The Role of Parafunctions, Emotions and Stress in Predicting Facial Pain

Background: The authors conducted a study to examine the degree to which parafunctions and emotional states predicted jaw pain in subjects with temporomandibular disorder (TMD) and control subjects.

Methods: Ninety-six subjects diagnosed with myofascial pain, myofascial pain and arthralgia, disk displacement or no TMD symptoms participated. The authors used experience sampling methodology to collect data on pain, behaviors and emotions. They paged subjects approximately every two hours, but not during sleep. When paged, subjects completed a brief questionnaire containing rating scales of jaw pain, masticatory muscle tension, time and intensity of tooth contact, mood and stress level.

Results: Analyses of variance showed that groups differed significantly (P < .05) in terms of pain; masticatory muscle tension; and a composite variable measuring time and intensity of contact; mood; and stress. The two myofascial pain groups scored higher on these measures than did the group with disk displacement and the control group. The authors used masticatory muscle tension, the composite variable, mood and stress to predict jaw pain using linear regression. The model was significant and accounted for 69 percent of the variance in jaw pain. Because tension was so highly correlated with jaw pain, the authors removed this variable and re-ran the analysis. The second model also was significant and accounted for 46 percent of the variance in jaw pain.

Conclusions: Parafunctional behaviors, especially those that increase muscle tension, and emotional states are good predictors of jaw pain levels in patients with TMD and healthy control subjects.

Clinical Implications: Treatment that helps patients reduce parafunctions, excess masticatory muscle tension, stress and emotional distress should be effective in reducing TMD pain.