# Effect of Altered Sleep Duration on Sleep Bruxism

## TL;DR

This study found that sleep deprivation increases sleep bruxism and stress, but recovery sleep can reduce bruxism by improving sleep quality.

## Contribution

The study experimentally demonstrates how sleep deprivation and recovery affect sleep bruxism and associated stress levels.

## Key findings

- Sleep bruxism event frequency was significantly lower during recovery sleep compared to baseline and second recovery sleep.
- Recovery sleep improved total sleep time, sleep efficiency, and deep sleep (N3) while reducing N2 sleep.
- Sleep deprivation increased sleepiness and stress while decreasing well-being.

## Abstract

Introduction: Inconsistent findings have been reported regarding the relationship between sleep bruxism (SB) and sleep quality; therefore, the aim of the present study was to investigate the effect of sleep deprivation (SD) on masticatory muscle activity during sleep.

Methods: Twenty-eight healthy participants were subjected to a five-day experimental protocol involving different sleep conditions, including baseline sleep (BS), one night of SD, and two nights of recovery sleep (RS1 and RS2). A portable electromyography device was used to measure SB events, and a Sleep Profiler device (Advanced Brain Monitoring Inc, Carlsbad, CA, USA) simultaneously recorded sleep parameters. The total sleep time, sleep efficiency, proportion of time spent in each sleep stage, microarousal index, and number of SB events were compared between the BS, RS1, and RS2 periods. The Epworth Sleepiness Scale, Stress Numerical Rating Scale-11, and World Health Organization-Five Well-Being Index for stress were used for subjective assessments, and values were compared between three time points (after BS, SD, and RS1).

Results: The SB event frequency was significantly lower during RS1 than during BS (P < 0.001) and RS2 (P = 0.022). During RS1, the total sleep time (P = 0.039), sleep efficiency (P = 0.047), and proportion of sleep time in N3 (P = 0.019) were significantly higher, whereas the proportion of time spent in N2 was lower (P = 0.032). After SD, sleepiness and stress significantly increased, whereas well-being decreased (P < 0.001).

Conclusion: SD affects SB events, the frequency of which can be reduced by improving sleep quality to lower stress levels.