title: Final irrigation protocols may affect intraradicular dentin ultrastructure.
abstract: OBJECTIVE
  The aim of this study was to evaluate the effect of different irrigation protocols on the root dentin structure using scanning electron microscopy (SEM) and transmission electron microscopy (TEM).
  
  
  METHODS
  Thirty-nine lower bovine incisors were hemisected longitudinally and randomly divided into 13 groups (n = 3). After the root halves were reassembled, it was applied a specific irrigation protocol for each group, as following: G1, distilled water (control); G2, 0.9% saline; G3, saline + 17% EDTA; G4, saline + PUI; G5, saline + PUI + EDTA; G6 to G9 received the same protocol as above replacing 0.9% saline by 2.5% NaOCl; and G10 to G13 by 2% CHX. One-half of each sample was prepared and evaluated using SEM and the other one by TEM observations.
  
  
  RESULTS
  TEM descriptive analysis showed modifications in dentin organic ultrastructure, characterized by the thinning of dentin collagen fibrils, caused by NaOCl, enhanced by EDTA and/or PUI. SEM analysis showed that NaOCl with PUI caused significantly larger erosion of the peritubular dentin than in all the other groups (P < 0.05), followed by NaOCl + EDTA and NaOCl + EDTA + PUI.
  
  
  CONCLUSIONS
  NaOCl caused ultrastructural alterations in the dentin collagen, and enhanced by EDTA and/or PUI, promoted peritubular and intertubular erosion.
  
  
  CONCLUSIONS
  The effect of irrigating solutions on dentin ultrastructure was still unclear. The acknowledgment about the kind of solution, concentrations, application time, and sequence of use was important to achieve the right sanitization without jeopardizing the dentin ultrastructure quality.
authors.affiliation: Department of Conservative Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Márcia Helena
authors.initials: MH
authors.lastname: Wagner
authors.affiliation: Department of Conservative Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Ricardo Abreu
authors.initials: RA
authors.lastname: da Rosa
authors.affiliation: Department of Endodontics, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: José Antonio Poli
authors.initials: JAP
authors.lastname: de Figueiredo
authors.affiliation: Department of Endodontics, University of São Paulo, Bauru, SP, Brazil.
authors.forename: Marco Antonio Húngaro
authors.initials: MAH
authors.lastname: Duarte
authors.affiliation: Department of Prosthodontics, University of Southern Santa Catarina, Tubarão, SC, Brazil. jeffripe@rocketmail.com.
authors.forename: Jefferson Ricardo
authors.initials: JR
authors.lastname: Pereira
authors.affiliation: Department of Conservative Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Marcus Vinicius Reis
authors.initials: MVR
authors.lastname: Só
mesh_terms: D000818:Animals; D002417:Cattle; D002710:Chlorhexidine / Q000494:pharmacology; D003786:Dental Pulp Cavity / Q000187:drug effects* / Q000648:ultrastructure; D003804:Dentin / Q000187:drug effects* / Q000648:ultrastructure; D004492:Edetic Acid / Q000494:pharmacology; D066298:In Vitro Techniques; D007180:Incisor; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D012388:Root Canal Irrigants / Q000494:pharmacology*; D012965:Sodium Chloride / Q000494:pharmacology; D012973:Sodium Hypochlorite / Q000494:pharmacology; D007507:Therapeutic Irrigation / Q000379:methods*
chemical_list: D012388:Root Canal Irrigants; D012965:Sodium Chloride; D004492:Edetic Acid; D012973:Sodium Hypochlorite; D002710:Chlorhexidine
keywords: Chlorhexidine; Dentine; EDTA; Endodontics; Sodium hypochlorite