Dentin bonding agents: correlation of early bond strength with margin gaps

Tensile and shear bond strengths between restorative resin and flat human dentin surfaces were determined 15 min after polymerization of various resin systems in combination with 5 dentin bonding agents. The maximum marginal contraction gaps around cylindrical dentin cavities were measured for the same material combinations. A correlation was established for the linear relationship between the logarithm of the contraction gaps and the shear bond strength (r=−0.88). However, the rather wide 95% interval of prediction indicates that strength values do not adequately delineate the effectiveness of dentin bonding agents when used in cylindrical cavities. Early determination of bond strengths and gap widths is considered suitable to estimate the clinical efficacy of dentin bonding agents.