Effect of activation mode of dual-cured resin cements and low-viscosity composite liners on bond strength to dentin

Objectives: The aim of this study was to investigate the influence of the activation mode of dual-cured resin cements and application of low-viscosity composite liners over dentin on bond strength (BS) of dentin-bonding agents (DBA). Methods: Three DBA (Single Bond; Prompt L-Pop and Clearfil SE Bond), their respective resin cements (RelyX ARC and Panavia F) and two low-viscosity composites (Filtek Flow and Protect Liner F) were tested. After removing the buccal enamel surfaces of 25 bovine incisors, each flat dentin surface was sectioned longitudinally and divided into two similar parts. The dentin surfaces were wet-abraded with 600-grit SiC paper and randomly divided into 10 groups. Experimental groups comprised the use of DBA and their respective dual-cured resin cements, with or without light- activation of resin cements. The low-viscosity resin was used only for the self-etching systems, Prompt L-Pop and Clearfil SE Bond. Three resin cement cylinders (0.5 mm high and 0.75 mm diameter) were built on each bonded dentin surface, using a tygon tubing mold. After water storage for 24 h, specimens were subjected to micro-shear testing. Data were statistically analyzed by two-way ANOVA and Tukey test. Results: Light-activation of resin cements resulted in significantly higher BS for all DBA versus groups in which the resin cements were allowed to self-cure. The low-viscosity composite application increased the BS only for Prompt L-Pop. Conclusions: The bond strength of resin cements to dentin is reduced if light-activation is not employed. The use of a low-viscosity composite liner resulted in improved bond strength only for the single-step self-etching adhesive. (C) 2007 Elsevier Ltd. All rights reserved.