Zirconia Ceramics 5Y-TZP
If the content of yttrium oxide as a stabilizer (5 mol %) is appropriately increased for zirconia ceramics, cubic zirconia crystals will become the main crystal phase of zirconia materials, so the semi-permeability is very good, so it is called "super-permeable oxide" zirconium". At the same time, due to its low content of tetragonal zirconia crystals, lack of phase transformation and toughening mechanism, low strength and toughness, less phase transformation occurs in the entire temperature range of sintering and cooling, and the material has almost no volume change, so some people will It is called "fully stabilized zirconia".
The ultra-transparent zirconia all-ceramic material launched in 2015 uses 5 mol% (9-12 wt%) of yttrium oxide as a stabilizer (5Y-TZP), and the alumina content is below 0.05 wt%, or almost no addition, cubic phase oxidation The content of zirconium crystal is greater than 70%, and the content of tetragonal phase is less than 30%. The material's semipermeability is very high, reaching ultra-transparent performance (research has shown that the TP value of ultra-permeable zirconia with a thickness of 1.0 mm reaches more than 35), and the general bending strength About 500~600 MPa, fracture toughness 2.2~2.7 MPa.m1/2.
In the case of high transparency and super transparency, and the appearance of different levels of polymer dispersion, dispersed all-ceramic materials of different colors have emerged. The light-transmitting oxidation separation material can simplify the pollination operation of the technicians, and at the same time make the all-ceramic crown possess and the light-transmitting gradual effect, which can better meet the full aesthetic requirements of the dyeing and dyeing all-ceramic crown in the aesthetic area.
The color gradation is clear and the color gradation is intricate, the color gradation is clear, the level is clear, the level is clear, and the level is clear. Wrong (4Y zirconium oxide) and super transparent zirconium (5Y zirconium oxide).
Disadvantages of gradual color split-layer all-ceramic materials: During CAD design, the placement of the crown in different ceramic blocks will affect the aesthetic effect of the crown; the detection of the interface between the color layers and the ceramic layers will affect the oxide fault Issues such as the strength of all-ceramic crowns require further research and observation.
Gradient color dispersion is mainly used for the restoration of heterochromatic all-ceramic crowns in the green area of the anterior teeth.
The semi-permeability of the fourth-generation zirconia all-ceramic material is almost similar to that of magnesium disilicate ceramics, and the aesthetics is very good, but the strength is super-heated ceramics. It is mostly used for anterior single crown and veneer restorations.