Flexure deformation of the temporomandibular joint disk in pseudodynamic magnetic resonance images

Objective.: The purpose of this study was to determine correlation of flexure disk deformation during jaw movement with other findings on magnetic resonance images and with clinical signs and symptoms in patients with anterior displacement of the temporomandibular joint disk. Study design.: T"1-weighted magnetic resonance images and gradient recalled acquisition in steady state magnetic resonance images were obtained in 62 subjects with flexure deformed disk in the jaw opening phase. Each disk deformation observed on a pseudodynamic image during jaw opening was classified as an upward or downward flexure deformation. The relationships between type of disk deformation, clinical signs and symptoms, and other findings on the magnetic resonance images were statistically analyzed by x^2 test. Results.: Of 80 delineated joints, 30 showed upward deformation and 50 showed downward deformation. There were significant differences between the upward and downward deformations in TMJ sound, TMJ pain, restricted jaw opening, extent of anterior displacement, and presence of disk reduction. Conclusions.: The type of disk deformation appeared to correlate with the clinical signs and symptoms and with the progress of internal derangement.