Objective: To compare changes in upper airway dimensions between isolated mandibular setback surgery and bimaxillary surgery using the SFA in patients with skeletal class III malocclusion.
Methods: A retrospective cohort study was conducted on 40 adult patients, equally divided into two groups: group 1 (mandibular setback using BSSO, n = 20) and group 2 (maxillary advancement combined with mandibular setback, n = 20). Airway measurements were obtained using acoustic pharyngometry at three time points: preoperative (T0), 1 month postoperative (T1), and 1 year postoperative (T2).
Results: At T1, both surgical approaches resulted in a statistically significant reduction in airway dimensions; however, the reduction was greater in group 1 than in group 2 in terms of volume (-22.84% vs. -7.96%) and cross-sectional area (-21.45% vs. -6.79%) (p < 0.01). The decrease in airway volume per millimeter of mandibular setback was significantly higher in group 1 (-1.168 cc/mm) compared to group 2 (-0.458 cc/mm) (p < 0.01). At T2, partial airway recovery was observed in both groups, with greater recovery in group 1; nevertheless, airway dimensions in group 2 remained significantly larger (p < 0.05).
Conclusion: Isolated mandibular setback using SFA leads to a substantial reduction in upper airway space, whereas bimaxillary surgery better preserves airway dimensions. Therefore, bimaxillary surgery should be considered for skeletal class III patients requiring large mandibular setbacks to minimize potential adverse effects on respiratory function.