EFFICACY OF TEMPORARY FIXED RETENTION FOLLOWING ...

More documents

Recommendations

Info

CHAPTER 6. SUMMARY AND CONCLUSIONS Postretention results are the method used to measure the success of orthodontic diagnosis and treatment. Tirk (1965, p 165) said, “The result of orthodontic therapy—good, bad, or indifferent—is only evident many years out of retention.” This longitudinal cephalometric and cast analysis examined the diagnostic records of cases treated comprehensively by several experienced orthodontists who use standard Edgewise mechanics. Of the 166 cases, 69 patients (23 males; 46 females) had been placed in a fixed mandibular canine-to-canine retainer and a maxillary removable retainer (traditional Hawley-type) at the end of active treatment for 2 to 3 years. The other 97 patients (20 males; 77 females) were placed in maxillary and mandibular removable retainers (traditional Hawleytype) for the same period of time. The two-fold purpose of this study was to: a) identify whether the type of retention—either Hawley retainers or Hawleys in combination with a fixed lingual retainer—provided greater long-term stability and b) review and document the long-term posttreatment changes of orthodontic cases. Treatment records were made at the start of treatment, at the end of active treatment, and at a long-term recall examination. The average long-term recall period for these patients is 16 years out of the active phase of treatment (13.5 years postretention). Major findings were: Temporary use (~ 2.5 years) of a mandibular fixed retainer following comprehensive orthodontic treatment appears to add little to long-term stability; therefore, if fixed retention is considered for retention, it should remain indefinitely to ensure stability. The amount of relapse seen in both groups was quite small, and the clinical difference between groups at the long term (average ~ 0.6 mm) was even smaller. Mandibular intercanine width was slightly expanded during treatment, but by the long-term recall examination, this dimension had returned to its pretreatment value. The maxillary and mandibular arches both became slightly narrower after treatment as measured by intermolar width and intercanine width. Overjet and overbite both increased after treatment. 131
About two-thirds (64%) of the correction of mandibular Incisor Irregularity was maintained over the long-term period. The mandibular Incisor Irregularity at the recall examination was less than 3.5 mm in 73% of cases, which is the limit suggested by Little (1975) as being clinically acceptable. There is a significant statistical association between the amount of change during treatment and the amount of relapse. Prediction of the amount of relapse from the treatment change takes the form of Y = 1.26 – 0.13(X) for the 166 cases in this study, meaning that a 1.0 mm change in Incisor Irregularity is associated with 0.13 mm of relapse. These results (~ 2.2 mm Incisor Irregularity at long-term recall) seem more stable than those reported in most long-term recall studies. It is likely that posttreatment changes and retention protocols will continue to cause discussion among the orthodontic community. Both groups of patients in this study treated under the Tweed guidelines remained extremely stable regardless of which retention protocol was used. However, patients must be conditioned to the potential occlusal changes that could occur, and it must be impressed on them the importance of their diligence in maintaining the stability of their dentition as they age. Further research should be done to determine if these same results could be expected for other treatment philosophies that do not observe such strict treatment parameters, i.e., upright mandibular incisors, minimal if any lower intercanine expansion, and the like. 132
