title: The effects of different concentrations of chlorhexidine gluconate on the antimicrobial properties of mineral trioxide aggregate and calcium enrich mixture.
abstract: BACKGROUND
  The aim of this study was to evaluate the antimicrobial activity of Mineral Trioxide Aggregate (MTA) and Calcium Enrich Mixture) CEM (mixed with different concentrations of chlorhexidine (CHX).
  
  
  METHODS
  Cements used in this in vitro study included Gray proRoot MTA and CEM with the microorganisms being entrococcus faecalis, streptococcus muntas, Candida albicans, Actinomyces, Escherichia coli, and a mixture of these microorganisms. CHX was used in the form of liquid at 0.2%, 2%, and 0.12% concentrations. Contact dilution and colony count method was used to evaluate the antibacterial activity of these cements. After 0, 24, 48, 72, and 96-hour intervals, we cultured the samples on blood agar medium. Colonies were counted after incubation at 37°. Data were statistically analyzed by a Kruskal-Wallis test to compare the antimicrobial activity of MTA and CEM.
  
  
  RESULTS
  All concentrations of CHX were mixed with MTA and the CEM had antibacterial activities on all microorganisms' strains except for the Enterococcus faecalis and the mixture group. MTA had better antibacterial activity than the CEM, but this difference was not significant (P = 0.13). The mixing of MTA and the CEM with CHX significantly increased the antibacterial properties of both cements (P < 0.03). There was no statistically significant difference between the different concentrations of CHX. The antibacterial activity of the materials increased through time.
  
  
  CONCLUSIONS
  The mixture of MTA and CEM with different concentration of CHX significantly increased the antibacterial activity.
authors.affiliation: Dental Research Center, Dental School, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Bidar
authors.forename: Mahboube
authors.initials: M
authors.lastname: Naderinasab
authors.forename: Ali
authors.initials: A
authors.lastname: Talati
authors.forename: Kiarash
authors.initials: K
authors.lastname: Ghazvini
authors.forename: Saeed
authors.initials: S
authors.lastname: Asgari
authors.forename: Behzad
authors.initials: B
authors.lastname: Hadizadeh
authors.forename: Maryam
authors.initials: M
authors.lastname: Gharechahi
authors.forename: Niloufar Attaran
authors.initials: NA
authors.lastname: Mashadi