Keywords: anxiety, bruxism, masticatory muscles, occlusion, pain, sensory thresholds
Aims: To investigate how trait anxiety and stress jointly affect the sensory and jaw motor responses to a tonic orofacial nociceptive stimulus.
Methods: Orthodontic separators were placed between the first molars in 45 adults with low (n = 14), intermediate (n = 17), and high (n = 14) trait anxiety. Tooth pain, occlusal discomfort, tooth clenching (as a jaw motor behavior), and situational stress were measured three times a day for 5 days using visual analog scales. Mixed-effects regression models were used to evaluate the sensory and motor outcome measures.
Results: Pain, discomfort, and frequency of tooth-clenching trajectories were affected by trait anxiety (P = .007, P < .001, and P = .055, respectively) and stress (P < .001, P < .001, and P = .044, respectively). Individuals with high anxiety reported their highest pain (17.7 ± 2.9 mm) and discomfort (35.2 ± 4.1 mm) 24 hours earlier than those with low anxiety (pain: 15.9 ± 2.6 mm, discomfort: 28.8 ± 3.7 mm). Tooth clenching decreased progressively in response to the stimulus (P < .001).
Conclusion: A tonic orofacial nociceptive stimulus triggers an avoidance jaw motor behavior. Both trait anxiety and situational stress heighten the sensory response to such a stimulus, but weakly affect the motor response to it.