Efficacy of Low-Level Laser Versus Transcutaneous Electrical Nerve Stimulation for Treatment of Myofascial Pain Syndrome: A Clinical Trial

Myofascial pain syndrome (MPS) is the most common cause of facial muscle pain. This study sought to assess the efficacy of transcutaneous electrical nerve stimulation (TENS) and low-level laser (LLL) for treatment of MPS in comparison with a sham laser control group. In this randomized controlled clinical trial, 55 MPS patients between 18-60 years old were randomly assigned to TENS, LLL (810 nm) or sham laser group. At the onset of treatment, 500 mg of methocarbamol and 250 mg of naproxen t.i.d. were prescribed for 10 days as the standard treatment protocol. Tenderness and pain of major muscles of mastication, minor muscles, and temporomandibular joint (TMJ) were evaluated using a visual analog scale (VAS). Maximum mouth opening and deviation and deflection of the jaw were also evaluated before and one month after the intervention. Data were analyzed using Kruskal-Wallis test and non-parametric Dunn’s test. Pain severity (VAS score) in the masseter, lateral pterygoid, and trapezius muscles (at the side of greater involvement) significantly decreased in both TENS and LLL groups after the treatment. In the sternocleidomastoid (SCM) and anterior temporalis muscles, significant pain reduction only occurred in LLL group. Mouth opening significantly increased in TENS group and decreased in LLL group. TMJ pain significantly decreased only in TENS group. Both TENS and LLL were efficient for treatment of MPS; however, the efficacy of TENS was found to be slightly higher than that of LLL.