Different contemporary resin cements for intracanal luting of glass fiber posts - Bonding and polymerization assessments

Abstract

This study evaluated the push-out bond strength (POBS) and the degree of conversion (DC) of contemporary resin cements employed for the luting of glass fiber posts, considering different root thirds and thermocycling aging. One hundred bovine incisors were assigned to five groups (n = 20): Universal resin cements (URCs) - Duo-link Universal, NX3 and RelyX Universal; Traditional adhesive resin cement (ARC) - RelyX Ultimate; and one self-etching resin cement (SERC) - Panavia V5. After luting glass fiber posts to intraradicular dentin, specimens were cut, and POBS was tested at 24h or after 10,000 thermocyclers. Failure modes were analyzed using a stereomicroscope. The degree of conversion (n = 3) was measured using Micro-Raman spectroscopy. Data were statistically analyzed by two-way (POBS) or one-way (DC) ANOVA and Tukey's post hoc test (α = 0.05). RelyX Universal and Duo-link Universal showed higher POBS than further cements at 24h and after thermocycling (p = 0.00644). Panavia V5 showed the lowest POBS. Coronal and middle thirds showed the highest POBS mean values for all resin cements, except for Panavia V5, which depicted similar bonding along all root thirds (p = 0.04571). Adhesive (cement-dentin) and mixed failures were the most prevalent for all groups. The coronal third showed the highest DC for all cements, and Panavia V5 depicted the lowest conversion, mainly in the apical third. This study demonstrated that the URCs may surpass traditional resin cement for luting glass fiber posts, but with similar polymerization.