Date of Award

5-2008

Document Type

Thesis

Degree Name

Master of Dental Science (MDS)

Program

Orthodontics

Research Advisor

Edward F. Harris, Ph.D.

Committee

Joe L. Wasson, D.D.S., M.S. Jere L. Yates, D.D.S., M.S.

Abstract

Orthodontics’ concern about facial esthetics has motivated the investigation of treatment options, and their effects, in hopes of discerning the optimal treatment for patients, both esthetically and functionally. In our efforts to determine the optimal treatment option for patients with Class II, division 1 malocclusions, we examined two current treatment methods’ effects on facial esthetics, namely (1) orthopedic functional therapy using a MARA in combination with Edgewise appliances and (2) Edgewise mechanics alone. This study was a retrospective esthetic evaluation of profile silhouettes (prior to and following orthodontic treatment) of 30 consecutively treated American white adolescents with Class II, division 1 malocclusions treated using Edgewise mechanics in conjunction with a MARA. These were compared to a matched sample treated with Edgewise mechanics alone. Subjects in the two treatment groups were matched, on a one-to-one basis, for demographic and cephalometric variables (SNA, SNB, ANB, FMA) to ensure comparability in the nature and severity of the malocclusions. The question was whether the use of a MARA in combination with Edgewise mechanics yielded a more esthetic facial profile than Edgewise treatment alone. Lay people, graduate orthodontic students, and experienced orthodontists rated the level of profile attractiveness before and after orthodontic treatment. Factorial ANOVA models were used to examine the effects (and interactions among) (1) the patient’s sex, (2) sex of the observer, and (3) the three groups of observers prior to and after treatment. Male observers, regardless of group, scored the patients’ faces as more esthetic (higher VAS score) than did the female observers (P < 0.0001), though a sex difference, if any, seems to depend on the specific individuals in the sample. The ANOVA tests of VAS scores also showed a highly significant difference in observer groups (P < 0.0001) with the experienced orthodontists scoring the profiles higher (more esthetic) than orthodontic residents or lay people. From a three-way ANOVA evaluating posttreatment VAS scores, the two treatments were esthetically indistinguishable statistically (P = 0.0808), having virtually identical median VAS scores ( = 44 with a MARA, = 42 without a MARA), as well as identical amounts of improvement when comparing the median pre- and posttreatment VAS scores (both increasing 10 points on average). Though marginally-significant differences were found in ANB after treatment (P = 0.03), similar esthetic endpoints were achieved regardless of treatment protocol. In summary, (1) both treatment protocols produced an improved level of profile attractiveness at the end of treatment, and (2) there was no difference between the two groups in the perceived amounts of profile change with treatment. MARA treatment in combination with Edgewise mechanics has measurable benefits, (1) it enhances mandibular growth and (2) it reduces ANB by moving B Point forward rather than restraining maxillary growth. It seems, however, that integumental profiles, along with variations in lip dimensions and other features outside the orthodontist’s control, converge to obscure the skeletodental corrections, at least to readily-discernible systematic extents.

DOI

10.21007/etd.cghs.2008.0091

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