Composite-to-metal bond; the effect of the opaque layer

ABSTRACT

The purpose of this study was to evaluate, if the presence of the opaque resin as an intermediary layer between the veneering composite and the metal alloy has a weakening effect on the overall composite-to-metal bond. In order to evaluate the effect of the opaque layer 15, pairs of gold rods were grit blasted, cleaned and primed with the mixed silane primer [MPTS/MPMS]. A thin layer of 70-micro m thickness of the opaque resins or the composite resins of Sinfony, Solidex, Pertac hybrid and Esthet.X was applied on the adhering surfaces of the rods before they were joined using Variolink II luting resin. All the bonded rods were stored dry for 24 hours. A Lloyd Universal Testing Machine was used to test the tensile bond strength at a cross head speed of l mm /min. The debonded surfaces were observed under an Olympus Optical Microscope and the mode of failure was recorded. ANOVA and Tukey's test were used to determine significant differences between the groups. There was no significant difference in the TBS of specimens prepared with the opaque resins when compared with the TBS of the control group or TBS of their relative composites. Most of the specimens showed a mixed mode of failure with the exception of Sinfony opaque, which showed cohesive failure. The opaque resin layer has no weakening effect on the overall composite-to-metal bond