Self-reported bruxism and temporomandibular disorders: findings from two specialised centres

The aims of this investigation were to report the frequency of temporomandibular disorders (TMD) diagnoses and the prevalence of self-reported awake and sleep bruxism as well as to describe the possible differences between findings of two specialised centres as a basis to suggest recommendations for future improvements in diagnostic homogeneity and accuracy. A standardised Research Diagnostic Criteria for TMD (RDC/TMD) assessment was performed on patients attending both TMD Clinics, viz., at the University of Padova, Italy (n=219; 74% women) and at the University of Tel Aviv, Israel (n=397; 79% women), to assign axis I physical diagnoses and to record data on self-reported awake and sleep bruxism. Significant differences were shown between the two clinic samples as for the frequency of TMD diagnoses (chi-square, P<0·001) and the prevalence of at least one positive response to bruxism items (chi-square, P<0·001). The more widespread use of TMJ imaging techniques in one clinic sample led to a higher prevalence of multiple diagnoses, and the higher prevalence of self-reported bruxism in patients with myofascial pain alone described in the other clinic sample was not replicated, suggesting that the different adoption of clinical and imaging criteria to diagnose TMD may influence also reports on their association with bruxism. From this investigation, it emerged that the features of the study samples as well as the different interpretation of the same diagnostic guidelines may have strong influence on epidemiological reports on bruxism and TMD prevalence and on the association between the two disorders.