Relationship Between Sleep Bruxism and Stress Determined by Saliva Biomarkers

Purpose: The aim of this study was to evaluate the relationship between sleep bruxism (SB) and perceived stress through the estimation of stress-related biomarkers (cortisol, α-amylase) in saliva. Materials and Methods: Forty-five volunteers (20 men, 25 women) participated in this study. Participants were divided into two groups (bruxers and nonbruxers) according to their answers in a standard bruxism assessment questionnaire outlined by the American Academy of Sleep Medicine. To confirm the preliminary diagnosis and to determine the severity of SB in the group of patients who had a positive self report for SB, a miniature, single-use electromyographic (EMG) device for SB detection (BiteStrip) was used. The perceived stress of the 45 participants was measured using the Perceived Stress Scale questionnaire. Unstimulated whole saliva was collected and levels of salivary cortisol and α-amylase were determined by enzyme-linked immunosorbent assay test and enzyme kinetic reaction, respectively. Nonparametric statistical methods were applied for data analyses. Results: Bruxers showed higher levels of perceived stress than nonbruxers (P .001). There was a moderate positive correlation between the 25 bruxers' BiteStrip scores and the salivary cortisol levels (Spearman rank correlation = 0.401, P = .047). Additionally, bruxers showed higher levels of cortisol than nonbruxers (P .001). On the contrary, salivary α-amylase levels were not significantly different in bruxers and nonbruxers (P = .414). Conclusions: These findings suggest that SB activity was related to higher levels of perceived psychological stress and salivary cortisol. Despite the limitations of the EMG recording device, a moderate positive correlation between BiteStrip score and cortisol levels was observed in bruxers.