Essentials of orthodontics

Essentials of ORTHODONTICS Aravind Sivaraj BDS MDS Professor and Head Department of Orthodontics Chhattisgarh Dental College and Research Institute Rajnandgaon, Chhattisgarh, India Foreword A Venkatesan ® JAYPEE BROTHERS MEDICAL PUBLISHERS (P) LTD New Delhi • London • Philadelphia • Panama www.ajlobby.com ® Jaypee Brothers Medical Publishers (P) Ltd Headquarters Jaypee Brothers Medical Publishers (P) Ltd 4838/24, Ansari Road, Daryaganj New Delhi 110 002, India Phone: +91-11-43574357 Fax: +91-11-43574314 Email: jaypee@jaypeebrothers.com Overseas Offices J.P Medical Ltd 83, Victoria Street, London SW1H 0HW (UK) Phone: +44-2031708910 Fax: +02-03-0086180 Email: info@jpmedpub.com Jaypee-Highlights Medical Publishers Inc City of Knowledge, Bld 237, Clayton Panama City, Panama Phone: +507-301-0496 Fax: +507-301-0499 Email: cservice@jphmedical.com Jaypee Brothers Medical Publishers (P) Ltd 17/1-B, Babar Road, Block-B, Shaymali Mohammadpur, Dhaka-1207 Bangladesh Mobile: +08801912003485 Email: jaypeedhaka@gmail.com Jaypee Medical Inc The Bourse 111, South Independence Mall East Suite 835, Philadelphia, PA 19106, USA Phone: + 267-519-9789 Email: joe.rusko@jaypeebrothers.com Jaypee Brothers Medical Publishers (P) Ltd Shorakhute, Kathmandu Nepal Phone: +00977-9841528578 Email: jaypee.nepal@gmail.com Website: www.jaypeebrothers.com Website: www.jaypeedigital.com © 2013, Jaypee Brothers Medical Publishers All rights reserved No part of this book may be reproduced in any form or by any means without the prior permission of the publisher Inquiries for bulk sales may be solicited at: jaypee@jaypeebrothers.com This book has been published in good faith that the contents provided by the author contained herein are original, and is intended for educational purposes only While every effort is made to ensure accuracy of information, the publisher and the author specifically disclaim any damage, liability, or loss incurred, directly or indirectly, from the use or application of any of the contents of this work If not specifically stated, all figures and tables are courtesy of the author Where appropriate, the readers should consult with a specialist or contact the manufacturer of the drug or device Essentials of Orthodontics First Edition: 2013 ISBN:   978-93-5090-329-2 Printed at www.ajlobby.com Dedicated to My father Mr K Sivaraj www.ajlobby.com Contents  vii Foreword In recent years, orthodontics has become one of the most vital subjects for study in the understanding of general dentistry Due to varied reasons, the subject has remained largely unexplored among general practitioners and undergraduate students There has been a huge hurdle for the general practitioners and undergraduates, who want to explore further in the field of orthodontics due to unavailability of compact text, highlighting all the essentials in orthodontics I find, Dr Aravind Sivaraj has made an honest attempt to fill up this lacuna in elaborating all the essentials of practical and clinical orthodontics What makes the book unique and hence worth possessing is its format and a large number of illustrations and diagrams make the understanding of the subject easy It is evident that a lot of meticulous thinking and hard work have gone into this work and the labor would be fruitful if the people for whom it is intended enjoy the book The interest and the efforts of Dr Aravind Sivaraj are highly commendable and the book should stand as an example to other young teachers to emulate I am sure that the book would not only be accepted and appreciated by all, but also many more editions of it, would be published with regular upgradation of the material contained in it A Venkatesan MDS Former Principal, Professor and Head Department of Orthodontics Tamil Nadu Government Dental College and Hospital Chennai, Tamil Nadu, India www.ajlobby.com Contents  ix Preface Essentials of Orthodontics is written in clear and simple language useful for the under­graduates in dentistry, general practitioners and as a quick reference guide for the postgraduates in orthodontics This book is edited from various textbooks, study materials and manuals in orthodontics THe purpose of the book is to educate