What is a benefit of high copper content in some amalgam brands?

High copper content in some amalgam brands is associated with decreased creep. Creep refers to the tendency of a material to deform permanently under the influence of mechanical stresses, which can occur when amalgam is subjected to masticatory forces over time.

Amalgams with higher copper content tend to have a more favorable microstructure. They typically contain fewer gamma II phase particles, which are more susceptible to corrosion and creep. By reducing the proportion of these weaker components, high copper amalgams enhance the overall strength and stability of the material. As a result, they are more resistant to deformation and maintain their integrity under functional loads, contributing to a longer-lasting restoration.

The other options highlight properties that are not benefits associated with high copper content. Increased gamma II phase and increased corrosion are undesirable characteristics, while decreased delayed expansion refers to the prevention of dimensional changes that can occur in amalgam due to moisture or excess zinc, which isn't directly related to the benefits of high copper content. Thus, the primary advantage of high copper amalgams is their ability to reduce creep, which directly translates into improved clinical performance.