Pulpal pressure and bond strengths of SuperBond and Gluma

The effects of storage under a simulated pulpal pressure on the shear bond strength of SuperBond and Gluma were evaluated using extracted, unerupted human teeth. Also evaluated was the effect of dentin position both vertically (i.e., superficial versus deep) and horizontally (center versus pulp horns) in the presence or absence of a pulpal pressure. Thirty-two cm of H2O pressure had no effect on the 24 hour shear bond strength of SuperBond C & B. There was also no significant difference in the bond strength of SuperBond to superficial versus deep dentin or central dentin versus dentin directly over pulp horns. The bond strengths of SuperBond ranged from 16.3-19.1 MPa. Gluma bonds were less than half as strong as those obtained with SuperBond C & B. Although there was no effect of dentin position on Gluma bond strength, in the presence of a pulpal pressure, the strength of the bonds fell in deep dentin especially over pulp horns. This testing protocol may prove of value in screening new dentin bonding systems.