RESUMEN
Chronic idiopathic oro-facial pain has become a common complaint, resulting increasingly in referral to the pain clinics world-wide, about 90% of the psychologically stress-related patients of the psychiatric clinic of Eastman Dental Hospital, London have been found to have associated idiopathic oro-facial pain. Psychological stress may produce a situation where oxidative stress might enhance the production of free radicals, especially OH radicals, in human biological fluids. Furthermore, it has been suggested that. OH radicals are responsible for the production of many systemic and local tissue injury diseases which may initially manifest as pain syndrome. It has been suggested that the oxygen free radical production of sailcloth, 2,3-dihydroxybenzoic acid (DHB) is a biological marker for the detection and quantification of OH radicals. Analyses of plasma samples collected from patients with chronic idiopathic orofacial pain and an equal number of age and sex matched control subjects revealed that the patient group had significantly increased evidence for circulating levels of 2,3-DHB after aspirin ingestion than control subjects. There was no significant difference in 2,5-DHB levels between the two groups. The urine samples from the same individuals showed evidence of measurable amounts of 2,3 and 2,5-DHB in both pre- and post-aspirin samples. These results suggest that OFRs may be involved in the aetiology of pain in patients that present with facial pain.