Objective: Osteoarthritic lesions of Temporomandibular joint(TMJ) were assessed by dental cone beam computed tomography(CBCT),and compared with conventional radiographic technology. Methods: The study was conducted retrospectively on 511 joints of 350 patients, who had undergone dental CBCT ,panoramic radiography,transcranial projection and transpharygeal projection of TMJ . The results were compared and the accuracy with CBCT was assessed. The types of osseous condylar abnormalities were observed.Results: (1) The occurrence of osteoarthritis in male and female were 59.04% and 69.66%, respectively, with no significant difference. (2) Compared with CBCT, panoramic radiography,transpharygeal projection examination showed no significant difference, with the accuracy being 90.64% and 94.10%,respectively;However, transcranial projection indicated a significant difference in comparison with CBCT and the accuracy was 86.97%. (3) A higher occurrence of osteoarthritic lesions of the condyle was sclerosis (39.86%). Bony proliferation or osteophyte (28.18%) and ill-defined cortical bone (18.90%) were followed. Conclusion: Cone beam CT, which reproduces multiple images including axial, coronal and sagittal planes of the joint, provides a complete radiographic investigation of the bony components of the TMJ. It is one of the best choices of imaging diagnosis of TMJ osteoarthritis. Panoramic radiography and transpharygeal projection examination are also good choices for showing osseous condylar abnormalities in the clinic, but transcranial projection examination is inferior.

Objective:To observe the clinical effect of arthrocentesis combined with liquid phase con-centrated growth factor(CGF)injection in the treatment of unilateral temporomandibular joint osteoarthri-tis(TMJOA),in order to provide a new treatment option for TMJOA patients.Methods:In this non-randomized controlled study,patients diagnosed with unilateral TMJOA who visited the center for tem-poromandibular joint disorder and orofacial pain of Peking University School and Hospital of Stomatology from June 2021 to January 2023 were selected as research objects.The patients were divided into experi-mental group and control group,which were selected by patients themselves.The experimental group re-ceived arthrocentesis combined with liquid phase CGF injection and the control group received arthrocen-tesis combined with HA injection.Both groups were treated 3 times,once every two weeks.The clinical effect was evaluated by the maximum mouth opening,pain value and the degree of mandibular function limitation 6 months after treatment.The change of condylar bone was evaluated by cone beam CT(CBCT)image fusion technology before and after treatment.Results:A total of 20 patients were included in the experimental group,including 3 males and 17 females,with an average age of(34.40± 8.41)years.A total of 15 patients were included in the control group,including 1 male and 14 females,with an average age of(32.20±12.00)years.There was no statistical difference in general information between the two groups(P＞0.05).There were no statistical differences in the mouth opening,pain value and the degree of jaw function limitation between the two groups before treatment(P＞0.05),and all of them improved 6 months after treatment compared with before treatment(P＜0.05).However,the mouth opening of experimental group was significantly higher than that of control group 6 months after treatment(P＜0.05),and the degree of jaw function limitation was significantly lower than that of con-trol group(P＜0.05).CBCT 2D images showed that the condylar bone of both groups was smoother after treatment than before treatment,and image fusion results showed that 10 patients(50.0％)in the experimental group and 5 patients(33.3％)in the control group had reparative remodeling area of con-dylar bone,and there was no statistical difference between them(P＞0.05).Except for one CGF pa-tient,the other patients in both groups had some absorption areas of condylar bone.Conclusion:The ar-throcentesis combined with liquid phase CGF injection can improve the clinical symptoms and signs of unilateral TMJOA patients in short term,and is better than HA in increasing mouth opening and impro-ving jaw function.CBCT fusion images of both patient groups show some cases of condylar bone repara-tive remodeling and its relevance to treatment plans still requires further study.