ObjectivesAny 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 MethodsThis 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.ResultsThe 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.ConclusionBimaxillary surgical correction of class III malocclusion did not cause statistically significant changes in the posterior airway space.