Effect of surface pre-treatments on the zirconia ceramic-resin cement microtensile bond strength.

Objective: To evaluate the influence of different surface treatments on the microtensile bond strength of resin cement to zirconia ceramic. Materials and methods: Twelve cylinder-shaped (∅ 12 × 5.25 mm high) blocks of a commercial zirconium-oxide ceramic (Cercon ® Zirconia, DENTSPLY) were randomly divided into 4 groups (n = 3), based on the surface treatment to be performed: (1) airborne particle abrasion with 125 μm Al 2O 3 particles (S); (2) selective infiltration etching (SIE); (3) experimental hot etching solution applied for 30 min (ST) and (4) no treatment (C). Paradigm MZ100 blocks (3M ESPE) were cut into twelve cylinders of 4 mm in thickness. Composite cylinders were bonded to conditioned ceramics using a resin cement (Calibra ®, DENTSPLY), in combination with the proprietary adhesive system. After 24 h bonded specimens were cut into microtensile sticks and loaded in tension until failure. Bond strength data were analyzed with Kruskall-Wallis and Dunn's Multiple Range test for multiple comparisons (p < 0.05). Failure mode distribution was recorded and the interfacial morphology of debonded specimens was analyzed using a scanning electron microscope (SEM). Results: Bond strength values achieved after SIE and ST treatment were significantly higher than after S treatment and without any treatment (p < 0.05). Premature failures were mostly recorded in the S group. Significance: Conditioning the high-strength ceramic surface with SIE and ST treatments yielded higher bond strengths of the resin cement than when zirconia ceramic was treated with airborne particle abrasion or left untreated.