Evaluating the efficacy of commonly used topical anesthetics.

PURPOSE This study compared the efficacy of commonly used topical anesthetics using an objective measuring scale. METHODS The following were tested: 5% EMLA cream, 10% cocaine, 10% lidocaine, 10% benzocaine, 1% dyclonine, and a placebo. A special instrument was designed to serve the purpose of pressure application on the gingiva to obtain a threshold discomfort level in grams before and after the topical delivery. The medicaments, in the quantity of 20 microL (2-3 drops) were placed on the maxillary anterior region using Beckman paper wicks in the form of discs. The topical anesthetics were left on the gingiva for 3 min and off for another 3 min. The instrument applied pressure progressively, and the pressure application was stopped when the subjects reported the initial feeling of discomfort. RESULTS 5% EMLA cream significantly reduced the pain threshold level followed by 1% dyclonine and 10% benzocaine. However, there was no significant difference between 10% cocaine, 10% lidocaine, and the placebo. The placebo effect was observed. CONCLUSIONS 5% EMLA cream was superior in performance to all other topical anesthetics. The remainder of the agents had no statistically different effect than the saline.