Pharyngeal airway volume among different vertical skeletal patterns using cone-beam computed tomography

Introduction
Pharynx morphology affects airway volume, facial growth pattern, risk of obstructive sleep apnea, and chewing pattern. Objectives: This study aimed to compare the pharyngeal airway volume among vertical skeletal patterns using cone-beam computed tomography (CBCT).

Material and methods
In this cross-sectional study, 100 CBCT images were selected from the archive of Department of Orthodontic of Hamadan Dental School, Iran. Among reviewed images, 60 cases met inclusion criteria. They were divided into three groups of long, normal, and short faces based on the posterior facial height to anterior facial height (PFH/AFH) ratio. Airway volume, minimum axial cross-section, airway length, midline area, and airway morphology were measured using ITK-SNAP software. Obtained data were transferred into SPSS 16 software and analyzed using ANOVA test.

Results
Volume, minimum axial cross-section, and other variables of the pharyngeal airway had no significant relation with skeletal vertical patterns. The average airway volume in men was 1712.348 mm3, which was more than that in women, and this value decreased by 67.175 mm3 with age increasing. The average airway volume also decreased by 46.346 mm3, with each unit increasing in PFH/AFH ratio.

Conclusions
In the present study, different vertical skeletal patterns and airway variables were not significantly correlated with each other. Airway volume decreased with increasing age, and it was observed larger in men than in women.