Abstract: Abstract: Objective To analyze the skeletal structure features of temporomandibular joint (TMJ) by using cone beam computed tomography (CBCT) in patients with sleep bruxism. Methods CBCT scanning was performed in the intercuspal position in 30 patients with sleep bruxism (sleep bruxism group) and 30 health adults (normal group). The reconstruction of TMJ images were analysed by Invivo5 software. Measurements of horizontal section include antero-posterior diameter, medial- lateral diameter and axial angel. Measurements of sagittal section include acetabulum depth, aricular eminence inclination, anterior space, superior space and posterior space. Measurements of coronal section include force angle. Results There were no significant differences in both sides of TMJ between sleep bruxism group and normal group（P > 0.05). Compared with control group, there were significant differences in antero- posterior diameter, medial- lateral diameter, acetabulum depth, anterior space and force angle in sleep bruxism group (P < 0.05). There were decreased antero posterior diameter, me⁃ dial-lateral diameter and increased acetabulum depth, anterior space and force angle in sleep bruxism group than those of control group. Conclusion The bilateral bone stuctures of TMJ are basically symmetry in patients with sleep bruxism. There is no significant change in condylar position in acetabulum , but there is a trend of absorbtion of anterior space and de⁃ crease of condyle in patients with sleep bruxism.

Key words: diagnostic imaging, image processing, computer-assisted, sleep bruxism, temporomandibular joint, cone beam computed tomography