Temporomandibular Disorders and Their Association with Sleep Disorders in Adults: A Systematic Review

Aims: To investigate the associations between temporomandibular disorders (TMDs) and sleep disorders in adult subjects. Methods: The PubMed, Embase, Evidence-Based Medicine Reviews, and ProQuest Dissertations & Theses databases were searched for studies published in English up to September 2019. Unpublished/gray literature and reference lists of identified articles were also examined. Inclusion criteria were male and female adults, presence or absence of a TMD based on the RDC/TMD or DC/TMD criteria, presence or absence of a sleep disorder according to the International Classification of Sleep Disorders, and any of the following study designs: cross-sectional, case-control, or longitudinal. Methodologic quality assessment was conducted using the National Heart, Lung, and Blood Institute quality assessment tools. Results: Twenty-two studies (11 cross-sectional, 9 case-control, 1 prospective cohort, and 1 mixed design) met the inclusion criteria. TMDs were assessed independently in relation to sleep bruxism (SB), obstructive sleep apnea (OSA), and sleep quality (SQ). All studies but one assessed TMDs using the RDC/TMD criteria. The relation between the TMD and the different sleep disorders was conflicting for SB and positive for OSA and SQ. Five studies were of good quality, and 17 were of fair quality. Conclusions: The evidence is inconclusive regarding the relationship between TMDs and SB and insufficient regarding the relationship with OSA. There is consistently fair evidence to support an association between TMD and SQ. This study highlights the need for higher-quality longitudinal studies to clarify the association between TMDs and sleep disorders.