Effectiveness of liposome-encapsulated benzocaine for topical anesthesia in dentistry

Objective: To evaluate the efficacy of liposome-encapsulated benzocaine on oral mucosa and pulpal anesthesia. Methods: In this double-blinded crossover study thirty healthy volunteers received 60mg of the following topical anesthetics: Liposome-encapsulated 10% benzocaine (LEB), 10% benzocaine gel (BG10), and 20% benzocaine gel (BG20- Benzotop®, DFL), in the buccal fold of the maxillary right canine for 2 minutes, in different sessions. After this period the duration of topical anesthesia was measured by pinprick test and pulpar response was assessed by electric pulp tester. After insertion of 30-G needles, pain was recorded on a visual analogue scale (VAS). The results were compared by the Friedman test and Wilcoxon sign-ranked test for pair-wise comparison as the post hoc test. Comparisons were considered significant at P < 0.05. Results: VAS (in cm) were (median and interquartile range) 1.4 (0.3–2.2), 1.7 (1.1-2.5) and 2.1 (0.9-2.7) for LEB, BG10, and BG20, respectively. There were no statistically significant differences (P = 0.5809) regarding VAS values among the groups. The median and interquartile range of duration of soft tissue anesthesia (in min) were 10 (7-12), 8 (4-10) and 7 (6-9) for LEB, BG10, and BG20, respectively. The LEB showed longer soft tissue anesthesia (P = 0.0085). There were no statistical significant difference between BG10 and BG20 (P > 0.05). All topical benzocaine formulations tested were not able to induce pulpal anesthesia (P > 0.05). Conclusion: Liposome-encapsulated 10% benzocaine gel reduced pain during needle insertion and showed longer duration of soft tissue anesthesia than 10 and 20% benzocaine gel formulations. However, it was unable to induce pulpal anesthesia.

Supported by FAPESP 2006/00121-9.