Understanding Masticatory Function in Unilateral Crossbites

Maria Grazia Piancino, MD, DDS, PhD, is Aggregate Professor and Researcher in orthodontics at the University of Turin, Turin, Italy. She has more than 25 years’ experience in clinical orthodontics and related research. Dr. Piancino has written for numerous international peer-reviewed publications in the field and lectures on mastication, chewing cycles, and orthodontics at scientific conferences and professional meetings internationally. She is widely regarded as an expert in chewing patterns. Stephanos Kyrkanides, DDS, MS, PhD, is Associate Dean for Research and Faculty Development, and Professor and Chair, Department of Orthodontics and Pediatric Dentistry, Stony Brook University School of Dental Medicine, Stony Brook, New York.

Foreword vii

Preface viii

How to Use This Book x

Acknowledgments xi

Chapter 1 Introductory Explanation of Masticatory Function 1

1.1 Introduction 2

1.2 The study of masticatory function 6

1.3 The evolution of electrognathography and electromyography 10

1.4 From the 1980s to today 23

1.5 Ready to start 24

References 26

Chapter 2 Physiology of Mastication: The Chewing Pattern and Masticatory Function 28

2.1 Introduction 29

2.2 Features of masticatory function 29

2.3 Terminology 34

2.4 The chewing pattern 37

2.5 The chewing pattern as an indicator of masticatory function 43

References 58

Chapter 3 Physiology of Mastication: Neuromuscular Control of Masticatory Function 61

3.1 Importance of the motor activity 62

3.2 The nervous system 65

3.3 Receptors in the stomatognathic system 69

3.4 Reflex movements 76

3.5 Automatic movements 77

3.6 Motor control: feedback and feed-forward 81

3.7 Neuromuscular control 83

3.8 Coordination of masticatory muscles during mastication 87

3.9 Neuromuscular adjustment to load 91

References 94

Chapter 4 Alterations to Masticatory Function in Unilateral Crossbites 98

4.1 Introduction 99

4.2 Crossbite=neuromuscular syndrome 100

4.3 Unilateral posterior crossbite 107

4.4 Alteration to masticatory function in unilateral posterior crossbite 112

4.5 Anterior crossbite=neuromuscular syndrome 136

References 141

Chapter 5 Therapy with Function Generating Bite Appliance: Actions and Effects on Malocclusion and Masticatory Function 144

5.1 Orthognathodontic therapy aimed to restore physiological neuromuscular equilibrium to the stomatognathic system 145

5.2 Dental–alveolar–basal actions and effects of function generating bite appliances 149

5.3 Therapy timing and duration and caries-free management 181

5.4 Compliance 182

References 182

Chapter 6 Cases 185

6.1 Introduction 186

6.2 Case 1: Right unilateral posterior crossbite (3 years, 9 months) 186

6.3 Case 2: Right unilateral posterior crossbite (6 years, 4 months) 189

6.4 Case 3: Positional crossbite (7 years, 6 months) 193

6.5 Case 4: Left unilateral posterior crossbite (7 years, 11 months) 200

6.6 Case 5: Right unilateral posterior crossbite (10 years, 3 months) 205

6.7 Case 6: Anterior open bite and left unilateral posterior crossbite (7 years, 9 months) 209

6.8 Case 7: Anterior open bite and bilateral posterior crossbite (7 years, 8 months) 215

References 215

Appendix 225

Index 227