The purpose of this study was to investigate the effects of repetitive transcranial magnetic stimulation(r TMS)on patients with sleep bruxism(SB).Twelve patients with SB were included in an open,single-intervention pilot study.r TMS at 1 Hz and an intensity of80%of the active motor threshold was applied to the‘hot spot’of the masseter muscle representation at the primary motor cortex bilaterally for 20 min per side each day for 5 consecutive days.The jaw-closing muscle electromyographic(EMG)activity during sleep was recorded with a portable EMG recorder at baseline,during r TMS treatment and at follow-up for 5 days.In addition,patients scored their jaw-closing muscle soreness on a 0–10 numerical rating scale(NRS).Data were analysed with analysis of variance.The intensity of the EMG activity was suppressed during and after r TMS compared to the baseline(P 5 0.04;P 5 0.02,respectively).The NRS score of soreness decreased significantly during and after r TMS compared with baseline(P,0.01).These findings indicated a significant inhibition of jaw-closing muscle activity during sleep along with a decrease of muscle soreness.This pilot study raises the possibility of therapeutic benefits from r TMS in patients with bruxism and calls for further and more controlled studies. The purpose of this study was to investigate the effects of repetitive transcranial magnetic stimulation (r TMS) on patients with sleep bruxism (SB). Twelve patients with SB were included in an open, single-intervention pilot study. R TMS at 1 Hz and an intensity of 80% of the active motor threshold was applied to the’hot spot’of the masseter muscle representation at the primary motor cortex bilaterally for 20 min per side each day for 5 consecutive days. jaw-closing muscle electromyographic (EMG) activity during sleep was recorded with a portable EMG recorder at baseline, during r TMS treatment and at follow-up for 5 days. In addition, patients scored their jaw-closing muscle soreness on a 0-10 numerical rating scale (NRS). Data were was analyzed with variance of intensity of the EMG activity was suppressed during and after r TMS compared to the baseline (P 5 0.04; P 5 0.02, respectively). The NRS score of soreness decreased significantly during and after r TMS compared with the baseline (P , 0.01). The findings indicate a significant inhibition of jaw-closing muscle activity during sleep along with a decrease of muscle soreness. This pilot study raises the possibility of therapeutic benefits from r TMS in patients with bruxism and calls for further and more controlled studies .