for the patient without soliciting patient input, is unacceptable. Patients have a right to autonomy and input into their treatment provided that it does no harm.

The 2001 Institute of Medicine report estimated that it takes an average of 17 years for new, effective medical research findings to become standard medical practice.¹ For example, there was a reemergence of the use of self-ligating brackets in the mid-1990s amid claims not only of faster ligation but also of quicker and more comfortable treatment. Several prospective clinical trials began to be published in 2005 and then two systematic reviews in 2010 concluded that in fact there was no difference in discomfort or treatment time when self-ligating brackets were used compared with conventional brackets. Yet despite the weight of evidence, these claims of faster treatment times and less discomfort are still made and supported by many orthodontists. As Dr Lysle Johnston, Jr, pointed out, our specialty tends to have a pessimistic attitude toward evidence and a minimal capacity to judge its quality. But what effect does this pessimism have on our patients? Can we as an orthodontic profession really wait 17 years to incorporate emerging quality evidence into our clinical practices?

With the exponential growth of information in today’s world, how does the busy orthodontist evaluate evidence that will affect his or her practice? This book was conceived out of a need for evidence regarding relevant clinical topics and ongoing controversies in orthodontics such as early treatment, bonding protocols, treatment of Class II and Class III malocclusions, asymmetries, impacted canines, root resorption, retention, and accelerated tooth movement. We have done our best to incorporate the best evidence available regarding these topics, and hopefully this book will show you not only how to judge quality evidence but also why it is so important to implement it.

Reference

1. Institute of Medicine. Crossing the Quality Chasm: A New Health System for the 21st Century. Washington, DC: National Academies Press, 2001.

Acknowledgments

This book would not have been possible without the support of the publisher, Quintessence, and the tedious and dedicated work of our editor, Leah Huffman. We especially want to thank all of the contributing authors who have taken the time to write chapters in this book.

Contributors

Tiziano Baccetti, DDS, PhD*

Assistant Professor

Department of Orthodontics

University of Florence

Florence, Italy

Thomas M. Graber Visiting Scholar

Department of Orthodontics and Pediatric Dentistry

University of Michigan School of Dentistry

Ann Arbor, Michigan

William A. Brantley, PhD

Professor and Director

Graduate Program in Dental Materials Science

Division of Restorative, Prosthetic, and Primary Care

Dentistry

College of Dentistry

The Ohio State University

Columbus, Ohio

Lam L. Cheng, BDSc, MDSc, MOrth RCS (ED),

MRACD (Ortho)

Honorary Associate Professor

Department of Orthodontics

Faculty of Dentistry

The University of Sydney

Sydney, Australia

M. Ali Darendeliler, BDS, PhD, Dip Orth, Certif Orth,

Priv Doc, MRACD (Ortho)

Professor and Chair

Department of Orthodontics

Faculty of Dentistry

The University of Sydney

Sydney, Australia

Theodore Eliades, DDS, MS, Dr Med, PhD

Professor and Director

Department of Orthodontics and Pediatric Dentistry

University of Zurich

Zurich, Switzerland

Sanjivan Kandasamy, BDSc, BSc Dent, Doc Clin

Dent, MOrth RCS, MRACDS

Clinical Senior Lecturer

Department of Orthodontics

University of Western Australia

Perth, Australia

Adjunct Assistant Professor

Department of Orthodontics

University of Saint Louis

St Louis, Missouri

Eric Liou, DDS

Director

Department of Orthodontics and Craniofacial Dentistry

Chang Gung Memorial Hospital

Taipei, Taiwan

Program Director

Department of Orthodontics

Graduate School of Craniofacial Medicine

Chang Gung University

Taoyuang, Taiwan

Peter G. Miles, BDSc, MDS

Senior Lecturer

Department of Orthodontics

University of Queensland School of Dentistry

Brisbane, Australia

Visiting Lecturer

Graduate Program in Orthodontics

Seton Hill University Center for Orthodontics

Greensburg, Pennsylvania

Private practice

Caloundra, Australia

Peter Ngan, DMD

Professor and Chair

Department of Orthodontics

West Virginia University School of Dentistry

Morgantown, West Virginia

James Noble, BSc, DDS, MSc, FRCD(C)

