Does upper premolar extraction affect the changes of pharyngeal airway volume after bimaxillary surgery in skeletal...

The purpose of this study was to assess the pharyngeal airway volume change after bimaxillary surgery in patients with skeletal Class III malocclusion and evaluate the difference in postoperative pharyngeal airway space between upper premolar extraction cases and nonextraction cases.

Cone-beam computed tomographic scans were obtained for 23 patients (13 in extraction group and 10 in nonextraction group) who were diagnosed with mandibular prognathism before surgery (T0) and then 2 months (T2) and 6 months after surgery (T3). Using InVivoDental 3-dimensional imaging software, volumetric changes in the pharyngeal airway space were assessed at T0, T2, and T3. The Wilcoxon signed-rank test was used to determine whether there were significant changes in pharyngeal airway volume between time points. The Mann-Whitney U test was used to determine whether there were significant differences in volumetric changes between the extraction and nonextraction groups.

Volumes in all subsections of the pharyngeal airway were decreased (P < .05) except for changes in the oropharyngeal airway volume in the nonextraction group from T0 to T2. There were significant differences between the extraction and nonextraction groups in the changes of oro- and total pharyngeal airway volumes from T0 to T3.

The null hypothesis was rejected. The extraction of upper premolars rather than nonextraction decreased the pharyngeal airway space more in patients with mandibular prognathism who planned to have bimaxillary surgery.