Effect of different surface treatments on bond strength and failure type of zirconium oxide ceramic: an in-vitro study.

Statement of problem: Establishing a reliable bond to zirconia-based materials has proven to be difficult, making it the major limitation against fabrication of adhesive zirconia restorations. Purpose: The aim of this in-vitro study was to determine the ability of a new experimental primer to improve the bond strength between resin cement and zirconium oxide based crowns. Material s and Methods: 15 resin-composite discs (Filtek Supreme, 3M-ESPE) were cemented on top of zirconia discs (Lava, 3M-ESPE) using resin cement (Panavia F2.0, GC), four test groups (n=15) according to zirconia surface treatment were identified: group 1(control) with no treatment of the zirconia surface, group 2 the zirconia disc was sandblasted prior to bonding procedures, in group 3 zirconia disc was coated with Panavia primer agent, and in group 4 the sandblasted zirconia disc was coated with an experimental primer. Micro-shear bond strength was performed and failure type was evaluated under Scanning Electron Microscopy-SEM. Resul t s: One-way analysis of variance followed by multiple comparison were conducted. There was no significant difference between group 1, group 2 and group 3, while significant difference was noted between the previous groups and group 4 (P 0.05). SEM observations of the specimens showed predominant interfacial failure type, especially in groups 1, 2 and 3; while in group 4 there was a predominant cohesive failure type between adhesive cement and resin composite.