What metal, when added to dental alloy, reduces the gamma phase?

Copper is known to reduce the gamma phase in dental alloys, particularly in silver-based amalgams. The gamma phase refers to the phase of dental amalgam that consists of the alloy with silver, mercury, and tin. This phase is desirable for its strength and durability. However, too much of the gamma phase can lead to brittleness.

By adding copper to the amalgam alloy, the formation of the gamma phase is inhibited, leading to an overall enhancement in the properties of the dental material. Copper promotes the formation of a stronger and more reliable gamma-2 phase that contributes to improved corrosion resistance and reduces the likelihood of fracture in the final restoration. This adjustment helps achieve better mechanical properties and longevity for dental restorations.

The other metals listed, while they do play important roles in dental alloy formulation, do not specifically serve the purpose of reducing the gamma phase to the same effective degree as copper. For example, silver contributes to the strength and clinical performance of the amalgam but does not directly mitigate the gamma phase. Gold and platinum are noble metals used for their excellent biocompatibility and resistance to corrosion, yet they also do not function to reduce gamma phase formation in dental alloys.