Dental casting alloys with a low content of noble metals: physical properties.

Several physical properties such as strength (UTS and fracture and proof stress), modulus of elasticity, strain (elastic and plastic elongation), hardness, and hardening ability were determined for five low-gold alloys and two conventional gold casting alloys (types III and IV). The composition and the structure (pores and defects) of the cast tensile test specimens were also studied. The results showed that alloys with a low content of noble metals could have properties comparable to those of the traditional types III and IV dental gold casting alloys. A marked difference was seen in the plastic elongation (ductility). A great number of defects (pores and oxide inclusions) were also observed, especially in the specimens with a high content of both palladium and silver.