Visiting Lecturer

Division of Orthodontics

University of Manitoba

Winnipeg, Manitoba

Canada

Visiting Clinical Lecturer

Graduate Program in Orthodontics

Seton Hill University Center for Orthodontics

Greensburg, Pennsylvania

Nikolaos Pandis, DDS, MS, Dr med dent, MSc

Private practice

Corfu, Greece

Daniel J. Rinchuse, DMD, MS, MDS, PhD

Professor and Associate Director

Graduate Program in Orthodontics

Seton Hill University Center for Orthodontics

Greensburg, Pennsylvania

Donald J. Rinchuse, DMD, MS, MDS, PhD

Professor and Program Director

Graduate Program in Orthodontics

Seton Hill University Center for Orthodontics

Greensburg, Pennsylvania

John J. Sheridan, DDS, MSD

Clinical Associate Professor

School of Orthodontics

Jacksonville University

Jacksonville, Florida

Timothy Tremont, DMD, MS

Clinical Associate Professor

Department of Orthodontics

West Virginia University School of Dentistry

Morgantown, West Virginia

Private practice

White Oak, Pennsylvania

*Deceased.

Introduction: Evidence-Based Clinical Practice

A quandary for the busy orthodontist in clinical practice is, What knowledge and information should I be using in clinical decision making? Some clinicians base their clinical decisions on their own unique observations and experiences, or perhaps even those of an expert currently on the lecture circuit, while other orthodontists base their clinical judgments on the available scientific evidence rather than anecdotal reports. Clinicians may also rotate back and forth between an experience-based and an evidence-based view. In recent years, it has been recognized that the ideal approach to decision making in health care should be based on scientific evidence rather than personal opinions.¹

What is evidence-based dentistry? A recent JADA article by Ismail and Bader² defined evidence-based dentistry as an unbiased approach to oral health care that follows a process of systematically collecting and analyzing scientific evidence with the objective of gaining useful decision-making information with minimal bias. So-called evidence scientists have prioritized each type of evidence according to the importance and weight it is accorded during decision making. At the low end of the hierarchy lies expert opinion, and at the high end lie high-quality meta-analyses and systematic reviews and randomized controlled trials (RCTs) with a very low risk of bias³ (Table 1-1). Being ranked as low-level does not necessarily mean that evidence is false but rather that the priority given to decision making is low because the potential cost versus benefit might be highly unfavorable for large numbers of patients.⁴ In fact, critical discoveries such as penicillin and DNA have emerged from lower levels of evidence. It should also be noted that although RCTs are considered the gold standard for assessing the effectiveness of treatment interventions, implementing them is not always feasible or ethical. For example, it would be unethical to randomize participants to smoking and nonsmoking groups with the objective to evaluate the effect of smoking on lung cancer; in such circumstances, high-quality observational studies must be used to determine causality. Finally, predictive models (prognostic and diagnostic) are best developed using high-quality prospective cohort studies because they are most likely to simulate real-life scenarios.

The orthodontist’s focus for clinical decision making should be on treatment protocols and strategies that are proven to be both efficacious and safe. To facilitate evidence-based decision making, a plethora of guidelines have been developed that aim at improving research methodology, reporting, appraisal, synthesis, and translation of scientific evidence into clinical practice. The EQUATOR Network website is an excellent source for accessing reporting guidelines.⁵ Among the guidelines pertinent to orthodontics are the CONSORT (Consolidated Standards of Reporting Trials),⁶ PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses),⁷ STROBE (Strength ening the Reporting of Observational Studies in Epidemiology),⁸ MOOSE (Meta-analyses of Observational Studies in Epide-miology),⁹ STARD (Standards for Reporting of Diagnostic Accuracy),¹⁰ AMSTAR (Assessment of Multiple Systematic Reviews),¹¹ SORT (Strength of Recommendation Taxonomy),¹² and the Cochrane risk of bias tools.¹³ These guidelines were developed and are continuously updated by evidence-based expert teams.

