EFFICACY OF TEMPORARY FIXED RETENTION FOLLOWING ...

More documents

Recommendations

Info

It is difficult to draw firm conclusions as to why total chin shows up as a statistically significant predictive variable at the pretreatment stage and again at posttreatment based on the results of the present study. The greater total chin dimension that persisted from the pretreatment stage to posttreatment stage in the fixed retention group was associated with more anteriorly positioned mandibular incisors at both treatment stages, as evidenced by greater IMPA and incisor depth. Many clinicians today consider fixed retention in the treatment planning phase when severe pretreatment Incisor Irregularity is present. In the present study, there was no statistical difference in Incisor Irregularity prior to treatment (5.4 mm in the fixed group versus 5.9 mm in the removable group). However, by the end of treatment, Incisor Irregularity was significantly greater in the group (0.5 mm versus 0.2 mm) in which a fixed retainer was used. Greater Incisor Irregularity at the end of treatment seems to have added to a sense of incomplete orthodontic correction and greater risk for future instability. A deeper Curve of Spee persisted in the fixed retention group following treatment (0.8 mm versus 0.4 mm), albeit small, and this was identified as a significant predictor in the multivariate statistical analysis. Incomplete leveling of the Curve of Spee seems to have influenced the decision in favor of using fixed retention. Yet when evaluating the amount of change in the Curve of Spee during the recall period, the removable group displayed a slightly greater relapse (0.6 mm versus 0.4 mm), revealing that fixed incisor retention added little to maintaining the Curve of Spee correction. Along this same line, lack of molar correction during treatment (where a Class I molar relationship was not fully achieved) was greater in the fixed retention group (1.5 mm versus 1.0 mm). This difference was statistically significant when evaluated univariately (Table A-2), and could have been the result of the decreased mandibular incisor uprighting also seen in this group. Considered together, there was a deeper Curve of Spee and greater molar relationship during treatment in the removable group than in the fixed retention group. This suggests that fixed retention could have been considered following treatment if there was a sense of incomplete correction or an inability to achieve the desired degree of orthodontic correction. Clinical Relevance Our perception is that the use of temporary fixed retention following orthodontic treatment has largely been abandoned. This is predominately because of concerns over maintenance responsibility, periodontal health, caries 125
and the hassle associated with placing the appliance following treatment. Results of the present study document that long-term stability is clinically no greater in patients retained by fixed retention for a short time following active treatment (ca. 2 years) than patients receiving removable retention alone. Therefore, when weighing the advantages versus disadvantages of placing a fixed lower retainer (time, money, trouble, maintenance, etc.), it seems that the fixed retainer has little clinical advantage if only placed temporarily, and that if a fixed retainer is to be used, it should be planned to remain in place indefinitely. Furthermore, studies have established that relapse occurs to some degree in combination with the normal aging process in most every patient, and that retention to some degree is needed following orthodontic treatment (Sillman 1964; Lundström 1969; Little et al. 1981, 1988; Behrents 1985a, 1985b, 1989; Al Yami 1999; Harris et al. 1999; Richardson 1999; Stephens et al. 2005). What continues to be debated is the broad question of why this relapse occurs and to what extent it will occur in individual patients. Currently, it seems the majority of fixed retainers, when placed, are anticipated to be left indefinitely. Littlewood et al. (2006) concluded that there is insufficient research on which to base clinical judgments. From their conclusions and based on the research presented here, it can be inferred that no current mode of retention is superior to another. One caveat to this conclusion is the individualized variability in growth changes that takes place in postorthodontic patients. Growth studies by Behrents (1985, 1986a, 1986b), Nanda (1971, 1990) and Harris et al. (1994, 1997) have documented the variability in craniofacial growth changes among individuals. These changes do not stop in young adulthood, but continue throughout life. It was probably on this premise that Riedel (1960) contended that all patients must be thoroughly evaluated to determine what type, if any, and for how long retention procedures should be undertaken. Interestingly, Nanda and Nanda (1992) proposed that retention devices should be differentially selected on the basis of dentofacial morphology and the anticipated magnitude and directions of growth instead of simply using the clinician’s retainer of choice for all cases. Nanda and Nanda (1992) stress the importance of maintaining “active” retention through the pubertal growth spurt until maxillomandibular growth is completed, and they assert that the clinician has to be alert to the growth pattern of each individual patient. Specific examples of customized retention cited by the authors include a) continued use of a high-pull headgear in long-face syndrome patients during the retention phase, b) addition of an anterior biteplane to the retaining device in short-face syndrome patients, and c) longer retention periods for patients experiencing a delayed pubertal growth spurt, i.e. patients with skeletal deep bite. 126
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: these variables indicate more anter
Page 139 and 140: Figure 5-2. Scatter-plot graph refl
Page 141 and 142: stability?” and “for how long?
Page 143 and 144: About two-thirds (64%) of the corre
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 187 and 188:
Table C-7. Results of ANCOVA tests
Page 189 and 190:
Page 191 and 192:
Page 193 and 194:
Page 195 and 196:
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?