We have previously reported that patients with temporomandibular disorders (TMD) exhibit enhanced sensitivity to experimentally evoked pain (1); however, the clinical relevance of this increased pain sensitivity remains unclear. The purpose of this study was to investigate the relationship of experimental pain sensitivity to clinical and psychosocial variables among patients with TMD.
Thirty-six TMD patients were studied, half of whom were pain sensitive (PS) and the other half pain tolerant (PT), based on their ability to tolerate an ischemic pain task. Responses to painful thermal and nonpainful visual stimuli as well as clinical/diagnostic symptoms and psychosocial variables were compared for the two groups (i.e., PS vs. PT).
Results indicated that, compared with PT patients, the PS group exhibited greater sensitivity to thermal pain and rated innocuous visual stimuli as more intense. PS patients also reported greater clinical pain, but in general the groups did not differ on diagnostic and psychosocial measures.
The results suggest that ischemic pain tolerance is a clinically relevant marker of pain sensitivity in TMD patients. These findings are consistent with the hypothesis that impairments in CNS inhibitory pathways may contribute to the pain associated with TMD.
Departments of Dental Ecology, *Endodontics, and †Pharmacology, Dental Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, U.S.A.
Manuscript submitted February 13, 1996; revision received May 7, 1996; accepted for publication July 10, 1996.
Address correspondence and reprint requests to Dr. R. B. Fillingim at Dental Research Center, University of North Carolina at Chapel Hill, CB 7455, Chapel Hill, NC 27599-7455, U.S.A.