Page 1 and 2:
EFFICACY OF TEMPORARY FIXED RETENTI
Page 3 and 4:
DEDICATION This thesis is dedicated
Page 5 and 6:
ABSTRACT Instability of the occlusi
Page 7 and 8:
CHAPTER 5. DISCUSSION .............
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
Page 57 and 58:
Figure 3-6. Illustration showing an
Page 59 and 60:
Figure 3-8. Illustration showing in
Page 61 and 62:
34. LR3 cusp tip point. 35. Right d
Page 63 and 64:
Figure 3-10. Illustration showing o
Page 65 and 66:
Figure 3-11. Illustration of Inciso
Page 67 and 68:
3. Go, Gonion (anatomic): The most
Page 69 and 70:
Figure 3-13. Depiction of the angle
Page 71 and 72:
Figure 3-15. Illustration of the me
Page 73 and 74:
Figure 3-17. Illustration of the me
Page 75 and 76:
Figure 3-19. Illustration of the an
Page 77 and 78:
Figure 3-21. Illustration of the up
Page 79 and 80:
Figure 3-22. Illustration of the to
Page 81 and 82:
Figure 3-24. Illustration of the po
Page 83 and 84:
the “older” Tweed force system,
Page 85 and 86:
The null hypothesis is: There was n
Page 87 and 88:
Figure 4-1. Distribution of the 166
Page 89 and 90:
occlusal issues are tolerated by bo
Page 91 and 92: 40 35 30 FMA (degrees) 25 20 15 10
Page 93 and 94: Figure 4-4. Plot of the average val
Page 95 and 96: larger ANB at the recall examinatio
Page 97 and 98: 21 19 Total Chin (mm) 17 15 13 11 9
Page 99 and 100: Figure 4-8. Box plot of the distrib
Page 101 and 102: which a Class I relationship was no
Page 103 and 104: Figure 4-11. Plot of mean Curve of
Page 105 and 106: Figure 4-13. Box plot of the distri
Page 107 and 108: Table A-4 addresses the question of
Page 109 and 110: Figure 4-16. Bar chart of the avera
Page 111 and 112: only sample changed significantly m
Page 113 and 114: 3 2 1 0 Canonical Variate 2 -1 -2 R
Page 115 and 116: 8 Anterior Discrepancy (ADisc) 6 4
Page 117 and 118: 40 Incisor Aspect Ratio (IAR) 30 20
Page 119 and 120: 1.5 Incisor Segment Depth (ISD) 1 0
Page 121 and 122: more stable (i.e., the mean change
Page 123 and 124: Molar Correction (MC) 10 8 6 4 2 0
Page 125 and 126: Anterior Segment Width (ASW) 1 0 -1
Page 127 and 128: final vertical positions. This phas
Page 129 and 130: decreased in both arches during the
Page 131 and 132: Figure 5-1. Plot of average Incisor
Page 133 and 134: Based on the present results, the u
Page 135 and 136: these variables indicate more anter
Page 137 and 138: and the hassle associated with plac
Page 139 and 140: Figure 5-2. Scatter-plot graph refl
Page 141: stability?” and “for how long?
Page 145 and 146: Baume LJ, Horowitz HS, Summers CJ,
Page 147 and 148: Case CS. Techniques and principles
Page 149 and 150: Glenn G, Sinclair PM, Alexander RG.
Page 151 and 152: Joondeph DR. Retention and relapse.
Page 153 and 154: Littlewood SJ, Millett DT, Doubleda
Page 155 and 156: Ormiston JP, Huang GJ, Little RM, D
Page 157 and 158: Rosenstein SW, Jacobson BN. Retenti
Page 159 and 160: Steadman SR. A philosophy and pract
Page 161 and 162: Zachrisson BU, Büyükyilmaz T. Bon
Page 163 and 164: Table A-1. Descriptive statistics a
Page 165 and 166: Table A-2. Descriptive statistics a
Page 167 and 168: Table A-3. Descriptive statistics f
Page 173 and 174: APPENDIX B. ANCOVA TESTS OF THE COM
Page 175 and 176: Table B-1. Continued. Sex Retention
Page 185 and 186: Table C-1. Results of ANCOVA tests
Page 193 and 194:
Table C-25. Results of ANCOVA tests
Page 195 and 196:
Table C-31. Results of ANCOVA tests
Page 197 and 198:
Table D-1. Descriptive statistics,
Page 199 and 200:
Page 201 and 202:
Page 203 and 204:
Table E-1. Two-way ANOVA tests eval
Page 205:
VITA Mark Owens was born on January
show all

EFFICACY OF TEMPORARY FIXED RETENTION FOLLOWING ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?