Clinical diagnoses and MRI findings in patients with TMD pain

The aim of this study was to compare the findings on magnetic resonance imaging (MRI) in temporomandibular disorders (TMD) pain patients with clinical diagnoses of myofascial pain or arthralgia/osteoarthritis in combination with myofascial pain according to the Research Diagnostic Criteria for TMD. The temporomandibular joints of 60 consecutive patients, 19 with myofascial pain and 41 patients with arthralgia/osteoarthritis in combination with myofascial pain were examined clinically and with MRI. Overall the most common MRI findings were different kinds of disc displacements and structural bone changes, which were found in both pain groups. However, disc displacements were found significantly (P=0.002) more often in the group arthralgia/osteoarthritis in combination with myofascial pain. One hundred and four joints were found to have no clinical diagnosis of disc displacements, but 64 of these joints had findings of disc displacements on MRI. Joint fluid was found in both pain groups. Patients having a combination of disc displacement and joint fluid were significantly (P=0.047) more common in the pain group arthralgia/osteoarthritis in combination with myofascial pain. In conclusion, the MRI findings of different kinds of disc displacement and structural bone changes were common in TMD patients. The clinical diagnoses for subdivision into myogenous only or combined arthrogenous and myogenous pain groups were not confirmed by MRI.