Introduction:
Bruxism, defined as repetitive masticatory activity, is a common condition with a multifactorial etiology. Although linked to stress and personality traits, few studies have examined medical students – a population with chronic academic stress, whose specialized knowledge may enhance self-report reliability. This study aimed to assess the association between personality traits and self-reported bruxism in this group.

Material and methods:
A cross-sectional survey was conducted among 204 students of the Medical University of Silesia (150 women, 54 men). Bruxism was assessed by self-report using a modified version of the Baron et al. questionnaire, while personality traits were measured with the NEO-FFI inventory. Group differences (non-bruxism, awake bruxism – AB, sleep bruxism – SB) were analyzed using ANOVA, and predictors of bruxism status evaluated through logistic regression.

Results:
Based on self-report, 56 participants (27.5%) were classified as having bruxism, including 26 (12.8%) with SB. ANOVA indicated significant differences only for conscientiousness (F(2,201) = 4.57; p = 0.011), with lower scores in the SB group compared to non-bruxers (p = 0.0088). Logistic regression showed higher conscientiousness was associated with lower odds of being classified as a bruxer; however, this association was borderline (OR = 0.87; 95% CI: 0.76–1.00; p = 0.051). No significant associations were observed for neuroticism, extraversion, openness, or agreeableness.

Conclusions:
In this cohort, lower conscientiousness was the most consistently observed trait associated with self-reported bruxism, particularly its sleep subtype. The multivariable findings were borderline and overall predictive performance modest; therefore, the results should be considered exploratory and hypothesis-generating, pending confirmation in studies using objective bruxism assessment.