EFFICACY OF TEMPORARY FIXED RETENTION FOLLOWING ...

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CHAPTER 2. REVIEW <strong>OF</strong> THE LITERATURE Historical Review of Retention and Relapse No other issue in orthodontics, with the possible exception of extractions, seems to receive as much attention as retention. Retention, as it pertains to orthodontics, has been defined by Moyers (1973, p 442) as “the holding of teeth following orthodontic treatment in the treated position for the period of time necessary for the maintenance of the result” (Blake and Bibby 1998, p 299). Over time, there have been different schools of thought regarding the prevention of relapse (Graber 1994). Henry Kaplan (1988) devoted a review article to the issue of retention. He noted that the problems associated with retention continue today and are just as debated and relevant now as they ever have been despite the considerable amount of attention the subject has received. Much of the early historical references found in this section were taken from Kaplan’s review of retention and also from George Huckaba’s analysis of relapse (1952). Although early clinicians recognized changes in the dentition following treatment, Evens in 1854 seems to be the first to mention the need for some type of retention. Emerson Angell in 1860 likewise recognized a need for retention following the expansion of the maxillary median suture (Weinberger 1926). Alfred Coleman (1865) was the first to describe the effects of muscular pressure on the dentition, in essence relapse, and one year later, C. A. Marvin described the physiologic reasons for retention (Weinberger 1926). Around the beginning of the twentieth century, the issue of retention had become widely recognized, and many prominent clinicians and authors such as Guilford (1898), Angle (1900), Lischer (1912), and Dewey (1914) included chapters dealing with retention in their texts. Kingsley (1908) recognized that there were challenges associated with retention, and admitted that regarding the retention issue, “I am agnostic, I don’t know, in each and every individual case I do not know” (Kaplan 1988, p 327). It was the opinion of Edward H. Angle (1900, 1907) that achieving a normal occlusion as a result of orthodontic treatment was the most crucial component necessary in achieving long-term stability, even at the expense of an expanded dental arch. In contrast, McCauley (1944) promoted maintaining inter-canine and inter-molar widths of the original malocclusion. In accordance with McCauley, Tweed (1944, 1945) also recognized the lack of stability in cases where arch expansion had occurred, and Tweed went on to advocate the extraction of teeth in order to prevent this. Tweed, along with Nance (1947), also proposed that the most stable position for mandibular incisors was upright over their supporting basal bone. 3
Strang (1952, p 794) claimed that “the primary causes of malocclusion lie hidden in the mysterious processes of growth and development, which are beyond our power to control,” and Strang recommended overcorrection as a means of reducing the incidence of post-treatment relapse. Reitan (1959, 1967) noted the potential effects that the periodontium and supporting structures could have on tooth position. Jackson (1904) and Edwards (1968, 1970, 1988) each described procedures aimed at reducing this influence by surgically separating the attached gingiva from the teeth for a period of time. Boese (1980) also advocated a surgical reduction of interproximal tooth structure to reduce the instability of teeth. Edward H. Angle (1907) wrote that the problems of retention are often taken too lightly and are greater than the problems encountered during active treatment. Perhaps during a time of extreme frustration, Hawley (1919) proclaimed that he would “give half of his fee to anyone who would be responsible for the retention of his results when the active appliance was removed” (Kaplan 1988, p 328). Milo Hellman (1936) stated that, “We are almost in complete ignorance of the factors which pertain to retention for the individual patient” (Kaplan 1988, p 325), and George Hahn (1944) referred to retention as “The Stepchild of Orthodontia.” Boley and coworkers (2003, p 277) showed optimism that long-term stability is not hopeless and that, “satisfactory long-term results can be achieved for most patients for whom evidence-based treatment objectives—including minimal alteration of the mandibular arch form and the retraction and uprighting or maintenance of mandibular incisors in their original position— have been met.” Based on his review of the literature on post retention stability of mandibular incisors, Boley (2007) also supported the contention of Little and coworkers (1990) who looked at retention of early treatment cases involving arch length increases, and concluded that decisions made during active treatment, such as lateral arch expansion and advancement of the mandibular incisors, make a difference in long-term stability. Levin (1972) stated that, “It is the obligation of the clinician to plan the retentive phase of orthodontic therapy for all adult patients before active treatment is begun (Kaplan 1988, p 326).” Graber (1994, p 909) noted that, “retention depends on what is accomplished during treatment.” This requires careful consideration of the factors that have the potential to affect posttreatment outcomes and stability. 4
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: Joondeph and Riedel (1994, p 908) d
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
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Figure 3-11. Illustration of Inciso
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3. Go, Gonion (anatomic): The most
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Figure 3-13. Depiction of the angle
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Figure 3-15. Illustration of the me
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Figure 3-17. Illustration of the me
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Figure 3-19. Illustration of the an
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Figure 3-21. Illustration of the up
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Figure 3-22. Illustration of the to
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Figure 3-24. Illustration of the po
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the “older” Tweed force system,
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The null hypothesis is: There was n
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Figure 4-1. Distribution of the 166
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occlusal issues are tolerated by bo
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40 35 30 FMA (degrees) 25 20 15 10
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Figure 4-4. Plot of the average val
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larger ANB at the recall examinatio
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21 19 Total Chin (mm) 17 15 13 11 9
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Figure 4-8. Box plot of the distrib
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which a Class I relationship was no
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Figure 4-11. Plot of mean Curve of
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Figure 4-13. Box plot of the distri
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Table A-4 addresses the question of
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Figure 4-16. Bar chart of the avera
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only sample changed significantly m
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3 2 1 0 Canonical Variate 2 -1 -2 R
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8 Anterior Discrepancy (ADisc) 6 4
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40 Incisor Aspect Ratio (IAR) 30 20
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1.5 Incisor Segment Depth (ISD) 1 0
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more stable (i.e., the mean change
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Molar Correction (MC) 10 8 6 4 2 0
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Anterior Segment Width (ASW) 1 0 -1
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final vertical positions. This phas
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decreased in both arches during the
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Figure 5-1. Plot of average Incisor
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Based on the present results, the u
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these variables indicate more anter
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and the hassle associated with plac
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Figure 5-2. Scatter-plot graph refl
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stability?” and “for how long?
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About two-thirds (64%) of the corre
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Baume LJ, Horowitz HS, Summers CJ,
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Case CS. Techniques and principles
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Glenn G, Sinclair PM, Alexander RG.
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Joondeph DR. Retention and relapse.
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Littlewood SJ, Millett DT, Doubleda
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Ormiston JP, Huang GJ, Little RM, D
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Rosenstein SW, Jacobson BN. Retenti
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Steadman SR. A philosophy and pract
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Zachrisson BU, Büyükyilmaz T. Bon
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Table A-1. Descriptive statistics a
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Table A-2. Descriptive statistics a
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Table A-3. Descriptive statistics f
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APPENDIX B. ANCOVA TESTS OF THE COM
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Table B-1. Continued. Sex Retention
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Table C-1. Results of ANCOVA tests
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Table D-1. Descriptive statistics,
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Table E-1. Two-way ANOVA tests eval
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VITA Mark Owens was born on January
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