Dentofacial and Occlusal Asymmetries

Birte Melsen is Visiting Professor of Orthodontics at the College of Dentistry, New York University in the USA and was Professor and Head of Orthodontics at Aarhus University in Denmark. Athanasios E. Athanasiou is Dean and Professor of Orthodontics at the School of Dentistry, European University Cyprus in Cyprus and Honorary Professor of Orthodontics at Mohammed Bin Rashid University of Medicine and Health Sciences in the UAE. He was Dean, Professor and Head of Orthodontics at the School of Dentistry, Aristotle University of Thessaloniki, Greece.

• List of Contributors xiv1 Introduction 1Birte Melsen and Athanasios E. AthanasiouReferences 3Part I Etiology 52 The Etiology of Dentofacial and Occlusal Asymmetries – An Overview 7Birte MelsenIntroduction 7Congenital 7Postnatally 8References 143 Congenital 153.1 Distortion/Malformation 16Pertti PirttiniemiEtiology – Definition 16Craniosynostosis 16Plagiocephaly 17Muscular Torticollis 17Developmental Dysplasia of the Hip 18Scoliosis 18Hemifacial Hyperplasia 18References 193.2 Syndromes and Rare Diseases with Asymmetry in the Craniofacial and Dental Regions 21Hans Gjørup and Dorte HaubekSyndromes and Rare Diseases 21Unilateral Overgrowth of Craniofacial or Dental Structures 22Unilateral Underdevelopment of Craniofacial or Dental Structures 25References 334 Acquired 374.1 Acquired Dentofacial Deformity and Asymmetry 38Peter B. Stoustrup and Thomas Klit PedersenIntroduction 39The Temporomandibular Joint (TMJ) and Its Association with Asymmetric Dentofacial Development 39Dental Occlusion and Acquired Skeletal and Dental Asymmetries 40Acquired Dentofacial and Dental Asymmetries 40Autoimmune Conditions 41Skeletal Growth Diseases 44Conditions with Skeletal Undergrowth 44Conditions with Skeletal Overgrowth 45Soft-tissue Conditions 46Temporomandibular Joint (TMJ) Conditions 46Temporomandibular (TMJ) Disc Displacement (Internal Derangement) 47Management of Acquired Dentofacial Deformity and Asymmetry 47Conclusion 50Acknowledgment 50References 51Part II Localization and Problem List 535 Examination of Special Features in Patients with Dentofacial and Occlusal Asymmetries 55Athanasios E. Athanasiou and Birte MelsenIntroduction 55Head Posture 56Functional Assessment 58Photographic Assessment 61Conclusion 61References 676 Imaging: Craniofacial Asymmetries 69David C. Hatcher and Vidhya VenkateswaranIntroduction 69Asymmetry 70Differential Diagnosis and Decision Tree for a Craniofacial Asymmetry 70Imaging for Asymmetry 70Analysis 71Overall Regional Changes Associated with the Developmental Onset of TMJ Disorders 72Common Disorders and Associated Local and Regional Changes 74Conclusions 78References 817 Cephalometric Radiographic Assessment of Facial Asymmetry 82Guilherme Janson and Aron Aliaga-Del CastilloIntroduction 82Radiographic Methods for Diagnosis of Asymmetry 82Concluding Remarks 89References 898 EMG and Ultrasonography of Masticatory Muscles 91Stavros KiliaridisIntroduction 91Understanding the Functional Profile of the Muscle 91Clinical Methods to Record Masticatory Muscles Functional Capacity 92Posterior Crossbite with Functional Shift. Effects on Masticatory Muscles? 95References 969 Localization and Problem List – 3-D Face Reconstruction 99Karine Evangelista, Camila Massaro, Antonio Carlos de Oliveira Ruellas, and Lucia H. Soares CevidanesIntroduction 99Facial Asymmetry Diagnosis and Complementary Exams for Facial Asymmetry Localization 100Image Analysis in CBCT Scans for Skeletal Asymmetry 102Head Orientation 102Scroll Through All Cross-Sectional Slices 102Assessment of the 3D Rendering Viewing from Different Perspectives 104List of Problems in Skeletal Craniofacial Asymmetries Through 3D Assessment 104Zygomatic and Maxillary Unilateral Hypertrophy 105Sinus and Maxillary Hypoplasia 105Unilateral Condylar Hyperplasia 107Unilateral Condylar Resorption 109Craniofacial Macrosomia 110Asymmetry Localization and Quantification 110Mirroring and Superimposition 111Quantification 113Determining the Asymmetry Directions 114Final Considerations 114Acknowledgments 114References 114Part III Management 11710 Treatment Approaches 11910.1 Very Early Treatment of Dentofacial Asymmetries: Why, When, and How? 120Ute E.M. Schneider-Moser and Lorenz MoserIntroduction 120Etiology 121Diagnostic Evaluation 121Very Early Treatment for Unilateral Posterior Crossbite with Class I, II, III Malocclusion 123What if a Class II Subdivision Develops After Early Crossbite Correction? 132What About Stability of Very Early Crossbite Correction? 