Association between Temporomandibular Joint Disorders and Salivary Cortisol Levels: A Systematic Review and Meta-Analysis

Abstract

Objective: Temporomandibular disorders (TMD) refer to various diseases involving the temporomandibular joint (TMJ), muscles of mastication, and related structures. Pain is generally the main feature of TMD, and these patients often suffer from significant degrees of stress in their daily lives. Patients with TMD usually have psychological stress as an important triggering factor. Patients with higher stress levels are more prone to bruxism and TMJ disorders. Excess cortisol secretion in TMD patients has been shown to have a defective response to stress. Several studies have shown that there is a positive correlation between salivary cortisol levels and TMD. The aim of this systematic review is to investigate the association between salivary cortisol levels and temporomandibular joint disorders.

Materials and methods: A systematic literature search was performed without restriction on publication start dateuntil October 2022 using four main electronic databases (PubMed, Web of science, Scopus and Embase) following PRISMA guidelines. Only case control studies were included in the study.The Joanna Briggs Institute critical appraisal checklist for case-control studies was utilized to appraise the selected articles.

Results: Of 1173 articles found in the search, 23 studies were eligible and 18 studies were meta-analyzed. A total of 696 TMD patients and 785 controls were included. Meta-analysis showed that salivary cortisol was significantly higher in TMD patients than in the controls. meta-regression showed that with increasing age in the studied subjects, the difference in mean salivary cortisol between the two groups decreases significantly.

Conclusion: The salivary cortisol level in patients with TMD is significantly higher than the controls. However, due to high degree of heterogeneity among the studies, more high quality studies are required to confirm the relationship.