An evaluation and correlation of airway space of pharynx, mandibular morphology, and tongue volume in skeletal classes and facial patterns – A cone beam computed tomography study

Objectives: Respiration and its function have a direct relationship with the pharyngeal airway, mandibular morphology, and tongue. The objective of this study was to evaluate and correlate pharyngeal airway space, mandibular morphology, and tongue volume in various skeletal classes and facial patterns. Material and Methods: A total of 120 pre-treatment cone beam computed tomography (CBCT) images were randomly classified into 3 skeletal classes (40/group). Each class was further categorized into hyperdivergent and hypodivergent growth patterns. Linear and angular measurements were estimated using three-dimensional digital imaging programs (Kavo 3D OnDemand software), and pharyngeal airway and tongue space were volumetrically analyzed by ITK-SNAP segmentation software. Results: All the measured variables showed highly significant differences except for the anterior-posterior angle of the mandible, which was statistically insignificant with P = 0.675. The simple regression was formulated to assess the volume of airway space. Conclusion: Hyperdivergent subjects had reduced pharyngeal airway space and tongue volume when compared to hypodivergent subjects. Among all the subgroups, Class III hypodivergent showed the highest pharyngeal airway volume and tongue volume, and the least was found in Class II hypodivergent. A direct relationship was estimated between airway mandibular morphology and tongue volume, recommending thorough analysis of oropharyngeal structures in a non-individualized way for orthodontic diagnosis and treatment planning.