Is There a Relationship between Salivary Cortisol and Temporomandibular Disorder: A Systematic Review

Background: This systematic review examines and evaluates the relationship between salivary cortisol levels and temporomandibular disorder (TMD) in young adult patients. Method: Six databases-PubMed, Scopus, Web of Science, Google Scholar, ProQuest, and Cochrane Library-were utilized to screen eligible studies. A systematic search was performed based on PECO questions and eligibility criteria. The research question for this review was "Do salivary cortisol levels correlate with TMD in individuals aged 18-40?" The risk of bias for quality assessment was determined by the Cochrane tool. PRISMA guidelines were followed while performing this review. Result: A total of fourteen studies were included in this review. Of these, eleven were observational studies (four cross-sectional and seven case-control), and three were randomized control trials. Eleven of the included studies presented a low to moderate risk in the qualitative synthesis. The total sample size of the included studies was 751 participants. The included studies suggest higher salivary cortisol levels in TMD patients than in healthy individuals. Conclusions: The findings of this review indicate higher salivary cortisol levels in adult patients with TMD than in healthy controls. Thus, supportive psychological treatment and clinical modalities should be provided to patients with TMD. Moreover, higher-quality studies with low heterogeneity are required to support this finding.