Objective Osteoarthritis (OA) of the temporomandibular joint (TMJ) is generally thought to be an age-related disease like those of other joints. This study aims to investigate the incidence of computed tomographic (CT) OA changes in Korean temporomandibular disorder (TMD) patients diagnosed by the Research Diagnostic Criteria for TMD (RDC/TMD). Materials and methods The clinical records and radiographs of 1038 TMD patients (297 men and 741 women with mean age 31.1 ± 17.4 and 34.0 ± 16.2, respectively) diagnosed based on RDC/TMD Axis I in 2010 were reviewed. Results The incidence rate of OA changes in TMD patients is estimated to 27.3%, and higher in women than in men (15.5% in men and 32.0% in women) by 2.3 odds (p < 0.001). It has no correlation with age, showing an almost flat incidence rate throughout the age from the 2nd decade and has no correlation as well with pain or disc displacement diagnosed according to RDC/TMD, while arthrosis/arthritis diagnosis based on RDC/TMD supplemented by plain radiographs shows high risk of OA changes on CT by 38.8 odds (p < 0.05). Conclusions These results imply that the OA changes in young Korean TMD patients are as common as in the old and have no correlation with clinical pain and noise. Considered with high prevalence of TMDs known in the young population, the overall/absolute OA changes in the TMJ can be even higher in the young than in the old population, not like in other joints.
Keywords: Incidence; computed tomography; osteoarthritis; temporomandibular joint.