Effect of incorporating BisGMA resin on the bonding properties of silane and zirconia primers.

STATEMENT OF PROBLEM: Some silane primers and some zirconia primers contain extra resins such as bisphenol A glycol dimethacrylate (BisGMA) in their formulations for better wetting. No studies exist on the bonding properties of zirconia and silane primers, which contain extra resins. PURPOSE: The purpose of this study was to investigate the effect of incorporating BisGMA resin on the bonding properties of silane and zirconia primers. MATERIAL AND METHODS: Silica-base lithium disilicate was etched and treated with BisGMA-incorporated Porcelain Primer, unmodified Porcelain Primer, or resin-containing Kerr Silane. Zirconia ceramic was airborne-particle abraded and treated with BisGMA-incorporated Monobond Plus, unmodified Monobond Plus, or BisGMA-containing ZPrime Plus. After primer treatment and cleaning with ethanol, the contact angles were measured to determine surface change (n=10). Shear bond strength tests were also performed to measure the adhesion strength between resin cements and ceramic surfaces (n=10). Data were statistically analyzed by 1-way ANOVA followed by the Tukey multiple comparison as a post hoc test (significance level .05). RESULTS: The incorporation of BisGMA resin did not significantly influence the bond strength or contact angle of the zirconia primer (P>.05), but it did significantly reduce those of the silane primer (P<.05). Resin-containing Kerr Silane (22 degrees, 23 MPa) had a similar contact angle and higher bond strength than the control (21 degrees, 18 MPa), but lower than Porcelain Primer (88 degrees, 34 MPa). Resin-containing ZPrime Plus (75 degrees, 29 MPa) had a similar contact angle and higher bond strength than both Monobond Plus (74 degrees, 18 MPa) and the control (15 degrees, 4 MPa). CONCLUSIONS: The addition of BisGMA resin significantly inhibited the efficacy of silane-containing porcelain primers but did not affect that of phosphate-containing zirconia primers.