Abstract: Objective To evaluate the resin bonding and microleakage of yttriastablized tetragonal zirconia polycrystal (YTZP) with or without alumina sandblasting combined with conditioning with two 10methacryloyloxydecyl dihydrogen phosphate (MDP) containing zirconia primers. Methods Shortterm shear bond strength (SBS) between composite resin and YTZP with different surface treatments was tested. Surface treatments of YTZP included the following, alumina sandblasting followed by conditioning with any one of the two brands of MDP containing zirconia primers, single conditioning with any one of the two brands of MDP containing zirconia primers, and single alumina sandblasting as the negative control group. Methylene blue staining was carried out to evaluate the microleakage. Results Single alumina sandblasting showed the lowest SBS. Prior to conditioning YTZP with MDP containing zirconia primer, alumina sandblasting improved the SBS further. YTZP showed single alumina sandblasting had the most serious microleakage. No matter whether sandblasting was performed, application of MDP containing zirconia primers decreased microleakage. Conclusions Alumina sandblasting combined with zirconia primers is a preferable means to improve resin bonding of YTZP.

Key words: zirconia, bond strength, phosphate monomer, micro-leakage, surface treatment