Unlocking the link between temporomandibular disorders and suicide ideation in pre-orthodontic patients: A moderated mediation model of depression and anxiety

Background: Temporomandibular disorders (TMD) are a series of musculoskeletal diseases with high prevalence. A few studies have reported the correlation between TMD and suicide ideation (SI). However, the underlying mechanism of the relationship lacks in-depth exploration. Methods: A cross-sectional study was conducted among 954 pre -orthodontic patients. TMD assessment was based on the quintessential five TMD symptoms (5Ts) questionnaire. Anxiety, depression and pain catastrophizing was evaluated by Seven -item Generalized Anxiety Disorder Scale (GAD -7), Nine -item Patient Health Questionnaire (PHQ-9), and Pain Catastrophizing Scale (PCS), respectively. Correlational and moderated mediated analysis was preformed to demonstrate the relationship between TMD and SI. Results: In pre -orthodontic patients, 31.87 % reported having TMD symptoms and 6.50 % declared SI during the past two weeks. The SI prevalence was 10.53 % in participants with TMD and 4.62 % in those without TMD. Intra-articular TMD, rather than pain -related TMD were especially related with SI. Individuals with TMD had higher risk to SI (r(s) = 0.112, adjusted OR = 2.213, p < 0.001). The effect of TMD on SI was fully mediated through depression (beta = 0.445, 95 % CI = [0.326, 0.563]). Anxiety exerted a negative moderating effect on the depression-SI relation (beta = -0.033, 95 % CI = [-0.047, -0.019]). Limitations: This study was a single -centered and cross-sectional survey. The data collection relied on selfreporting methods. Conclusions: A positive link between TMD and SI was disclosed. The effect of TMD on SI was fully mediated through depression with anxiety as a negative moderator.