Effect of etching time and acid concentration on resin shear bond strength to primary tooth enamel.

The present study compared the shear bond strength of two commercially available systems to human primary enamel. Ground and unground enamel was conditioned for 15 seconds with 37% phosphoric acid siliceous gel. A 60-second application was used as a standard reference. Ten percent phosphoric acid in a polymer gel was also evaluated following a 20-second application to ground and unground primary enamel. No statistically significant difference was demonstrated between the mean values determined for each group. Compared with tests on permanent enamel with the same materials and conditions, it was concluded that no statistically significant difference exists between shear bond strengths to the enamel of the two dentitions.