Comparison of flexure resistance between two rod and paste solders in base metal alloy

Soldering is used in fixed prosthodontics, for different purposes such as connecting separate parts of the bridge, recontouring proximal and occlusal contacts and repairing casting voids. The aim of this study was to compare the flexural resistance of two rod and paste solders used in base metal alloys. Thirty rectangular specimens (1×4×30 mm) were made using super cast base alloy. The samples were sectioned into two equal parts and were placed in a soldering investment as pairs with 0.3 mm gaps between them. They were divided into 2 groups and soldered with rod solder in one group and paste solder in the other. The samples were subjected to a flexure test on a Universal Testing Machine. Statistically analysis was performed using F- and t-tests. The minimum and maximum flexural resistance was 107.2N and 301.2N for the rod- and 62.8N and 109.3N for the paste solders, respectively. The mean flexural resistance was 196.5N in the rod solder group and 89.8N in the paste solder group. A significant difference in flexural resistance was observed between the two study groups (P=0.001). The results of this study indicated that flexural resistance of the rod solders was significantly higher than the paste solders.