Tensile Strength Of Solder Joints Research Articles

M ost casting and soldering techniques currently used in dentistry were developed specifically for dental gold alloys. The newer base metal or nonnoble alloys have higher melting ranges and other characteristics that differ from those of gold alloys. Practical application and routine use of these alloys have drawn varied and often conflicting reports from dentists and laboratories concerning their abilities to be cast and soldered accurately. Cast crowns and fixed partial dentures are soldered either before or after the application of porcelain. These two operations are called preceramic soldering and postceramic soldering, respectively. The postsolder must melt below the fusing temperature of the porcelain. If a direct flame is placed on the porcelain, it can cause porcelain fracture. To avoid this damage, the operation is performed in an oven. In both techniques, it is of interest to determine the comparative tensile strengths of solder joints of commercially available nonnoble alloys and solders used according to manufacturers’ directions. Determination of the reliability and reproducibility of such solder joints is also of importance, as is the determination of the site of fracture (solder, parent metal, or interface of the two). In addition, technique recommendations to improve the strength and reliability of nonnoble solder joints are of value to the dental profession. Sloan et al.’ reported soldering various combinations of alloys with their recommended solders with noble, “semiprecious,” and nonnoble metals. When base alloys were involved, the resultant fracture was most often at the interface of the solder and the parent metal. To date,

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