Search

Ceramics are widely used as dental restorative materials because of their superior wear resistance, chemical stability, biocompatibility, and aesthetic features. In this paper, the chemical compositions, microstructures and mechanical properties of dental ceramics were introduced, based on the wear mechanisms of typical dental ceramics and their abrasiveness with opposing human teeth, the main progress concerning the tribological performance optimization of dental ceramics were summarized, and it was pointed out that the mismatch of tribological properties between ceramics and human teeth seriously restricts the clinical application of dental ceramics. Then the in vitro test methods of tribological properties of dental ceramic materials are analyzed and summarized from the aspects of laboratory test medium, friction pair, load, displacement and cycle times. Finally, the future development trends of dental ceramics were discussed from the perspective of bionic tribology. It was pointed out that bionic design of ceramic matrix composites is a promising strategy for overcoming the mismatch of tribological property between dental ceramic restorations and human teeth.

Objective To analyzed the DKK1 expression in early osteogenic and adipogenic differentiation of BMSCs in rats and to explore its regulating mechanism. Methods DKK1 gene expression in early adipogenic and osteogenic differentiation was detected using real4ime PCR. And the DKK1 expression was also detected after hormone treatment. Results The expression level of DKK1 gene after 6, 12, 24, and 48h adipogenic induction was higher than that in control group and the difference was significant (P < 0. 01). The expression level of DKK1 gene after 0. 5 and 6h osteogenic induction was obviously lower than that in control group and the difference was significant (P < 0. 05). The expression level of DKK1 gene of BMSCs after 3, 6, 12, and 24 h hormone treatment was higher than in control group (P < 0. 05). Conclusion DKK1 plays an important role in early osteogenic and adipogenic differentiation by BMSCs. The hormone affects osteogenic and adipogenic differentiation by regulating the expression of DKK1. [ABSTRACT FROM AUTHOR]