For generations, dentists placed silver-colored fillings in millions of teeth. But behind their familiar appearance lies a controversial ingredient: mercury. Now that Europe has largely phased them out, Americans are asking an uncomfortable question—why are they still permitted in the United States?

not made entirely of silver.

Dental amalgam is a mixture of metals, typically containing:

Approximately 50% elemental mercury by weight.
Silver, which contributes strength and durability.
Tin, which helps influence the material’s properties.
Copper, which improves strength and corrosion resistance.
Sometimes zinc, depending on the formulation.

Mercury serves a specific purpose: it binds the other metals together, allowing dentists to shape the mixture before it hardens into a strong restoration.

This combination made amalgam one of the most widely used filling materials in dental history.

But it also created a lasting controversy.

Mercury is a recognized toxic substance. Although the