SYNTHESIS AND CERAMIC PROCESSING OF ALUMINA AND ZIRCONIA BASED COMPOSITES INFILTRATED WITH GLASS PHASE FOR DENTAL APPLICATIONS / Síntese e processamento de compósitos  á base de alumina e zircônia com infiltração de fase vítrea para aplicações  odontológicas

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The interest for the use of ceramic materials for dental applications started due to the good aesthetic appearance promoted by the similarity to natural teeth. However, the fragility of traditional ceramics was a limitation for their use in stress conditions. The development of alumina and zirconia based materials, that associate aesthetic results, biocompatibility and good mechanical behaviour, makes possible the employment of ceramics for fabrication of dental restorations. The incorporation of vitreous phase in these ceramics is an alternative to minimize the ceramic retraction and to improve the adhesion to resinbased cements, necessary for the union of ceramic frameworks to the remaining dental structure. In the dentistry field, alumina and zirconia ceramic infiltrated with glassy phase are represented commercially by the In-Ceram® systems. Considering that the improvement of powders synthesis routes and of techniques of ceramic processing contributes for good performance of these materials, the goal of the present work is the study of processing conditions of alumina and/or 3 mol% yttria-stabilized zirconia ceramics infiltrated with aluminum borosilicate lanthanum glass. The powders, synthesized by hydroxide coprecipitation route, were pressed by uniaxial compaction and pre-sintered at temperature range between 950 and 1650oC in order to obtain porous ceramics bodies. Vitreous phase incorporation was performed by impregnation of aluminum borosilicate lanthanum powder, also prepared in this work, followed by heat treatment between 1200 and 1400oC .Ceramic powders were characterized by thermogravimetry, X-ray diffraction, scanning and transmission electron microscopy, gaseous adsorption (BET) and laser diffraction. Sinterability of alumina and /or stabilized zirconia green pellets was evaluated by dilatometry. Pre-sintered ceramics were characterized by apparent density measurements (Archimedes method), X-ray diffraction and scanning electron microscopy. Vickers impression tests and citotoxicity essays were performed after glass phase incorporation. Considering the structural integrity of samples, homogeneity of microstrutures, high fracture toughness values (3.6 4.9 MPa.m1/2) and no citotoxity effects, it was verified that alumina based ceramics, prepared from coprecipitated powders, are adequate for production of dental frameworks infiltrated by vitreous phase.

ASSUNTO(S)

prótese odontológica infiltração vítrea metal-free. prótese odontológica alumina infiltração vítrea alumina metal-free zircônia zircônia

ACESSO AO ARTIGO

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