141Summary 141References 14210.2 Tooth Movement and Goal-oriented Mechanics in the Treatment of Patients ExhibitingAsymmetry 144Bhavna Shroff, Steven M. Siegel, Steven J. Lindauer, and Birte MelsenIntroduction 144Diagnosis – Problem List 145Molar Rotation (First Order) 147Molar Tipping (Second Order) 149Posterior Crossbite (Third Order) 150Early Loss of Mandibular Deciduous Canines 150Treatment 152Correction of Unilateral Molar Rotation 152Current Mechanics Used to Correct a Class II Subdivision Malocclusion 153Unilateral Tip-back Mechanics 156Conclusion 158References 15911 Treatment Principles 16111.1 Dentofacial Orthopedics in the Management of Hemifacial Microsomia and Nager Syndrome Cases 162Birte Melsen and Athanasios E. AthanasiouIntroduction 162Case Reports 163Discussion 171Conclusion 173References 17311.2 Rational Diagnosis and Treatment of Dental Asymmetries 175Joseph Bouserhal, Nikhillesh Vaiid, Ismaeel Hansa, Zakaria Bentahar, Lea J. Bouserhal, and Philippe J. BouserhalIntroduction 175Classification of Dental Asymmetries 176Diagnosis of Dental Asymmetries 176Management of Posterior Dental Asymmetries 179Management of Anterior Dental Asymmetries 181Conclusions 195Acknowledgment 195References 19512 Orthodontics, Maxillofacial Surgery, and Asymmetries 19612.1 Dental Arch Shape in Relation to Class II Subdivision Malocclusion 197Birte Melsen and Padhraig S. FlemingIntroduction 197Dental Arch Form 197Case 1 198Case 2 199Discussion 199References 20712.2 Asymmetric Application of Lingual Arches 208Kwangchul ChoyIntroduction 208Color Code of the Wire and Force System 209Shape-driven Concept 209Force-driven Concept and Definition of Shapes 210Unilateral Expansion 210Simulation of Force System 211Unilateral Tip-back and Unilateral Tip-forward 214Summary 216References 21912.3 Skeletal Anchorage for the Correction of the Canted Occlusal Plane 220George Anka and Athanasios E. AthanasiouTreatment of the Canted Occlusal Plane 220Biomechanics for the Correction of the Canted Occlusal Plane 225The Trans-Palatal Arch (TPA) Plus Hooks 225Details of TPA Plus Hooks 231The Propeller 237The Ulysses and the Anka-Jorge Plate 240Extrusion 247Conclusion 251References 25412.4 Managing the Class II Subdivision Malocclusion with Extraction Camouflage: Case Reports 256Cesare Luzi and Emese SzabòIntroduction 256Case 1 256Case 2 259Conclusions 264References 26812.5 The Use of Aligners for Correction of Asymmetries 269Eugene Chan and M. Ali DarendelilerIntroduction 269Dental Corrections (Non-extraction Therapies) 270Dental Corrections (Extraction Therapies) 285Skeletal Anchorage Therapies 294Surgical Intervention 309Conclusions 321References 32812.6 TMJ Conditions Causing Facial Asymmetry: Diagnosis and Treatment 329Larry M. WolfordIntroduction 329Overdevelopment 329Unilateral Facial Under-development 335Adolescent Internal Condylar Resorption (AICR) 336Reactive Arthritis 338Trauma 339TMJ Ankylosis 339Hemifacial Microsomia (HFM) 341Connective Tissue/Autoimmune Diseases (CT/AI) 344References 34612.7 Distraction Osteogenesis in Maxillofacial Surgery 351Ioannis Iatrou and Nadia Theologie-LygidakisIntroduction 351Biological Basis 351Staging of Distraction Osteogenesis 352Indications for Distraction Osteogenesis 352The Distractors and Their Function 353Preoperative Patient Evaluation 353Surgical Procedure 354Postoperative Procedure – Activation of the Device 358Complications 359Orthodontic Collaboration 361Distraction Osteogenesis and/or Conventional Orthognathic Surgery 362Conclusion 362References 36212.8 Maxillo-mandibular Growth in Hemifacial (or Craniofacial) Microsomia 364Maria Costanza Meazzini di SeysselIntroduction – Clinical Appearance 364Craniofacial Growth in Hemifacial Microsomia 364Long-term Growth After Distraction Osteogenesis of the Mandible 368Long-term Results After Costochondral Graft in Growing Patients with Hemifacial Microsomia 368Clinical and Prognostic Differences in the Orthopedic and Surgical Treatment of Hemimandibular Hypoplasia in Hemifacial Microsomia versus Pseudo-hemifacial Microsomia (or Condylar Coronoid Collapse Deformity) 371References 37712.9 Special Treatment Considerations of Face Asymmetries 380Giampietro FarronatoIntroduction 380Diagnosis 380Categories of Asymmetry 384Special Treatment Considerations 393References 40412.10 The Vertical Component of Asymmetry: Etiology and Treatment 406Joseph G. GhafariThe Three-dimensional Nature of Asymmetry 406Interaction between Maxillary and Mandibular Asymmetries 407Unimaxillary Vertical Asymmetry not Affecting the Symmetry of the Other Jaw 411Conclusion 416References 41612.11 Helping Children and Their Families with Facial Differences – Patient Centered Outcomes and Experiences 418Eleftherios G. KaklamanosIntroduction 418The Face as a Functional Structure and as an Element of Identity 419The Facial Difference from the Patient’s Perspective 420The Facial Difference from the Family Perspective 422Psychosocial Support for Children and Families 422References 423Index 429