title: Influence of surface modification techniques on shear bond strength between different zirconia cores and veneering ceramics.
abstract: OBJECTIVE
  Veneering porcelain might be delaminated from underlying zirconia-based ceramics. The aim of this study was the evaluation of the effect of different surface treatments and type of zirconia (white or colored) on shear bond strength (SBS) of zirconia core and its veneering porcelain.
  
  
  METHODS
  Eighty zirconia disks (40 white and 40 colored; 10 mm in diameter and 4 mm thick) were treated with three different mechanical surface conditioning methods (Sandblasting with 110 µm Al(2)O(3) particle, grinding, sandblasting and liner application). One group had received no treatment. These disks were veneered with 3 mm thick and 5 mm diameter Cercon Ceram Kiss porcelain and SBS test was conducted (cross-head speed = 1 mm/min). Two and one way ANOVA, Tukey's HSD Past hoc, and T-test were selected to analyzed the data (α=0.05).
  
  
  RESULTS
  In this study, the factor of different types of zirconia ceramics (P=.462) had no significant effect on SBS, but the factors of different surface modification techniques (P=.005) and interaction effect (P=.018) had a significant effect on SBS. Within colored zirconia group, there were no significant differences in mean SBS among the four surface treatment subgroups (P=0.183). Within white zirconia group, "Ground group" exhibited a significantly lower SBS value than "as milled" or control (P=0.001) and liner (P=.05) groups.
  
  
  CONCLUSIONS
  Type of zirconia did not have any effect on bond strength between zirconia core and veneer ceramic. Surface treatment had different effects on the SBS of the different zirconia types and grinding dramatically decreased the SBS of white zirconia-porcelain.
authors.affiliation: Department of Prosthodontics and Torabinejad Dental Research Center, School of Dentistry. Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Ramin
authors.initials: R
authors.lastname: Mosharraf
authors.forename: Mansour
authors.initials: M
authors.lastname: Rismanchian
authors.forename: Omid
authors.initials: O
authors.lastname: Savabi
authors.forename: Alireza Hashemi
authors.initials: AH
authors.lastname: Ashtiani