Objectives: This study evaluated the long term changes up to 1 year in the pharyngeal airway space after bilateral sagittal split ramus osteotomy mandibular setback surgery and bimaxillary surgery through three-dimensional computed tomography analysis.
Materials and Methods: A total of 37 patients diagnosed with skeletal class III malocclusion underwent BSSRO setback surgery only (Group 1, n=23) or bimaxillary surgery (Group 2, n=14). Cone-beam computed tomography scan were taken before surgery (T0), 2 months after surgery (T1), 6 months after surgery (T2) and 1 year after surgery (T3). The nasopharynx (Nph), oropharynx (Oph), hypopharynx (Hph) volume and anteroposterior (AP) distance were measured through the InVivo Dental Application version 5.
Results: In Group 1, Oph volume and Hph volume were significantly decreased and maintained after the surgery (T1). In Group 2, Nph volume, Oph volume and Hph volume were decreased and relapsed at 1 year postoperatively (T3).
Conclusion: In Class III malocclusion patients, mandibular setback surgery only showed a greater reduction in pharyngeal airway space than bimaxillary surgery, and bimaxillary surgery was more stable in terms of airway. Therefore, it is important to evaluate the airway space before surgery and include it in the surgical plan.
