Effect of various surface treatments on the interfacial adhesion between zirconia cores and porcelain veneers

Predictable success of zirconia-based all-ceramic restoration is dependent on the stable bonding between ceramic veneer and zirconia core. The study investigated the effect of surface treatments on interfacial binding between zirconia and ceramic veneer under thermal stress. The surfaces of 60 yttria-stabilized zirconia beams were polished. Half underwent sandblasting. The polished-only and polished–abraded specimens then received a liner, a glass-based bonder, or no intermediate layer (n=10/subgroup). All specimens were veneered, subjected to thermal cycling, and subjected to the four-point bending test to calculate the energy release rate. Five Raman spectra were obtained with a line scan across the interface. The data were analyzed with two-way ANOVA with a significance level of 0.05. Scanning electron microscopy revealed the interfacial crack pattern. The interfaces with the intermediate ceramics were significantly more resistant to four-point bending than others (p=0.011). Raman imaging suggested the interfacial diffusion between the zirconia cores and porcelain veneers. The crack failure mode was adhesive for all specimens. Under simulated physiological conditions, strong adhesion at the interface of porcelain-veneered zirconia complexes could be achieved with the application of intermediate ceramic layers.