Comparison of Clinical and MRI Diagnoses in TMJ Lock Closed

Objectives: The aim of this study was to investigate the validity of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) for the diagnostic subgroup of disc displacement without reduction using MRI diagnosis as a gold standard. Methods: Sixty-two patients (124 joints) with limitation of mouth opening who visited the orofacial pain clinic in the Department of Oral Medicine, Seoul National University Dental Hospital were analyzed. The subjects were 37 females and 25 males, with a mean age of 28.0 ± 11.0 (ranged from 13 to 74 years). The clinical evaluation including mandibular range of motion, joint sounds, joint and muscle pain on palpation, and pain on mandibular opening was performed to each subject, and diagnoses for the disc position were done according to the RDC/TMD. Bilateral sagittal and coronal MRIs were taken to confirm the presence or absence of disc displacement or disc reduction during mouth opening. We categorized diagnosis of the TMJ disc position as no disk displacement (NDD), disc displacement with reduction (DD-R), and disc displacement without reduction (DD-NR). Results: The predictive values of the RDC/TMD examination were 0.59 (sensitivity 54%) for DD-R, 0.79 (sensitivity 83%) for DD-NR, and 0.85 (sensitivity 86%) for the disk displacement (DD-R or DD-NR). The overall diagnostic agreement between the RDC/TMD diagnoses and MRI diagnoses was 66.1% with a fair kappa value of 0.43 (p<0.01). The diagnostic agreement ratios for the DD-NR, DD-R, and NDD were 78.6%, 59.4%, and 36.4%, respectively. Conclusions: The results of the study suggest that clinical diagnosis using RDC/TMD is predictive for the presence of disc displacement, but not for the disc reduction status during mouth opening. The clinical examination is of limited value in determining the true position of the TMJ disk and its functional movement.