New generation low level laser effect on masseter muscle oxygenation, bite force and algometric changes in myofacial pain syndrome: a randomised, placebo-controlled clinical trial

The aim of this study was to compare the effectiveness of different types of low level laser treatment (LLLT) in reducing pain levels, changing oxygen saturation and bite force in patients with myofacial pain syndrome (MPS). 45 patients were randomly assigned to three groups: Group 1 (GRR laser, n = 15) received LLLT with Gallium-Aluminium-Arsenide (GaAlAs) diode laser with a wavelength of 904 nm and red laser with a wavelength of 650 nm over masseter muscle region. Group 2 (Nd: YAG laser, n = 15) were treated with Neodymium-doped Yttrium Aluminium Garnet laser with a wavelength of 1064 nm and the same protocol with Nd: YAG laser was performed in the Group 3 (placebo, n = 15) using sham device. Pain was evaluated by visual analogue scale (VAS), change in oxygen concentration in the masseter muscle was measured by functional near-infrared spectroscopy- fNIRS and bite force was measured with Flexiforce sensors before and after treatment. There was a significant decrease in VAS scores after treatment in all three groups. When pain scores were compared, a greater reduction was seen in the Group 1 and Group 2. The change in oxygen saturation level was not statistically significant in all three groups (p > 0.05). Bite force values showed a significant decrease in treatment groups (p < 0.05), while there was no significant change in the placebo group (p > 0.05). Nd: YAG and GRR laser treatments were effective in reducing the pain caused by MPS and in reducing bite force values. Clinically, GRR laser system provides more effective results with its regional and practical application. ClinicalTrials.gov ID: NCT06442553.