The interplay of sleep disorders and orofacial pain: A systematic review.

Background: Chronic orofacial pain (OFP) and sleep disorders are highly prevalent conditions that significantly impact quality of life. Increasing evidence suggests a bidirectional relationship between these disorders, whereby sleep disturbances may exacerbate OFP and vice versa. This systematic review synthesizes current evidence on the influence of sleep disorders on chronic OFP and explores additional factors that may contribute to this interaction. Material and Methods: A systematic review was conducted following PRISMA 2020 guidelines and registered the study with PROSPERO (CRD4202525111587). PubMed, Scopus, and Web of Science were searched for relevant literature published between 2004 and March 2024. Randomized controlled trials, cross-sectional studies, case-control studies, and cohort studies examining the association between sleep disorders and OFP were included. Ten studies met the eligibility criteria. Results: A consistent association was identified between chronic OFP and sleep disorders, particularly insomnia and obstructive sleep apnea (OSA), with stronger correlations observed in women. Limited evidence also suggests that OFP severity may increase with age and that greater sleep disturbance correlates with more intense pain. Limitations: The paucity of high-quality studies specifically addressing the relationship between sleep disorders and chronic orofacial pain was a notable issue. Additionally, there was significant methodological heterogeneity among the included studies, especially regarding study design, diagnostic criteria, and assessment tools. The decision to include only studies focused on orofacial pain and to exclude other categories of pain-related diseases, such as temporomandibular joint disorders (TMD), introduced an additional challenge and resulted in a reduction of the number of selected studies. Conclusions: There is a strong connection between chronic orofacial pain (OFP) and sleep disorders, particularly insomnia and obstructive sleep apnea (OSA). Addressing sleep-related issues could be an effective complementary approach in managing OFP, especially in female patients. More research is necessary to clarify the underlying mechanisms and to develop targeted, interdisciplinary interventions.