Dynamic MRI motion analysis of the condyle and articular disk in the sagittal plane during mouth opening and closing

Abstract

We used dynamic magnetic resonance imaging (MRI) to analyze the velocity and excursion of the condyle and articular disk during mouth opening and closing. These parameters were compared between individuals with clicking sounds in the temporomandibular joint (TMD group, n=6) and those with no abnormalities in the joint (normal group, n=7). We used a Signa Horizon LX[○!R] (1.5 Tesla, GE Inc., Wisconsin, USA) at fast SPGR, 7.7/1.4 ms TR/TE, 8mm thickness, and 40 sec duration. Each subject was instructed to open as widely as possible and then to close over a period of 40 seconds, during which time we measured the velocity and excursion of the condyle and articular disk. The degree of anterior displacement of the articular disk was quantified in the TMD patients. Compared with normal subjects, the degree of variance in movement velocity for opening and closing movements was significantly greater for the TMD patients. These findings suggest that dynamic MRI is useful for observing and quantifying the dynamics of the articular disk and that the degree of fluctuation in the velocity of articular disk movement is significantly greater for patients with clicking sounds.