Evaluation of Soldered Joints of Two Base Metal Ceramic Alloys: Supercast and Minalux

Background: Different soldering techniques have a variety of applications in dentistry. One of the most important uses of soldering is to join multiple-unit fixed partial dentures together. In this Study, two base metal alloys (Supercast and Minalux) were soldered  and their tensile, compressive and flexural strengths were measured and compared to each other. Materials and methods: In this in-vitro study, an aluminum pattern was made by a milling machine according to ASTM (American Society for Testing Material). Eighteen acrylic resin Patterns were duplicated by flasking using putty indices according to the original aluminum pattern. Acrylic resin patterns were divided into two groups of nine and each group was cast with two different alloys named Supercast and Minalux. All eighteen metal rods were separated by 0.008-inch disc and soldered with Vera-solder by means of gas-oxygen torch. Three patterns of each alloy were selected for each of the compression, tensile and flexural tests. Tensile strength was measured by Instron a universal machine and flexural and compression strengths were measured by Dartec machine. Statistical analysis was done by Mann - Whitney test. Results: The mean tensile, flexural and compressive strengths for supercast alloy was 347.6, 44.01 and 1014.8MPa respectively and the mean for tensile, flexural and compressive strengths for Minalux alloy was 350.03, 51.70 and 938.17 MPa respectively. Statistical analysis showed no significant differences between the two alloys in all the three mentioned tests. (p>0.05) Conclusion: Tensile, flexural and compressive strengths of the two soldered alloys, Minalux and supercast, showed no significant differences. Minalux is an alloy manufactured in Iran with the advantage of not including Beryllium, a cariogenic element, as one of the ingredients of the alloy; therefore, it is suggested that Minalux be used instead of supercast in soldering procedures in fixed prosthodontics.