Comparative study of bond strength to human and bovine dentine at three different depths

Abstract

The aim of this study was to compare the bond strength to three different depths of remaining human and bovine dentin, through shear bond strength test, and to establish a possible relationship among the depths of the substrates to contribute for the replacement of human dentin in bond strength tests. Forty-eight human teeth (H) and forty-eight bovine teeth (B), freshly extracted, stored in distilled water and frozen at -18 ° C for at most four weeks were used in this study. 240-, 400-, 600- and 800-grit sandpapers were used to expose the dentin and standardize the smear layer at 0.5, 1.0 and 2.0mm of dentin thickness. Scotchbond Multi-Purpose Plus adhesive system was used following the manufacturer’s instructions, on a standardized area of 4mm, followed by the incrementally application of Z100 resin composite (3M). The shear bond test was performed in the Instron Universal machine at cross-head speed of 0.5mm/min. Statistical analysis was performed by ANOVA (p <0.05). There were significant differences in bond strength between H and B teeth, with the highest values for H teeth. There was a significant difference in bond strength to the depths analyzed but there was similarity in behavior between H (0.5mm) and B (2mm) substrates. Bovine substrate can be used for laboratory studies of bond strength as indicative of the initial performance of new products, although the differences related to human substrate should be observed.