| 3003 Herbst Appliance: A Cephalometric Comparison of Stepwise Versus Full Advancement | ||
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J. ZETTLER, E.P. HICKS, G.T. KLUEMPER, J.F. YEPES, and A.J. BRANSCUM, University of Kentucky, Lexington, USA Introduction: There is considerable controversy regarding the relative skeletal/dental benefits of step-by-step vs. full Herbst advancement. Thus far, evidence is inconclusive. Objective: To use cephalometric analysis to compare the immediate (upon removal) and short-term results of step-by-step versus full advancement of the Herbst appliance. Also, to compare the results using two analyses, one using a constructed Frankfort Horizontal the other, the Modified Pancherz analysis. Material & Method: Preliminary data on 53 (N=53) Herbst treated class II patients has been collected from two orthodontic practices, one using full advancement (N=25) and one using step-by-step advancement (N=28). Radiographs of pre-treatment (T1), post-Herbst (T2), and short-term interval (T3) (N=25 vs. N=8) have been traced using a constructed Frankfort Horizontal as the reference line. Total class II correction for incisors and molars was calculated by the sum of the four components (maxilla, maxillary dental, mandible, and mandibular dental) contributing to the improvement. A percentage of the total correction for each component was then calculated. T1 was compared with T2 and T3 for both techniques and both analyses. Results: The custom analysis created by the authors has shown T1-T2 overjet correction of 54.1% skeletal/46.9% dental for full versus 79.5% skeletal/20.5% dental for step-by-step advancement. Molar correction was 38.2% /61.8% and 37.4%/62.6% respectively. T1-T3 overjet correction was 40%/60% versus 56.5%/43.5% and molar correction was 46.5%/53.5% and 66.3%/33.7% respectively. The modified Pancherz analysis has shown T1-T2 overjet correction of 81.9%/18.1% versus 141%/-41% and molar correction of 64% /36% and 65.7%/34.3%, respectively. T1-T3 overjet correction was 77% /23% versus 96.9%/3.1% and molar correction was 34.5%/65.5% and 132.2%/-32.2% respectively. These are preliminary results not based on the full sample size which will be reported. Statistical analysis of these data is forthcoming. Conclusions: (Preliminary) Step-by-step advancement produces more skeletal correction initially and maintains a small advantage throughout treatment. | ||
| Seq #303 - Malocclusion 3 10:45 AM-12:00 PM, Saturday, March 24, 2007 Ernest N. Morial Convention Center Exhibit Hall I2-J | ||
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