Caracterização de sistemas cerâmicos aluminizados infiltrados por vidro

• Autor(a) principal: Silva, Thiago Moitrel Pequeno da
• Data de Publicação: 2013
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/14056
• topic: Ceramic; Fluorescence; Granulometric; In-Ceram; Metal-free; Cerâmica; Fluorescência; Granulometria; In-Ceram; Metal-free; CNPQ::CIENCIAS DA SAUDE::ODONTOLOGIA

This work took place because of the very few information available about ceramic systems widely used at the dental market. The aim of this study was to characterize and analyze the microstructure, composition and mechanical properties of these materials, testing the compatibility of the systems and the assumption that they all have excellent properties. This study characterized and compared the In-Ceram ceramic systems (Vita Zahnfabrik, Bad Säckingen, Germany), Vitro-Ceram (Angelus, Londrina, Brazil) and Alglass (EDG, São Carlos, Brazil) using the following methods: 1 - Analysis of the vitreous phase by X-ray fluorescence; 2 - Analysis of the particle size of the crystalline phase and the vitreous phase; 3 - Evaluation of resistance at the equibiaxial test; 4 - Analysis of the microstructure by scanning electron microscopy (SEM). The RX fluorescence analysis of the glass phase of the three systems showed that their compositions in relation to their main elements, such as lanthanum (La2O3), aluminum (Al2O3) and silicon (SiO2), are similar, differing in the additives which serves to give color and other settings. According to the results, it can be seen that Vitro-Ceram and In-Ceram have similar particle size, and the alumina from the Alglass system showed a more heterogeneous composition with grains larger than 10 µm and a large amount of grains below 0,6 µm. This allows a larger agglomeration of the grains, forming a more compact ceramic structure after pre-sintering, which creates pores of small diameter and without interconnection. This fact undermines vitreous infiltration in the final ceramic composite, which can result in a material with more defects and a reduction of the mechanical properties. Also, the glass was also characterized, which showed no similarity between the three systems, but its high grain facilitates its handling and the overlap over the structure of pre-sintered alumina, not interfering in their infiltration. In the bending test, the groups composed by the alumina present at the In-Ceram system had the highest average, being statistically different from the other groups. Despite showing higher values of resistance, the groups with the alumina present at the Vitro-Ceram system did not statistically differ from the groups of Alglass system s alumina. The infiltration of different glasses in the same alumina did not statistically influenced the mechanical strength of the materials. However, groups using the glassy phase of Alglass showed higher resistance. In the fractographic validation analysis none of the samples had to be discarded because of its fracture failure, in which 70% of the specimens of the three studied ceramic systems had low-power fractures, 30% suffered fractures of average strength and no sample suffered a high-strength fracture. Lower values found for the Vitro-Ceram ceramic system can be justified by the presence of much larger blisters and pores inside the material, thus, this feature translates into loss of mechanical strength of the ceramic. As much as all ceramic systems are suitable for clinical use, the In-Ceram material stands out for its features and reliability.