ICB Dental Schoolclassification of ceramics for dental use Dra. Analy Solano Zaragoza Dr. Alfredo Nevárez Rascón
Ceramics Formed from inorganic nature nonmetals, which are obtained by the action of heat and whose final structure is partially or completely crystalline. FIG 1: http://www.google.com.mx/imgres?q= feldespato Main components: • Feldspar (81%) • Quartz (15%) • kaolin (4%) FIG 2: http://www.google.com.mx/imgres?q=cuarzo •Metal oxides FIG 3:http://www.google.com.mx/imgres?q=caolin
Feldspar When broken glass, is responsible for the translucency of porcelain. Serve as a matrix of quartz Melts at 1300 C Tends to react with heat, spent time distorting the piece turn white and shade. FIG 4: http://www.google.com.mx/imgres?q=feldespato
The quartz Constitutes the crystalline face Hardening of the massIs used as filler
The kaolin Increases the ability of the porcelain mold before baking Reacts with the feldspar and gives rigidity Facilitates mixing with water while maintaining the form during drying and firing. FIG 5: Mat Caolin http://www.google.com.mx/imgres?q=caolin
Metal oxides Copper: green Cobalt: blue Titanium: yellow-brown Magnesium lavender blue Zirconium, titanium and tin: opacacidad Iron oxide: brown
Majority of dentalceramics: Have a mixed structure. Formed by a glassy matrix (whose atoms are disordered). Massive particles are more or less large crystallized minerals (whose atoms are arranged uniformly if). FIG 6 http://scielo.isciii.es/pdf/rcoe/v12n4/revision1.pdf
Classification by chemical composition.Feldspathic ceramics:composition. feldspar: translucency Quartz: Crystalline The kaolin: confer plasticity and facilitates the management of the ceramic when not yet sintered.FEATURES: Excellent optical properties Relative fragile. FIG 7 : Mainly used for coating metal http://www.google.com.mx/imgres?q=ceramicas+f or ceramic structures. eldespaticas
PROPERTIES OF feldspathic Greater resistance. Contain the quartz and kaolin Ceramic mass incorporated elements that increase the mechanical strength
Zirconia Ceramics In1965, Hughes joined M cLean and feldspathic porcelain quantities of aluminum oxide by reducing the proportion of quartz. Improved toughness. Exceeds 50% alumina is produced a significant increase in opacity
Composed of highly sintered zirconia (95%), partially stabilized with yttrium oxide (5%). High toughness by the crystalline microstructure Opaque (no glassy phase) Main structure for the core of the restoration. FIG 8: Diferencie http://www.google.com.mx/imgres?q=ceramicas+zirconi o
vitro ceramic Molded to desired shape. Translucent glassy a esthetic. Fragile. Manufacture in glassy state, non- FIG 9: crystalline and is subsequentlyhttp://www.google.com.mx/imgres?q=vitroceramicas converted to the crystalline state by heat treatment.
Classification according to the preparation technique Refractory dye and Condensation Design model of primary impression resistant, to dimensional changes during the heat treatment. porcelain is applied to refractory models to sintered And final corrections. FIG 11: FIG 10: http://www.google.com.mx/imgres?q=mu%C3%http://www.google.com.mx/imgres?q=mu B1%C3%B3n+refractario %C3%B1%C3%B3n+refractario
Replacing a lost wax technique Waxed the pattern which may be the inner cap or full restoration introduced i Fig 12: nto a cylinder andhttp://www.google.com.mx/imgres?q=cera+p%C 3%A9rdida+de+uso+odontologico calcined wax. The ceramic is heated to its melting point Ceramic injection is pushes it into the mold. Fig 13: http://www.google.com.mx/imgres?q=cera
Computer-assisted technologyComposed of 3 phases:scanning, design and machining. Scanning: Recorded three- dimensional by using cameras or sapphire tip. Design: In the computer using specialized software. Machining: milling in a unit that transfers the dimensions of Fig 14: CAD CAM the software and http://metal-engravings.com/metal- engraving/cad-cam-2.html makes the model.
ADVANTAGES DISADVANTAGES• Translucency • Low resisteance to the impact• Chemical Stability • Low tencional resisteance• Thermal expansion • Fragilcoefficient close to the tooth• Biocompatibility • Porosity• High compressive strength and • Contractionabrasion.• Good marginal fit