Comparison of reliability of lateral cephalogram and computed tomography for assessment of airway space

The oropharyngeal (OP) and nasopharyngeal structures seems to play roles in the development of the dentofacial complex. Soft palate as a part of nasopharyngeal and OP apparatus has an important role in phonation, deglutition and respiration. The aim of this study was to find whether any correlation exists between the three types of malocclusion and airway space using lateral cephalogram and computed tomography (CT) and to compare its reliability. To obtain important information on the morphology of the soft palate on lateral cephalogram and to determine its etiopathogenesis in obstructive sleep apnea (OSA).

Lateral cephalogram of 45 subjects were used to measure the pharyngeal airway. The subjects were divided into three groups (each group included 15 subjects) according to ANB angle: Class I (ANB angle 2-4°), Class II (ANB angle > 4°), Class III (ANB angle ≤ 2°).

The result showed a significant reduction in pharyngeal airway in ANB Class II. Type I soft palate, leaf-shape was found in maximum subjects. The volume of airway size showed higher statistical significance with the greater coefficient of variation on CT in relation to corresponding cephalometric airway area.

The sagittal skeletal pattern is a contributory factor in variations in the upper airway dimensions. The measurements acquired from both the modalities are reliable and reproducible, but CT gives the better assessment of cross-sectional dimensions of airway space. Morphology of the soft palate can be used as references for etiological research of OSA.