Which element increases amalgam strength and allows setting expansion?

Which element increases amalgam strength and allows setting expansion?

• A. Silver
• B. Copper
• C. Tin
• D. Zinc

Answer: (A)

The strength of dental amalgam comes from the phases that form when the mercury interacts with the alloy. Silver helps create the strong gamma-1 (Ag-Hg) and the matrix phase (gamma, mainly Ag-Sn) that bear most of the load in the set material. By promoting these stronger phases, a silver-rich alloy increases overall strength and reduces the weak, tin-mercury gamma-2 phase that would otherwise compromise integrity. At the same time, this balance allows the cementing expansion that occurs during setting to occur in a controlled way, aiding marginal seals without compromising durability. In this context, silver is the element most closely associated with enhancing strength while permitting the intended setting expansion.

The strength of dental amalgam comes from the phases that form when the mercury interacts with the alloy. Silver helps create the strong gamma-1 (Ag-Hg) and the matrix phase (gamma, mainly Ag-Sn) that bear most of the load in the set material. By promoting these stronger phases, a silver-rich alloy increases overall strength and reduces the weak, tin-mercury gamma-2 phase that would otherwise compromise integrity. At the same time, this balance allows the cementing expansion that occurs during setting to occur in a controlled way, aiding marginal seals without compromising durability. In this context, silver is the element most closely associated with enhancing strength while permitting the intended setting expansion.