Resumo

MOLINA, Anthony et al. METALLOGRAPHIC CHARACTERIZATION OF OVERDENTURE BARS MANUFACTURED BY OVERCASTING ABUTMENTS FOR DENTAL IMPLANTS. Rev Fac Odontol Univ Antioq [online]. 2013, vol.25, n.1, pp.26-43. ISSN 0121-246X.

INTRODUCTION: the difficulty in handling conventional dentures in fully edentulous patients may be improved by using anchorage systems on dental implants for overdentures. The goal of this study was to conduct a metallographic characterization of a system of bars for overdentures by overcasting a metal base alloy on prefabricated titanium alloy abutments. METHODS: using a design of overdenture bars, made with an addition of prefabricated titanium (Ti-6Al-4V) and a metal base alloy (Ni65-Cr22%,5%-Mo9,5%), a metallographic characterization of the overcasting process was performed by analyzing its influence on the microstructure of two commercial dental alloys: Ti-6Al-4V and Ni65%-Cr22,5%- Mo9,5% (Wiron 99) using scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), light microscopy analysis (LM), and stereomicroscopy (EM). RESULTS: the findings suggest that during overcasting a chemical bonding occurs due to the presence of oxygen between these two alloys, showing heterogeneous dendritic structures along the samples due to thickness irregularities on the bars and to precipitations of their molybdenum borders. CONCLUSIONS: from a metallographic perspective, the chemical bonding of the two alloys (Ni65-Cr22%, 5%-Mo9, 5% and Ti-6Al-4V) after overcasting suggests that overcasting between these two alloys is a viable option for placing structures on implant abutments.

Palavras-chave : dental implants; overdentures; metallography; microscopy; segregation.

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