Ceramics are used for making crowns, bridges, artificial denture teeth, and implants. Generally, allceramic restorations have been confined to the anterior region until recently with the introduction of monolithic lithium dioxide and zirconia restorations. Dental ceramics for ceramicmetal restorations belong to this compositional range and are commonly referred to as dental porcelains. Veneering porcelains typically consist of glass or crystalline phase of aluminum oxide. Denry 8 discovered that in the vicinity of leucite crystals in porcelain there were microcracks whose origin they ascribed to the difference between thermal expansion of leucite and that of the glass matrix. The preparation of dental glassceramic composites with. Leucite glass ceramics are made by the controlled crystallization of leucite in the same ternary phase system sio 2 al 2 o 3 k 2 o as the conventional feldspathic porcelains, but with a greater content k 2 o of at least 12 wt. The key variables in the design of a medical glassceramic are glass composition, phase assemblage, and the crystalline microstructure, which are the. Rock salt structure two interpenetrating fcc lattices nacl, mgo, lif, feo have this crystal structure introduction to materials science, chapter, structure and properties of ceramics university of tennessee, dept.
Conventionally, leucite crystallises incongruently from a precursor containing potassia, alumina, silica and other. Dental porcelain is used as veneers on metal frameworks metal ceramic restoration and on minimally prepared anterior teeth, and for denture teeth. Leucite porcelain fused to metals for dental restoration ceramics silikaty 53 3 225230 2009 227 crystallisation the glassceramics used in dentistry are produced from highly viscous alkali aluminosilicate glasses 8. Part ii recent advances in dental ceramics srinivasa raju datla 1, ram a krishna alla 2, venkata ramaraju alluri 1, jithendra babu p 1, anusha konakanchi 3. The earlier ceramics are very fragile and can not with stand the high tensile forces. To show that hydrothermally synthesized leucite powder is a suitable material for the preparation of leucite dental ceramics, following research was undertaken.