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 inter mediate-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 wit h 22 (35%) of 62 asymptomatic volunteers. Complete disk displacement was fo und in 46 (40%) of 115 joints in patients compared with three (2.4%) of 124 joints in asymptomatic volunteers, whereas partial disk displacement occur red in 26 (22.6%) and 27 (21.8%) joints, respectively. Two types of complet e disk displacement, anterolateral and anterior, occurred frequently in pat ients, seldom in volunteers. Only minor differences were found between othe r types of disk displacement when prevalence in patients was compared with that of volunteers. The disk reduced to a normal position on open-mouth ima ges in all joints in the volunteers compared with 76% of the joints in pati ents. CONCLUSION: TMJ disk displacement was less prevalent and was of a different type in asymptomatic volunteers compared with patients with pain and dysfu nction.