Anterior joint space narrowing in patients with temporomandibular disorder

Purpose: The aim of this work is to investigate changes in the anterior joint space (AJS) and the relationship of such changes to clinical symptoms in chronic temporomandibular joint disorder (TMD) patients, and to compare symptoms between chronic and acute TMD patients. Methods: Data from 100 TMD patients diagnosed based on the Diagnostic Criteria for Temporomandibular Disorders (55 women; mean age 34.34 ± 14.88 years) including 50 patients with acute TMD (aTMD) and 50 patients with chronic TMD (cTMD) were analyzed. The AJS was calculated based on cone-beam computed tomography images analyzed using AutoCAD software (Autodesk Inc., San Francisco, CA, USA). The presence of osteoarthritis (OA) in the temporomandibular joint (TMJ) was evaluated using bone scintigraphy. Results: Bilateral OA was significantly more frequent in patients with cTMD than in those with aTMD (50% vs. 30%; p < 0.05). Significant differences in the AJS of the TMJs were found between patients with cTMD and those with aTMD. AJS values of both right and left TMJs were significantly smaller in the patients with cTMD than in those with aTMD (4.18 ± 1.71 mm ² vs. 7.35 ± 1.71 mm ² , and 6.20 ± 2.88 mm ² vs. 7.34 ± 2.47 mm ² , respectively; p < 0.05). In patients with cTMD, narrowed AJS was correlated with increased dysfunction index (r = −0.373, p < 0.01). Conclusions: Over time, AJS of the TMJ can be narrowed in TMD patients, causing aggravation of TMJ dysfunction.