Research on Influence of Metallurgy Factors on the Quality of Metal Components in Metal-Ceramic Prosthetic Restorations

Résumé

The paper summarizes the characteristics of the metal component in the structure of metal-ceramic fixed prostheses and the technological conditions for obtaining it. The paper presents partial results of an experimental study on identifying the causes that favor the generation of defects during the stages of metal melting-casting, defects which in turn may be causes of failure in metal-ceramic restorations. The type of defect identified elucidates both the cause of and effects on the quality of metal-ceramic bond. The study was conducted by light and electron microscopy analysis of samples from two non-noble dental alloys (Co-Cr and NiCr), samples taken from casting network, supply channels and metal crown. Results of the analysis performed with a scanning electron microscope SEM fitted with an energy spectrometer EDAX revealed the presence of oxide inclusions, chemical and structural heterogeneity, alloy solidification shrinkage voids and discontinuities caused by lack of technological discipline in the steps of metallurgical alloy processing, particularly the lack of rigorous assessment of temperature and optimum casting time and exposure of the molten alloy into contact with the atmosphere for a long time.