Comparison of Morphine and Diclofenac Intra-articular Injection in Temporomandibular Joint Disorders: A Randomized Controlled Clinical Trial

 Intra-articular injection has been used in patients with chronic temporomandibular joint (TMJ) pain for several years; however, there are still doubts regarding its effectiveness and duration of action. The aim of this study was to compare the analgesic effects of intra-articular injection of morphine, diclofenac, and isotonic saline on the patients with chronic TMJ pain. 

 Sixty-six patients with TMJ pain were enrolled in a prospective randomized double-blind and placebo-controlled clinical study. Patients were randomly allocated into three groups in which 12 patients consisted in each group. The analgesic effect of intermittent morphine injection (10 mg/ml), diclofenac sodium (25mg/ml), and normal saline was evaluated. In each group, pain reduction was evaluated by using visual analog scale (VAS) by following time points: 10, 60 min, and a week after injection. 

 All patients in the three groups experienced pain reduction during the experiment. Among them, patients who received morphine showed significantly more reduction in pain than the other the two groups at 60 minutes (P<0.05) and a week after the second injection (P<0.001). 

 Regardless of the type of treatment, TMJ pain was initially reduced presumably due to the arthrocenthesis effect of the drug or because of the placebo effect. According to the analytical results, 10 mg of morphine had a longer effect on pain reduction followed by diclofenac.