The Relationship Between Sleep Bruxism and Obstructive Sleep Apnea—A Narrative Review

Introduction Sleep bruxism (SB) and obstructive sleep apnea (OSA) are prevalent sleep‐related disorders that compromise sleep architecture and share pathophysiological mechanisms, including sleep fragmentation, autonomic activation, and microarousals. The potential interrelationship between these conditions has gained increasing research attention. Objective To investigate the association between SB and OSA by analysing available evidence on shared mechanisms and clinical implications. Methods This is a narrative literature review structured according to the SANRA guidelines. Searches were conducted in PubMed, SciELO, and the CAPES Periodicals Portal. Studies published in Portuguese or English, preferably within the last ten years, directly addressing the relationship between SB and OSA were included. Results Fourteen studies were selected, including observational studies, prospective clinical studies, randomized clinical trials, and systematic reviews. Most analyzed studies ( n = 9) suggested an association between SB and OSA, with a temporal relationship in which SB episodes—predominantly the phasic subtype—followed respiratory events (apneas/hypopneas), particularly in mild‐to‐moderate OSA. However, five studies, mostly systematic reviews, reported inconclusive or weak associations, attributing heterogeneity to methodological diversity, lack of diagnostic standardization (polysomnography with masseter electromyography), and insufficient control of confounding variables such as body mass index and comorbidities. Conclusion Available evidence suggests a non‐causal interrelationship between SB and OSA. In mild‐to‐moderate OSA, phasic SB may act as a compensatory response to obstructive events, though this remains a hypothesis requiring further longitudinal and standardized investigation.