title: Effect of dentin powder on the antimicrobial properties of hyperpure chlorine-dioxide and its comparison to conventional endodontic disinfecting agents.
abstract: BACKGROUND
  Previously we found that the high purity chlorine-dioxide(ClO2) has a very potent disinfectant efficacy on oral pathogenic microorganisms and as a root canal irrigant it is able to eliminate the experimental Enterococcus faecalis(E. faecalis) infection from the root canal system. This study examines whether the presence of dentin powder influences the antibacterial efficacy of ClO 2.
  
  
  METHODS
  In an in vitro dentin powder model the following irrigants were tested against planktonic E. faecalis: 2% chlorhexidine (CHX), 2.5% sodium hypochlorite (NaOCl), 0.12%ClO2 (Solumium) and one local root canal medicament: saturated Ca(OH)2. Survival of bacteria exposed to agents without and with human dentin powder or preincubated with dentin powder was investigated. The effect of the dentin powder on ClO2 concentration was investigated by titrations.
  
  
  RESULTS
  Without dentin powder ClO 2 killed all E. faecalis and delivered the best result already after 1 minute; however, after longer contact time with dentin the difference between the disinfectants disappeared. The presence of dentin powder decreased the concentration of ClO 2 and attenuated the antibacterial efficiency of ClO2 and Ca(OH)2, but did not decrease of CHX and NaOCl.Preincubation with dentin powder caused significant loss of antibacterial activity of all investigated agents, ClO2 and Ca(OH)2 having the highest reduction.
  
  
  CONCLUSIONS
  As the presence of dentin powder had a negative effect on the efficacy of disinfectants, the importance of elimination of dentin scrapings and smear layer from the root canal system during endodontic treatments is highly recommended. ClO 2 can be effective for a final rinse.
authors.forename: Anna
authors.initials: A
authors.lastname: Herczegh
authors.forename: Milán
authors.initials: M
authors.lastname: Gyurkovics
authors.forename: Ágoston
authors.initials: Á
authors.lastname: Ghidan
authors.forename: Marianna
authors.initials: M
authors.lastname: Megyesi
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Lohinai
mesh_terms: D002126:Calcium Hydroxide / Q000037:antagonists & inhibitors / Q000494:pharmacology; D002710:Chlorhexidine / Q000037:antagonists & inhibitors / Q000494:pharmacology; D017606:Chlorine Compounds / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D003470:Culture Media; D003804:Dentin / Q000737:chemistry*; D013293:Enterococcus faecalis / Q000187:drug effects* / Q000254:growth & development; D006801:Humans; D010087:Oxides / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D010933:Plankton / Q000187:drug effects / Q000254:growth & development; D011208:Powders / Q000737:chemistry* / Q000494:pharmacology; D012388:Root Canal Irrigants / Q000494:pharmacology*; D012973:Sodium Hypochlorite / Q000037:antagonists & inhibitors / Q000494:pharmacology; D013997:Time Factors
chemical_list: D017606:Chlorine Compounds; D003470:Culture Media; D010087:Oxides; D011208:Powders; D012388:Root Canal Irrigants; C025109:chlorine dioxide; D012973:Sodium Hypochlorite; D002126:Calcium Hydroxide; D002710:Chlorhexidine