title: Antimicrobial effects of calcium hydroxide and chlorhexidine on Enterococcus faecalis.
abstract: BACKGROUND
  Endodontic treatment is commonly based on nonspecific elimination of intraradicular microorganisms. Although some authors prefer single-visit root canal operations for endodontic treatment, several studies have shown the importance of intracanal medication between sessions to kill microorganisms that biomechanical preparations alone cannot achieve. The purpose of this study was to evaluate the efficacy of calcium hydroxide Ca(OH)(2) and chlorhexidine gel on the elimination of intratubular Enterococcus faecalis.
  
  
  METHODS
  Human uniradicular teeth contaminated with E. faecalis were treated with Ca(OH)(2), 2% chlorhexidine gel, Ca(OH)(2) plus 2% chlorhexidine gel, or saline (0.9% NaCl) as a negative control. Samples obtained at a depth of 0 to 100 mum and 100 to 200 mum from these root canal preparations were analyzed for bacterial load by counting the number of colony-forming units (CFUs) and bacterial viability using fluorescence microscopy.
  
  
  RESULTS
  A significant decrease in the number of CFUs and the percentage of viable E. faecalis was observed after treatment with either Ca(OH)(2) or chlorhexidine when compared with the control group. Additionally, chlorhexidine gel had a significantly higher antimicrobial efficacy as measured by the number of CFUs and the percentage of viable cells than Ca(OH)(2). No differences were observed between the antimicrobial properties of chlorhexidine gel with and without the addition of Ca(OH)(2).
  
  
  CONCLUSIONS
  Both Ca(OH)(2) and chlorhexidine have antimicrobial effects on E. faecalis. Chlorhexidine had increased antimicrobial activity when compared with Ca(OH)(2.) Ca(OH)(2) combined with chlorhexidine showed similar antimicrobial activity to chlorhexidine alone.
authors.affiliation: Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, SP 17012-901, Brazil. ronanjacques@hotmail.com
authors.forename: Ronan J R
authors.initials: RJ
authors.lastname: Delgado
authors.forename: Thaís H
authors.initials: TH
authors.lastname: Gasparoto
authors.forename: Carla R
authors.initials: CR
authors.lastname: Sipert
authors.forename: Claudia R
authors.initials: CR
authors.lastname: Pinheiro
authors.forename: Ivaldo G
authors.initials: IG
authors.lastname: Moraes
authors.forename: Roberto B
authors.initials: RB
authors.lastname: Garcia
authors.forename: Clóvis M
authors.initials: CM
authors.lastname: Bramante
authors.forename: Ana P
authors.initials: AP
authors.lastname: Campanelli
authors.forename: Norberti
authors.initials: N
authors.lastname: Bernardineli
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D000891:Anti-Infective Agents, Local / Q000008:administration & dosage / Q000494:pharmacology*; D002126:Calcium Hydroxide / Q000008:administration & dosage / Q000494:pharmacology*; 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* / Q000254:growth & development; D005782:Gels; D006801:Humans; D008422:Materials Testing; D050296:Microbial Viability / Q000187:drug effects; D008855:Microscopy, Electron, Scanning; D012388:Root Canal Irrigants / Q000008:administration & dosage / Q000494:pharmacology*; D012965:Sodium Chloride; D013997:Time Factors
chemical_list: D000890:Anti-Infective Agents; D000891:Anti-Infective Agents, Local; D004338:Drug Combinations; D005782:Gels; D012388:Root Canal Irrigants; D012965:Sodium Chloride; D002126:Calcium Hydroxide; D002710:Chlorhexidine