HESI General Chairside Assisting Practice Exam

Which component of amalgam alloy helps reduce discoloration?

1. Zinc

2. Silver

3. Mercury

4. Copper

The correct answer is: Copper

The presence of copper in amalgam alloy plays a significant role in reducing discoloration. Copper not only enhances the mechanical properties of the amalgam but also contributes to a more stable, less tarnishable material. When copper is added to dental amalgams, it helps create a phase that is less prone to corrosion and oxidation compared to traditional amalgams that do not contain copper, particularly those that only use silver and mercury. This reduced susceptibility to oxidation results in a more aesthetically pleasing amalgam restoration, as it maintains its color and resists the dulling effects that can accompany exposure to oral fluids and food particles. Zinc, silver, and mercury, while essential components of the amalgam mixture, do not offer the same benefits regarding discoloration. Zinc can help prevent oxidation in some formulations but can produce other issues, such as expansion. Silver provides strength and enhances the overall quality of the amalgam but does not directly affect discoloration. Mercury is necessary for the amalgamation process but does not have properties that help in preventing discoloration either.