The relationship between chronic TMJD pain, F2-isoprostane and comorbidities

Objectives: It has been proposed that ischemia contributes to chronic TMJD pain. The aim of this study was to determine the association between TMJD pain chronicity and muscle, synovial fluid, and plasma F2-isoprostane (F2I) content, and whether this association is influenced by self-report of temple headache, anxiety and depression. Methods: The study sample consisted of: pain-free subjects without TMJ disc displacement with reduction (TMJ DD, n=13), pain-free TMJ DD subjects (n=14), and TMJ DD subjects with masseter pain and TMJ arthralgia (n=16). All subjects completed questionnaires to assess for pain chronicity (Graded Chronic Pain Scale), temple area headache (Research Diagnostic Criteria/TMD-History Questionnaire), anxiety and depression (Symptom Check-List 90-Revised). Masseter muscle, TMJ synovial fluid and blood were snap frozen, archived at -140°C, and assayed using ELISAs to measure F2I. Univariate and multivariate linear regression analyses (Procedure Mixed, SAS Institute) were performed to determine the association between chronic TMJD pain and F2I and whether this association changed by self-report of temple headache, anxiety and depression. Results: In univariate analyses, chronic TMJD pain was found to be associated with muscle F2I content (b=-4.5, P=0.003), temple headache (b=4, P<0.001), anxiety (b=5.3, P=0.002) and depression (b=2.3, P=0.02). Furthermore, muscle F2I was related to temple headache (b=-0.29, P=0.003), anxiety (b=-0.38, P=0.03) and depression (b=-0.24, P=0.01), using univariate analyses. The significant association between chronic TMJD pain and F2I remained when the model was adjusted for anxiety and depression (b=-3.6, P=0.02), but not when adjusting for temple headache (b= -1.8, P=0.20). Conclusions: Muscle F2-isoprostane, anxiety and depression are independently related to chronic TMJD pain. The association between F2-isoprostane and chronic TMJD pain appears to be influenced by the occurrence of temple headache. This suggests that both peripheral and central pain mechanisms influence TMJD chronicity.

Supported by NIH/NIDCR U01-DE013331 and NIDCR N01-DE22635.