Is there an association between sleep bruxism and obstructive sleep apnea? A case-control polysomnographic investigation.

Objectives: To estimate the statistical and epidemiological association between Sleep bruxism (SB) and Obstructive sleep apnea (OSA) based on OSA severity, and to describe sleep data findings within the analyzed population.

Methods: A case-control study (N = 37) was conducted on subjects with and without OSA. All subjects underwent a full-night polysomnographic recording at the Sleep Unit (Clinical Neurophysiology Department) of San Carlos University Hospital. The diagnosis and severity of OSA were determined using ICSD-3 and AASM-2.6 scoring. The definitive SB diagnosis was obtained through a self-report test, physical examination, and PSG recordings. Variables used to study the association between both conditions included the apnea and hypopnea episodes, the Apnea-hypopnea index (AHI), the number of SB episodes per night, and the bruxism index. Chi, correlations, and ANOVA were calculated. The epidemiological association was calculated using the OR.

Results: SB showed an epidemiological association with OSA, with an OR of 0.15 (0.036-0.68), suggesting it could be considered a protective factor (p < 0.05). OSA patients presented fewer average SB episodes (6.8 ± 12.31) than non-OSA patients (25.08 ± 31.68). SB episodes correlated negatively (p < 0.05) with the AHI and the number of hypopneas (p < 0.05). The average number of SB episodes was significantly higher in patients with mild OSA compared to those with severe OSA.

Conclusions: In this sample of patients with subclinical and mild OSA, SB may act as a protective factor. However, confirmation of these results with a larger sample size is necessary.