The relationship between sleep bruxism and sleep-related respiratory events under oral … – Nature

New research suggests that oral appliance therapy may help reduce the frequency of sleep bruxism by decreasing the respiratory events and related arousals that often trigger the condition.

The study, which analyzed the relationship between muscle activity during sleep bruxism and sleep-related respiratory events, focused on patients diagnosed with obstructive sleep apnea (OSA).

Study Methodology and Participant Data

The research was conducted at Fukuoka University Hospital between October 2020 and May 2025. The study enrolled 21 participants, consisting of 10 males and 11 females, with a mean age of 57.8 ± 16.0.

To measure masseter muscle activity, researchers used an identical single-channel wearable electromyography device. Participants underwent polysomnography (PSG) and electromyography (EMG) evaluations both at baseline and following the implementation of oral appliance (OA) therapy.

Key Findings on Respiratory Improvement

The results of the PSG evaluations indicated a significant improvement in the apnea-hypopnea index (AHI), which moved from 17.3 ± 7.3 at baseline to 12.3 ± 10.7 during reevaluation.

the researchers observed that the total number of sleep bruxism episodes and the number of episodes per hour significantly decreased.

The data also showed a significant increase in the spontaneous arousal index specifically during the rapid eye movement (REM) stage of sleep.

Impact Across Patient Groups

The study categorized participants into two groups based on the effectiveness of the oral appliance therapy:

• The effective group included 10 participants who achieved an AHI reduction of 50% or more, or had an AHI of less than 5 during reevaluation.
• The ineffective group included 11 participants who experienced an AHI reduction of less than 50% and maintained an AHI of 5 or more during reevaluation.

The findings revealed that significant reductions in total sleep bruxism episodes and episodes per hour were observed in the ineffective group rather than the effective group.

The research was authored by Yuriko Dotsu, George Umemoto, Chikara Yoshimura, Ritsuko Miyachi, and other contributors.