Effect of Silane Concentration on Resin Bond Strength of Zirconia

Objective. To compare resin bond strength of zirconia using different concentrations of silane. Background. Silanes are commonly used in dentistry to enhance resin bonding of tribochemical-coated zirconia. However, there is no information on the optimal concentration of silane to use. Method. Zirconia (ZrO2) blocks were sectioned into plates (10x4x2mm) and polished through to 600 grit. Plates were divided into 4 groups (n=20/group), air-abraded (100μm Al2O3, 0.38MPa, 10mm, 20s), tribochemicalcoated (CoJet – 0.28MPa , 10mm, 15s), then silane-treated as follows: 1) ZrO2, treated with commercial silane (Control - 1vol% solution of 3-methacryloyloxypropyltrimethoxysilane (MPS) in ethanol-water mixture), 2) ZrO2, treated with 1vol% solution MPS mixture, 3) ZrO2, treated with 2.5vol% solution MPS mixture, and 4) ZrO2, treated with 5vol% solution MPS mixture. Composite blocks (3x3mm) were resin bonded to silanized surfaces. Shear bond strength of specimens was then tested using a universal testing machine (crosshead speed of 1mm/min) after storage in deionized water (37°C) for 24 h and 60 days. The effect of water storage duration on bond strengths was evaluated using one-way ANOVA with a Tukey’s test for multiple comparisons if groups were significant (p < 0.05). Results. Use of commercial silane resulted in significantly greater bond strength after 24 hr; no significant difference observed between other silane groups. Bond strength between groups after 60 days was not significant; significant decrease in bond strength for all groups when compared to 24 hr. Conclusion. The resin bond strength of zirconia is not improved by increasing the concentration of MPS in silane solutions