Abstract
The replacement of the metal used as infrastructure in prosthetic restorations with yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) raised questions regarding the quality of the bond strength between the ceramic infrastructure and veneer. Therefore, surface treatments were developed in order to improve porcelain-Y-TZP bond strength. The objective of this study was to evaluate the effect of a surface treatment on the bond strength between the porcelain veneer and Y-TZP, as well as to compare the results with a metal-ceramic control group. Three experimental groups were evaluated (n=10): YC - Y-TZP infrastructure veneered with VM9 porcelain; YB - Y-TZP infrastructure veneered with a bond agent and VM9 porcelain; MC - nickel-chrome infrastructure veneered with opaque and VM13 porcelain. Specimens were produced using slices of the infrastructure materials. A porcelain cylinder (3 mm diameter, 6 mm height) was built over the infrastructures and sintered according to the manufacturer recommendation. Specimens were subjected to a shear bond strength test in a universal testing machine at 0.5 mm/min cross-head speed. After testing, failure modes were classified as adhesive, cohesive or combined. Shear bond strength (σf) data were analyzed with one-way ANOVA (α=0.05). σf mean values (standard deviation) in MPa were: YC - 19.7 (7.8); YB - 22.5 (6.4); MC - 24.2 (6.6). There was no statistical difference between groups (p=0.377). There was an association among the experimental group and the failure mode. Only YC and YB groups showed porcelain cohesive failure. It was concluded that Y-TZP infrastructure show similar shear bond strength to the porcelain than the “gold standard” metal-ceramic. The application of a bond agent had no influence in the bond strength results.
Keywords:
ceramic; partial fixed denture; shear strength
