EFFICACY OF TEMPORARY FIXED RETENTION FOLLOWING ...
EFFICACY OF TEMPORARY FIXED RETENTION FOLLOWING ... EFFICACY OF TEMPORARY FIXED RETENTION FOLLOWING ...
TABLE OF CONTENTS CHAPTER 1. INTRODUCTION ...................................................................................1 CHAPTER 2. REVIEW OF THE LITERATURE .........................................................3 Historical Review of Retention and Relapse ............................................................ 3 Etiology of Post-Orthodontic Relapse ....................................................................... 5 Arch Dimension and Tooth Extraction ..................................................................5 Occlusion and Posttreatment Tooth Position .....................................................10 Periodontal and Gingival Supporting Tissues ....................................................14 Mandibular Incisor Dimensions and Approximal Contacts ............................15 Environmental Factors and Neuromusculature .................................................16 Continued Physiologic Growth and Development............................................18 Third Molars ............................................................................................................22 Time Out of Treatment ...........................................................................................23 Severity of Pretreatment Malocclusion and Posttreatment Stability ...............25 Prevention of Post-Orthodontic Relapse ................................................................ 26 Types of Mechanical Retention .............................................................................26 Duration of Retention .............................................................................................30 Additional Retention Methods .............................................................................31 Summary ..................................................................................................................... 33 Significance of Research ............................................................................................ 34 CHAPTER 3. MATERIALS AND METHODS .........................................................36 Sample Selection ......................................................................................................... 36 Sample Description .................................................................................................... 38 Description of Data Entry ......................................................................................... 38 Digitized Landmarks ................................................................................................. 45 Cast Analysis .............................................................................................................. 50 Cephalometric Analysis ............................................................................................ 53 Cephalometric Landmarks ....................................................................................53 Computed Measurements .....................................................................................56 Statistical Analysis ..................................................................................................... 67 Sample Demographics .............................................................................................. 71 Edgewise Mechanics .................................................................................................. 71 Research Expectations ............................................................................................... 73 CHAPTER 4. RESULTS ................................................................................................75 Cephalometric and Cast Analysis ........................................................................... 75 Sexual Dimorphism ................................................................................................... 77 Retention Differences ................................................................................................ 84 Multivariate Analysis .............................................................................................. 100 Amount of Relapse .................................................................................................. 103 Extraction Pattern ..................................................................................................... 110 vi
CHAPTER 5. DISCUSSION ......................................................................................115 Sample Considerations ............................................................................................ 116 Discussion Topics ..................................................................................................... 117 Previous Research and Present Findings...........................................................117 Explanation for Stability ......................................................................................122 Predictors for Fixed Appliances ..........................................................................123 Clinical Relevance .................................................................................................125 CHAPTER 6. SUMMARY AND CONCLUSIONS ................................................131 LIST OF REFERENCES ..............................................................................................133 APPENDIX A. DESCRIPTIVE STATISTICS FOR ALL VARIABLES ..............151 APPENDIX B. ANCOVA TESTS OF THE COMPARABILITY OF CASES (FIXED VERSUS REMOVABLE RETENTION) WHILE CONTROLLING FOR SEXUAL DIMORPHISM ..................................................................................162 APPENDIX C. ANCOVA TESTS EVALUATING WHETHER THE AMOUNT OF CHANGE DEPENDS ON THE TYPE OF RETENTION, WITH PATIENT’S SEX AND TIME-OUT-OF-TREATMENT AS COVARIATES ..............................................................................................................173 APPENDIX D. DESCRIPTIVE STATISTICS FOR THOSE VARIABLES EXHIBITING SIGNIFICANCE FOR SEXUAL DIMORPHISM ........................185 APPENDIX E. EXTRACTION PATTERNS ............................................................191 VITA ...............................................................................................................................194 vii
- Page 1 and 2: EFFICACY OF TEMPORARY FIXED RETENTI
- Page 3 and 4: DEDICATION This thesis is dedicated
- Page 5: ABSTRACT Instability of the occlusi
- Page 9 and 10: LIST OF FIGURES Figure 3-1. All cas
- Page 11 and 12: Figure 4-14. Box plot of the distri
- Page 13 and 14: Joondeph and Riedel (1994, p 908) d
- Page 15 and 16: Strang (1952, p 794) claimed that
- Page 17 and 18: malocclusion must be maintained if
- Page 19 and 20: e aimed at maintaining, in most ins
- Page 21 and 22: three time intervals: during treatm
- Page 23 and 24: mechanical treatment does not neces
- Page 25 and 26: elation, the masticatory system wil
- Page 27 and 28: exerted on the denture from the buc
- Page 29 and 30: In summary, the variance in tongue
- Page 31 and 32: Sinclair and Little (1983, p 114) a
- Page 33 and 34: Study and 43 orthodontically treate
- Page 35 and 36: and Sakols 1982; Vaden et al. 1997;
- Page 37 and 38: years postretention. Årtun et al.
