Copyright and use of this thesis This thesis must be used in accordance with the provisions of the Copyright Act 1968. Reproduction of material protected by copyright may be an infringement of copyright and copyright owners may be entitled to take legal action against persons who infringe their copyright. Section 51 (2) of the Copyright Act permits an authorized officer of a university library or archives to provide a copy (by communication or otherwise) of an unpublished thesis kept in the library or archives, to a person who satisfies the authorized officer that he or she requires the reproduction for the purposes of research or study. The Copyright Act grants the creator of a work a number of moral rights, specifically the right of attribution, the right against false attribution and the right of integrity. You may infringe the author’s moral rights if you: - fail to acknowledge the author of this thesis if you quote sections from the work - attribute this thesis to another author - subject this thesis to derogatory treatment which may prejudice the author’s reputation For further information contact the University’s Copyright Service. sydney.edu.au/copyright The Sydney Intrusion Spring (SIS): An appliance for the intrusion of posterior maxillary teeth. A Prospective Clinical Study Riaan Foot B.Ch.D, GradDip.Dent (Ortho) Discipline of Orthodontics Faculty of Dentistry University of Sydney Australia A thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Clinical Dentistry (Orthodontics) October 2011 Dedication To my beautiful and loving wife Kristelle, for your love, support and encouragement. You have travelled across the world and sacrificed so much in order for me to fulfil my dreams. I am eternally indebted to you. I love you with all my heart, now and forever. To my mother and father, Elize and Wynand Foot. Thank you for instilling in me the values of hard work, dedication and perseverance. Your love, support and nurturing have made me the man I am today. Thank you for the tremendous sacrifices that you have made over the years, so your children may have a better life. Words will never be enough. To my brother, Adriaan for keeping me grounded. To all the teachers and coaches that I’ve had over the years. Thank you for moulding me, encouraging me and sharing so freely of your time, knowledge and passion. To all my friends, who’ve made life’s journey such an exhilarating, interesting and fruitful experience. Continuous effort - not strength or intelligence - is the key to unlocking our potential. ~Sir Winston Churchill~ 2 | P a g e Acknowledgement Sincere gratitude is expressed to the following: Professor M Ali Darendeliler, Head of Department, Discipline of Orthodontics, University of Sydney for his supervision and support throughout this thesis. Dr Oyku Dalci, Lecturer, Discipline of Orthodontics, University of Sydney for her supervision of the project. Dr Carmen Gonzales, Senior Lecturer, Discipline of Orthodontics, University of Sydney for her supervision of the project. Ms Maria Missikos, Mr’s Steve Warczac, Jose Mendez and Daniel Baek at the Orthodontic Laboratory, SDH for the construction of the bonded acrylic appliance (often to very demanding deadlines) and laboratory support during the project. Mr Chaiy Rungsiyakull and Prof Qing Li at the School of Aerospace, Mechanical and Mechatronic engineering, University of Sydney for the laboratory testing of several generations and incarnations of the Sydney Intrusion Spring. 3 | P a g e Dr Peter Petocz, Department of Mathematical Sciences, Macquarie University for his assistance with the statistical analysis. Ms Natalie Dolnik and American Orthodontics for their generosity in the donation of the miniscrews and surgical equipment used for placement, during the project. Mrs Dee Macpherson and Dentaurum for the generous donation of the β‐titanium wire used in the construction of the Sydney Intrusion Spring. Colgate Oral Care, Australia for the donation of the post‐operative mouthwash used during the project. To those that have provided assistance and guidance in proofreading‐ Dr Olivia Rogers, Dr Sarah Neitzert and Mrs Johanna Rossouw. Your sharp eyes, keen minds and continuous encouragement have been invaluable. Finally, to my classmates and colleagues, Saad Al‐Mozany, Johnathan Grove and Daniel Tan. Truly, no man could have asked for a better ‘bunch of lads’ to undertake this journey of ‘baptism through fire’ with. Your strength of character and dedication has been an inspiration. Thank you for forging the bonds of friendship that will last a lifetime. 4 | P a g e Declaration CANDIDATE CERTIFICATION This is to certify that the candidate carried out the work in this thesis in the Orthodontic Department at the University of Sydney, and this work has not been submitted to any other university or institution for a higher degree. 5 | P a g e Table of Contents Dedication ............................................................................................................................................... 2 Acknowledgement .................................................................................................................................. 3 Declaration .............................................................................................................................................. 5 1. Basic facial growth: ........................................................................................................................... 10 1.1 Maxilla: ........................................................................................................................................ 10 1.1.1 Embryology .......................................................................................................................... 10 1.1.2 Post‐natal Maxillary growth ................................................................................................. 10 1.2 Mandible ..................................................................................................................................... 13 1.2.1 Embryology .......................................................................................................................... 13 1.2.2 Post‐natal Mandibular growth ............................................................................................. 13 2.0 Skeletal Anterior Open Bite malocclusion ...................................................................................... 16 2.1 Definition .................................................................................................................................... 16 2.2 Prevalence ................................................................................................................................... 