Self-etch Dentin Bonding Agent as Primer for Zirconia Ceramics

Objectives: This study was conducted to identify the feasibility of using a self-etch dentin bonding agent as primer for zirconia ceramics.  Methods: Xeno IV  bonding agent (X4), Self-Cure Activator (SCA) and Calibra resin cement (CL) were used. The surface of Cercon Zirconia was conditioned as follows: The surface was sandblasted with 50 mm Al₂O₃ particles for 10 seconds with Micro Etcher at a distance of 10 mm with a 90° angle of the nozzle to the surface. It was rinsed, ultrasonically cleaned and dried with compressed air. Stainless steel rods (3.17 mm in diameter) were sandblasted, ultrasonically cleaned and dried. When a bonding agent was used, it was applied for 1 minute and then light cured 10 seconds, if applicable. The cement was applied to surface of steel rod and placed onto tooth surface and allowed self-cure under load.  Specimens were stored in 37°C water for 24-hr.  Half of the specimens were thermocycled 5000 times between 5 °C and 55 °C. Shear bond strength (SBS) was obtained with Instron 4400 at crosshead speed of 1 mm/min. The data was analyzed with ANOVA (n=6, a=0.05, Tukey HSD test).  Results: Mean values for SBS (MPa) with standard deviations are listed below:

	CL only	X4/ No Cure	X4:SCA (1:1)/Light Cure
24 hr	9.6±4.6Ab	19.7±4.4Ba	18.7±3.6Ba
Thermocycled	0Aa	13.0 ±3.6Ba	13.4±3.7Ba

 *Within the same row, groups connected by the same upper letter are not significantly different. Within the same column, groups connected by the same lower letter are not significantly different.

Conclusion: X4 one-bottle self-etch adhesive promises an effective primer for zirconia ceramics, significantly enhancing bonding of resin cement, even in self-cure mode of cement and without prior light cure of the primer .