title: The effect of air-abrasion and heat treatment on the fracture behavior of Y-TZP.
abstract: OBJECTIVE
  This study evaluated how the flexural strength and fracture behavior of a zirconia-based ceramic (Y-TZP) were affected by pre- and post-sintering mechanical and thermal treatments.
  
  
  METHODS
  Treatments included sandblasting with different particle size and type (30μm SiO2; 50 and 110μm Al2O3) and thermal conditioning. Two hundred bar-shaped specimens of pre-sintered Y-TZP ceramic (Lava Frame, 3M) were prepared (specimen dimensions: 25mm length×4mm width×0.7mm thickness) and divided into three groups (before sintering, after sintering and after sintering with heating treatment). The before sintering group specimens were airborne-particle abraded prior to dense sintering. Specimens from the after sintering group were airborne-particle abraded after sintering. The after sintering with heating treatment group specimens were submitted to a heating procedure after airborne-particle abrasion. The controls were the specimens that were sintered and not treated with any conditioning procedures. The specimens from all experimental conditions were analyzed by SEM, CLSM and XRD. All specimens were tested in four-point bending. Data were statistically analyzed using one-way ANOVA and Post Hoc tests (α=0.05). A Weibull analysis was used to analyze the strength reliability.
  
  
  RESULTS
  Sandblasting pre-sintered zirconia before sintering significantly decreased the flexural strength, except when the smallest blasting particles were used (30μm SiO2). Phase transformation (t-m) was observed after sandblasting and reverse transformation (m-t) was observed after heating.
  
  
  CONCLUSIONS
  Sandblasting with 30μm SiO2 and 50μm Al2O3 allowed lower phase transformation. However, 30mm SiO2 presented better reliability.
authors.affiliation: School of Dentistry, University of Alberta, Edmonton, Alberta, Canada. Electronic address: passos@ualberta.ca.
authors.forename: Sheila P
authors.initials: SP
authors.lastname: Passos
authors.affiliation: School of Dentistry, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Bernie
authors.initials: B
authors.lastname: Linke
authors.affiliation: School of Dentistry, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Paul W
authors.initials: PW
authors.lastname: Major
authors.affiliation: School of Dentistry, University of Alberta, Edmonton, Alberta, Canada; Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: John A
authors.initials: JA
authors.lastname: Nychka
mesh_terms: D020906:Air Abrasion, Dental / Q000009:adverse effects*; D001840:Dental Bonding; D003793:Dental Restoration, Permanent; D003799:Dental Stress Analysis; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D008422:Materials Testing; D015019:Yttrium / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
chemical_list: C499362:yttria stabilized tetragonal zirconia; D015019:Yttrium; D015040:Zirconium; C028541:zirconium oxide
keywords: Flexural strength; Heat treatment; Surface treatment; Y-TZP