Temporomandibular joint disk displacement: Comparison in asymptomatic volunteers and patients

PURPOSE: To compare the prevalence and type of temporomandibular joint (TMJ) disk displacement in asymptomatic volunteers with those in patients. MATERIALS AND METHODS: Bilateral oblique sagittal and oblique coronal intermediate-weighted magnetic resonance (MR) images of the TMJs in 58 patients with pain and dysfunction were analyzed and compared with corresponding MR images of 62 asymptomatic volunteers. RESULTS: Forty-five (78%) of 58 patients had disk displacement compared with 22 (35%) of 62 asymptomatic volunteers. Complete disk displacement was found in 46 (40%) of 115 joints in patients compared with three (2.4%) of 124 joints in asymptomatic volunteers, whereas partial disk displacement occurred in 26 (22.6%) and 27 (21.8%) joints, respectively. Two types of complete disk displacement, anterolateral and anterior, occurred frequently in patients, seldom in volunteers. Only minor differences were found between other types of disk displacement when prevalence in patients was compared with that of volunteers. The disk reduced to a normal position on open-mouth images in all joints in the volunteers compared with 76% of the joints in patients. CONCLUSION: TMJ disk displacement was less prevalent and was of a different type in asymptomatic volunteers compared with patients with pain and dysfunction.