Zirconia Bond Strength With Experimental Mussel-Biomimetic Primer in Wet Conditions

Objectives: This in vitro study measured and compared shear bond strength (SBS) of an experimental mussel-biomimetic primer to zirconia in wet surface conditions.
Methods: KATANA Zirconia STML specimens were sectioned, sintered, and embedded in acrylic resin. Specimen surfaces were finished with 600 grit silicon carbide abrasive with cooling water, and air-particle abraded with 50 μm aluminum oxide. A total of 100 (n=25) samples were prepared and split into four study groups, the first two acting as the controls: ceramic primer (Clearfil Ceramic Primer Plus) on dry surface, ceramic primer on wet surface, experimental primer on dry surface, and experimental primer on wet surface. After primer applications of 10 seconds, the surfaces were air-sprayed, micro brushed with bonding agent (Optibond Solo Plus), and light cured for 20 seconds. Cylindrical composite samples (2.1mm diameter, 3 mm height) were bonded to the zirconia surfaces by packing the material into cylindrical shaped plastic matrices and curing with a light cure for 40 seconds. The specimens were stored for 48 hours at room temperature (24°C) and then mounted in a universal testing machine. SBS was determined at a crosshead speed of 0.5 mm/min and expressed in MPa. ANOVA and Pair wise comparison with Tukey tests were used for statistical analysis.
Results: Mean SBS values were 33.6 MPa and 25.4 MPa for the dry and wet control groups, respectively. Mean SBS values were 32.1 MPa and 32.7 MPa for the dry and wet experimental groups, respectively. While the results for the dry groups were not different (p>0.05), there was a statistically significant difference in the results between the wet experimental and control groups (p<0.05). Wet surfaces did not change bonding performance of experimental primer.
Conclusions: The pre-treatment of zirconia surfaces with a mussel-biomimetic primer may improve the bond strength to the surfaces in wet surface conditions.