Oral behaviors mediate the relationship between anxiety and painful temporomandibular disorders

Objectives: Anxiety is strongly associated with chronic musculoskeletal pain, including painful temporomandibular disorders (p-TMD). Non-functional oral behaviors—such as wake-time tooth clenching or keeping the lower jaw in a tense position—are prevalent stress-related behaviors among individuals with elevated anxiety. These behaviors are thought to act as maladaptive coping strategies increasing strain on the masticatory muscles and the temporomandibular joint, thereby enhancing peripheral nociceptive input and contributing to the onset or persistence of p-TMD in individuals with high anxiety. While this behavioral pathway is theoretically supported, it has yet to be empirically verified. This study investigated whether non-functional oral behaviors mediate the relationship between anxiety and p-TMD. Design: We recruited 299 adults with p-TMD (myofascial pain and/or arthralgia) and 374 pain-free controls. Anxiety levels and the frequency of non-functional oral behaviors were assessed using the Generalized Anxiety Disorder scale and the Oral Behavior Checklist, respectively. Mediation analysis was conducted to examine both the direct (anxiety → p-TMD) and indirect (anxiety → oral behaviors → p-TMD) pathways. Results: Mediation analysis revealed that non-functional oral behaviors fully mediate the relationship between anxiety and p-TMD. Conclusion: Non-functional oral behaviors are a key behavioral mechanism linking anxiety to p-TMD. These findings highlight the importance of targeting oral behaviors in interventions for TMD pain, particularly among individuals with high anxiety, and provide a foundation for future research into behavioral and neural mechanisms underlying TMD.