Two-dimensional and volumetric airway changes after bimaxillary surgery for class III malocclusion

OBJECTIVES: Any change in maxilla and mandible position can alter the upper airway, and any decrease in the upper airway can cause sleep disorders. Thus, it is necessary to assess airway changes after repositioning of the maxilla and mandible during orthognathic surgery. The purpose of this study was to evaluate linear and volumetric changes in the upper airway after bimaxillary surgery to correct class III malocclusion via cone-beam computed tomography (CBCT) and to identify correlations between linear and volumetric changes. MATERIALS AND METHODS: This was a prospective cohort study. CBCTs from 10 class III patients were evaluated before surgery and three months after. The Wilcoxon one-sample test was used to evaluate the differences in measurements before and after surgery. Spearman's rank correlation coefficient was used to test the correlation between linear and volumetric changes. RESULTS: The results show that the nasopharyngeal space increased significantly, and that this increase correlated with degree of maxillary advancement. No significant changes were found in volumes before and after surgery. A correlation was found between linear and volumetric oropharyngeal changes. CONCLUSION: Bimaxillary surgical correction of class III malocclusion did not cause statistically significant changes in the posterior airway space.

Prediction of mandibular third molar impaction

Mandibular third molar impaction is a major problem in modern dentistry. The incomplete eruption of third molars remains a serious problem in dentistry, primarily because of its high incidence and clinical consequences.The purpose of this study was to relate the impaction of third molars to individual patterns of facial growth, as well as to the gonial angle. A group of 100 subjects with impacted mandibular third molar and a group of 75 subjects whose lower third molars had erupted. Both formed part of a cross-sectional study on prediction of impaction. There was at least 2 degrees difference between two groups. The mean value for gonial angle in erupted cases was 126 +/- 6 which is not so different from the standard ranges in the literature. Gonial angle can be used as one of impaction indices. Less value of gonial angle is in association with impacted third molar compared with erupted teeth