The Effect of Aging and Surface treatments on Micro-shear Bond Strength of Resin Nano-Ceramic Material Using Two Resin Cements

Abstract

Purpose: To evaluate the effect of aging and different surface treatments on micro-shear bond strength of two resin cements to resin nano-ceramic composite blocks using an in-vitro study. Materials and methods: Blocks of resin nano-ceramic (Lava Ultimate, 3M, St Paul, Minnesota, USA) were used to prepare eight plates having the following dimensions: (14mm × 12mm × 2mm). After plates preparation they were assigned to two main groups according to the surface treatment applied, either hydrofluoric acid etching and silane or sandblasting and silane. Scanning electron microscope (SEM) was used to analyze the surface topography of the Lava-Ultimate plates before and after application of surface treatments. Two resin cements were used; dual cured adhesive resin cement (Bifix QM, VOCO, Cuxhafen, Germany) and dual cured self-adhesive resin cement (Bifix SE, VOCO, Cuxhafen, Germany) to create a five resin micro-cylinders received on each lava ultimate plate. Ten specimens from each subgroup were tested after 24 hours and the other ten specimens were tested after aging in saline for 6 months. Micro-shear bond strength test was applied until failure. . Multi-factorial ANOVA test and One-way ANOVA followed by pair-wise Tukey’s post-hoc tests were used to analyze the data. Results: Both resin cements showed statistically significant decrease on bond strength after aging. Before aging, both surface treatments with adhesive resin cement showed statistically significant higher micro-shear bond strength mean values than with self-adhesive resin cement. After aging sandblasting showed a statistically significant higher micro-shear bond strength mean values with adhesive resin cement, while hydrofluoric acid etching revealed a statistically non-significant higher values with adhesive resin cement than self-adhesive resin cement. Conclusion: For both surface treatments and resin cements aging had a detrimental effect on micro- shear bond strength.