Which component of amalgam increases strength and expansion?

Which component of amalgam increases strength and expansion?

• A. Copper
• B. Silver
• C. Gold
• D. Lead

Answer: (A)

Copper in amalgam alloys changes the set reaction by tying up tin and preventing the formation of the weak tin–mercury phase. This shifts the reaction toward copper–tin intermetallics that are strong and corrosion-resistant. With this change, the material cures to a tougher structure, showing higher strength and better dimensional stability, with less creep and marginal leakage. In contrast, the other metals don’t provide the same beneficial phase balance: gold and silver are more inert participants, and lead introduces toxicity and poorer properties. So, adding copper enhances strength and improves the dimensional behavior of the set amalgam.

Copper in amalgam alloys changes the set reaction by tying up tin and preventing the formation of the weak tin–mercury phase. This shifts the reaction toward copper–tin intermetallics that are strong and corrosion-resistant. With this change, the material cures to a tougher structure, showing higher strength and better dimensional stability, with less creep and marginal leakage. In contrast, the other metals don’t provide the same beneficial phase balance: gold and silver are more inert participants, and lead introduces toxicity and poorer properties. So, adding copper enhances strength and improves the dimensional behavior of the set amalgam.