At the core of the Cochrane collaboration (www.cochrane.org) is a database that prepares, maintains, updates, and promotes systematic reviews. Since its inception in 1993, over 15,000 contributors from over 100 countries have been involved with the Cochrane collaboration, making it the largest organization related to this type of work.¹³

In the past, narrative reviews were the only form in which multiple studies on a particular topic were reported in peer-reviewed journals. Narrative reviews are associated with a high risk of bias because they offer no systematic, transparent method for searching for studies, including studies, appraising the studies that are included, or conducting data abstraction and qualitative or quantitative (Fig 1-1). (meta-analysis) synthesis Recognition of these shortcomings opened the way to systematic reviews, which, if properly conducted, are more useful for resolving controversies and provide more accurate intervention effect estimates, thus powering the cycle of knowledge (Fig 1-2). As previously mentioned, systematic reviews require transparent and carefully controlled methodology in order for their results to be valid because combining mismatched data may justify the well-known GIGO (garbage in, garbage out) label.¹⁴ The main biases encountered with systematic reviews are selection bias (selective study inclusion), publication bias (studies with significant results are more likely to be published than studies with nonsignificant results), and heterogeneity of quality of included studies. The inclusion in systematic reviews of only a portion of the available studies, which are not sufficiently homogenous in quality, number of participants, interventions, and outcomes, impedes the generation of valid results. ¹³

Fig 1-1 Types of reviews.

Fig 1-2 The cycle of knowledge.

An important consideration is the translation of scientific evidence into clinical practice. Several tools have been developed to help clinicians make sense of and apply the published scientific evidence. One of the most recent initiatives aimed at bridging the gap between evidence and clinical practice is GRADE (Grading of Recommendations, Assessment, Development, and Evaluation),¹⁵ which also has been incorporated into the Cochrane systematic reviews. The GRADE approach postulates that clinical practice guidelines should consider not only the quality of the available evidence but also the values and preferences of patients, its safety, and its cost¹⁶ (Fig 1-3). This approach has only two recommendation levels: strong and weak. GRADE recognizes all outcomes and classifies them as either critical, important but not critical, or not important. The evidence is then graded for all outcomes and is assigned one of four ratings, as shown in Table 1-2. After deliberation, a recommendation—either strong or weak—is given, depending on the previous information and whether there is one approach accepted across the board (strong recommendation) or alternative options for the patient are available that he or she is likely to accept and follow. In other words, according to GRADE, based on the available evidence, if we are certain that the benefits clearly outweigh the risks and other burdens, then we are likely to make a strong recommendation regarding the intervention of interest. For example, when deciding between full orthodontic bonding and full banding from molar to molar, a strong recommendation for bonding may be given because the benefits of bonding compared with banding clearly outweigh the risks and other burdens. A myopic approach would be to consider only the fact that bands might have lower failure rates compared with brackets. A more appropriate approach would be to consider other associated outcomes, such as time required to band, patient discomfort, periodontal problems, decay under failing bands, patient esthetics, extra space required and increased probability for extractions, and cost.

Fig 1-3 Determinants of the strength of recommendation according to GRADE.¹⁶

However, if benefits and risks are balanced or if there is uncertainty about the benefits and risks, then a weak recommendation is likely. For example, when deciding between one-stage and two-stage orthodontic treatments in the absence of clear evidence favoring either approach, fully informed patients are likely to make different choices depending on their values and preferences. While a patient with a large overjet who is concerned about esthetics and potential damage of the maxillary front teeth might opt for early treatment, a more cost-conscious patient may choose the one-stage treatment approach.

Forrest and Miller¹⁷ defined evidence-based clinical practice (EBCP) as the integration of the best research evidence with clinical expertise and patient values. It integrates scientific or evidence-based orthodontics with patient preferences and patient autonomy, clinical or patient circumstances, and clinical experience and judgment. Pertinent to this paradigm is the dictum made by Dr Lawrence Jerrold¹⁸: Never treat a stranger. Knowing the patient’s chief complaint and obtaining a complete patient history (medical, dental, and social) are essential. According to Principle 1 of the American Association of Orthodontists’ Principles of Ethics and Code of Professional Conduct,¹⁹ Members shall be dedicated to providing the highest quality orthodontic care to their patients within the bounds of the clinical aspects of the patient’s conditions, and with due consideration being given to the needs and desires of the patient.

