A case-control investigation of the psychological and physiological stress markers with salivary cortisol levels in patients with temporomandibular joint disorders: A short clinical study.

Aims: This study aimed to determine the association of stress and salivary cortisol levels in the adult Indian population with and without temporomandibular disorder (TMD) and to validate it with bite force. Settings and Design: The present study had an observational, case-control study design. Materials and Methods: This study sample comprised two groups of 25 cases and 25 controls between 18 and 45 years of age. Diagnostic criteria-TMD questionnaire Axis I was used to assess TMD classification, the TMD Disability Index and modified Perceived Stress Scale (PSS) questionnaires were filled, and salivary cortisol levels were measured using electrochemiluminescence immunoassay (ECLIA). Bite force analysis was performed using a portable load indicator. Statistical Analysis Used: To characterize and analyze the study variables, means, standard deviations, Mann-Whitney U-test, and logistic regression were employed (STATA 14.2 [Texas, USA]). Shapiro-Wilk test was used to test the normality of the data. P < 0.05 was considered statistically significant (95% power). Results: Female gender was proportionately higher in both the groups (P = 0.508), TMD Disability Index was significantly higher for cases (P < 0.001), TMD cases perceived higher stress levels (P = 0.011), there was no statistically significant difference in salivary cortisol level between cases and controls (P = 0.648), and the median bite force was lower for cases (P = 0.0007). Conclusions: This study concluded that the chance of developing TMD increased with age. An increase in the TMD Disability Index score and modified PSS scores; and a decrease in the bite force increased the likelihood of TMD. Modified PSS score was negatively correlated with salivary cortisol concentrations, indicating a two-way response to TMD symptoms.