Caracterização de sistemas cerâmicos aluminizados infiltrados por vidro, por meio de microscopia eletrônica de varredura e resistência à flexão / Characterization of glass-infused alumina-based ceramic systems by means of scanning electron microscopy and flexural strength

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Objective: The purpose of this study was to characterize and compare glass-infused alumina-based ceramic systems by using X-Ray diffraction, scanning electron microscopy (SEM) and flexural strength with a three-point bending test. The ceramic systems used were: (IC)- In-Ceram Alumina (VITA), (VC)- Vitro-Ceram (Angelus) and (AG)- Alglass (Celmat). The crystalline phase of each material was identified through X-Ray diffraction. Ten bar specimens (25X4X1,20.1) of each material were produced following the manufacturers instructions according to ISO 6872. The specimens were taken to a universal testing machine to evaluate flexural strength with a three-point bending test, with a constant load of 500Kgf, crosshead speed of 0,5mm/min and a 15mm distance between supports. The data was submitted to ANOVA (p<0.01) statistical analysis. The fractured specimens underwent SEM analysis in different conditions: sandblasted surface, polished surface, fractured surface and alumina without infiltration. Results: a second crystalline phase of yttrium-stabilized zirconia was identified in VC. Mean values of flexural strength were (MPa): VC (48338.3)= IC (456,629.4) >AG(263,837.8). The micro morphology presented distinct characteristics for each system, with differences in relation to size and distribution of the alumina particles, and the ability of glass infiltration. Fracture analysis showed similar behavior contouring most alumina particles and though others. Conclusions: 1 Vitro-Ceram system presents a second crystalline phase composed of yttrium-stabilized zirconia while Alglass and In-Ceram presented only alumina in their crystalline phase. 2 In-Ceram and Vitro-Ceram systems presented higher flexural strength values than Alglass and statistically similar between them. 3 Alglass system presented several areas where glass infiltration did not occur, which might explain its worse mechanical results. 4 The mode of crack propagation showed to be similar in all three systems, being most frequently observed through the glassy phase and sometimes though an alumina particle.

ASSUNTO(S)

microscopia eletrônica de varredura microstructure cerâmicas scanning electron microscopy aluminium oxide Óxido de alumínio materiais dentários dental materials odontologia microestrutura ceramics cerâmica odontológica

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