Effects of different surface treatments on the bonding strength and tightness of zirconia-resin cement interface

Objective To explore the effects of different surface treatments on the bonding strength and tightness of zirconia-resin cement interface. Methods The zirconia ceramic discs were divided into three groups according to the surface treatment Methods The zirconia ceramic discs were divided into three groups according to the surface treatment methods: no surface treatment group, sandblasting group and sandblasting + primer (z-prime Plus)group, and the zirconia - resin cement micro-shear bonding specimens were made respectively. The bonding strength was tested by universal testing machine and the fracture mode was calculated. Scanning electron microscopy (SEM) was used to observe the bonding interface tightness. Results Bonding strength was lowest in the no surface treatment group (4.4±2.1) MPa, and adhesion failure accounted for 92% in the fracture mode. Compared with no surface treatment group, the bonding strength of sandblasting group was significantly increased (18.2±4.5) MPa, and the cohesive failure rate in the fracture mode was 54%. The bonding strength was highest in sandblasting + primer group (31.0±4.7) MPa, and the cohesive failure accounted for 71% in the fracture mode. Scanning electron microscopy of the bonding interface showed that there were many cracks between zirconia and resin cement in the sandblasting group. The length of interfacial cracks in the no surface treatment group and sandblasting + primer group was significantly reduced compared with that in the sandblasting group. Conclusions The combination of alumina sandblasting with primer coating can significantly improve the bonding strength and interface tightness between zirconia and resin cement.