16 2.3 Aetiology ..................................................................................................................................... 16 2.3.1 Hereditary Factors ............................................................................................................... 17 2.3.2 Environmental Factors ......................................................................................................... 19 2.4 Clinical features ........................................................................................................................... 20 2.5 Cephalometric features .............................................................................................................. 22 2.6 Neuromuscular features ............................................................................................................. 23 2.7 Features of associated malocclusion .......................................................................................... 24 2.8 Differences between Skeletal and Dental Open bite malocclusion ............................................ 24 3.0 Conventional methods of Open bite Treatment ............................................................................. 26 3.1 Extra‐oral appliances ................................................................................................................... 26 3.1.1 Headgear: ............................................................................................................................. 26 3.1.2 Vertical Pull Chin Cup therapy: ............................................................................................ 28 3.2 Functional orthopaedic appliances ............................................................................................. 29 3.2.1 Functional Regulator‐4 appliance (FR‐4): ............................................................................ 29 3.2.2 Bionator/Activator appliance: .............................................................................................. 30 3.3 Orthodontic appliances ............................................................................................................... 31 3.3.1 Passive posterior bite blocks: ............................................................................................... 31 3.3.2 Magnetic bite block appliance: ............................................................................................ 32 3.3.3 Spring‐loaded bite block appliance: ..................................................................................... 33 6 | P a g e 3.3.4 Multiloop Edgewise Archwire therapy (MEAW): ................................................................. 34 3.3.5 Fixed appliances and elastics: .............................................................................................. 35 3.3.6 Other tooth borne intrusion appliances: ............................................................................. 35 3.4 Extraction treatment ................................................................................................................... 36 3.5 Combination Orthodontic and Orthognathic surgical treatment ............................................... 37 3.6 Muscle exercise treatment ......................................................................................................... 39 3.7 Stability of treatment .................................................................................................................. 40 3.7.1 Non‐surgical orthodontic treatment .................................................................................... 40 3.7.2 Combined orthodontic‐orthognathic surgical treatment .................................................... 42 4.0 Skeletal anchorage and molar intrusion ......................................................................................... 44 4.1 History ......................................................................................................................................... 44 4.2 Animal studies ............................................................................................................................. 45 4.3 Human studies ............................................................................................................................ 46 4.4 Physiological effects of molar intrusion ...................................................................................... 51 4.4.1 Periodontal implications ...................................................................................................... 51 4.4.2 Pulpal neurovascular implications ....................................................................................... 51 4.4.3 Root resorption .................................................................................................................... 52 4.4.4 Adjacent anatomical structures ........................................................................................... 53 4.5 Stability of molar intrusion treatment using skeletal anchorage ............................................... 53 5.0 Biomechanics .................................................................................................................................. 55 5.1 Intrusion ...................................................................................................................................... 55 5.2 Orthodontic Miniscrew anchorage ............................................................................................. 56 5.2.1 History .................................................................................................................................. 56 5.2.2 Miniscrews versus miniplates .............................................................................................. 57 5.2.3 Miniscrew placement ........................................................................................................... 58 5.2.4 Miniscrew loading ................................................................................................................ 60 5.2.5 Stability and failure of miniscrews ....................................................................................... 61 5.2.6 Adverse effects associated with miniscrews ....................................................................... 63 5.2.7 The Aarhus Anchorage System™ ......................................................................................... 67 6.0 The Sydney Intrusion Spring ........................................................................................................... 68 6.1 Introduction ................................................................................................................................ 