title: A study of the relation between erosion and microhardness of root canal dentin.
abstract: OBJECTIVE
  The aim of this study was to find a relation between erosion and microhardness of root canal dentin after irrigation with different canal irrigants.
  
  
  METHODS
  Seventy-two single-canal human premolar teeth were selected and enlarged by rotary Protaper files. The middle part of each root was transversely sectioned to a 4-mm slice. The initial microhardness values of intact specimens were measured at depths of 100 microm and 500 microm from the pulp-dentin interface using a Vickers microhardness tester. the specimens were divided into 6 groups of 12 specimens and were treated as follows: 1: 2.6% NaOCl, 2: 17% EDTA (5 minutes) then 2.6% NaOCl (5 minutes), 3: 17% EDTA (1 minute) then 2.6% NaOCl (1 minute), 4: MTAD (5 minutes), 5: 2% Chlorhexidine (5 minutes), and 6: saline (control), respectively. Posttreatment microhardness values were obtained in the same manner as the initial ones. Afterwards, the specimens were prepared for scanning electron microscopy analysis. The amount of dentin erosion was examined.
  
  
  RESULTS
  Group 2 showed the most erosive effect on dentin (P < .0001) along with the least decrease of dentin microhardness at depth of 100 microm, whereas MTAD showed the most reduction of dentin microhardness and less erosive effect on dentin.
  
  
  CONCLUSIONS
  It can be concluded that erosion is not the main factor in decreasing the dentin microhardness, whereas the amount of irrigant penetration might be the main cause.
authors.affiliation: Department of Dental Materials, Faculty of Dentistry, Azad University of Medical Sciences, Tehran, Iran. saghiri@gmail.com
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Saghiri
authors.forename: Abbas
authors.initials: A
authors.lastname: Delvarani
authors.forename: Payman
authors.initials: P
authors.lastname: Mehrvarzfar
authors.forename: Golnaz
authors.initials: G
authors.lastname: Malganji
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Lotfi
authors.forename: Bahareh
authors.initials: B
authors.lastname: Dadresanfar
authors.forename: Ali Mohammad
authors.initials: AM
authors.lastname: Saghiri
authors.forename: Sahar
authors.initials: S
authors.lastname: Dadvand
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001641:Bicuspid; D003786:Dental Pulp Cavity / Q000187:drug effects* / Q000648:ultrastructure; D003804:Dentin / Q000187:drug effects* / Q000648:ultrastructure; D003808:Dentin Solubility / Q000187:drug effects*; D005260:Female; D006244:Hardness / Q000187:drug effects*; D006801:Humans; D008297:Male; D012388:Root Canal Irrigants / Q000494:pharmacology*; D018709:Statistics, Nonparametric; D014077:Tooth Erosion / Q000139:chemically induced; D055815:Young Adult
chemical_list: D012388:Root Canal Irrigants