title: Liposomal encapsulation improves the duration of soft tissue anesthesia but does not induce pulpal anesthesia.
abstract: OBJECTIVE
  To compare the topical and the pulpal anesthesia efficacy of liposomal and plain benzocaine formulations.
  
  
  METHODS
  Double-blinded, randomized crossover study.
  
  
  METHODS
  University ambulatory dental center.
  
  
  METHODS
  30 ASA physical status I volunteers.
  
  
  METHODS
  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.
  
  
  METHODS
  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.
  
  
  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 B20, 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 [B10 = 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.
authors.affiliation: Department of Physiological Sciences, Piracicaba Dentistry School, State University of Campinas - UNICAMP, 13414-903 Piracicaba, São Paulo, Brazil.
authors.forename: Michelle
authors.initials: M
authors.lastname: Franz-Montan
authors.forename: André L R
authors.initials: AL
authors.lastname: Silva
authors.forename: Leonardo F
authors.initials: LF
authors.lastname: Fraceto
authors.forename: Maria C
authors.initials: MC
authors.lastname: Volpato
authors.forename: Eneida de
authors.initials: Ed
authors.lastname: Paula
authors.forename: José
authors.initials: J
authors.lastname: Ranali
authors.forename: Francisco C
authors.initials: FC
authors.lastname: Groppo
mesh_terms: D000287:Administration, Topical; D000293:Adolescent; D000328:Adult; D000766:Anesthesia, Dental / Q000379:methods*; D000772:Anesthesia, Local / Q000379:methods; D000779:Anesthetics, Local / Q000008:administration & dosage*; D001566:Benzocaine / Q000008:administration & dosage*; D018592:Cross-Over Studies; D003782:Dental Pulp / Q000187:drug effects; D004311:Double-Blind Method; D005260:Female; D005782:Gels; D006801:Humans; D008081:Liposomes; D008297:Male; D009061:Mouth Mucosa / Q000378:metabolism*; D010147:Pain Measurement; D013997:Time Factors; D055815:Young Adult
chemical_list: D000779:Anesthetics, Local; D005782:Gels; D008081:Liposomes; D001566:Benzocaine