Propriedades ópticas e microestrutura de materiais cerâmicos de restauração dentária / Optical properties and microstructure of ceramic materials for dental restoration

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The aim of this work was to advance in the understanding of the mechanisms related to the optical behavior of different ceramic materials as a function of thickness, used for dental restoration, to determine the absorption and scattering coefficients and to correlate them to the microstructural characteristics of each material. The masking ability and the contrast ratio of ceramic material as monolith, bilayer and cemented restoration were also evaluated. For this, four dental ceramics, one porcelain and three glass-infiltrated ceramic composites of InCeram System (alumina/glass, alumina/zirconia/glass, and spinell/glass), besides one dental composite resin used as resinous substrate and one resinous cement for luting. The scattering and absorption coefficients were determined by the Beer-Lambert and Kubelka-Munk models using spectral curves of transmittance and reflectance (with white and black backs) generated in a spectrophotometer in the 300 to 800 nm wavelength range. The microstructure of each material was analyzed by scanning electron microscopy with elemental mapping, X-ray diffraction, and chemical analysis by X-ray fluorescence. The optical behavior of studied materials was affected by the microstructural characteristics and thickness of the material. The values of scattering coefficient, S, of evaluated ceramics were significantly higher than the values of absorption coefficient, K, in the visible range. Equations for the prediction of reflectance and transmittance spectral curves of bilayer and cemented restorations were proposed.

ASSUNTO(S)

microstructure optical properties propriedades ópticas cerâmica ceramics composites microestrutura translucidez. compósitos translucency

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