title: Structural analysis of bovine root dentin after use of different endodontics auxiliary chemical substances.
abstract: BACKGROUND
  The use of chemical substances in endodontics during chemical-mechanical preparation may alter the structure of dentin, mainly collagen, which contributes considerably to the mechanical properties of this structure. This study evaluated the effect of different auxiliary chemical substances during endodontic treatment in root canal walls by implementing polarized light microscopy (PLM) and scanning electron microscopy (SEM).
  
  
  METHODS
  Sixty bovine incisors were randomly divided into six groups (n = 10): G1, 5.25% NaOCl + 17% EDTA; G2, 2% chlorhexidine (CHX) gel; G3, 5.25% NaOCl; G4, 17% EDTA; G5, 2% CHX + 17% EDTA; and G6, 0.9% sodium chloride solution (control). Teeth were chemomechanically prepared and fractured into two fragments. One fragment was used for PLM, and the other was used for SEM analysis.
  
  
  RESULTS
  Groups treated with 5.25% NaOCl, whether associated or not associated to 17% EDTA, presented a significantly different birefringence pattern compared with the control group. The results revealed that groups irrigated with 2% CHX and EDTA, independently or combined, did not present any significant differences compared with the control group. SEM analysis showed structural alterations of the root canal inorganic matrix for all groups that used 17% EDTA.
  
  
  CONCLUSIONS
  It is possible to conclude that 5.25% NaOCl, whether associated or not associated with 17% EDTA, causes alterations in the dentin collagen. The obtained SEM images revealed demineralization areas for groups that used 17% EDTA alone or associated with other substances.
authors: Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil.
authors: Danna Mota
authors: DM
authors: Moreira
authors: José Flávio Affonso
authors: JF
authors: Almeida
authors: Caio Cezar Randi
authors: CC
authors: Ferraz
authors: Brenda Paula Figueiredo de Almeida
authors: BP
authors: Gomes
authors: Sérgio Roberto Peres
authors: SR
authors: Line
authors: Alexandre Augusto
authors: AA
authors: Zaia
mesh_terms: D000818:Animals; D001718:Birefringence; D002417:Cattle; D002710:Chlorhexidine / Q000009:adverse effects; D003094:Collagen / Q000187:drug effects; D003786:Dental Pulp Cavity / Q000033:anatomy & histology / Q000187:drug effects; D003804:Dentin / Q000033:anatomy & histology / Q000187:drug effects*; D004492:Edetic Acid / Q000009:adverse effects; D008855:Microscopy, Electron, Scanning; D008859:Microscopy, Polarization; D011897:Random Allocation; D012388:Root Canal Irrigants / Q000009:adverse effects*; D012973:Sodium Hypochlorite / Q000009:adverse effects
chemical_list: D012388:Root Canal Irrigants; D003094:Collagen; D004492:Edetic Acid; D012973:Sodium Hypochlorite; D002710:Chlorhexidine