THREE-DIMENSIONAL CHARACTERIZATION OF MAXILLARY MOLAR DISPLACEMENT SUBSEQUENT TO HEADGEAR TREATMENT WITH RESPECT TO TIME AND FORCE OF APPLICATION – DEVELOPMENT AND PILOT TEST OF A NOVEL STUDY METHOD By YOSSI BAR-ZION A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2000 ACKNOWLEDGMENTS To my family my Mother and Father, Yael, Dani, and Hila I am grateful for all your help and support. I know that none of my accomplishments would have been possible without your patience and the sacrifices you have made over the years. To Mandy, thanks for all the moral and emotional support through the years we shared together. I look forward to a lifetime of happiness together. I would like to thank the members of my committee Drs. Wheeler, Dolce, Gibbs, and McGorray. I would particularly like to thank Dr. Wheeler for his mentorship throughout this project and for all his help and guidance through my clinical training. I would also like to acknowledge Marie Taylor, research coordinator, and Debbie Walls, clinical assistant, for their help with the clinical aspect of the project. ii TABLE OF CONTENTS ACKNOWLEDGMENTS............................................................................................... ii LIST OF TABLES.......................................................................................................... v LIST OF FIGURES ....................................................................................................... vi ABSTRACT ................................................................................................................ viii CHAPTERS 1 INTRODUCTION...................................................................................................1 Purpose of Study......................................................................................................3 Objectives................................................................................................................3 2 REVIEW OF THE LITERATURE ..........................................................................5 Historical Overview.................................................................................................5 Monitoring of Time............................................................................................5 Monitoring of Force...........................................................................................6 Measurement of Tooth Displacement.................................................................8 Summary............................................................................................................... 14 3 MATERIALS AND METHODS ........................................................................... 15 Orthodontic Time/Force Recording (OTFR) Headgear........................................... 15 Development of Tooth Displacement Measurement ............................................... 18 Stable Reference Point ..................................................................................... 19 Three-Dimensional Digitizing.......................................................................... 21 Three-Dimensional Analysis............................................................................ 24 Clinical Data Collection......................................................................................... 28 Subject Selection.............................................................................................. 28 Inclusion criteria.......................................................................................... 29 Exclusion criteria......................................................................................... 29 Study Design.................................................................................................... 29 Data Analysis ........................................................................................................ 32 Testing of the Three-Dimensional Molar Measurement System (objective 1) .. 32 Analysis of Timing Data (objectives 2 and 3)................................................... 33 iii Analysis of Force Data (objective 4) ................................................................ 34 Analysis of Tooth Displacement (objective 5).................................................. 35 4 RESULTS AND DISCUSSION............................................................................. 36 Tooth Displacement Characterization of a Selected Study Model........................... 36 Timing Data........................................................................................................... 43 Correlation of the OTFR Headgear with Third-Person Log Book..................... 45 Correlation of Timing Headgear with Commercial Timing Device................... 46 Correlation of Timing Headgear with Commercial Timing Device and Patient Diary................................................................................................ 48 Force Data............................................................................................................. 50 Variations between Headgears ......................................................................... 55 Variations within Headgears over Time............................................................ 58 Tooth Movement Data........................................................................................... 59 5 SUMMARY AND CONCLUSIONS ..................................................................... 68 REFERENCES ............................................................................................................. 71 BIOGRAPHICAL SKETCH......................................................................................... 76 iv LIST OF TABLES Table page 3-1. Sample of data captured spreadsheet. ............................................................... 24 4-1. Pretreatment averaged digitized values............................................................. 37 4-2. Post-treatment averaged digitized values. ......................................................... 37 4-3. Timing data – spreadsheet summary................................................................. 44 4-4. OTFR and third party logbook correlation........................................................ 45 4-5. Affirm and third party logbook correlation....................................................... 46 4-6. Affirm and OTFR correlation........................................................................... 47 4-7. Patient’s diary, Affirm, and OTFR headgear data. ............................................ 48 4-8. Subject 1 – Modeling voltage as a function of force (weight). .......................... 55 4-9. Subject 2 – Modeling voltage as a function of force (weight). .......................... 56 4-10. Subject 3 – Modeling voltage as a function of force (weight). ......................... 56 4-11. Subject 4 – Modeling voltage as a function of force (weight). ......................... 57 4-12. Subject 5 – Modeling voltage as a function of force (weight). ......................... 57 4-13. Serial study models centroid distance data....................................................... 60 4-14. Summary of total and annualized centroid change. .......................................... 61 4-15. Descriptive statistics of molar displacement. ................................................... 61 4-16. Linear trends of centroid graphs. ..................................................................... 63 v LIST OF FIGURES Figure page 3-1. Orthodontic Time / Force Recording Headgear. ................................................. 15 3-2. Schematics of electronic circuitry of the OFTR headgear. .................................. 17 3-3. Three-day data capture of sample patient............................................................ 18 3-4. Custom Nance appliance. ................................................................................... 20 3-5. Study model of Nance cemented in place. .......................................................... 21 3-6. Templates placed on study model....................................................................... 22 3-7. Centroid displacement and spatial analysis......................................................... 22 3-8. MicroScribe 3DX............................................................................................... 23 3-9. Finite element analysis. ...................................................................................... 25 3-10. Centroid displacement and spatial analysis......................................................... 26 3-11. Finite element analysis. ...................................................................................... 26 3-12. Sample object rendering (simulation). .............................................................. 27 3-13. Sample of serial superimposition object rendering (simulation). ............................. 27 3-14. Computer generated emulation of three-dimensional displacement. ................... 28 3-15. Study design flow chart...................................................................................... 30 4-1. Pretreatment models........................................................................................... 37 4-2. Post-treatment models........................................................................................ 37 4-3.