title: Antimicrobial and cytotoxic effects of phosphoric acid solution compared to other root canal irrigants.
abstract: Phosphoric acid has been suggested as an irrigant due to its effectiveness in removing the smear layer.
  
  
  OBJECTIVE
  The purpose of this study was to compare the antimicrobial and cytotoxic effects of a 37% phosphoric acid solution to other irrigants commonly used in endodontics.
  
  
  METHODS
  The substances 37% phosphoric acid, 17% EDTA, 10% citric acid, 2% chlorhexidine (solution and gel), and 5.25% NaOCl were evaluated. The antimicrobial activity was tested against Candida albicans, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Actinomyces meyeri, Parvimonas micra, Porphyromonas gingivalis, and Prevotella nigrescens according to the agar diffusion method. The cytotoxicity of the irrigants was determined by using the MTT assay.
  
  
  RESULTS
  Phosphoric acid presented higher antimicrobial activity compared to the other tested irrigants. With regard to the cell viability, this solution showed results similar to those with 5.25% NaOCl and 2% chlorhexidine (gel and solution), whereas 17% EDTA and 10% citric acid showed higher cell viability compared to other irrigants.
  
  
  CONCLUSIONS
  Phosphoric acid demonstrated higher antimicrobial activity and cytotoxicity similar to that of 5.25% NaOCl and 2% chlorhexidine (gel and solution).
authors.affiliation: Endodontics Division, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil.
authors.forename: Maíra
authors.initials: M
authors.lastname: Prado
authors.affiliation: Endodontics Division, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil.
authors.forename: Emmanuel João Nogueira Leal da
authors.initials: EJ
authors.lastname: Silva
authors.affiliation: Endodontics Division, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil.
authors.forename: Thais Mageste
authors.initials: TM
authors.lastname: Duque
authors.affiliation: Endodontics Division, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil.
authors.forename: Alexandre Augusto
authors.initials: AA
authors.lastname: Zaia
authors.affiliation: Endodontics Division, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil.
authors.forename: Caio Cezar Randi
authors.initials: CC
authors.lastname: Ferraz
authors.affiliation: Endodontics Division, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil.
authors.forename: José Flávio Affonso de
authors.initials: JF
authors.lastname: Almeida
authors.affiliation: Endodontics Division, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil.
authors.forename: Brenda Paula Figueiredo de Almeida
authors.initials: BP
authors.lastname: Gomes
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology*; D041702:BALB 3T3 Cells; D001419:Bacteria / Q000187:drug effects* / Q000254:growth & development; D002176:Candida albicans / Q000187:drug effects* / Q000254:growth & development; D002470:Cell Survival; D002710:Chlorhexidine / Q000494:pharmacology; D019343:Citric Acid / Q000494:pharmacology; D015169:Colony Count, Microbial; D003603:Cytotoxins / Q000494:pharmacology*; D004492:Edetic Acid / Q000494:pharmacology; D008422:Materials Testing; D051379:Mice; D008826:Microbial Sensitivity Tests; D010756:Phosphoric Acids / Q000494:pharmacology*; D012388:Root Canal Irrigants / Q000494:pharmacology*; D012973:Sodium Hypochlorite / Q000494:pharmacology; D013997:Time Factors
chemical_list: D000890:Anti-Infective Agents; D003603:Cytotoxins; D010756:Phosphoric Acids; D012388:Root Canal Irrigants; D019343:Citric Acid; D004492:Edetic Acid; D012973:Sodium Hypochlorite; C030242:phosphoric acid; D002710:Chlorhexidine