Purpose: The purpose of this study was to compare the morphologic changes of the upper airway space in Class III patients underwent mandibuler set back or bimaxillary surgery (maxillary advancement and mandibular setback) by computed tomography at 2 levels: soft palate and base of tongue Materials and Methods:The sample is consisted of 47 patients in 2 groups who had been diagnosed with Class III skeletal deformities and had been treated by mandibular setback or bimaxillary surgery (maxillary advancement and mandibular setback).Anteroposterior, lateral, cross sectional area dimensions of the airway at the level of soft palate and base of tongue was measured pre-and postoperatively on computed tomography images.Results: However, anteroposterior dimensions of the airway decreased in both groups (p<.0001), the reduction was significantly less in cases treated with bimaxillary surgery (p<.05). In mandibular setback surgery group, the cross sectional area of the airway decreased significantly (p<.001) Although, the cross sectional area of the airway decrease in bimaxillary surgery group, the reduction was not statistically significant (p>.05).Conclusions: This study suggested that bimaxillary surgery could prevent narrowing of the upper airway in the correction of Class III deformities rather than mandibular setback surgery .

The purpose of this study was to examine the changes in the temporomandibular joint (TMJ) and ramus after sagittal split ramus osteotomy (SSRO) with and without Le Fort I osteotomy.The subjects consisted of 87 Japanese patients diagnosed with mandibular prognathism with and without asymmetry. They were divided into 2 groups (42 symmetric patients and 45 asymmetric patients). The TMJ disc tissue was assessed by magnetic resonance imaging (MRI) and the TMJ space, condylar and ramus angle were assessed by computed tomography (CT) preoperatively and postoperatively.Medial joint space on the deviation side in the asymmetry group was significantly larger than that in the symmetry group (P=0.0043), and coronal ramus angle on the non-deviation side in the asymmetry group was significantly larger than that in the symmetry group preoperatively (P=0.0240). The horizontal condylar angle on the deviation side in the asymmetry group was significantly larger than that in the symmetry group (P=0.0302), posterior joint space on the non-deviation side in the symmetry group was significantly larger than that in the asymmetry group postoperatively (P=0.00391).The postoperative anterior joint space was significantly larger than the preoperative value on both sides in both groups (the deviation side in the symmetry group: P=0.0016, the non-deviation side in the symmetry group: P<0.0001, the deviation side in the asymmetry group: P=0.0040, the non-deviation side in the asymmetry group: P=0.0024). The preoperative disc position could was not changed in either group. These results suggest that significant expansion of anterior joint space could occur on the deviation side and non-deviation side in the asymmetry group as well as on both sides in the symmetry group, although disc position did not change in either group.

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