Underlying mechanism of sleep bruxism in patients with obstructive sleep apnea or insomnia

The thesis aimed to uncover the mechanisms behind sleep bruxism (SB) in patients with obstructive sleep apnea (OSA) or insomnia. Chapter 2 reviewed the associations between SB and other sleep disorders, finding that SB is more common in patients with OSA, restless leg syndrome, gastroesophageal reflux disease, insomnia, Parkinson’s disease (PD), REM behavior disorder (RBD), and sleep-related epilepsy. Sleep arousal was identified as a common factor, except in RBD and PD. Chapter 3 explored the prevalence and risk factors of SB in OSA patients, revealing that nearly half of OSA patients also have SB. Male sex, lower body mass index, and more light sleep were identified as risk factors. SB episodes were often time-related to arousals but not directly correlated with respiratory events. Chapter 4 examined the impact of mandibular advancement appliance (MAA) therapy on jaw-closing muscle activities (JCMAs) in OSA patients. Effective MAA therapy significantly reduced JCMAs related to oxygen desaturations with arousals but had no significant effect without arousals. Chapter 5 compared SB episodes in different sleep positions in OSA patients, finding SB more frequent in the supine position than in non-supine position, and associated with arousals in both positions. Chapter 6 investigated SB occurrence in insomnia patients, finding no significant difference between insomnia patients and controls, or between those with varying distress levels. The thesis concluded that SB occurrence is linked to sleep arousals, suggesting further research to identify other contributing factors.