The Effects of Botulinum Toxin on Sleep Bruxism: An Electromyographic Study with the Portable Bruxoff Holter System

Background: Sleep bruxism involves repetitive jaw-muscle activity, including teeth clenching, grinding, or mandibular bracing. Despite the growing interest in botulinum toxin type A (BTX-A) as a therapeutic intervention for bruxism, evidence remains limited, particularly regarding studies using portable electromyography (EMG) monitoring devices. This study evaluated the effects of BTX-A injections into the masseter muscle on the reduction of bruxism activity, as measured using the portable electromyographic Holter Bruxoff system. Methods: Adult patients with diagnosed sleep bruxism were monitored for two nights using the Bruxoff device to record masseter EMG activity, respiratory rate, and heart rate. After receiving standardized bilateral masseter BTX-A injections, participants underwent the same monitoring protocol 40 days later. Statistical analyses compared pre- and post-treatment values, and effect sizes were calculated. Results: Ten participants (60% women; mean age 47.6 ± 4.4 years) completed the study. The Bruxism Index showed a marked reduction, dropping from 12.2 ± 1.32 at baseline to 7.4 ± 1.35 after 40 days, a statistically significant change (t (9) = 10.23, p < 0.001; Cohen's d = 3.25). Average heart rate also decreased significantly, from 64.4 ± 2.99 to 62.6 ± 2.63 (t (9) = 2.86, p = 0.018; Cohen's d = 0.91). However, the respiratory rate measurement remains stable. Conclusions: BTX-A injections into the masseter muscles produced a marked reduction in sleep-related bruxism activity as measured by portable EMG. These findings support BTX-A as a promising and effective treatment option for sleep bruxism.