SENSORY AND PAIN THRESHOLDS TO OROFACIAL ARGON-LASER STIMULATION IN PATIENTS WITH CHRONIC BURNING MOUTH SYNDROME

Objective: Psychophysical assessments of orofacial sensory function we re performed in order to investigate neurophysiological aspects of the burning mouth syndrome (BMS). Design: Sensory and pain thresholds to brief argon laser stimulation were determined on six test regions, whi ch included the tip of tongue, the lower lip mucosa and skin, the bucc al mucosa, the anterior hard palate, and the dorsum of the hand. Setti ng: The experimental examination was performed at the Pain Clinic Unit at the Royal Dental College. Patients: Twenty-three elderly denture-w earing patients diagnosed as suffering from BMS were studied, and a co ntrol group included 23 age-, sex-, and denture-matched subjects. The obtained thresholds were compared between groups. Results: Sensory thr esholds were significantly higher and ratios between pain and sensory thresholds significantly lower in patients with BMS on all the tested regions. Pain thresholds were significantly elevated on the lower lip skin, the anterior hard palate, and the hand in patients with BMS. At sensory threshold level, a faint pinprick perception was often reporte d by patients with BMS contrary to a perception of warmth described by control subjects. The intraregional variations in sensory and pain th resholds on the hard palate, the lower lip mucosa, and on the skin wer e similar in both groups, but differences occurred in sensory threshol ds on the tongue in patients with BMS. Conclusions: The presence of ab normal prepain perceptions and disturbances in the perception of nonno ciceptive and nociceptive thermal stimuli applied on both pain-affecte d and normal regions suggest a perceptual deficit unrelated to specifi c pathophysiological mechanisms in BMS. However, it appears that a psy chological explanation of BMS should be used cautiously, as the presen t results suggest alterations in sensory function.