title: Effectiveness of 2% chlorhexidine gel and calcium hydroxide against Enterococcus faecalis in bovine root dentine in vitro.
abstract: OBJECTIVE
  To evaluate the effectiveness of 2% chlorhexidine gluconate gel and calcium hydroxide (Ca(OH)2) as intracanal medicaments against Enterococcus faecalis.
  
  
  METHODS
  One hundred and eighty dentine tubes prepared from intact freshly extracted bovine maxillary central incisors were infected in vitro for 7 days with E. faecalis. The specimens were divided into four groups, according to the intracanal medicament used, as follows: Group 1: 2% chlorhexidine gluconate gel; Group 2: calcium hydroxide in a viscous vehicle (polyethyleneglycol 400); Group 3: 2% chlorhexidine gluconate gel + calcium hydroxide and Group 4: Brain Heart Infusion (BHI) broth (control group). The medicaments were placed into the canal lumen and left there for experimental times of 1, 2, 7, 15 and 30 days. After each period, irrigation with sterile saline to remove the medicament was performed and the canals were dried with sterile paper points. Dentine chips were removed from the canals with sequential sterile round burs at low speed. The samples obtained with each bur were immediately collected in separate test tubes containing BHI broth. The tubes were incubated at 37 degrees C and daily observed for microbial growth, visualized by the medium turbidity.
  
  
  RESULTS
  Chlorhexidine gel alone completely inhibited the growth of E. faecalis after 1, 2, 7 and 15 days. Calcium hydroxide allowed microbial growth at all experimental times. The combination of chlorhexidine and Ca(OH)2 was effective after 1 and 2 days demonstrating 100% antibacterial action; however, its antibacterial activity reduced between 7 and 15 days.
  
  
  CONCLUSIONS
  Under the conditions of this study, it can be concluded that 2% chlorhexidine gel alone was more effective against E. faecalis than calcium hydroxide (P < 0.05). However, its antibacterial activity depended on how long it remained inside the root canal.
authors.affiliation: Endodontic Department, Piracicaba Dental School, State University of Campinas-UNICAMP, Piracicaba, SP, Brazil. bpgomes@fop.unicamp.br
authors.forename: B P F A
authors.initials: BP
authors.lastname: Gomes
authors.forename: S F C
authors.initials: SF
authors.lastname: Souza
authors.forename: C C R
authors.initials: CC
authors.lastname: Ferraz
authors.forename: F B
authors.initials: FB
authors.lastname: Teixeira
authors.forename: A A
authors.initials: AA
authors.lastname: Zaia
authors.forename: L
authors.initials: L
authors.lastname: Valdrighi
authors.forename: F J
authors.initials: FJ
authors.lastname: Souza-Filho
mesh_terms: D000818:Animals; D000891:Anti-Infective Agents, Local / Q000008:administration & dosage / Q000494:pharmacology*; D002126:Calcium Hydroxide / Q000494:pharmacology*; D002417:Cattle; D002710:Chlorhexidine / Q000008:administration & dosage / Q000494:pharmacology*; D015169:Colony Count, Microbial; D003786:Dental Pulp Cavity / Q000382:microbiology*; D003804:Dentin / Q000382:microbiology*; D004338:Drug Combinations; D013293:Enterococcus faecalis / Q000187:drug effects*; D005782:Gels; D012388:Root Canal Irrigants / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D000891:Anti-Infective Agents, Local; D004338:Drug Combinations; D005782:Gels; D012388:Root Canal Irrigants; D002126:Calcium Hydroxide; D002710:Chlorhexidine