Abstract: Mophological changes of the condyle in adult patients with open bite by CBCT observation Abstract Objective To investigate the relationship between the condylar morphology and malocclusions with different overbite depths. Methods The samples were divided into two groups:G1,malocclusion with normal amount of overbite;G2,openbite malocclusion.To ascertain the morphology of the different condyles, 80 mandibular condyles of 40 adult cases, ranging from 18 to 36 years of age, were assessed using CBCT. Measureing and calculating the upper condylar height to the ramus height ratio(UCH/RH)and the condy height to the width ratio(CW /TCH).The condylar morphology was classified into four types:Type A,straight;Type B, anteriorlyinclined; TypeC, posteriorly inclined,and Type D,spiky or finger-shaped.The symmertry of the condyle and ramus in vertiacl dimension between the right and left side was calculated with the asymmetric index formula. Results ①The open bite group has a significantly smaller amount of TCH/RH and CW /TCH than normal overbite group（P<0.05）;②Type A and C have normal condylar shapes that comprised 73% while Type B and D have abnormally condylar shapes that comprised 26.7% of the open bite group. ③the openbite group showed condylar height asymmetry（P<0.05）.Conclusions openbite group has a shorter condyle relative to the ramus than normal bite group, and showed condylar height asymmetry, abnormally condylar shapes higher than normal bite groups.

Key words: Open bite, Temporomandibularjoint, Condylar morphology, CBCT