Abstract: Objective: To analyze the relationship between upper airway and mandible morphology in patients with skeletal Ⅲ class malocclusion by CBCT. Methods: Thirty volunteers with individual normal occlusion and 30 patients with high-angle skeletal Ⅲ class malocclusion were selected. All samples were scanned by cone-beam CT, and reconstructed and measured by Mimics17.0 medical software. Differences between two groups were assessed using independent sample t-test. Correlations between two groups were evaluated using pearson’s coefficient. Results: There were 16 significant correlational measurements between mandible and upper airway of the skeletal Ⅲ class malocclusion group. Eighteen measurements showed significant differences between individual normal occlusion and the skeletal Ⅲ class malocclusion (P＜0.05), which were the coronal diameter, height, cross-sectional area, and volume of nasopharyngeal segment, the sagittal diameter, cross-sectional area, and volume of palatalpharyngeal segment, the cross-sectional area and volume of lingual pharynx, the total volume of upper airway, mandibular body length, mandibular length, mandibular angle, mandibular ramus volume, mandibular body volume, mandibular chin volume, mandibular total volume, and chin angle. Conclusion: The upper airway morphology of class Ⅲ sagittal skeletal was correlated with mandibular parameters, both of which influenced each other. Differences in the upper airway and mandibular morphology were statistically significant between two groups.

Key words: Skeletal Ⅲ class malocclusion, Upper airway, Mandibular, Correlation, CBCT