Resin Cements as Core Build-Up Materials: Impact of Universal Adhesives on Fiber Post Cementation

Eleven resin cements, used as core build-up materials in this study, were evaluated via the following measurements: (a) push-out force between root dentin and fiber post; (b) pull-out force between core build-up material and fiber post; (c) shear bond strength of resin cement to root dentin; (d) flexural strength of resin cement; and (e) flexural modulus of elasticity of resin cement. All tests were performed at two time periods: after 1-day storage in water (Base) and after 20,000 thermocycles (TC 20k). For the push-out test, single-rooted human premolars were used to create simulated cavities. The specimens were sectioned horizontally perpendicular to their long axes into 2-mm slices. These slices were then subjected to push-out test to determine the bond strength between human root dentin, resin cement layer, and the fiber post. There were no significant differences in bond strength between Base and TC 20k. Therefore, surface pretreatments of multiple substrates with universal adhesives for fiber post cementation could ensure not only strong, but also durable, adhesion over time.