Comparing short- and long-term effects of mandibular advancement with versus without maxillary setback on the oropharyngeal airway in skeletal Class II individuals: An extensive 2-year follow-up study

Abstract Objective This study assessed 2-year oropharyngeal airway changes in skeletal Class II patients after mandibular advancement without maxillary posterior displacement (MAWMP) versus mandibular advancement with maxillary setback (MAWMS). Materials and methods A total of 25 MAWMP and 57 MAWMS patients underwent CBCT preoperatively (T0) and at 3 months (T1) and 2 years postoperatively (T2). The total upper airway volume (V), minimum cross-sectional area (CSAmin), and volumes of the nasopharynx (VNA), velopharynx (VVE), and glossopharynx (VGL) were measured via Dolphin Imaging. Results MAWMP significantly increased V, CSAmin, VNA, VVE, and VGL by 38.86%, 69.49%, 22.31%, 46.05%, and 46.94%, respectively, at T1 (P<0.01) and 21.85%, 43.11%, 13.85%, 19.73%, and 25.38%, respectively, at T2 (P<0.05). From T1 to T2, V, CSAmin, VVE, and VGL decreased by 12.24%, 15.56%, 18.02%, and 14.67%, respectively (P<0.05). Multivariate regression revealed that each 1 mm advancement of the PNS and B points increased V by 1038.18 mm³ and VVE by 519.11 mm³; PNS advancement increased VNA by 708.30 mm³ (P<0.05). Compared with MAWMS, MAWMP yielded greater short-term improvements (V: +11175.00 vs. +3638.00 mm³; P<0.001) and superior long-term stability in V and VNA (P<0.05). Intriguingly, the combined advancement of PNS and B point may be a robust predictor for postoperative changes of the upper airway volume. Conclusion MAWMP induces sustained upper airway expansion for 2 years, which is driven primarily by hard-tissue advancements. Compared with MAWMS, this technique has superior short- and long-term efficacy, providing guidance for the optimized management of skeletal Class II patients.