Immediate and short-term effects of phototherapy on pain, muscle activity, and joint mobility in women with temporomandibular disorder: a randomized, double-blind, placebo-controlled, clinical trial

Abstract

Objectives: The aim of the present study was to evaluate the immediate and short-term effects of phototherapy on pain intensity, the pressure pain threshold (PPT), maximum vertical mandibular movement, and the electrical activity of the masseter and temporal muscles in women with temporomandibular disorder (TMD).

Methods: Sixty women were randomly allocated to four different groups and submitted to phototherapy with a combination of super-pulsed laser (905 nm), red (640 nm), and infrared (875 nm) light emitting diodes in the same equipment on the masseter (three points) and temporal (two points) muscles bilaterally in a single session. The following doses were used in each point of application: Group 1 – 2.62 J; Group 2 – 5.24 J; Group 3 – 7.86 J; placebo group. Pain intensity was determined using the visual analog scale. The PPT was analyzed using a digital algometer. Vertical mandibular movement was measured using digital calipers. Myoelectrical activity of the masseter and temporal muscles was measured using electromyography. Four evaluations were performed: pre-intervention, immediately after, 24 and 48 hours after phototherapy.

Outcomes: A significant reduction in pain intensity during the post-treatment evaluations in comparison to the pretreatment evaluation was observed in group 1 (Median difference = 2.60 [95% CI = 1.35–3.85]) and group 2 (Median difference = 2.2 [95% CI = 0.98–3.42]) especially after 48 hours and group 3 (Median difference = 2.50 [95% CI: 0.56–4.46]) especially after 24 hours, with a moderate effect size, but no effect was found regarding the other variables.

Conclusions: A single session of combined phototherapy was capable of reducing pain intensity in individuals patients with TMD.

ClinicalTrials.gov (NCT02018770).

Implications for Rehabilitation

• Phototherapy device combining two light sources (LED and laser), and different densities in the same device is a novelty in the rehabilitation market, and has proved to be a useful intervention for people with temporomandibular disorders.

• This mode of phototherapy is another option that assists in the rapid intervention in pain symptoms, promoting a considerable degree of comfort to the patient moments after its application.

Keywords:

• Temporomandibular joint disorder
• electromyography
• physical therapy modalities
• lasers
• phototherapy

Acknowledgements

The authors are grateful to the research team and all participants as well as University Nove de Julho, and the Brazilian fostering agencies, the State of São Paulo Research Assistance Foundation, and Coordination for the Improvement of Higher Education Personnel.

Disclosure statement

The authors report no conflicts of interest.

Additional information

Funding

Funding for this study was provided by the State of São Paulo Research Foundation.