| Teeth defect is a common oral trauma which influences people’s health and beauty. Dental restorative materials developed from the earliest metal to metal-ceramic, recently, it has become possible to fabricate all-ceramic restorations that are highly resistant to fracturing, even when they are used in the posterior region. It must satisfy the physical, chemical and biological compatibility, and fit appearance, convenient condition. The mechanical properties of zirconia (zirconium dioxide, ZrO2) are the highest ever reported for any dental ceramic, which naturally has generated considerable interest. Since it is also characterized by low thermal conductivity, low corrosion potential, good radiographic contrast, and good biologic compatibility it is considered a most promising dental material. In this study, The various types of zirconia commercially available in dentistry are summarized in the first part, together with their toughened mechanism. Different preparation methods and influence factors are concluded from the ceramics engineering literature regarding meta-stable zirconia ceramics to establish a context for understanding current and emerging zirconia based dental ceramics in the second part.(1) Densities of the samples decreases with the increase of content of YAG, while their porosities differs in a wave linear. The sample without adding YAG has a maximum bulk density, apparent density and a minimum porosity (2) Linear shrinkage and volume shrinkage of the sintered samples decrease first and then increase with the increase of content of YAG. When8%YAG is added, Linear shrinkage and volume shrinkage simultaneously achieve minimum of13.1305%and30.1071%, respectively.(3) The Vickers hardness of the samples first increases then decreases with the increase of content of YAG The sample adding2%YAG shows a maximum Vickers hardness(4) The XRD diagrams show that the main phase of the samples is the eutectic melt formed by ZrO2and Y2O3and interestingly form of the eutectic melt differs when YAG content changes. however a visible YAG diffraction peak appears when10%YAG is added to the sample, which indicates that a single YAG phase separates out. |
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