Effects of zirconia surface treatments on resin-zirconia bond

Abstract

Objectives: To investigate the effects of Er,Cr:YSGG laser, selective infiltration coating (SIE) and sandblasting of zirconia surface on microtensile bond strength (MTBS) of resin to zirconia. Methods: Zirconia blocks were sectioned into specimens of standard size followed by sintering. Sintered specimens were then polished, cleaned and randomly assigned into 5 groups with the following surface treatments: 1) 3.0W laser; 2) 4.0W laser; 3) SIE; 4) sandblasting and 5) no treatment. Composite resin blocks were bonded to the treated zirconia surfaces using the standard adhesive and resin cement. After 24 hrs, the specimens were cut into resin-zirconia microbars (1mm×1mm×6mm). Each group was subdivided into two groups (n=20) i.e. 24-hr dry storage, 1-month water storage at 37°C. After artificial aging, microtensile bond strength (MTBS) tests were carried out using a universal testing machine. 2-way ANOVA was used for data analysis. The level of significance was set at 0.05. Analysis of failure modes was also performed. Results: In the dry groups, significant differences in MTBS (p<0.05) were found among the groups in the following order: SIE > sandblasting/3W > 4W/control. In the water storage groups, SIE showed significant higher MTBS than the remaining groups. The MTBSs of water storage specimens were significantly lower than the dry specimens (p<0.05) except the ones in 4W groups (p>0.05). Conclusions: Zirconia surface treatments including Er,Cr:YSGG laser, selective infiltration etching and sandblasting could enhance the resin-zirconia bonding in dry condition. With the exception of selective infiltration etching, water degradation seemed to be detrimental to the bond.