Many factors influence the final result of the prostheses made in Zirconia.
Zirconia blocks on the market, even though they are chemically similar to each other, once processed may have very different mechanical and optical characteristics.
In order to achieve a constant quality level, the manufacturing process of these materials requires a high level of specialisation, starting from preparation and control of the granulates. CO.N.CE.P.T. uses the best Japanese powders for production of semi-finished products in Zirconia.
Each lot of raw materials first goes through strict incoming controls, including:
- chemical composition
- radioactivity test
- granulometric distribution
- shrinkage control
- density control
Zirconia is obtained using chemical processes or through Zirconium Silicate and Baddeleyite electrofusion.
The quality of the granulate considerably influences porosity and possible defects in the sintered product:
- the size of the grains has an effect on performance of the material (nanometric dimensions of the crystals guarantee high mechanical resistance and high resistance to chemical agents)
- distribution of the grains, on the other hand, may influence hydrothermal stability of the sintered material.
- distribution of the additives influences the porosity and therefore translucency of the material. Medical applications need high-quality Zirconia purified with a controlled production process. The method used is hydrolysis of Zirconium sand, following purification with chlorhydric acid and subsequent calcination.
CO.N.CE.P.T. uses Japanese powders produced with this method.