title: Do smear-layer removal agents affect the push-out bond strength of calcium silicate-based endodontic sealers?
abstract: OBJECTIVE
  To evaluate the effect of 17% ethylenediaminetetraacetic acid (EDTA), 2.25% peracetic acid (PA) or 10% citric acid (CA) on the push-out bond strength of calcium silicate-based endodontic sealers [MTA Fillapex (Angelus, Londrina, Brazil) and Total Fill BC Sealer (FKG, La Chaux-de-Fonds, Switzerland)] to root dentine after different periods of immersion in phosphate-buffered saline (PBS). AH Plus (Dentsply DeTrey, Konstaz, Germany) was used as a reference material for comparison.
  
  
  METHODS
  Thirty human maxillary incisors were selected and three 1-mm discs were obtained from the middle third of each root. On the axial surface of each disc, three 0.8-mm-diameter holes were drilled through the dentine. After standardized irrigation, each dentine disc from the same root was treated for smear-layer removal with one of the three tested chelating solutions: EDTA, PA or CA. After that, the holes were dried with paper points and filled with one of the three test root canal sealers. The filled dental slices were further immersed in PBS solution (pH 7.2) for 7 days (T1) or 30 days (T2) at 37 °C, before the push-out assay. Friedman, Kruskal-Wallis and Mann-Whitney tests were used respectively to estimate the impact of the independent variables (solutions, sealers and period of PBS immersion) on the push-out bond strength. The level for significance was set at α = 5% and data were further subjected to a Bonferroni correction.
  
  
  RESULTS
  Solutions and periods of immersion did not significantly influence the displacement resistance (P = 0.285, and P = 0.104, respectively) of sealers to root dentine. On the other hand, the type of sealer significantly affected the push-out bond strength (P = 0.000). AH Plus was associated with greater resistance to dislodgment compared with Total Fill BC Sealer and MTA Fillapex (P = 0.000). MTA Fillapex resulted in the lowest push-out bond strength (P = 0.000).
  
  
  CONCLUSIONS
  The use of different chelating agents did not influence the push-out bond strength of endodontic sealers. Calcium silicate-based sealers had lower push-out bond strength values compared with a conventional epoxy resin-based sealer (AH Plus).
authors.affiliation: Department of Endodontics, Rio de Janeiro State University, Rio de Janeiro, Brazil.
authors.forename: N K
authors.initials: NK
authors.lastname: Carvalho
authors.affiliation: Department of Endodontics, Rio de Janeiro State University, Rio de Janeiro, Brazil.
authors.forename: M C
authors.initials: MC
authors.lastname: Prado
authors.affiliation: Department of Endodontics, School of Dentistry, Grande Rio University (UNIGRANRIO), Rio de Janeiro, Brazil.
authors.forename: P M
authors.initials: PM
authors.lastname: Senna
authors.affiliation: Department of Paediatric Dentistry, Rio de Janeiro Federal University, Rio de Janeiro, Brazil.
authors.forename: A A
authors.initials: AA
authors.lastname: Neves
authors.affiliation: Department of Restorative Dentistry II, Federal University of Maranhão, São Luis, Brazil.
authors.forename: E M
authors.initials: EM
authors.lastname: Souza
authors.affiliation: Department of Endodontics, Rio de Janeiro State University, Rio de Janeiro, Brazil.
authors.forename: S R
authors.initials: SR
authors.lastname: Fidel
authors.affiliation: Department of Endodontics, Rio de Janeiro State University, Rio de Janeiro, Brazil.
authors.forename: L M
authors.initials: LM
authors.lastname: Sassone
authors.affiliation: Department of Endodontics, Rio de Janeiro State University, Rio de Janeiro, Brazil.|Department of Endodontics, School of Dentistry, Grande Rio University (UNIGRANRIO), Rio de Janeiro, Brazil.
authors.forename: E J N L
authors.initials: EJNL
authors.lastname: Silva
mesh_terms: D017610:Calcium Compounds / Q000627:therapeutic use*; D001840:Dental Bonding / Q000379:methods*; D003799:Dental Stress Analysis; D006801:Humans; D010895:Pit and Fissure Sealants / Q000737:chemistry* / Q000627:therapeutic use; D012387:Root Canal Filling Materials / Q000737:chemistry* / Q000627:therapeutic use; D017640:Silicates / Q000627:therapeutic use*; D016369:Smear Layer / Q000628:therapy*
chemical_list: D017610:Calcium Compounds; D010895:Pit and Fissure Sealants; D012387:Root Canal Filling Materials; D017640:Silicates; C031293:calcium silicate
keywords: calcium silicate-based sealers; push-out bond strength; root canal irrigants