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 s ubstitutes for human primary and permanent dentin in shear bond strength te sts for dentin adhesives. Materials and Methods: 30 bovine permanent centra l incisors, 30 human primary and 30 human third molars were cut mesiodistal ly. The pulpal and buccal dentin surfaces of the buccal cuts were milled wi th 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 manufactur er on each buccal and pulpal surface, except in primary teeth where only th e buccal surface was used. Shear bond strength was determined after 24 hour s of storage in an aqueous solution. The results were statistically analyze d using the Wilcoxon- or the Mann-Whitney-U-test. Results: There were no di fferences 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 an d buccal aspect. Significant differences were found between bovine root den tin and human primary dentin (17.4 +/- 8.3 vs. 7.7 +/- 5.0, P< 0.001). Sign ificant differences were also found between bovine root dentin and human pe rmanent dentin (17.4 +/- 8.3 vs. 13.3 +/- 6.1, P< 0.05), and bovine root an d coronal dentin (17.4 +/- 8.3 vs. 15.2 +/- 7.6, P< 0.05). Furthermore, sig nificant differences were recorded between human primary and human permanen t 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).