Study Of Nano-sized Zirconia Particles Composited Zirconia Ceramic Toughed By Alumnia Fibers

Esthetic demands of patients and clinicians have lead to thedevelopment of all-ceramic restorations. All-ceramic is the mostpromising dental material in the future. But the major drawbacks ofbrittleness i.e. poor fracture toughness of ceramic restrict it'sapplications as ideal dental material. A vast amount of research hasbeen conducted in the last few decades to improve the toughness ofceramics. Among the various monolithic ceramics, yttria stabilizedtetragonal zirconia polycrystalline ceramics(Y-TZP) have beenregarded as a potential dental ceramic. The high toughness of Y-TZPceramics is attributed to stress induced transformation of thetetragonal(t-ZrO2) phase to the monoclinic(m-ZrO2) phase in the stressfield of propagating cracks, a phenomenon known as 'transformationToughening'.Nanoscale ceramics show superior properties to conventionalceramics. The quality of the sintered ceramic depends on theproperties of the initial powder, such as sinterability, purity,homogeneity, dispersal and particle size. Monodispersed nanoscalezirconia powder is a favorite material in the preparation of advancedceramic with uniform nanostructure and properties. There are so manymethods to synthesis nano-sized yttria stabilized zirconia powder.Precipitation of inorganic salt solutions provides an economical routefor the production of large quantities of zirconia nanoparticles becausethis approach makes use of inexpensive inorganic salts as a startingmaterial. But there are so many coagulates in the prepared zirconiaparticles by conventional precipitation method. We preparednano-sized zirconia particles with good dispersal by quickprecipitation method under supersonic conditions.Toughening brittle ceramics is a major research object. One wayis to incorporate fibrous into ceramic to hinder the propagation ofcracks. There are several literatures reporting the effects of alμminaparticles on the mechanical properties of 3Y-TZP ceramic. But thereis no report about the role of alμmina on 3Y-TZP ceramic. In ourresearch, alμmina fiber was incorporated into 3Y-TZP ceramicthrough milling method. Result indicates that alμmina incorporatedinto 3Y-TZP ceramic can enhance the bending strength of 3Y-TZPceramic while decreasing the density of the sintered ceramic and alμmina fibrous can well combine with zirconia crystal.