title: Push-out bond strength of a nano-modified mineral trioxide aggregate.
abstract: BACKGROUND
  To analyze the push-out bond strength of Angelus WMTA (Angelus Dental Products), a nano-modification of WMTA (Kamal Asgar Research Center) and Bioaggregate (Innovative Bioceramix).
  
  
  METHODS
  Sixty 2-mm-thick root sections were prepared from 60 single-rooted human teeth. The dentin disks were randomly divided into three groups (n = 20) and filled with Angelus WMTA, Nano-WMTA, or Bioaggregate, respectively. Push-out bond strength values of the specimens were measured by a universal testing machine and examined under scanning electron microscope at × 40 magnification to determine the nature of the bond failure. The data were analyzed with a Kruskal-Wallis test.
  
  
  RESULTS
  The greatest mean for push-out bond strength (138.48 ± 11.43 MPa) was observed for the nano-modification of WMTA. The values decreased to 110.73 ± 11.19 and 25.64 ± 5.27 MPa for Angelus WMTA and Bioaggregate, respectively. There were significant differences between the groups (P < 0.001). Inspection of the samples revealed the bond failure to be predominantly adhesive type except for the nano-modification group, as some samples also exhibited cohesive failures.
  
  
  CONCLUSIONS
  It is concluded that the force needed for the displacement of the nano-modification of WMTA (NWMTA) was significantly higher than for Angelus WMTA and Bioaggregate.
authors.affiliation: Department of Dental Materials and Craniofacial Research Center, Dental School, Azad University (Tehran Branch), Tehran, Iran. saghiri@gmail.com
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Saghiri
authors.forename: Franklin
authors.initials: F
authors.lastname: Garcia-Godoy
authors.forename: James L
authors.initials: JL
authors.lastname: Gutmann
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Lotfi
authors.forename: Armen
authors.initials: A
authors.lastname: Asatourian
authors.forename: Hadi
authors.initials: H
authors.lastname: Ahmadi
mesh_terms: D017607:Aluminum Compounds / Q000737:chemistry*; D017610:Calcium Compounds / Q000737:chemistry*; D002126:Calcium Hydroxide / Q000737:chemistry*; D003799:Dental Stress Analysis; D003804:Dentin / Q000737:chemistry*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D004338:Drug Combinations; D019544:Equipment Failure Analysis; D006801:Humans; D006882:Hydroxyapatites / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D049329:Nanostructures / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D012387:Root Canal Filling Materials / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry*; D014092:Tooth Root / Q000737:chemistry*
chemical_list: D017607:Aluminum Compounds; C557009:BioAggregate; D017610:Calcium Compounds; D017220:Dentin-Bonding Agents; D004338:Drug Combinations; D006882:Hydroxyapatites; D010087:Oxides; D012387:Root Canal Filling Materials; D017640:Silicates; C086631:mineral trioxide aggregate; D002126:Calcium Hydroxide