Effect of Low Level Laser Therapy (LLLT) on muscle pain in temporomandibular disorders - an update of literature

Introduction: Temporomandibular disorders are complex pathologies with multifactorial aetiology. Due to this matter, different therapeutic approaches have been developed, one of them being physical therapy (also known as physiotherapy). Low-level laser therapy is often used in treating musculoskeletal diseases, TMJ pain and, although the exact mechanism of LLLT has not yet been completely elucidated, it seems that this kind of therapy induces analgesic, anti-inflammatory and bio-stimulating effects. The aim of this study was to create an update of scientific literature regarding the clinical use of LLLT in patients with temporomandibular disorders, and to identify the impact of this therapy on reducing pain in the masticatory muscles. Methods: A research of literature was performed - articles published over the last 10 years (January 2009 until December 2019) were searched for by introducing a combination of different keywords on the PubMed and ScienceDirect databases. Results: A total number of 294 articles were found. After applying inclusion and exclusion criteria, 28 articles were taken into consideration for our study, and among them, 9 were systematic meta-analyses or literature reviews and 19 were clinical studies. Conclusion: Low level laser therapy may effectively reduce pain in patients suffering from muscular- and/or joint-specific TMDs, but the effect appears to last only for a short period of time, and can be achieved only in less complex cases. LLLT may also improve oro-facial functions by reducing muscular activity. This research also reveals the need for better-designed clinical trials with larger sample sizes, in order to evaluate the efficacy of LLLT on improving the signs and symptoms of TMDs.