Predicting Jaw Pain in TMD Patients and Controls

Objectives: Parafunctions can produce TMD pain, and emotional distress, especially depression, is common in individuals with chronic TMD pain. The goal of this study was to examine the degree to which parafunctions and emotional states predicted jaw pain in TMD patients and normal controls. Methods: Ninety-six individuals diagnosed with myofascial pain, myofascial pain and arthralgia, disc displacement only, or no TMD symptoms, according to the Research Diagnostic Criteria, participated. Experience sampling methodology was used to collect data on pain, behaviors, and emotions. Subjects were paged approximately every two hours, but not during sleep. When paged, they completed a brief questionnaire containing rating scales of jaw pain, parafunctional behaviors (tension in the masticatory muscles and a composite variable assessing time and intensity of contact), and emotional states (mood and stress). On average, subjects completed 47.6 questionnaires during the one week of paging. The mean scores for predictor and criterion variables were computed for each individual. Results: For the regression model, the predictor variables were scores on parafunctions and emotional states, and the outcome variable was jaw pain. The model was significant, F(4,91) = 54.8, p , .001 and accounted for 70.7% of the variance in jaw pain. Follow-up t-tests showed that the coefficient was significant only for masticatory muscle tension. Because tension was so highly correlated with jaw pain and accounted for a high proportion of unique variance in the model, this variable was removed, and the analysis re-run. The second model (time/intensity of contact, mood, and stress) was also significant, F(3,92) = 28.22, p < .001 and accounted for 47.9% of the variance in jaw pain. Coefficients for the remaining predictors were significant, p < .05. Conclusions: Parafunctional behaviors, especially muscle tension, and emotional states can predict pain levels in TMD patients and normal controls. Supported by NIH/NIDCR DE13563.