Biopsychosocial assessment of temporomandibular disorder symptoms across bruxism subtypes in dental students: associations with stress, sleep quality, and insomnia

Background: This study aimed to determine the prevalence of self-reported bruxism among dental students and to examine its association with stress, sleep quality, insomnia, and temporomandibular disorder (TMD) symptoms. Methods: A total of 480 dental students participated in the study. Based on self-reported questionnaires (subject-based assessment), participants were classified into four groups: combined bruxism, sleep bruxism, awake bruxism, and non-bruxism. Bruxism-related parameters were assessed using the Fonseca Anamnestic Index (FAI), Perceived Stress Scale-10 (PSS-10), Pittsburgh Sleep Quality Index (PSQI), and Insomnia Severity Index (ISI). Statistical analyses were performed using Pearson’s chi-square and Kruskal-Wallis tests to compare group differences, followed by multinomial logistic regression analyses to adjust for confounders. Statistical significance was defined as p < 0.05. Results: The overall prevalence of self-reported bruxism was 73.3% and was significantly higher in women (p = 0.001). The proportions of sleep bruxism, awake bruxism, and combined bruxism were 17.1%, 11.9%, and 44.4%, respectively. In univariate analyses, the combined bruxism group demonstrated significantly greater TMD symptom severity as measured by the FAI (p < 0.001; η2 = 0.28). In addition, perceived stress (PSS-10; p < 0.001; η2 = 0.04), sleep quality (PSQI; p = 0.008; η2 = 0.02), and insomnia severity (ISI; p = 0.006; η2 = 0.02) also differed significantly between groups; however, the corresponding effect sizes were small. In multinomial logistic regression analyses, only FAI remained independently associated with bruxism subtypes, whereas stress measures, sleep-related parameters, and demographic variables were not retained as significant predictors after adjustment. Conclusions: Within the limitations of a subject-based assessment, self-reported bruxism was frequently observed among dental students. Although combined bruxism was associated with higher TMD symptoms, stress, and sleep disturbances in univariate analyses, only TMD symptom severity remained independently associated after adjustment. These findings highlight the importance of assessing bruxism subtypes separately in relation to TMD symptom burden.