Properties of 3D Pro Multi-layer Zirconia
An abundance of raw materials can be found in nature for 3D Pro multi-layer zirconia fabrication (about 0.02% of the earth crust) , first of all, the Zirconiumis a transition metal element, and it has a pure crystalline form as a white and ductile metal and it has an amorphous form as a blue-black powder. Even it is the 18-th element in earth crust as spreading, zirconium may be found in nature only combined with silicate oxides or as a free oxide. Zirconia occurs in three phases: monoclinic (m), cubic (c), and tetragonal (t). In pure ZrO2 the monoclinic phase is stable up to 1170°C; but the transformation on cooling appears 100°C below 1170°C. When it cools down it has a volumetric expansion of 3-4%. The cracks may appear as this volume change is sufficient to exceed the elastic limit of the ZrO2. It’s found that 3D pro multi-layer zirconia may remain stable at room temperatures by alloying it with other cubic oxides, called stabilizers. Until now the most used stabilizers to apply biomaterials are CaO, MgO, Y2O3 and CeO2, but only ZrO2-Y2O3 has a self ISO standard for surgical use.
After extensive evaluations of 3D pro multi-layer zirconia’s biocompatibility no local or systemic cytotoxic effects or adverse reactions have been found. The bone response of zirconia in vivo and the inflammation adjacent to zirconia have been shown to be acceptable. Additionally, bacteria and pathogen seem to adhere to zirconia just as much as other materials do.
The most important components of esthetic tooth appearance are: color, fluorescence, opalescence and translucency. One major drawback of full contour zirconia restorations is their opacity.
Lately, colored 3D pro multi-layer zirconia with improved translucency has been developed to closely match colors of human teeth. The flexural strength of this new material is 650-1100 MPa and has a fracture resistance of up to 6 MPam 1/2. These conveniences have made it the 3D pro multi-layer zirconia used more and more for crowns and bridges in lateral applications. For excellent esthetics, it is important to reproduce the translucency of the natural tooth, as it provides an enchanted natural appearance of the prosthetics. Translucency is the substance property that allows the passage of light and its dispersion, and then the objects will not be seen clearly through the material. This property could be defined as a state between transparency and complete opacity. Translucency can be regulated by controlling the absorption, reflection, and transmission of light through the material. The translucency is higher when the reluctance is low and the transmission is high. In a few studies it has been reported that translucency is affected by the layer’s thickness and by the grain size.
The dental restorative materials have different degrees of opacity which provides helpful information for diagnose. The 3D pro multi-layer zirconia can be added in dental filling composite materials because it represents an X-ray opaque agent. In a study conducted in order to assess the X-ray opacity of zirconia, four different materials (pure titanium, NANOZR, Y-TZP, alumina plates) with the same thickness (0,2-2mm) and human tooth were tested against an X-ray agent. It has been found that Y-TZP and NANOZR showed increased opacity.