The authors conducted a study to evaluate whether temporomandibular joint, or TMJ, disorder subgroups are related to magnetic resonance imaging, or MRI, diagnoses of TMJ internal derangement, or ID; osteoarthrosis, or OA; effusion; and bone marrow edema.
The TMJ disorder group was composed of 118 subjects with TMJ pain who were assigned a clinical unilateral single diagnosis of a specific TMJ disorder. The control group consisted of 46 subjects who did not have TMJ pain. Sagittal and coronal magnetic resonance images were obtained to establish the prevalence of ID, OA, effusion and bone marrow edema. The authors used a multiple logistic regression analysis to compute the odds ratios, or OR, for MRI features for control subjects versus four groups of subjects who had TMJ pain: ID type I (n = 35), ID type III (n = 39), capsulitis/synovitis (n = 26) and degenerative joint disease, or DJD, (n = 18).
MRI diagnoses that did not contribute to the risk of TMJ pain included disk displacement, or DD, with reduction and effusion. Significant increases in the risk of experiencing TMJ pain occurred selectively with DD without reduction (OR = 10.2:1; P = .007) and bone marrow edema (OR = 15.6:1, P = .003) for the ID type III group and with DD without reduction (OR = 11.7:1, P = .054) for the DJD group. Subjects in the group with ID type I were less likely to be associated with an MRI finding of OA than were control subjects (OR = 1:5.6).
Therapy for subjects with TMJ based on the evaluation of concomitant morphological abnormalities, whether prophylactically or as treatment for TMJ disorders, may be unwarranted.
While the contribution of MRI variables to the TMJ pain subgroups was not zero, most of the variation in each TMJ pain population was not explained by MRI parameters. Thus, MRI diagnoses may not be considered the unique or dominant factor in defining TMJ disorder populations.