Bovine dentin as a substitute for human dentin in shear bond strength measurements

Purpose: To evaluate the suitability of bovine coronal and root dentin as substitutes for human primary and permanent dentin in shear bond strength tests for dentin adhesives. Materials and Methods: 30 bovine permanent central incisors, 30 human primary and 30 human third molars were cut mesiodistally. The pulpal and buccal dentin surfaces of the buccal cuts were milled with a bur to a thickness of 1.0 mm. A dentin adhesive and a hybrid composite were applied exactly according to the instructions given by the manufacturer on each buccal and pulpal surface, except in primary teeth where only the buccal surface was used. Shear bond strength was determined after 24 hours of storage in an aqueous solution. The results were statistically analyzed using the Wilcoxon- or the Mann-Whitney-U-test. Results: There were no differences in shear bond strengths between human permanent dentin and bovine coronal dentin (13.3 +/- 6.1 vs. 15.2 +/- 7.6), and between each pulpal and buccal aspect. Significant differences were found between bovine root dentin and human primary dentin (17.4 +/- 8.3 vs. 7.7 +/- 5.0, P< 0.001). Significant differences were also found between bovine root dentin and human permanent dentin (17.4 +/- 8.3 vs. 13.3 +/- 6.1, P< 0.05), and bovine root and coronal dentin (17.4 +/- 8.3 vs. 15.2 +/- 7.6, P< 0.05). Furthermore, significant differences were recorded between human primary and human permanent dentin (7.7 +/- 5.0 vs. 13.3 +/- 6.1, P< 0.001) and bovine coronal dentin (7.7 +/- 5.0 vs. 15.2 +/- 7.6, P< 0.001).