Abstract: PURPOSE: To analyze the features on cone-beam CT (CBCT) and MRI of temporomandibular joint disorder (TMD). METHODS: The data of 45 patients with TMD treated in Nantong Hospital of Stomatology from August 2018 to May 2020 were collected. All patients completed CBCT and MRI within 2 weeks, and the characteristics of TMJ and masticatory muscle lesions on CBCT and MRI were evaluated, including joint space stenosis, bone destruction, bone hyperplasia and sclerosis, condyle deformation, bone cystoid degeneration, articular disc displacement, joint capsule effusion and masticatory muscle lesions. SPSS 25.0 software package was used for data analysis. RESULTS: According to TMD clinical classification, 31 cases (68.9%) were classified as type I painful diseases, and 14 cases (31.1%) were classified as type II joint diseases. Among the 90 joints of 45 patients, the number of TMJ and masticatory muscle lesions detected by MRI (71/90) was significantly higher than the number of lesions detected by CBCT (58/90) (P=0.032). Among them, the number of articular disc displacement (19/90), joint capsule effusion (28/90) and masticatory muscle edema (22/90) were significantly higher than the number of cases detected by CBCT which was 3/90, 8/90 and 5/90 (P<0.001). The number of cases of hyperosteosis (18/90) and condyle mutation (15/90) detected by CBCT was significantly higher than the number of cases detected by MRI which was 8/90 and 6/90 (P<0.05). CBCT and MRI had no significant differences in detecting joint space stenosis, bone destruction and cystoid degeneration(P>0.05). CONCLUSIONS: Both CBCT and MRI have high clinical value in evaluating TMD. CBCT has advantages in evaluating bone quality, while MRI has a good effect in evaluating joint discs and soft tissues.

Key words: Cone-beam CT, Magnetic resonance imaging, Temporomandibular joint disorder