Changes involving temporomandibular joint, masticatory musculature, and associated structures characterize temporomandibular dysfunction (TMD). The analgesic and anti-inflammatory effect produced by photobiomodulation has contributed to pain relief and functional improvement. However, the parameters to be used have not yet been well established. The aim of this study is to compare the efficacy of three different photobiomodulation dosimetries in the treatment of patients with TMD. A randomized, double-blind, placebo-controlled clinical trial with 44 subjects divided into the groups 8 J/cm2 (n = 11), 60 J/cm2 (n = 11), 105 J/cm2 (n = 11), and control (n = 11). Pain, symptom severity, and joint mobility were evaluated before and after a ten-session protocol of photobiomodulation with AlGaAs laser (830 nm), at a power density of 30 mW/cm2. The mouth opening increased in the 8-J/cm2 group from 10.49 ± 4.68 to 15.40 ± 6.43 degrees, and in the right protrusion from 9.80 ± 4.2 to 12.56 ± 5.40 degrees after the intervention protocol (p < 0.05). All groups significantly decreased pain (p < 0.05). 830-nm laser photobiomodulation was effective in reducing TMD pain and symptoms at all doses tested. Only the doses of 8 J/cm2 were effective regarding maximal opening and protrusion of the mandible.
Keywords: Lasers; Low-level light therapy; Physical therapy modalities; Temporomandibular joint disorders; Temporomandibular joint dysfunction syndrome.