Measurement of the thermal pain threshold of the hard palate

¹ Department of Physiology, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; and John B. Pierce Foundation Laboratory, New Haven, Connecticut

Using thin-walled aluminum thermodes individually fitted to the roof of the mouth, the pain threshold of the hard palate was measured in four subjects. By rapidly circulating hot water and water at 37 C alternately, the temperature of the thermode could be raised and lowered between a neutral and a test level. Temperature within the thermode was measured in every observation by a fine wire thermocouple in the circulating water. Temperature between the thermode and the hard palate was also measured over the entire range of temperatures studied, and a correction for the gradient across the thermode wall was determined and applied to the water temperature. Stimuli between 40 C and 49 C were administered. Each subject was exposed to 288 stimuli in six experimental periods. The range of stimuli reported as painful was from 44.5 C for the first reports of pain to 47.7 C which always evoked pain. A preliminary study was made of the buccal temperature changes occurring during drinking hot beverages, and evidence indicates the sipping of air with small amounts of the hot liquid maintains the tissue temperatures within tolerable limits.