Abstract: Objective To discuss the chin soft tissue thickness of adults with different skeletal patterns. Methods All the subjects were divided into three groups according to different skeletal patterns and each group included 20 patients.The images were constructed into 3dimensional (3D) model using medical image processing software Dolphin Imaging 11.0.The reference planes were established and the two points,pogonion of hard tissue (Po) and soft tissue (Pos) were located on the 3D model.The chin soft tissue thickness was calculated statistically. Results There was no gender difference in terms of the chin soft tissue thickness (P>0.05) and it was not affected by skeletal patterns.The coordinate of it was affected by the skeletal patterns (class Ⅰ and class Ⅱ,class Ⅱ and class Ⅲ).There were significant differences in the z coordinate of point Po (P<0.05,class Ⅰ and class Ⅲ; class Ⅱ and class Ⅲ). Conclusions The chin soft tissue thickness of different skeletal patterns showed significant differences and the differences existed in the horizontal plane primarily.There were significant differences in Point Po between class Ⅰ and class Ⅱ,class Ⅱ and class Ⅲ,which would provide guidance for the diagnosis and orthodontic treatment.

Key words: skeletal pattern, chin soft tissue, thickness, Cone-Beam CT