Dentin bonding: influence of bonded surface area and crosshead speed on bond strength

This study investigated the influence of the bonded surface area and the crosshead speed on the dentin bond strengths of self-etch adhesives. Bovine mandibular incisors were mounted in self-curing resin and the facial surfaces were wet ground with #600 silicon carbide (SiC) paper. The dentin surfaces were treated according to the manufacturer's instructions. Adhesives were applied, and the resin composites were condensed into molds (2.4 or 4.0 mm in internal diameter), placed on to the dentin, and then light activated. Ten samples per test group were shear tested at crosshead speeds of 0.1, 0.5, 1.0, 5.0, and 10.0 mm/min. The results showed that higher crosshead speeds were associated with higher dentin bond strengths. This relationship was more significant for specimens with a smaller dentin bonding surface area.