The purpose of this study was to investigate the factors affecting the postsurgical mandibular stability for both one- and two-jaw surgery. 18 for one-jaw surgerys and 24 for two-jaw surgerys among skeletal class III malocclusion patients who experienced orthodontic treatment and orthognathic surgery at Pusan National University Hospital were selected Lateral cephalograms taken at the first visit, after presurgical orthodontic treatment, immediately after surgery and follow-up over 6 months, were traced. Based ANOVA, multiple linear regression analysis was completed for one-jaw surgery with postsurgical stability as the criterion and the magnitude of mandibular setback, the change of mandibular incisor height during surgery, the changes of mandibular plane angle and mandibular incisor angle during presurgical orthodontic treatment as affecting factors. Same analysis was completed for two-jaw surgery with postsurgical stability as the criterion and the-magnitude of mandibular setback as affecting factor.
The results were as follows:
1. In the one-jaw surgery cases, the magnitude of mandibular setback the change of mandibular incisor height during surgery, the changes of mandibular plane angle and mandibular incisor angle during presurgical orthodontic treatment explained the variability in postsurgical stability with a significant R´´ value of 0.84.
2. In the two jaw surgery cases, the magnitude of mandibular setback explained the variability in postsurgical stability with a significant R´ value of 0.28.
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