Effect of Surface Anesthetics on Tongue Sensory Function

BACKGROUND: Lidocaine hydrochloride (LDCA) is one of the medications used to treat burning mouth syndrome (BMS). The purpose of this study is to investigate whether benzocaine (BEN) can also be used for the treatment and examination of BMS. This study used quantitative sensory testing to investigate the effects of two surface anesthetics on the sensory function of the tongue tip. METHODS: Thirty healthy women participated in this study. All participants completed a single-blind, randomized crossover study. Surface anesthetics- (2%LDCA, 20%BEN) and vaseline (control) were applied to the tongue tip. The experiment was conducted over three days, with each drug applied on a different day in a randomized order. The mechanical detection threshold (MDT), mechanical pain threshold (MPT), and numerical rating scale (NRS) were measured at the following points: before application of the drug (pre), immediately, at 5, 15, 30, and 60 minutes after application of the drug. RESULTS: MDT immediately (P < 0.01), at 5 (P < 0.01) and 15 (2%LDCA: P = 0.0112, 20%BEN: P = 0.0128) minutes after application of the drug were significantly higher than pre-values in both local anesthetic sessions. MPT immediately (P < 0.01), at 5 (P < 0.01), 15 (P < 0.01), and 30 (P = 0.0026) minutes after application of 2%LDCA was significantly higher than pre-values. MPT immediately (P < 0.01), at 5 (P < 0.01) and 15 (P = 0.0057) minutes after application of 20%BEN was significantly higher than pre-values. NRS scores did not differ significantly between measurement periods or between drugs. CONCLUSIONS: This study suggested that 2%LDCA and 20%BEN may have comparable anesthetic effects on the sensory function of the healthy tongue tip.