Influence of adhesive polymerization mode on dentin bond strength of direct core foundation systems

This study examined the influence of various adhesive systems on dentin bond strength of direct core foundation resins. Two commercially available direct core foundation resin systems and 2 adhesive polymerization modes were used. Facial bovine dentin surfaces were wet ground on 600-grit SiC paper. Dentin surfaces were treated according to the manufacturers' instructions and were light polymerized (control). Chemical- and light-polymerized adhesive systems were used separately. The resin paste was condensed into a mold and bonded to the dentin surface. Ten specimens per test group were stored in water at 37 degrees C for 24 hours, and a shear test was conducted at a crosshead speed of 1.0 mm/minute using a universal testing machine. Analysis of variance (ANOVA) and Duncan's multiple comparison test were performed (alpha = 0.05). Dual polymerization of resin pastes revealed higher bond strength with the combination of light-polymerized adhesive (22.8-24.3 MPa), but significantly lower bond strength with the combination of a chemical-polymerized adhesive (4.2-5.7 MPa). The present data suggests that dentin bond strengths in direct core foundation systems can be influenced by the combination of adhesive and resin paste.