Effects of Surface Anesthetics on Sensory Function in a Tongue Pain Model

抄録

This study aimed to examine the effects of surface anesthetics on the somatosensory function in a capsaicin - induced tongue pain model and included 14 healthy women. To establish the tongue pain model, 0.2 mL of 0.1％ capsaicin cream was applied to the tongue tip along with Vaseline（as control）, 2％ lidocaine HCl and 20％ benzocaine as（as surface anesthetics）. The numerical rating scale（NRS）for pain induced by capsaicin, mechanical detection threshold（MDT）, and mechanical pain threshold（MPT）were measured before capsaicin application（pre）in three sessions, NRS scores were significantly higher immediately post - capsaicin application, immediately, and 5 min post - drug application than pre（p<0.05）. In three sessions, the NRS scores were significantly lower immediately and 5, 15, 30 and 60 min post - drug application than that immediately post - capsaicin application（p<0.05）. In both local anesthetics sessions, the MDT immediately, 5 and 15 min post - drug application were significantly higher than that immediately post - capsaicin application（p<0.01）. In the 2％ lidocaine HCl session, the MPT immediately and 5 min post - drug application were significantly higher than immediately post - capsaicin application（p<0.01）. Thus, the application of 2％ lidocaine HCl and 20％ benzocaine induced temporary changes in the detect tactile and pain thresholds of the tongue pain model, suggesting that they contribute to pain reduction. The 2％ lidocaine HCI may be a better aid in the diagnosis of neuropathic pain than 20％ benzocaine.