title: Effects of chlorhexidine and sodium hypochlorite on the microhardness of root canal dentin.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the effects of endodontic irrigants on the microhardness of root canal dentin.
  
  
  METHODS
  Thirty extracted single-rooted human teeth were used. The crowns were sectioned at the cementoenamel junction. Each root was transversely sectioned into cervical, middle, and apical segments, resulting in 90 specimens. The 3 sections of each root were separately mounted in an individual silicon device with acrylic resin. The specimens were randomly divided into the following 3 groups (n = 30), according to the irrigant solution used: (1) group 1, control (saline solution); (2) group 2, 2% chlorhexidine gluconate solution; and (3) group 3, 1% sodium hypochlorite (NaOCl). After 15 minutes of irrigation, dentin microhardness was measured on each section at 500 microm and 1000 microm from the pulp-dentin interface with a Vickers diamond microhardness tester in Vickers hardness number (VHN).
  
  
  RESULTS
  Data obtained were analyzed using analysis of variance and the Tukey test (5%). Specimens irrigated with 2% chlorhexidine (group 2) or 1% NaOCl (group 3) presented lower values of dentin microhardness, with significant difference in relation to the control group (P < .05).
  
  
  CONCLUSIONS
  It could be concluded that chlorhexidine and NaOCl solutions significantly reduced the microhardness of root canal dentin at 500 microm and 1000 microm from the pulp-dentin interface.
authors.affiliation: Department of Oral Biosciences and Diagnosis, School of Dentistry, Paulista State University-UNESP, Sao Jose dos Campos, Sao Paulo, Brazil.
authors.forename: Luciane Dias
authors.initials: LD
authors.lastname: Oliveira
authors.forename: Cláudio Antonio Talge
authors.initials: CA
authors.lastname: Carvalho
authors.forename: Willian
authors.initials: W
authors.lastname: Nunes
authors.forename: Marcia Carneiro
authors.initials: MC
authors.lastname: Valera
authors.forename: Carlos Henrique Ribeiro
authors.initials: CH
authors.lastname: Camargo
authors.forename: Antonio Olavo Cardoso
authors.initials: AO
authors.lastname: Jorge
mesh_terms: D000704:Analysis of Variance; D000891:Anti-Infective Agents, Local / Q000494:pharmacology*; D001641:Bicuspid; D002710:Chlorhexidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D003786:Dental Pulp Cavity; D003804:Dentin / Q000187:drug effects*; D006244:Hardness / Q000187:drug effects; D006801:Humans; D012388:Root Canal Irrigants / Q000494:pharmacology*; D012973:Sodium Hypochlorite / Q000494:pharmacology*; D018709:Statistics, Nonparametric
chemical_list: D000891:Anti-Infective Agents, Local; D012388:Root Canal Irrigants; D012973:Sodium Hypochlorite; C010882:chlorhexidine gluconate; D002710:Chlorhexidine