Self-etching primer systems: changes in dentin bond strength with time.

The purpose of this study was to investigate the development of shear bond strength of resin composites using self-etching primer systems. Four different types of self-etching primer systems with different combinations of their recommended resin composites were used. Bovine incisors were mounted in self-curing resin and the facial surfaces were wet ground on #600-SiC paper to expose the dentin. The shear bond strengths of ten samples per test group were measured at a crosshead speed of 1.0 mm/min after storage for 5, 10, and 60 min, and 24 h in distilled water at 37 degrees C. One-way ANOVA followed by Dunnett's test (alpha = 0.05) was used to examine the significance of differences between the mean bond strength at 24 h and each of the other storage periods. The dentin bond strengths of all the materials tested increased with prolonged storage time. Such differences in the changes in bond strength might have clinical implications if a restoration is subjected to high stress immediately after it has been placed. It is important to consider the development of dentin bond strength to allow the materials sufficient maturation time prior to functional loading or application of other forms of external stress.