Comparison of pharyngeal airway volume among different vertical skeletal patterns: a cone-beam computed tomography study.

OBJECTIVE: To test the null hypothesis that there are no significant differences in pharyngeal airway volumes among adult patients with different vertical skeletal patterns and a clinically normal sagittal skeletal pattern using cone-beam computed tomography (CBCT). MATERIAL AND METHODS: The study sample consisted of 100 adult patients (45 men and 55 women; mean age = 24.0 +/- 5.3 years) with a normal sagittal skeletal pattern divided into three groups according to the vertical skeletal patterns: high angle (32 patients: 15 women and 17 men), low angle (34 patients: 14 women and 20 men), and normal angle (34 patients: 16 women and 18 men) groups. Nasopharyngeal, oropharyngeal, and total airway volumes of patients in all vertical groups were calculated. Group differences were analyzed using one-way analysis of variance and post hoc Tukey tests. RESULTS: Nasopharyngeal airway volume in the high-angle group (mean = 6067.9 +/- 1693.9 mm(3)) was significantly lower than that of the low- and normal-angle groups (P < .01). Oropharyngeal airway volume was highest in the low-angle group (mean = 15,957.6 +/- 6817.2 mm(3)) and significantly decreased in the control (mean = 11,826.1 +/- 4831.9 mm(3); P = .008) and high angle (mean = 10,869.1 +/- 4084.1 mm(3); P = .001) groups. Total airway volume was highest in the low-angle group (mean = 24,261.6 +/- 8470.1 mm(3)) and lowest in the high-angle group (mean = 16,937.0 +/- 5027.4 mm(3); P < .001). CONCLUSION: The null hypothesis was rejected. Significant differences were found in pharyngeal airway volumes among different skeletal vertical patterns.