Abstract: Objective: To investigate the therapeutic effect of low-level Ga-Al-As laser therapy on temporomandibular joint pain. Methods: Fifty patients with temporomandibular joint pain were divided into laser treatment group (n=25) and control group (n=25) according to the principle of randomization and double blindness. Patients in the laser treatment group were treated with low-level Ga-Al-As laser therapy, and patients in the control group were treated with simulated laser irradiation that emitted the same red indicator light. The irradiation time of both groups was 5 min, and the irradiation was performed once a day for 3 consecutive days. The patient's maximum vertical opening, protrusion excursion, affected side lateral excursion, offside lateral excursion, pressure pain threshold and visual analogue scale were measured before and after each treatment. The corresponding scores were recorded, and analysis of variance of repeated measurements was used for statistical analysis. Results: After laser treatment of low-level Ga-Al-As laser therapy, the mandibular functional movement (P<0.05) and pain symptoms (P=0.001) were significantly improved. Patients in the control group showed no significant difference in mandibular functional movement and pain symptoms compared with those before treatment (P>0.05). Conclusion: Low-level Ga-Al-As laser therapy can effectively alleviate the symptoms of temporomandibular joint pain and improve the mandibular functional movement. The laser has the advantages of short treatment, high efficiency, no pain, no side effects, and has certain clinical application value.

Key words: Low-level Ga-Al-As laser, Temporomandibular joint（TMJ）pain, Pressure pain threshold