the students with clear thoughts on the subject with emphasis on the deep understanding of the concepts and theories in orthodontics The text is written for rapid and easy uptake, with only a few classical illustrations and a handful of carefully chosen references Many topics are well covered in other texts, and not need a lengthy description, but where clinical precision or a new concept is involved, a full explanation is provided The book is designed for the dental students, orthodontic residents and general dentists to understand the basic concepts and essential procedures regarding the diagnosis, treatment planning and treatment of patients, who have relatively simple malocclusion problems and to consult the specialist in case of complex problems Readers will essentially learn about the mechanics of how appliances move teeth, the different types of appliances, and the latest orthodontic materials in the market A much-needed text for the dental students and also an excellent resource for dentists, who want to expand their practice The book is not intended to compete with the major texts on the theory and techniques that form the basis of contemporary orthodontic teaching and practice However, the book will be a valuable and welcome addition to the existing texts in orthodontics Orthodontics is constantly changing and has become a dynamic field in dentistry and medicine Rapid advancement in the orthodontic technology and techniques has transformed the field into the first and best specialty in dentistry Every possible step has been taken to prevent any errors and mistakes in the subject; any such occurrence is highly unintended and unfortunate Comments and suggestions are highly appreciated Aravind Sivaraj www.ajlobby.com Contents  xi Acknowledgments I believe that orthodontics is one of the finest professions, as it combines the best of both the science and art of dentistry The greatest appreciation, we can demonstrate to our profession is to impart and pass on knowledge and expertise to students and fellow colleagues First of all, I wish to thank M/s Jaypee Brothers Medical Publishers (P) Ltd, New Delhi, India, for accepting my manuscript for publication into a book I sincerely thank all my teachers, well-wishers, colleagues, friends and students, who inspired me to write the book My heartfelt thanks to my mother, wife, daughter and son Their sacrifices and support have been overwhelming I wish to take this opportunity to express my sincere gratitude to all the people responsible for the publication of the book Finally, I thank God Almighty for this wonderful science of orthodontics www.ajlobby.com Contents  xiii Contents Introduction Introduction to Orthodontics  • Definitions • Orthodontist History of Orthodontics  • Orthodontics in India • Evolution of Orthodontic Appliances Growth and Development General Principles and Concepts  • Definitions • Factors Affecting Physical Growth 10 • Concepts of Growth 11 • Types of Growth Data 17 • Methods of Gathering Growth Data 18 • Methods of Studying Growth 19 • Mechanism of Bone Growth 20 • Osteogenesis (Mechanism of Bone Formation) 20 • Theories of Growth 23 Prenatal Growth and Development  28 • Period of Ovum 28 • Period of Embryo 28 • Prenatal Development of Maxilla 32 • Development of Palate 32 • Development of Maxillary Sinus 33 • Develop­ ment of Tongue 33 • Prenatal Development of Mandible 34 • Meckel’s Cartilage 34 • Endochondral Bone Formation 35 • Prenatal Growth of Temporo­mandibular joint 35 Postnatal Growth and Development  35 • Neonatal Skeleton 36 • Postnatal Growth of the Cranial Vault 36 • Postnatal Growth of the Cranial Base 36 • Postnatal Growth of Maxilla 38 • Postnatal Growth of Mandible 40 • Mandibular Rotation 42 • Postnatal Growth of TMJ 43 Summary of Facial Growth Changes 44 www.ajlobby.com xiv  Essentials of Orthodontics Development of Dentition and Occlusion  44 • Bud Stage 45 • Cap Stage 45 • Bell Stage 45 • Periods of Occlusal Development 46 • Predental Period 46 • Deciduous Dentition Period 48 • Mixed Dentition Period 50 • Permanent Dentition Period 53 Functional Development  57 • Normal Milestones of Development 58 • Puberty and Adolescence 59 • Masti­cation 59 • Deglutition 60 • Respiration 62 • Speech 64 • Trajectories of Force 65 • Wolff’s Law of Transformation of Bone 66 Psychological Development  66 • Psychology (Study of Psyche) 67 • Theories of Psychological Development 67 • Beha­vior in Orthodontics 72 • Behavior Development 73 • Behavior Mana­ge­ment 73 • Basic Approaches to Child Management in Orthodontics 77 • Ephebodontics 77 Clinical Importance of Growth and Development in Orthodontics  78 • Infancy and Early Childhood 78 • Juvenile Period 79 • Adolescent Growth 79 • Clinical Implications of Regional Development 79 Occlusion and Malocclusion 83 Occlusion 83 • Terminology 83 • Types of Cusps 84 • Arrangement of Teeth in Humans 84 • Imaginary Occlusal Planes and Curves 84 • Centric Relation and Cen­tric Occlusion 85 • Centric Contacts 85 • Eccentric Occlusion 86 • Disclu­­­sion 86 • Angle’s Concept of Normal Occlusion 87 • Begg’s Concept of Normal Occlu­sion (Attritional Occlusion) 88 • Roth’s Concept of Functi­­onal Occlusion 88 • Andrews Six Keys to Normal Occlusion 89 Classification of Malocclusion  90 • Malocclusion 90 • Classification 90 • Types of Malocclusion 91 • Systems of Classification 93 Epidemiology of Malocclusion  101 Applications of Epide­mio­logical-Principles 101 • Study Designs 102 • Bias in Research 104 • Statistics Measurement of Data 106 • Hypothesis Testing 106 Indices of Malocclusion  109 • Index 109 Anthropology 117 • Anthropology and Orthodontics 120 • Early Primates 121 Etiology 127 Etiology of Malocclusion  127 • Classification of Etiologic Factors in Malocclusion 127 • Etiology for Specific Types of Malocclusion 133 www.ajlobby.com Contents  xv Habits 135 • Definition 135 • Classification of Habits 135 • Thumb Sucking and Finger Sucking 137 • Tongue Thrusting Habit 142 • Mouth-breathing 147 • Lip Biting and Lip Sucking 151 • Bruxism 151 • Finger Nail Biting 153 • Tongue Sucking 154 • Pillowing Habits 154 Nutrition in Orthodontics  154 • Effect of Nutritional Status on Tooth Movement and Tissue Response to Appli­­­ances 154 • Dietary Counseling for Plaque Control and General Health in the Orthodontic Patient 156 • Nutritional Considerations in the Orthognathic Surgical Patient 156 • Nutritional Factors in the Etiology of Craniofacial Anomalies 157 Genetics in Orthodontics  158 • History 159 • Molecular Basis of Inheritance 159 • Genetics in Orthodontic Perspective 161 Orthodontic Diagnosis 166 Orthodontic Diagnosis  166 • Esthetics in Orthodontics 166 • Golden Section 167 Diagnostic Aids in Orthodontics  171 • Essential Diagnostic Aids 171 • Supplemental Diagnostic Aids 172 • Case History 172 • Clinical and General Examinations 173 • Functional Examination 180 • Orthodontic Study Models 185 • Total Dentition Space Analysis 193 • Inference to Deficits and Decisions 195 • Radiographs Used In Orthodontic Diagnosis 196 Cephalometrics 198 • Facial Photographs 218 Computers in Orthodontics  236 • Characteristics of a Computer 237 • Uses of Computer in Orthodontics 238 Sterilization in Orthodontics  243 • Sterilization 243 Orthodontic Treatment Planning General Factors in Orthodontic Treatment Planning  246 • Setting-up Goals 246 • Enlisting the Treatment Objectives 246 • Age Factor in Orthodontics 249 • Treatment and Age 250 • Tooth Movement and Age 251 • Young Versus Adult Patients 251 • Phases of Orthodontic Treatment 252 • Limitations in Orthodontics 253 Methods of Gaining Space  253 • Proximal stripping (Reprox­i­mi­­zation, Slenderization, Disking and Proximal Slicing) 254 • Expansion 255 • Types of Appliances Used 257 • Slow Expansion 260 www.ajlobby.com 246 ... redirection of the functional forces within the craniofacial complex.” American Association of Orthodontics (1993) American Association of Orthodontics (AAO) renamed the specialty from Orthodontics to Orthodontics. .. of Appliances Used 257 • Slow Expansion 260 www.ajlobby.com 246 xvi  Essentials of Orthodontics • Extractions in Orthodontics 262 • Distalization 267 • Uprighting of Molars 269 • Derotation of. .. mature dentofacial structures, including those conditions that require movement of teeth or correction of malrelationships and malfor­mations of their related structures and 2  Essentials of Orthodontics