A Study on Dental Soldering. (Part XI). Tensile Strength of Presoldered Joints of Gold, Palladium and Nickel-Chromium Alloy Soldered by Forcused Energy of Infrared.

The purpose of this study was to compare the difference of the tensile strength of presoldered joints between the infrared soldering and the torch soldering with regard to Au-Pt, Pd-Cu and Ni-Cr alloy.The conclusions were obtained as follows:1. No significant difference of the tensile strength of presoldered joints were obtained between the infrared soldering and the torch soldering respectively in Au-Pt, Pd-Cu alloy. In Ni-Cr alloy, the tensile strength of presoldered joints presoldered by the infrared soldering was statistically stronger than the torch soldering (α=0.05). However, the revised tensile strength of both soldering in the alloy were similar.It was suggested that porosity might be one of critical factors on the tensile strength of presoldered joints.2. Comparing porosity ratio of presoldered joints between the infrared soldering and the torch soldering, no significant difference were obtained respectively in Au-Pt and Pd-Cu alloy. In Ni-Cr alloy, porosity ratio of the infrared soldering was one-third as much as the torch soldering.It had to be recomended that the infrared soldering should be employed when Ni-Cr alloy was used.