title: Antibacterial effect of calcium hydroxide combined with chlorhexidine on Enterococcus faecalis: a systematic review and meta-analysis.
abstract: OBJECTIVE
  Enterococcus faecalis (E. faecalis) is the most frequently isolated strain in failed endodontic therapy cases since it is resistant to calcium hydroxide (CH). Whether a combination of CH and chlorhexidine (CHX) is more effective than CH alone against E. faecalis is a matter of controversy. Thus, the aim of this study was to conduct a systematic review and meta-analysis of the literature.
  
  
  METHODS
  A comprehensive search in PubMed, EMbase, EBSCOhost, The Cochrane Library, SciELO, and BBO databases, Clinical trials registers, Open Grey, and conference proceedings from the earliest available date to February 1, 2013 was carried out and the relevant articles were identified by two independent reviewers. Backward and forward search was performed and then inclusion and exclusion criteria were applied. The included studies were divided into "comparisons" according to the depth of sampling and dressing period of each medicament. Meta-analysis was performed using Stata software 10.0. The level of significance was set at 0.05.
  
  
  RESULTS
  Eighty-five studies were retrieved from databases and backward/forward searches. Fortyfive studies were considered as relevant (5 in vivo, 18 in vitro, 18 ex vivo, and 4 review articles). Nine studies were included for meta-analysis. Inter-observer agreement (Cohen kappa) was 0.93. The included studies were divided into 21 comparisons for meta-analysis. Chi-square test showed the comparisons were heterogeneous (p<0.001). Random effect model demonstrated no significant difference between CH/CHX mixture and CH alone in their effect on E. faecalis (p=0.115).
  
  
  CONCLUSIONS
  According to the evidence available now, mixing CH with CHX does not significantly increase the antimicrobial activity of CH against E. faecalis. It appears that mixing CH with CHX does not improve its ex vivo antibacterial property as an intracanal medicament against E. faecalis. Further in vivo studies are necessary to confirm and correlate the findings of this study with the clinical outcomes.
authors.affiliation: Department of Endodontics, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Masoud
authors.initials: M
authors.lastname: Saatchi
authors.affiliation: Department of Endodontics, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Shokraneh
authors.affiliation: Torabinejad Dental Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Hooman
authors.initials: H
authors.lastname: Navaei
authors.affiliation: Department of Biostatistics and Epidemiology, School of Public Health, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Maracy
authors.affiliation: Department of Microbiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Hasan
authors.initials: H
authors.lastname: Shojaei
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002126:Calcium Hydroxide / Q000494:pharmacology*; D002417:Cattle; D002710:Chlorhexidine / Q000494:pharmacology*; D003786:Dental Pulp Cavity / Q000187:drug effects / Q000382:microbiology; D004338:Drug Combinations; D013293:Enterococcus faecalis / Q000187:drug effects*; D006801:Humans; D012390:Root Canal Therapy / Q000379:methods
chemical_list: D000900:Anti-Bacterial Agents; D004338:Drug Combinations; D002126:Calcium Hydroxide; D002710:Chlorhexidine