Restauração metalocerâmica: um estudo comparativo da compatibilidade térmica de ligas Ni-Cr e porcelanas odontológicas

Abstract

One of the technological applications where a metal-ceramic compatibility is necessary, is the dental restoration build-up, known as metaloceramic. In this case, a porcelain is fused on a metal substructure to have a dental prosthesis. The basic requirement for the success of this dental restoration is the adjustment of the thermal expansion coefficient of each material to achieve a compression stress on the ceramic layer. This study was carried out to obtain the thermal expansion curves for Ni-Cr alloy and dental porcelains to analyze the thermal compatibility between metal-ceramic. Simulating the introduction of a product on the market, an experimental Ni-Cr alloy was developed and compared with another largely commercialized Ni-Cr alloy. By analyzing these data, it was possible to verify the compatibility of each metal-ceramic pair regarding the thermal expansion behavior, using the Yamamoto’s (1985) methods. In conclusion, the results of the new experimental alloy showed values that can include it as one more option inside the Ni-Cr alloy family used in metaloceramic dental restoration. The results clearly indicate that the methodology and equipment applied to this work are adequate to proceed a comparative study on thermal compatibility of Ni-Cr alloys and dental porcelains.