RGO: Revista Gaúcha de Odontologia ()
Casting failures in denture structures with ferrule attachment to implants: an in vitro test
Abstract
Objective: To use metallographic analysis to evaluate the quality of Co-Cr and Ti CP alloy casting processes routinely used in dentures with ferrule attachment to implants. Methods: An aluminum base simulating a mandible was machined, onto which prototype wax patterns were sculped, consisting of eight bars, measuring 3 mm in diameter with an extension of 6 cm. Four Ti bars were cast by the voltaic arch technique and four of Co-Cr alloy by the gas and air technique using a blowtorch. The eight finished bars were cut, embedded in resin for metallographic analysis, and were then called test specimens (TS). They were analyzed by the naked eye and macrographically at 100 X magnification using electronic microscopy. Results: The analysis result showed that the four titanium castings with the use of voltaic arch presented defects such as voids, cracks, porosities and slags. The four bars cast with Co-Cr by the gas and air technique using the blowtorch were shown to be satisfactory, even with the presence of dendritic microstructure. Conclusion: It was concluded that the lack of quality observed in these laboratory processes is due to both the low learning curve of the technicians and possible defects in the equipment used.
