title: In vitro assessment of the immediate and prolonged antimicrobial action of chlorhexidine gel as an endodontic irrigant against Enterococcus faecalis.
abstract: OBJECTIVE
  The aim of this study was to assess in vitro the antimicrobial activity of 2% chlorhexidine gel against Enterococcus faecalis , comparing it to other endodontic irrigants (2% chlorhexidine liquid and 5.25% sodium hypochlorite).
  
  
  METHODS
  Eighty roots of human mandibular premolars were prepared by serial instrumentation technique, autoclaved, and contaminated for 7 days with E faecalis monocultures. The roots were then divided into 5 groups according to the irrigant substance used during the standardized biomechanical preparation. In order to evaluate the antimicrobial action of the irrigant substances, 3 microbial samples were taken: initial (before the biomechanical preparation); post-treatment (immediately after the biomechanical preparation), and final (7 days after the biomechanical preparation). The microbiological samples were plated to count the colony-forming units (CFU).
  
  
  RESULTS
  The 2% chlorhexidine gel and 2% chlorhexidine liquid significantly reduced the E faecalis CFU in the post-treatment and final microbiological samples. The 5.25% sodium hypochlorite also reduced the E faecalis CFU immediately after the root canal instrumentation, but it was not able to keep the root canal free of detectable E faecalis in the final sample.
  
  
  CONCLUSIONS
  The 2% chlorhexidine gluconate (gel and liquid) antimicrobial ability was more effective than 5.25% sodium hypochlorite in keeping low CFU of E faecalis for 7 days after the biomechanical preparation.
authors.affiliation: Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil.
authors.forename: Fábio Roberto
authors.initials: FR
authors.lastname: Dametto
authors.forename: Caio Cezar Randi
authors.initials: CC
authors.lastname: Ferraz
authors.forename: Brenda Paula Figueiredo de Almeida
authors.initials: BP
authors.lastname: Gomes
authors.forename: Alexandre Augusto
authors.initials: AA
authors.lastname: Zaia
authors.forename: Fabricio Batista
authors.initials: FB
authors.lastname: Teixeira
authors.forename: Francisco José
authors.initials: FJ
authors.lastname: de Souza-Filho
mesh_terms: D000891:Anti-Infective Agents, Local / Q000008:administration & dosage*; D001641:Bicuspid; D002710:Chlorhexidine / Q000008:administration & dosage / Q000031:analogs & derivatives*; D015169:Colony Count, Microbial; D013293:Enterococcus faecalis / Q000187:drug effects*; D005782:Gels; D006801:Humans; D012388:Root Canal Irrigants / Q000008:administration & dosage*; D018915:Root Canal Preparation / Q000379:methods*; D012973:Sodium Hypochlorite / Q000494:pharmacology; D018709:Statistics, Nonparametric
chemical_list: D000891:Anti-Infective Agents, Local; D005782:Gels; D012388:Root Canal Irrigants; D012973:Sodium Hypochlorite; C010882:chlorhexidine gluconate; D002710:Chlorhexidine