In vitro Comparative Shear Bond Strength to Procera AllZirkon

CAD/CAM systems using zirconium-oxide ceramics for the fabrication of copings and frameworks (e.g., Procera AllZirkon, Nobel Biocare) become very popular and the quest for adequate bonding techniques, material selection, and the compatibility of different bonding systems is of high interest. The phosphate-containing resin cement Panavia (Kuraray) is the preferred cement for a strong resin bond to zirconia. However, research on the influence of silanization on the resin bond of this cement and the performance of conventional resin cements is controversial. Objectives: This study evaluated shear bond strength of the resin cements Panavia F (Kuraray) and RelyX ARC (3M ESPE) in combination with their corresponding ceramic primers/bonding agents Clearfil SE Bond/Clearfil Porcleain Bond Activator(CSB/PBA, Kuraray) and Ceramic Primer/Single Bond (CP/SB, 3M ESPE) to sandblasted Procera AllZirkon intaglio surface. Methods: 40 Procera AllZirkon specimens were sandblasted and composite-resin cylinders were bonded to the ceramic surface with the following material combinations: Group A (Panavia/no bond), Group B (Panavia/CSB/PBA), Group C (RelyX ARC/CP/SB), Group D (RelyX ARC/CSB/PBA). Shear bond strength was tested in an INSTRON after storage of the specimens in distilled water for 3 days. One-way ANOVA and Tukey’s HSD post-hoc tests were used to compare and separate the groups with respect to mean shear bond strength (a=0.05). Results: Mean shear bond strengths differed significantly among the four groups. Group D (25.1 MPa) was superior to groups C (16.9 MPa) and A (17.4 MPa). Group B (20.1 MPa) ranked just below Group D but produced bond strengths that were not statistically different from the other groups. Conclusions: The bonding agent/ceramic primer Clearfil SE Bond/Clearfil Porcleain Bond Activator seems to provide a superior bond with the resin cements Panavia and especially Rely X ARC. More research will be necessary to test other cement and bonding-agent combinations before clinical recommendations can be given.