- Page 39 and 40: adjustment, if necessary. This abil
- Page 41 and 42: Duration of Retention The premise i
- Page 43 and 44: The reduction in tooth structure of
- Page 45 and 46: 4. The most stable position of the
- Page 47 and 48: CHAPTER 3. MATERIALS AND METHODS Sa
- Page 49 and 50: The present sample consisted of the
- Page 51 and 52: Figure 3-2. Illustration of how mol
- Page 53 and 54: Figure 3-3. Illustration showing di
- Page 55 and 56: Figure 3-5. Illustration showing mi
TABLE <strong>OF</strong> CONTENTS<br />
CHAPTER 1. INTRODUCTION ...................................................................................1<br />
CHAPTER 2. REVIEW <strong>OF</strong> THE LITERATURE .........................................................3<br />
Historical Review of Retention and Relapse ............................................................ 3<br />
Etiology of Post-Orthodontic Relapse ....................................................................... 5<br />
Arch Dimension and Tooth Extraction ..................................................................5<br />
Occlusion and Posttreatment Tooth Position .....................................................10<br />
Periodontal and Gingival Supporting Tissues ....................................................14<br />
Mandibular Incisor Dimensions and Approximal Contacts ............................15<br />
Environmental Factors and Neuromusculature .................................................16<br />
Continued Physiologic Growth and Development............................................18<br />
Third Molars ............................................................................................................22<br />
Time Out of Treatment ...........................................................................................23<br />
Severity of Pretreatment Malocclusion and Posttreatment Stability ...............25<br />
Prevention of Post-Orthodontic Relapse ................................................................ 26<br />
Types of Mechanical Retention .............................................................................26<br />
Duration of Retention .............................................................................................30<br />
Additional Retention Methods .............................................................................31<br />
Summary ..................................................................................................................... 33<br />
Significance of Research ............................................................................................ 34<br />
CHAPTER 3. MATERIALS AND METHODS .........................................................36<br />
Sample Selection ......................................................................................................... 36<br />
Sample Description .................................................................................................... 38<br />
Description of Data Entry ......................................................................................... 38<br />
Digitized Landmarks ................................................................................................. 45<br />
Cast Analysis .............................................................................................................. 50<br />
Cephalometric Analysis ............................................................................................ 53<br />
Cephalometric Landmarks ....................................................................................53<br />
Computed Measurements .....................................................................................56<br />
Statistical Analysis ..................................................................................................... 67<br />
Sample Demographics .............................................................................................. 71<br />
Edgewise Mechanics .................................................................................................. 71<br />
Research Expectations ............................................................................................... 73<br />
CHAPTER 4. RESULTS ................................................................................................75<br />
Cephalometric and Cast Analysis ........................................................................... 75<br />
Sexual Dimorphism ................................................................................................... 77<br />
Retention Differences ................................................................................................ 84<br />
Multivariate Analysis .............................................................................................. 100<br />
Amount of Relapse .................................................................................................. 103<br />
Extraction Pattern ..................................................................................................... 110<br />
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