Contingent Electrical Stimulation Reduces Muscle Symptoms Related to Sleep Bruxism

Objectives: Sleep bruxism (SB), characterized by repetitive jaw-muscle activity during sleep, has been linked to temporomandibular disorders (TMD), orofacial pain and headache. Contingent electrical stimulation (CES) of the facial skin has been shown to reduce electromyographic (EMG) activity associated with bruxism. The aim of this study was to demonstrate the efficacy of CES using a new generation of Grind Care device (GC3+) to reduce various muscle symptoms comparing two different stimulus intensities of CES.
Methods: Sixty definite SB patients (25 men and 35 women, average age ± SD: 36 ± 13 years old), clinically screened and confirmed by a 2-week use of GC3+ out of 93 probable SB patients, were allocated into one of 3 groups (High CES /Low CES /Placebo) in a randomized order and a single-blind manner for another 2-week trial period with GC3+. At baseline and after the intervention, the participants were asked to score muscle pain intensity, as well as unpleasantness, tiredness, tension, soreness and stiffness, on 0-10 numerical rating scales (NRS). A two-way analysis of variance (ANOVA) model with factors of groups (3 levels) and sessions (3 levels) was used to analyze the outcome parameters. The study adhered to Good Clinical Practice and was approved by the regional ethical committee.
Results: At baseline, NRS scores of tension were significantly higher than NRS scores of pain (P = 0.027). There was a significant decrease in NRS scores of tension (17.5 ± 4.6%; P = 0.015) and soreness (15.0 ± 5.1%; P = 0.024) in the High CES group after the intervention compared to the baseline.
Conclusions: This study suggests that different levels of CES might have an impact on muscle symptoms related to sleep bruxism, and that perceived levels of tension and soreness are more susceptible to intervention than perceived pain intensity.