Pharyngeal Airway Changes after Bimaxillary Orthognathic Surgery--Preliminary Results.

INTRODUCTION Dentofacial deformity, a deviation from normal facial proportions and dental relationships, is corrected by jaw repositioning in all three spatial planes, which changes the position and tension of the surrounding tissues, bones and muscles. These changes may also affect the dimensions of the pharyngeal airways (PA). OBJECTIVE The aim of this study was to evaluate and compare three-dimensional PA changes in patients treated by a combination mandibular set-back/maxillary advancement versus patients that had bimaxillary advancement with genioplasty. METHODS The sample consisted of 7 patients treated by combined mandibular set-back/maxillary advancement and 7 patients treated with bimaxillary advancement surgery. Nasopharyngeal (NP) volume, oropharyngeal (OP) volume and the area of maximum constriction (AMC) in the OP were measured on CBCT scans (2 mA/120 kV/12" FOV) taken before (T1) and 3 months after surgery (T2). Paired samples t-test was used for analyzing statistical significance of changes (p ≤ 0.05). RESULTS OP volume and AMC increase after bimaxillary advancement was statistically significant, while for the mandibular set-back group the increase was non-significant. NP volume was not reduced in any of the two groups. No significant differences in PA dimensions were found between groups at neither T1 nor T2 time points. CONCLUSION Results suggest that the combination of mandibular set-back/maxillary advancement did not reduce airway dimensions, while bimaxillary advancement surgery led to a statistically significant increase in the OP dimensions.