Correlation between upper airway morphological changes and jaw movement after bimaxillary orthognathic surgery in patients with skeletal Class Ⅲ malocclusion

Abstract

Objective To investigate the morphological changes in the upper airway after bimaxillary surgery in patients with skeletal Class Ⅲ malocclusion and the relationship between jaw movement and airway changes using CBCT. Methods This study involved 44 individuals(21 males and 23 females)receiving Class Ⅲ bimaxillary surgery. Preoperative and 3-6-month postoperative CBCT data were examined using Dophin3D 11.95 software. The alterations before and after upper airway surgery were analysed using paired t-test and non-parametric Wilcoxon rank sum test. The association between airway alterations and jaw movement was examined using Pearson’s correlation coefficient. Results Patients who underwent Class Ⅲ bimaxillary surgery had significantly reduced upper airway volume, sagittal cross-sectional area, and minimum cross-sectional area(P<0.01). A correlation exists between oropharyngeal volume change and point B change(P<0.05). When B point recession was >7 mm, the decrease in upper airway volume increased significantly(P<0.01), as did the risk of minimum cross-sectional area of the patient’s airway(P<0.01). Conclusion Class Ⅲ bimaxillary surgery reduces upper airway capacity. Postoperative reduction in upper airway capacity coincides with mandibular recession. Mandibular recession(>7 mm)may reduce postoperative upper airway capacity and increase the risk of OSAHS. Patients at risk of upper airway stenosis should have their protocol modified to reduce airway risk.

Keywords

• |skeletal class ⅲ malocclusion|bimaxillary orthognathic surgery|pharyngeal airway|cone-beam computed tomography