title: A Novel Dentin Push-out Bond Strength Model That Uses Micro-Computed Tomography.
abstract: BACKGROUND
  Current push-out experimental methods used in endodontic research should be improved. This study introduced a novel dentin push-out bond strength model that uses micro-computed tomography (μCT).
  
  
  METHODS
  Roots filled with gutta-percha cones and different resin-based sealers (n = 10) were sectioned transversely to obtain two 2-mm-thick slices per root third. The first slice was subjected to a push-out test by using a material testing stage fitted inside a μCT scanner. The apparatus was scanned before and after the test to evaluate areas of filling material ruptures. The images provided by μCT were also used to generate models for a 3-dimensional finite element analysis. Confocal laser scanning microscopy was used to assess failure modes after the test and to measure interfacial gaps in slices not subjected to push-out. Bond-strength and gap data were statistically analyzed (P < .05).
  
  
  RESULTS
  Proper coefficients of variation (average less than 30%) were observed for all the experimental conditions. The finite element analysis helped explain the results of bond strength and root-filling ruptures. A significant, moderate, indirect correlation was observed between the bond strength and gaps.
  
  
  CONCLUSIONS
  The micromechanical model with the μCT images resulted in a consistent root-filling bond strength evaluation.
authors.affiliation: Department of Dentistry, State University of Montes Claros-Unimontes, Montes Claros, Minas Gerais, Brazil.
authors.forename: Manoel
authors.initials: M
authors.lastname: Brito-Júnior
authors.affiliation: Department of Restorative Dentistry, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil.
authors.forename: Graziela Bianchi
authors.initials: GB
authors.lastname: Leoni
authors.affiliation: Department of Restorative Dentistry, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil.
authors.forename: Rodrigo Dantas
authors.initials: RD
authors.lastname: Pereira
authors.affiliation: Department of Dentistry, School of Dentistry, Federal University of Sergipe, Aracaju, Sergipe, Brazil.
authors.forename: André Luis
authors.initials: AL
authors.lastname: Faria-e-Silva
authors.affiliation: Faculty of Dentistry, University of Ribeirão Preto-UNAERP, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Erica Alves
authors.initials: EA
authors.lastname: Gomes
authors.affiliation: Faculty of Dentistry, University of Ribeirão Preto-UNAERP, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Yara Teresinha
authors.initials: YT
authors.lastname: Silva-Sousa
authors.affiliation: Department of Restorative Dentistry, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil. Electronic address: sousanet@forp.usp.br.
authors.forename: Manoel Damião
authors.initials: MD
authors.lastname: Sousa-Neto
mesh_terms: D003799:Dental Stress Analysis; D003804:Dentin / Q000737:chemistry* / Q000000981:diagnostic imaging*; D020342:Finite Element Analysis; D006171:Gutta-Percha / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing / Q000379:methods*; D018915:Root Canal Preparation; D014092:Tooth Root; D055114:X-Ray Microtomography
chemical_list: D006171:Gutta-Percha
keywords: Confocal laser scanning microscopy; finite element analysis; micro-computed tomography; root filling bond strength