# Daytime Sleepiness and Dispositional Optimism Are Related to Awake Bruxism Among Patients With Painful Temporomandibular Disorders

## TL;DR

This study finds that daytime sleepiness and being optimistic are linked to awake bruxism in patients with painful jaw disorders.

## Contribution

The study identifies new associations between awake bruxism, daytime sleepiness, and dispositional optimism in TMD patients.

## Key findings

- Daytime sleepiness is associated with increased frequency of teeth grinding and clenching.
- Dispositional optimism is linked to lower frequency of teeth grinding.
- The associations have small effect sizes and may play a modest role in awake bruxism.

## Abstract

Awake bruxism (AB) is a multifactorial condition that has been linked to several physiological and psychological factors. The aim of this study was to investigate the potential association between AB‐related behaviours, daytime sleepiness, and dispositional optimism.

A cross‐sectional study was conducted at the Academic Centre for Dentistry Amsterdam (ACTA). Participants with pain‐related temporomandibular disorders (TMD) that worsened with function were included. The survey comprised subjective assessment of the frequency of AB‐related oral behaviours (items adopted from the Standardised Tool for the Assessment of Bruxism, STAB), anxiety and depression (Patient Health Questionnaire‐4, PHQ‐4), daytime sleepiness (Epworth Sleepiness Scale, ESS), and dispositional optimism (Revised Life Orientation Scale, LOT‐R). Spearman's rank correlation and Mann–Whitney U tests were used for bivariate analysis. Ordinal logistic regression was conducted to determine the associations between AB behaviours, ESS and LOT‐R while controlling for age, sex, smoking status, anxiety and depression.

A total of 1661 patients were included, with a mean age of 42 years, of whom 77.6% were women and 84.2% were nonsmokers. Bivariate analyses showed significant associations between the frequency of AB‐related oral behaviours, ESS and LOT‐R. In the regression models, daytime sleepiness was found to be associated with increased frequency of teeth grinding, clenching and contact, but not with mandible bracing. Dispositional optimism was associated with a lower frequency of teeth grinding. Although statistically significant, the observed associations reflected small effect sizes.

This study demonstrates an association, albeit with a small effect size, between the frequency of certain self‐reported AB behaviours and both daytime sleepiness and dispositional optimism. These findings suggest that, while these factors may play a modest role, they deserve consideration as potential contributors to the report of AB.

Daytime sleepiness and dispositional optimism are related with awake bruxism among patients with painful temporomandibular disorders.