The use of pseudo-dynamic magnetic resonance imaging for evaluating the relationship between temporomandibular joint anterior disc displacement and joint pain.

The relationship between temporomandibular joint (TMJ) pain and the magnetic resonance imaging (MRI) finding of articular disc displacement is debated. The purpose of this study is to investigate the correlation between TMJ pain and anterior disc displacement (ADD) using pseudo-dynamic MRI. A retrospective review of MRI studies was carried out on 130 TMJs in 65 patients presenting unilateral TMJ pain. The contralateral asymptomatic joints served as the control group. Bilateral oblique sagittal and coronal MRIs as well as pseudo-dynamic studies in the oblique sagittal plane were obtained. The disc-condyle relationship was divided into three subtypes (normal disc position, ADD with reduction, and ADD without reduction), based on the pseudo-dynamic MRI findings. Fisher's exact test was used to determine whether the TMJ pain was linked to ADD. The results showed that TMJ pain was significantly related to ADD (with and without reduction) compared to the group with a normal disc position (P=.0001). A significant correlation was found between TMJ pain and the ADD subtype without reduction, as compared to the ADD subtype with reduction (P=.0156). These data suggest that a displaced disc, particularly in the subtype without reduction, is an important source of pain.