No abstract

Dental porcelain fused to metals (PFM) is one of the most widely applied restoration material, because of its excellent esthetics, biocompatibility and wear resistance [1, 2]. In the literature of specialty (dentistry) there is not made a clear distinction between porcelain and ceramic, while referring to ceramics as being all these materials derived from mixtures of metallic oxides, being in opposition with metal alloys [3-5]. The aim of this study was to obtain and characterize dental porcelains, dentine type, in the following oxide system: SiO2-K2O-Al2O3-Na2O-B2O3-MgOCaO, reinforced with nanometric particles of monoclinic zirconia. The method selected for the preparation of the porcelain powders is through solid-state reactions.

One of the major objectives of dental medicine that should be mentioned is the use of increasingly powerful materials of coronary restoration, as regards to their biomechanical, biofunctional and bio‐prophylactic characteristics. Nanotechnologies often provide the techniques used in the field of filler particles. Solutions to obtain a first generation of composite material with nanoparticles with dimensions between 5–75 nm have been successfully tested. It has been important to also obtain conglomerates with dimensions between 0.2–0.6 mm, that should be present. The present paper describes the preparation through sol–gel methods and aims to characterize ceramic nanoparticles used as filling inorganic materials for dental composites for esthetical restorations. We have obtained nanometric powders of silica and zirconia/silica. Thermal treatments were conducted at temperatures between 700 °C and 1200 °C for 2 hours. The powders had been analyzed as regards to their mineralogical composition, granulometric distribution and microstructure. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Cordierite based ceramic porous materials are very promising for filtering applications, due to their low thermal expansion coefficient, but also due to high chemical stability and good mechanical resistance. The cordierite powders were obtained through the co-precipitation method, while the porous ceramics were prepared by mixing the ceramic powder with an organic compound, which will burn during consequent thermal treatments, leading to an open pore ceramic web. Samples with different proportions of glucose were thermally treated at temperatures between 1050 and 1400oC. The samples were analyzed in what it concerns the mineralogical composition, open porosity and pores distribution, compressive strength and microstructure.