Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Study Objective: To compare the topical and the pulpal anesthesia efficacy of liposomal and plain benzocaine formulations Design: Double-blinded, randomized crossover study. Setting: University ambulatory dental center Patients: 30 ASA physical status 1 volunteers Interventions: Volunteers received, in three different sessions, topical application of liposome-encapsulated 10% benzocaine (LB10), 10% benzocaine gel (B10), and 20% benzocaine gel (B20) in the right maxillary canine mucobuccal fold Measurements: Pain associated with the needle insertion was rated by visual analog scale (VAS) and the duration of topical anesthesia was recorded Pulpal anesthesia was evaluated using an electric pulp tester Main Results: VAS values (median. 1st - 3rd quartiles) were 17 cm (11 - 25), 14 cm (3 - 22), and 21 cm (9 21) for B10, LB10, and 1320, respectively No differences were noted among the groups (Friedman test, P = 0 58) Soft tissue anesthesia was also not different The LB10 [10 (8 - 12) min] showed longer soft tissue anesthesia (Friedman test, P < 0 01) than the other agents [1310 = 8 (5 - 10) min, and B20 = 7 (6 - 9) min] None of the topical benzocaine formulations tested induced pulpal anesthesia Conclusions: The encapsulation of benzocaine into liposome increased the duration of soft tissue anesthesia However, it did not induce pulpal anesthesia (C) 2010 Elsevier Inc All rights reserved225313317DFL Ind Corn Ltda, Rio de Janeiro, BrazilConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)