Comparison of microtensile bond strength to enamel and dentin of human, bovine, and porcine teeth

PURPOSE: To determine the bond strengths promoted by an adhesive system to human, bovine, and porcine enamel and dentin, and compare their etched micromorphology by scanning electron microscopy. MATERIALS AND METHODS: Thirty sound freshly extracted teeth were used in this study: ten human third molars, ten bovine incisors, and ten porcine molars. The crowns of human (H), bovine (B), and porcine (P) teeth were ground with 600-grit SiC paper to expose either enamel (E) or mid-depth dentin (D) surfaces. After application of the adhesive resin, composite crowns approximately 8 mm high were built up with TPH Spectrum composite. After 24 h of water storage, specimens were serially sectioned in the buccal-lingual direction to obtain 0.8 mm slabs, which were trimmed to an hourglass shape of approximately 0.8 mm2 at the bonded interface. Specimens were tested in tension in a universal testing machine (0.5 mm/min). Results were statistically analyzed with ANOVA and Tukey's test at the 95% confidence level. RESULTS: Tukey's test showed significant differences between bond strengths obtained on enamel and dentin (p < 0.05). However, there were no statistically significant differences in microTBS between human, bovine, and porcine teeth. SEM observations revealed a similar dentinal morphology for the three species. However, porcine enamel specimens presented a very different distribution of enamel prisms. CONCLUSION: Bovine teeth proved to be possible substitutes for human teeth in either dentin or enamel bond testing. However, even though porcine teeth provided enamel and dentin bond strengths similar to human and bovine teeth, enamel morphology presented a very different configuration.