[Effects of nano-zirconium hydroxide coating on resin bonding of 10-methacryloxy decyldihydrogen phosphate-conditioned zirconia].

OBJECTIVE: This study evaluated the influence of alkaline coating of nano-zirconium hydroxide on resin bonding of 10-methacryloxy decyldihydrogen phosphate (MDP)-conditioned zirconia. METHODS: A total of 140 yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) plates were prepared and sandblasted with alumina particles, and then subjected to different surface treatment. Resin bonding specimens were prepared with a MDP-free resin cement and tested for shear bond strength (SBS). X-ray photoelectron spectroscopy (XPS) was used to investigate the formation of chemical bond on the surface of Y-TZP treated successively with nano-zirconium hydroxide coating and MDP containing primer. RESULTS: The two alkaline coatings increased the 24 h SBS compared to control groups, and groups using nano-zirconium hydroxide coating yielded higher SBS. After thermocycling, no statistical difference was observed between groups, but SBS decreased significantly compared to the 24 h SBS (P<0.05). XPS analysis detected -OH bond on the surface of Y-TZP treated with nano-zirconium hydroxide coating, and -P-O-Zr bond was detected on the surface of Y-TZP treated with nano-zirconium hydroxide coating and MDP-containing primer. CONCLUSIONS: Alkaline coatings improved the bonding of resin to zirconia conditioned with MDP-containing primers.