Caracterização da interface entre cilindros de pilares de implante e ligas fundidas de Co-Cr com diferentes técnicas de fundição

• Autor(a) principal: Rodrigues Neto, Dimas João
• Data de Publicação: 2017
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da PUC_RS
• Texto Completo: http://tede2.pucrs.br/tede2/handle/tede/7369
• topic: Fundição Odontológica; Ligas Odontológicas; Co-Cr Ligas; Implantes Dentários; Pilares Protéticos; CIENCIAS DA SAUDE::ODONTOLOGIA

For a satisfactory clinical performance, pre-fabricated Co-Cr cylinders must have metallurgical compatibility to Co-Cr based cast alloys. A uniform interface with adequate union and resistance, with absence of interfacial reaction and porosities must be obtained. The present in vitro study aimed to evaluate the metallurgical compatibility at the interface between pre-fabricated Co-Cr cylinders and alloys for Co-Cr compound casting applying different casting techniques. In manuscript 2 the metallurgical compatibility and the interface between implant and alloy cylinders were evaluated for Co-Cr casting with different melting temperatures. Methodology: Three pre-fabricated Co-Cr prosthetic implant cylinders (Neodent, Pi-Brånemark, Dentium) were subjected to casting with Co-Cr alloy using different casting techniques (Flame Torch, Induction / Centrifugation, Induction / Vacuum). Optical microscopy and Scanning Electron Microscopy (SEM) were used to characterize the obtained microstructures. The elementary composition of the cylinders and diffusion characteristics in the interfacial region between molten alloy and cylinder were determined by dispersive energy spectroscopy (EDS). Vickers microhardness was measured at interface, cylinder and cast alloy. The ANOVA and Tukey test were used to evaluate microhardness values. In the manuscript 2 cylinders based on Co-Cr were overfused with alloys with different melting temperatures and all microstructural analysis and microhardness tests were performed. Results: In the manuscript 1 a union between pre-fabricated cylinders and Co-Cr based alloys was observed microstructurally. An ideal interface was obtained with absence of interfacial reaction or significant porosities with the casting with the induction techniques (centrifugation and vacuum), but excess of porosities and failures were observed with the Torch casting technique. In manuscript 2 a microstructural bond was observed between the alloys and the cylinder, evidencing that both high melt alloy and low melt alloy presented compatibility with the Co-Cr cylinder. Microhardness values, both in manuscript 1 and in manuscript 2 also proved to form a satisfactory interface. Conclusions: It was concluded from manuscript 1 and 2 that both high and low melt temperature Co-Cr have metallurgical compatibility to pre-fabricated Co-Cr cylinders, showing an ideal interface. However, the technique of casting applied is relevant, and the torch technique has been shown to be less indicated due to the lack of standardization of the obtained results.