The fillings referred to as "silver" are actually a mixture of
silver, tin, copper, and mercury, and are more properly called
amalgam fillings. The silver, tin, and copper are provided in a
powder form by various manufacturers, with silver being the
major constituent (40 to 70 percent), and tin and copper
constituting 4 to 33 percent each, depending on the
manufacturer. This powder is then mixed rapidly with mercury in
a special machine, usually by the dental assistant, yielding a
liquid that is from 50 to 60 percent mercury. The filling
material is then placed in the tooth and smoothed with various
dental tools. |DID YOU KNOW . . . Mercury (Hg), sometimes known
as quicksilver, is named for the speedy Roman god who served as
messenger for the other gods. The silver-white chemical is the
only common metal that is a liquid at room temperature. It is
used in thermometers, barometers, and some batteries, as well as
in dental amalgams. Since the 1970s, there has been controversy
in the dental profession regarding