Why is it that we need to use mercury for amalgam fillings?

Binder: Because the resulting chemical compound binds the different metals in silver fillings together. There are still no studies that show them to be detrimental and they are cost friendly for the service that they give.

To bind the alloy: Half of a dental amalgam filling is mercury and the other half is a powdered alloy of silver, tin, and copper. Mercury is used to bind the alloy particles together to provide a strong, and durable material.