Influence of different types of acetylene-oxygen flames on the carbon content of a dental Co-Cr alloy.

The influence of different acetylene-oxygen flames on the carbon content of a dental cobalt-chromium alloy, type A, was studied under standardised casting conditions. The alloy was cast, both immediately after the formation of the Bull's eye and after prolonging the melting time. Further, the effect of re-casting, varying the amount of alloy casted and using different sections of the same acetylene-oxygen flame when melting was studied. The results showed on the one hand that the chemical character of the section of flame used and not the gasmixture as such determined the carbon content of the casting, and on the other that the acetylene-oxygen flames can increase but not decrease the carbon content in the casting. Increase of the carbon content of a cobalt-chromium alloy causes a considerable change in its microstructure.