Abstract
PURPOSE: This prospective observational study investigates whether changes in the direction and magnitude of occlusal plane angulation influence upper airway volume in adult patients undergoing orthognathic surgery. METHODS: Data were collected preoperatively and 7 days and 6 months postoperatively. Cone beam computed tomography (CBCT) was used to measure occlusal plane angulation and upper airway volume. All measurements were performed by a single, calibrated researcher trained by a gold standard specialist. Statistical significance was set at p < 0.05. RESULTS: Forty-eight patients were included: 27 women (56,25%) and 21 men (43,75%), with a median age of 29 years (range 18-52). Skeletal classifications were as follows: 19 class II (39,58%), and 29 class III (60,42%). Occlusal plane rotation was counterclockwise in 24 patients (50%) and clockwise in 24 patients (52%). Rotational changes were minor (0-2°) in 24 cases (50%) and major (> 2°) in the remaining 24 cases. No significant differences were observed in rotation direction or magnitude between class II and III patients (p > 0.05). CONCLUSION: Class II patients showed a significant increase in oropharyngeal volume (p = 0.026), while class III patients showed an increase in nasopharyngeal volume (p = 0.003), regardless of occlusal plane changes. Additionally, nasopharyngeal volume increased significantly in class III patients with clockwise (p = 0.035) and counterclockwise (p = 0.037) rotations.