Abstract: Objective: To study the difference of airway three-dimensional structure and condylar sagittal position in the glenoid fossa in skeletal class Ⅱ adults, and the relationship among them. Methods: 73 adult skeletal class Ⅱ orthodontic patients, CBCT was performed, and Dolphin Imaging 11.9 software was used to conduct 3D reconstruction and measurement of the subjects. Relevant measurements including ordinary cephalometric measurements SNA, SNB, FMA, ANB; airway related measurements upper airway superior plane sagittal distance Ls, inferior plane sagittal distance Li, superior plane cross-sectional area Ss, inferior plane cross-sectional area Ls, upper airway three-dimensional volume V, minimum cross-sectional area Smin, superior angle of upper airway As, inferior angle of upper airway Ai, total angle of upper airway (equals As+Ai); condylar sagittal position related measurements anterior articular space (left LDa, right RDa ), superior articular space (left LDs, right RDs ), posterior articular space (left LDp, right RDp ), linear ratio (left LLR, right RLR). Students’ t test and Pearson linear correlation analysis were performed using GraphPad Prism 7.0 software. Results: As for the difference between the skeletal class Ⅱ adult male orthodontic patients with retruded and normal mandible, there exists significant difference of Ai, A, LDp, LLRand RDp. For the female group, there exists significant difference of As and Ai. As for further analysis of above, for the male group, ANB has a relative correlation with Ai and A, and has aninverse correlation with LLR. As for the female group, ANB has an inverse correlation with Asand relative correlation with Ai. Conclusions: There exists relatively relationship among the retruded mandible, upper airway structure and condyle sagittal position.

Key words: Skeletal Ⅱ maloclussion, Temporomandibular joint, Airway, 3D reconstruction