This study investigated the effect of low-level
laser therapy (LLLT) on the masticatory performance
(MP), pressure pain threshold (PPT), and pain intensity in
patients with myofascial pain. Twenty-one subjects, with
myofascial pain according to Research Diagnostic Criteria/
temporomandibular dysfunction, were divided into laser
group (n012) and placebo group (n09) to receive laser
therapy (active or placebo) two times per week for 4 weeks.
The measured variables were: (1) MP by analysis of the
geometric mean diameter (GMD) of the chewed particles
using Optocal test material, (2) PPT by a pressure algometer,
and (3) pain intensity by the visual analog scale (VAS).
Measurements of MP and PPT were obtained at three time
points: baseline, at the end of treatment with low-level laser
and 30 days after (follow-up). VAS was measured at the
same times as above and weekly throughout the laser therapy.
The Friedman test was used at a significance level of
5 % for data analysis. The study was approved by the Ethics
Committee of the Federal University of Sergipe (CAAE:
0025.0.107.000-10). A reduction in the GMD of crushed
particles (p<0.01) and an increase in PPT (p<0.05) were seen only in the laser group when comparing the baseline and end-of-treatment values. Both groups showed a decrease in pain intensity at the end of treatment. LLLT promoted an improvement in MP and PPT of the masticatory muscles.