Abstract: Objective To compare symphysis morphology among Class Ⅲmalocclusion patients with different facial vertical skeletal patterns. Methods Incisor mandibular plane angle (IMPA), symphysis height (LH) and the thickness of?alveolar bone among mandibular incisor area were measured in 73 CBCTs of adult patients. Results Variations in the mandibular plane have a negative correlation with IMPA and a positive correlation with LH, and IMPA has a positive correlation with the thickness of the buccal alveolar bone. Conclusions An increased trend of long-faced in Class III malocclusion led to variable-length of symphysis height,more lingual inclination of mandibular incisor,and decreasing thickness of the Buccal alveolar bone.

Key words: skeletal Class III malocclusion, symphysis morphology, Incisor mandibular plane angle, CBCT