title: Shear bond strengths between alumina-toughened zirconia cores and veneering ceramics and their susceptibility to aging.
abstract: OBJECTIVE
  To evaluate the shear bond strength (SBS) between alumina-toughened zirconia (ATZ) cores and veneering ceramics, investigate the effect of aging in artificial saliva on SBS and compare it with that of yttria-stabilized tetragonal zirconia polycrystals(Y-TZP).
  
  
  METHODS
  Bars of ATZ and Y-TZP were layered with veneering ceramics in accordance to the recommendation of the manufacturer. Half of each group (n = 10) was aged at 134 °C (under 2 bar pressure) in an autoclave for 48 h. Subsequently, all specimens were subjected to shear force in a universal testing machine. The interface and fractured surface of the specimens were evaluated using scanning electron microscopy and X-ray energy dispersive spectroscopy.
  
  
  RESULTS
  The initial mean SBS values in MPa±SD were 28.9±8.0 for ATZ and 26.2±7.6 for Y-TZP. After aging, the mean SBS values for ATZ and Y-TZP were 22.9±4.9 MPa and 22.8±6.9 MPa, respectively. Neither the differences between the SBS values of the ATZ and Y-TZP groups nor the influence of aging on all groups were statistically significant.
  
  
  CONCLUSIONS
  The SBS between the ATZ core and the veneering ceramics was not affected by aging. The SBS of ATZ to veneering ceramics was not significantly different compared with that of Y-TZP.
authors.affiliation: State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, P.R. China.
authors.forename: Yong-Qi
authors.initials: YQ
authors.lastname: Zhao
authors.forename: Jiang
authors.initials: J
authors.lastname: Li
authors.forename: Jing-Chao
authors.initials: JC
authors.lastname: Zhang
authors.forename: Yun-Mao
authors.initials: YM
authors.lastname: Liao
authors.forename: Jun-Jun
authors.initials: JJ
authors.lastname: Lu
authors.forename: Wei
authors.initials: W
authors.lastname: Li
mesh_terms: D000537:Aluminum Oxide / Q000592:standards*; D002516:Ceramics / Q000592:standards*; D003801:Dental Veneers / Q000592:standards*; D008855:Microscopy, Electron, Scanning; D011475:Prosthesis Failure; D012464:Saliva, Artificial / Q000494:pharmacology; D033081:Shear Strength; D013057:Spectrum Analysis; D015019:Yttrium / Q000592:standards; D015040:Zirconium / Q000592:standards*
chemical_list: D012464:Saliva, Artificial; C499362:yttria stabilized tetragonal zirconia; D015019:Yttrium; D015040:Zirconium; D000537:Aluminum Oxide