Initial treatment for patients with temporomandibular disorders: pain relief and muscle tone relief by photobiomodulation therapy using carbon dioxide laser

Abstract Purpose To investigate the efficacy of photobiomodulation therapy (PBMT) with a CO2 laser (Bel Laser, Takara Belmont, CO. Ltd., Osaka, Japan; wavelength 10.6 μm) (tissue surface absorption effects) in conjunction with mouth opening training in patients with temporomandibular disorders (TMDs). Methods This is a retrospective study on TMD patients with pre- and post-treatment assessments. The study included 36 patients (7 men and 29 women, mean age 58.2 years (SD 18.3)) (after excluding 4 patients due to dropouts, loss to follow up or refusal of treatment) with symptoms of pain and muscle tenderness during mouth opening. Treatment included Amfenac sodium (50 mg per day, thrice daily after meals) for 1–2 weeks for acute symptoms. Based on the diagnostic criteria for TMD, we identified the trigger point (muscle contracture site). We implemented muscle massage and stretching therapy as mouth opening training after PBMT. The laser irradiance conditions were as follows: output 1.5 W, on time 0.01 s, off time 0.05 s, and repeat pulse. Distance between the laser source and the skin was approximately 10 cm; irradiation time was 3 min (approximately 56.9 J/cm2). Mouth opening training involved massaging the areas of muscle contracture that were the trigger points, as well as muscle stretching to improve temporomandibular joint flexibility. One PBMT cycle and mouth opening training was conducted per week for four cycles. We determined the effects before and after intervention. A numeric rating scale (NRS; range 0–10) was used to evaluate pain, and maximum mouth opening (MMO) capacity was also assessed. Data were analyzed using the Wilcoxon signed-rank test. Results The mean (SD) pain levels, as determined via NRS, were 4.9(3.6) and 2.7 (3.0) (p < 0.001), before and after four treatment cycles, respectively. The mean (SD) of MMO was 39.6 (5.9) and 44.6 mm (4.8) (p < 0.001), before and after treatment, respectively. Conclusion The current study suggests that PBMT using a CO2 laser combined with mouth opening training is effective for the treatment of temporomandibular disorders.