What is the primary benefit of using high-copper dental amalgam compared to traditional low-copper formulations?

The primary benefit of using high-copper dental amalgam compared to traditional low-copper formulations is its increased resistance to marginal breakdown due to lower creep.

- Traditional low-copper amalgams contain a significant amount of the phase called gamma-2 (Sn-Hg), which is prone to corrosion and mechanical degradation over time.
- This phase contributes to increased creep, a time-dependent deformation under stress, which ultimately leads to marginal breakdown, marginal leakage, and reduced longevity of the restoration.

- High-copper amalgams were developed to eliminate or significantly reduce the gamma-2 phase by increasing the copper content (typically above 12%).
- The excess copper reacts with tin to form a more stable Cu-Sn phase, which has superior mechanical properties.
- As a result, high-copper amalgams exhibit much lower creep values, enhanced strength, and better corrosion resistance compared to low-copper amalgams.

This improved marginal integrity reduces the incidence of marginal breakdown, enhancing the durability and clinical success of dental restorations.

- Option 2 is incorrect because amalgam restorations are metallic and not designed for esthetics or enhanced color matching.
- Option 3 is incorrect as the setting time is not significantly improved with high-copper formulations.
- Option 4 is incorrect because amalgam does not release fluoride.

In summary, the key advantage of high-copper dental amalgam is its improved marginal durability due to reduced creep and elimination of the gamma-2 phase.

Reference: Mark, T. and Smith, J. *Dental Materials*, Vol. 3, Chapter 7, pp. 225-230