The Effect of Combined Sandblasting and Piranha Solution Treatment on Resin Cement Bond Strength to Zirconia: An In Vitro Study

This in vitro study investigated whether piranha solution treatment, applied alone or following sandblasting, enhances the shear bond strength of resin cement to zirconia. Fifty zirconia specimens were assigned to five groups: no treatment, sandblasting (SB), piranha solution (Pi), sandblasting followed by piranha solution treatment (SB + Pi), and double piranha treatment (Pi + Pi). Shear bond strength was measured after 24 h water storage, and failure modes were recorded. The SB + Pi group produced significantly higher bond strength than all other groups. Single treatments (SB, Pi, and Pi + Pi) yielded statistically comparable values, all exceeding the untreated control. Notably, double piranha application offered no benefit over a single application. These findings are preliminary and limited to short-term in vitro conditions; the piranha protocol is not feasible for direct clinical use due to safety constraints, and no aging or surface characterization data were obtained.