68 6.2 Wire properties, Beta titanium wire ........................................................................................... 69 6.3 Beta titanium wire welding ......................................................................................................... 70 6.4 Force delivery characteristics ..................................................................................................... 72 7 | P a g e 7.0 Cone beam computed tomography (CBCT) .................................................................................... 73 7.1 History and basic principles ........................................................................................................ 73 7.2 Radiation exposure ..................................................................................................................... 74 7.3 Accuracy of measurements ......................................................................................................... 74 7.4 Dolphin Imaging® (V 11.0) rendered cephalograms and digital tracing ..................................... 75 7.5 Superimposition .......................................................................................................................... 76 8.0 Aims................................................................................................................................................. 79 9.0 References: ..................................................................................................................................... 80 10. Manuscript ...................................................................................................................................... 95 10.1 Abstract ......................................................................................................................................... 99 10.2 Introduction and Literature review............................................................................................. 101 10.3 Materials and Methods ............................................................................................................... 110 Patient selection ............................................................................................................................. 110 Appliance components and design ................................................................................................. 110 Miniscrew placement ...................................................................................................................... 111 Appliance placement and loading ................................................................................................... 112 Data analysis ................................................................................................................................... 112 10.4 Results ......................................................................................................................................... 114 10.5 Discussion .................................................................................................................................... 116 10.6 Conclusion ................................................................................................................................... 125 10.7 Acknowledgements ..................................................................................................................... 126 10.8 References .................................................................................................................................. 127 10.9 List of Figures .............................................................................................................................. 133 Figure 1‐ Sydney Intrusion Spring (SIS) and bonded acrylic appliance ........................................... 134 Figure 2‐ Patient KB at appliance placement .................................................................................. 135 Figure 3‐ Subject KB at the conclusion of active intrusion ............................................................. 138 Figure 4‐ Subject KB after appliance removal and the placement of retention appliances ........... 139 Figure 5‐ Cephalometric landmark identification and legend ........................................................ 140 Figure 6‐ Sydney Intrusion Spring (SIS) force delivery graph .......................................................... 143 Figure 7‐ Posterior open bite, post intrusion, due to anterior occlusal interferences ................... 144 Figure 8‐ Maxillary regional superimposition ................................................................................. 145 Figure 9‐ Sydney Intrusion Spring (SIS) in the presence of poor oral hygiene ................................ 146 10.10 List of Tables ............................................................................................................................. 147 Table I‐ Summarized cephalometric changes from T1 to T2 .......................................................... 148 8 | P a g e 11. Future directions ........................................................................................................................... 149 12. Appendix ....................................................................................................................................... 153 Appendix 1‐ Three dimensional superimposition, Subject KB ........................................................ 154 Appendix 2‐ Subject ME, prior to appliance placement ................................................................. 156 Appendix 3‐ Subject ME, at start of active intrusion ...................................................................... 157 Appendix 4‐ Subject ME, at end of active intrusion........................................................................ 157 Appendix 5‐ Subject ME, after appliance removal ......................................................................... 158 Appendix 6‐ The Sydney Intrusion Spring ....................................................................................... 159 Appendix 7‐ Sydney Intrusion Spring laboratory testing ................................................................ 161 Appendix 8‐ Baasel Lasertec, Dentaurum desktop laser welder .................................................... 162 Appendix 9‐ Cephalometric measurements of Subjects at T1 ........................................................ 163 Appendix 10‐ Cephalometric measurements of Subjects at T2 ...................................................... 164 9 | P a g e
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