In the past, orthodontics, like medicine, was to an extent paternalistic (ie, the doctor knows what is best, and the patient should not question his or her recommendations). Currently, however, orthodontics is practiced with the requirement of obtaining informed consent from patients who are autonomous and have a right to govern their health care as long as it does no harm. This, coupled with a multitude of information and misinformation that is easily accessible by patients, challenges orthodontists to effectively communicate with their patients.

Clinical practice requires clinical experience and judgment in formulating treatment decisions. Because there are no universally accepted protocols in orthodontic practice, orthodontists may default to what they know best or what works in their hands. At the same time, they may be required to make a choice in using a particular treatment technique without having had appropriate training, such as the use of orthodontic temporary skeletal anchorage devices. Orthodontic manufacturers are often in a position to provide this training, but their primary motivation may be to sell product and not to provide clinicians with objective education. Perhaps the lack of science may be not only a result of the lack of orthodontist demand for it but also related to the knowledge that errors in orthodontic treatment usually do not affect patients’ lives to the same extent as potential harm from drugs or major surgery. How else might we account for the lack of universally accepted treatment modalities and yet a vast array of opinions and beliefs by orthodontists?

O’Brien and Sandler²⁰ argue that clinical decisions are largely governed by anecdotal evidence and the training and experience of the clinician. This may lead clinicians to remember their good cases that are often several standard deviations from the mean. The results of orthodontic trials are often refuted by the clinician because they may challenge long-held beliefs (cognitive biases). As pointed out by Hicks and Kluemper,²¹ our brains generally use two modes of reasoning: heuristic or so-called right-brain (intuitive, automatic, implicit processing) and analytic or left-brain (deliberate, rule-based, explicit processing) reasoning. Cognitive biases and errors in clinical orthodontics arise under conditions of uncertainty, leading to greater reliance on heuristic thinking and possibly predictable errors in judgment.

Given the overwhelming volume of orthodontic literature published each year, how does the busy clinician have the time to read and make sense of the available evidence and then apply it to daily practice? The recent emphasis on systematic reviews and meta-analyses may allow the practicing orthodontist better access to the totality of evidence during clinical practice. On the other hand, because systematic reviews are relatively new in the field of orthodontics and there is a lack of high-quality studies, the results are often inconclusive and necessitate further high-quality research. However, the introduction of systematic reviews in conjunction with the refinement of clinical trial methodology and the standardization of publication guidelines is likely to increase the quality of orthodontic evidence in the long term. Already the American Dental Association (ADA) has developed an evidence-based website²² with the objective of publishing critical summaries of systematic reviews from dental research that would present the available evidence, conclusions, and clinical recommendations to the practicing dentist.

With EBCP, there is more potential to be critical and questioning of new technologies, biased views, and unsubstantiated claims. For instance, in the past, even though the straight-wire or pre-adjusted edgewise appliances achieved universal acceptance, few had scrutinized whether they had any clinical advantages or disadvantages like we have done and currently do for self-ligating brackets. Do they shorten treatment time, reduce chair time, or lessen discomfort? Are they more hygienic, and do they achieve superior treatment results? Harradine pointed out that no study ever demonstrated that pre-adjusted edgewise appliances were superior to plain edgewise, but the former are overwhelmingly preferred for reasons that are regarded by clinicians as being self-evident and in no need of the highest order of scientific proof.²³ For example, in a retrospective study comparing the treatment results of the Roth (straight-wire) appliance and standard edgewise appliance using two occlusal indices, no significant differences were found between the two appliances.²⁴ In fact, despite using the Roth appliance, experienced orthodontists still found it difficult to obtain all of Andrews’s Six Keys to Normal Occlusion.²⁵

In summary, orthodontics has been described as an art and a science, but the art in the practice of orthodontics seems to have eclipsed the science. This chapter presented the rationale for incorporating an EBCP model into clinical practice. Also, a cursory review of the current guidelines and standards for developing and reporting RCTs, systematic reviews, and meta-analyses were described. The purpose of this book is to provide the orthodontist with an evidence-based perspective on a variety of important orthodontic topics and to challenge the practicing orthodontist to reflect on his or her current treatment protocols from an evidence-based perspective. Dr Lysle Johnston, Jr, has questioned the value our profession has for academia and science, stating that In effect, the specialty will have to decide if academia is anything more than a front for a calling that seems to have decided that science is irrelevant . . . and to survive, more is needed than fantastic hands and great results. Easier, quicker, better: in 2011, any two will do.²⁶ Perhaps this book will give the practitioner more appreciation of what academics and researchers do and how evidence impacts clinical orthodontic decision making and practice.

