Temporomandibular Disorders as Contributors to Primary Headaches: A Systematic Review

Aims: To systematically review the literature assessing associations between TMDs and primary headaches.Methods: Using validated clinical criteria, studies on TMDs and primary headaches published up to January 10, 2023 were identified using six electronic databases. This review adhered to the PRISMA 2020 guidelines and 27-item checklist and is registered on PROSPERO (CRD42021256391). Risk of bias was evaluated using the National Institutes of Health Quality Assessment Toolkits for Observational Cohort and Cross-Sectional Studies.Results: Two independent investigators rated 7,697 records against the primary endpoint and found 8 records meeting the eligibility requirements. Migraine was found to be the most common primary headache related to TMDs (61.5%), followed by episodic tension-type headache (ETTH; 38.5%). A moderate association was found for mixed TMDs with migraine and ETTH, with a large sample size and multiple studies included (n = 8). A very low-quality association was found for myalgia-related TMDs with migraine and ETTH (included studies, n = 2).Conclusion: The association between TMDs and primary headaches is of great interest given the possible effectiveness of TMD management in reducing headache intensity/frequency in patients with TMDs and headache comorbidity. A moderate association was found for mixed TMDs with primary headaches, in particular migraine and ETTH. However, owing to the overall moderate certainty of evidence of the present findings, further longitudinal studies with larger samples investigating possible associated factors and using accurate TMD and headache category assignment are needed.