EFFECT OF SURFACE TREATMENT AND ARTIFICIAL AGING ON MICROTENSILE BOND STRENGTH OF ZIRCONIA TO RESIN CEMENT

Statement of problem: Reliable bond to zirconia based materials has proven to be difficult which is the major limitation against luting zirconia restorations.
Purpose: This in vitro study compared effect of selective infiltration etching (SIE) and tribo-chemical silica sandblasting (TSS) on microtensile bond strength to zirconia based material before and after different artificial aging intervals.
Materials and methods: Twenty Lava plus high translucency zirconia disks (3 M, ESPE) were randomly divided into two study groups according to their surface treatment: (a) selective infiltration etching (SIE) and (b) tribo-chemical silica sandblasting (TSS). Zirconia disks were bonded to composite resin specimens using Panavia F2.0 resin cement. Zirconia resin bond strength was evaluated using the microtensile bond strength test (MTBS) and the test was repeated before and after the following intervals of accelerated artificial aging; 1 week, 2 weeks, 3 weeks and 4 weeks of water storage (37°C). A repeated measures ANOVA and Bonferroni post-hoc tests were used to analyze the data.
Results: The interaction between surface treatments and storage times were statistically significant. Data analysis revealed significant differences between the two surface treatments (P<0.05).Selective infiltration etched specimens demonstrated relatively higher MTBS values than TSS (48.5 and 24.8 MPa).SEM examination of broken microbars revealed more interfacial failure type for TSS than SIE specimens that showed a predominantly cohesive failure type.
Conclusions: Selective infiltration etching provided superior micro-tensile bond strength results compared to tribo-chemical silica sandblasting. Established bond strength by selective infiltration etching was not affected by artificial aging as tribo-chemical silica sandblasting.