References

1. Rinchuse DJ, Rinchuse DJ, Kandasamy S. Evidence-based versus experienced-based views on occlusion and TMD. Am J Orthod Dentofacial Orthop 2005;127:249–254.

2. Ismail AI, Bader JD. Practical science: Evidence-based dentistry in clinical practice. J Am Dent Assoc 2004;135:78–83.

3. Harbour R, Miller J. A new system for grading recommendations in evidence based guidelines. BMJ 2001;323:334–336.

4. Santoro MA, Gorrie TM (eds). Ethics and the Pharmaceutical Industry. Cambridge: Cambridge University Press, 2005.

5. Equator Network. http://www.equator-network.org. Accessed 3 February 2012.

6. Moher D, Hopewell S, Schulz KF, et al. CONSORT 2010 explanation and elaboration: Updated guidelines for reporting parallel group randomised trials. Int J Surg 2012;10:28–55.

7. Liberati A, Altman DG, Tetzlaff J, et al. The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: Explanation and elaboration. J Clin Epidemiol 2009;62:e1–e34.

8. von Elm E, Altman DG, Egger M, et al. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: Guidelines for reporting observational studies [in Spanish]. Rev Esp Salud Publica 2008;82:251–259.

9. Stroup DF, Berlin JA, Morton SC, et al. Meta-analysis of observational studies in epidemiology: A proposal for reporting. Meta-analysis Of Observational Studies in Epidemiology (MOOSE) group. JAMA 2000;283:2008–2012.

10. Bossuyt PM, Reitsma JB, Bruns DE, et al. Towards complete and accurate reporting of studies of diagnostic accuracy: The STARD initiative. The Standards for Reporting of Diagnostic Accuracy Group. BMJ 2003;326:41–44.

11. Shea BJ, Grimshaw JM, Wells GA, et al. Development of AMSTAR: A measurement tool to assess the methodological quality of systematic reviews. BMC Med Res Methodol 2007;7:10.

12. Ebell MH, Siwek J, Weiss BD, et al. Strength of recommendation taxonomy (SORT): A patient-centered approach to grading evidence in the medical literature. Am Fam Physician 2004;69:548– 556.

13. Higgins JPT, Green S (eds). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 [updated March 2011]. The Cochrane Collaboration 2011. Available from www.cochrane-handbook.org. Accessed 3 February 2012.

14. Borenstein M, Hedges LV, Higgins JPT, Rothstein HR. Introduction to Meta-Analysis. Chichester: Wiley, 2009.

15. GRADE Working Group website. http://www.gradeworkinggroup.org. Accessed 8 February 2012.

16. Guyatt G, Oxman AD, Akl EA, et al. GRADE guidelines: 1. Introduction—GRADE evidence profiles and summary of findings tables. J Clin Epidemiol 2011;64:383–94.

17. Forrest JL, Miller SA. Evidence-Based Decision Making: A Traditional Guide for Dental Professionals. Philadelphia: Lippincott, Williams & Wilkins, 2008.

18. Jerrold L. Litigation, legislation, and ethics. When patients lie to their doctors. Am J Orthod Dentofacial Orthop 2011;139:417–418.

19. The American Association of Orthodontists. Principles of Ethics and Code of Professional Conduct, adopted May 1994, amended 2005.

20. O’Brien K, Sandler J. In the land of no evidence, is the salesman king? Am J Orthod Dentofacial Orthop 2010;138:247–249.

21. Hicks EP, Kluemper GT. Heuristic reasoning and cognitive biases: Are they hindrances to judgments and decision making in orthodontics? Am J Orthod Dentofacial Orthop 2011;139:287–304.

