Examining the Influence of Glycemic Management During Sleep on Sleep‐Related Bruxism: A Pilot Study

BACKGROUND: Rhythmic masticatory muscle activity (RMMA) is a biomarker of sleep-related bruxism (SRB). Sleep quality and sympathetic nervous system activity are associated with SRB onset. We focused on fluctuations in blood glucose levels during sleep, which are considered to affect these factors. OBJECTIVES: This study aimed to clarify the effects of stabilising blood glucose levels through dietary instructions on SRB improvement. METHODS: Nineteen healthy adults diagnosed with SRB were included in this study. The first 7 days were the non-intervention period, and the second 7 days were the dietary instruction period (prohibiting sugary beverages, alcohol consumption and high-carbohydrate snacks). A portable continuous glucose monitoring device, polysomnography, electromyography and pulse oximetry were used to measure and compare the interstitial fluid glucose concentration (which is highly correlated with blood glucose levels), electroencephalogram frequency analysis, RMMA frequency per hour (RMMA Index) and heart rate variability. RESULTS: After instruction, blood glucose fluctuations during sleep [standard deviation of glucose concentration in interstitial fluid (11.0 ± 5.5 to 5.7 ± 3.3 mg/dL, p < 0.01)] decreased significantly and RMMA Index (9.9 ± 3.7 to 7.0 ± 2.8 episodes/h, p < 0.001) also decreased significantly. Analysis of heart rate variability showed a decrease in sympathetic nervous activity, but there were no significant changes in sleep quality indicators based on electroencephalogram analysis. CONCLUSION: Stabilisation of blood glucose levels during sleep may improve SRB, particularly by suppressing sympathetic nervous system activity.