Electromyographic evaluation of a low-level laser protocol for the treatment of temporomandibular disorder: a randomized, controlled, blind trial.
Camila Haddad Leal de Godoy, Lara Jansiski Motta, Eugenio Jose Garcia and 6 others
PMID 29643585WHAT IT FOUND
Active low-level laser in 9 participants did not reduce jaw muscle electrical activity after 12 sessions.
Mean bite-task activity increased, while mean bite-task activity in the sham group of 7 decreased. The paper gives only descriptive changes.
Key findings
01During a bite-task, active laser increased mean anterior temporal muscle activity (right 67.1 to 69.6; left 68.4 to 69.3), while sham decreased it (right 76.2 to 73.0; left 79.6 to 71.7).
02During a bite-task, active laser increased mean masseter activity (right 49.1 to 56.7; left 51.6 to 58.8), while sham decreased it (right 60.3 to 56.5; left 56.6 to 46.3).
03During chewing, active laser increased mean activity in the measured temporal and masseter muscles, while sham decreased mean activity in those muscles.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The study was a small preliminary convenience sample, with 9 active laser and 7 sham participants, and the analysis was descriptive. It measured EMG muscle activity, not pain, jaw function, or clinically important symptoms, so it cannot show symptom improvement. The paper does not report whether EMG assessors or clinicians were blinded, and it does not report dropouts. Participants were aged 14 to 23 and excluded if they had dentofacial anomalies, incomplete permanent dentition through to the second molars, orthodontic or orthopedic treatment of the jaws, psychological treatment, or physical therapy using muscle relaxants, anti-inflammatory agents, or bite plates, so results may not apply to many TMD patients. Active laser did not reduce mean muscle activity; changes were reported only descriptively and individual responses varied.
Declared interests
All listed authors declared no conflict of interest. The study received support from São Paulo Research Foundation (FAPESP), grant 2012/07759-0.
The easy way to misread this
Do not conclude that low-level laser therapy reduces jaw muscle activity or TMD pain. In the active laser group, mean bite-task activity increased, and the paper reports no pain outcomes or significance testing.