Corrosion and strength of dental low-gold brazing materials

Previous studies have shown the clinical feasibility of using three alternatives to dental casting gold alloys Type 3. In the present study brazed specimens of these alternatives were evaluated using a corrosion test and a tensile test according to a proposed ISO Standard (ISO/DIS 9333). Brazed specimens of a high-gold alloy were used as a reference. Furthermore, the microstructure of the brazed joints and the fracture surface characteristics were monitored. The present study revealed that none of the specimens exhibited any visual sign of chemical attack after suspension in the test solution for 7 days. The tensile strength testing resulted in stresses at fracture point that met the requirements of the proposed ISO Standard. All fractures were of the ductile type. Cohesive failures were seen in all specimens except in the reference alloy (JS C) specimens. No clear relationship between fracture surface appearance and tensile strength was found. Distinct demarcation lines between brazing and parent materials were seen. Based on the present results there seems to be no reason to reject the use of brazed constructions made of the alternative alloys Midas, Rajah, and Albacast.