22. ADA Center for Evidence-Based Dentistry. http://ebd.ada.org. Accessed 3 February 2012.

23. Harradine N. Northcroft Memorial Lecture self-ligation: Past, present and future. J Orthod 2009;36:260–271.

24. Kattner PF, Schneider BJ. Comparison of Roth appliance and standard edgewise appliances treatment results. Am J Orthod Dentofacial Orthop 1993;103:24–32.

25. Andrews LF. The six keys to normal occlusion. Am J Orthod 1972; 62:296–309.

26. Bowman SJ. Educator profile: An interview with Dr J Lysle E. Johnston, Jr, DDS, MS, PhD: Part 1. Orthod Pract US 2011;2:6–9.

Early Intervention: The Evidence For and Against

In this chapter, various aspects of early intervention are evaluated, and some of the controversies surrounding early intervention are examined. Topics covered include the advantages and disadvantages of early treatment, early expansion, E-space preservation, and the efficacy of the mandibular lingual arch.

Class II Early Treatment

Because of the controversy regarding early treatment and particularly early treatment of Class II malocclusion, the arguments against and for early treatment are presented separately.

The evidence against early treatment

The early randomized controlled trial (RCT) studies showing no efficacy are primarily those regarding treatment of Class II malocclusions with functional appliances such as the bionator, Fränkel, twin block, headgear, or bite plate.¹–⁴ These studies show a temporary effect of functional appliances in early phase I or stage 1 treatment, but the effects are lost during the second phase, so there is no net effect. Dr Lysle Johnston calls this process a mortgage on growth,⁵ meaning that you borrow a little growth prematurely during phase I treatment, but you pay it back later. Therefore, the overall effect of the second phase of treatment is the same as that obtained in patients who received late treatment only. In other words, you cannot grow mandibles, and there is limited advantage to two-stage treatment.

However, these RCTs are best for establishing causality, and because they are generally highly controlled with a narrow perspective, they might not be suitable for generalizations. Other limitations of RCTs, particularly in regard to efficacy of Class II treatment outcomes, include the following: They are expensive and time-consuming; clinical trials with orthodontic appliances are difficult because the appliance is one of several factors affecting the outcome; blinding is rarely possible; compliance is mostly self-reported; dropouts may be the ones not responding to treatment; and results show the average effect of treatment and disregard the many phenotypes of Class II, allowing the possibility that a more refined, stratified sample would produce different results.

The Cochrane Review has provided systematic reviews of literature based on primary research⁶ with very low levels of bias with regard to early intervention with functional appliances for treatment of Class II malocclusions. For Class II, division 1 malocclusions, the evidence suggests that there is no advantage to providing two-stage orthodontic treatment for children with prominent maxillary anterior teeth over one-stage treatment during early adolescence.⁷ Early orthodontic treatment seems to have no real effect on the overall outcome of treatment during adolescence. There appear to be minor improvements to the skeletal pattern when functional appliances are used in early adolescence, but these changes do not appear to be clinically significant.⁷

An RCT was designed to evaluate the efficacy of early orthodontic treatment of Class II malocclusion on the incidence of incisor trauma in the initial phase of treatment in headgear or bite plane, bionator, and observation (no treatment) groups followed by a second phase with fixed appliances.⁸ In this investigation, early treatment was shown not to affect the incidence of incisor injury, and the majority of injuries that occurred before or during treatment were minor. Thus, the cost-benefit ratio of orthodontic treatment primarily to prevent incisor injury may not be justified. In this study, it was reported that a significant number of the children already had some incisor trauma before early orthodontic treatment commenced, and early orthodontic treatment would need to start at the time the permanent maxillary incisors erupted in order to evaluate the effectiveness of preventing dental injuries. Therefore, further research is needed to support the claim that certain Class II malocclusions with maxillary protrusion have accident-prone profiles and warrant early orthodontic treatment from a cost-benefit perspective.

Von Bremen and Pancherz⁹ showed that for Class II, division 1 malocclusion, treatment in the permanent dentition was more efficient for both duration and outcome than treatment in early or late mixed dentition. In addition, treatment