The effect of intra-articular injection of ultracain in the temporomandibular joint in patients with preauricular pain: a randomized prospective double-blind placebo-controlled crossover study.

OBJECTIVES: To evaluate the distinguishing ability of intra-articular anesthesia from placebo in orofacial pain patients with pain located in the temporomandibular joint (TMJ) region, aiming at a validation of intra-articular anesthesia injection as a diagnostic test of pain in the TMJ region.

MATERIALS AND METHODS: A randomized prospective double-blind, placebo-controlled crossover study was conducted among 19 patients (18 females, 1 male) with pain in the TMJ region. The short-term effects of intra-articular ultracain and saline injections on pain and maximum mouth opening were measured and analyzed.

RESULTS: Compared with placebo injections, a statistically significant difference in pain scores was found after intra-articular injection of a local anesthetic on Visual Analog Scale values. The maximum mouth opening scores did, however, not differ between the 2 groups.

DISCUSSION: TMJ injection with local anesthesia leads to the decrease of pain in patients with preauricular pain. To establish the source of pain, injection of a local anesthetic in the TMJ may be used as a diagnostic tool. However, the results of diagnostic injections should still be interpreted cautiously.