Cell-Free Biomimetic Mineralization Strategies to Regenerate the Enamel Microstructure

The distinct architecture of native enamel gives it its exquisite appearance and excellent intrinsic-extrinsic fracture toughening properties. However, damage to the enamel is irreversible. At present, the clinical treatment for enamel lesion is an invasive method; besides, its limitations, caused by the chemical and physical difference between restorative materials and dental hard tissue, makes the restorative effects far from ideal. With more investigations on the mechanism of amelogenesis, biomimetic mineralization techniques for enamel regeneration have been well developed, which hold great promise as a non-invasive strategy for enamel restoration. This review disclosed the chemical and physical mechanism of amelogenesis; meanwhile, it overviewed and summarized studies involving the regeneration of enamel microstructure in cell-free biomineralization approaches, which could bring new prospects for resolving the challenges in enamel regeneration.

Fracture Toughness of Glass infiltrated (3Y-TZP/Al2O3) Composite

Five different 3 mol.% yttria-tetragonal zirconia polycrystals/alumina (3Y-TZP/Al2O3) -glass specimens have been fabricated by the glass infiltration method. graphite additives were added to the (3Y-TZP/20Wt.%Al2O3) to obtain porous structure. The ATZ (Alumina Toughened Zirconia) skeleton have prepared by the normal compaction method. The specimen had been infiltrated by the glass (18Wt.% lithium hydroxide, 72 wt. % feldspar, and 10Wt.% nano Titanium oxide) at 1185ᵒC. Results showed that the porosity of (3Y-TZP/Al2O3) composite was increased while bulk density decreased with increasing graphite additives. The elastic modulus of (3Y-TZP/Al2O3)-glass was decreased (159-109GPa) with increasing the amount of glass infiltrated. Hardness was constant for all the specimens in value of (5.66 GPa), while increment of materials fracture toughening was due to the increasing the glass weight fraction, the kIc was lied between (0.53-1. 54MPa.m1/2). The glass infiltrated (3Y-TZP/Al2O3) process was successfully increased the fracture toughness by penetrated different amounts of glass into the (3Y-TZP/Al2O3) structure.