Re: Found out that my new filling was Amalgam!

Amalgam (also called silver filling)

See also: Dental amalgam controversy

Amalgam fillings are an alloy of mercury (from 43% to 54%) along with silver, tin, zinc and copper. Due to the known toxicity of mercury, the main component of amalgam fillings, there is an ongoing dental amalgam controversy on the use of this filling material.

After widespread adoption and wildly varying standards, the multitude of formulas for making amalgams were standardised into the gamma-2-phase amalgam formula in 1895.

The gamma-2-phase amalgams contain approximately equal parts 50% of liquid mercury and 50% of an alloy powder containing:

• > 65% silver (Ag)
• < 29% tin (Sn)
• < 6% copper (Cu)
• < 2% zinc (Zn)
• < 3% mercury (Hg)

Around 1970, the ingredients changed for manufacturing cost reasons to the new non-gamma-2 form. The gamma-2-free amalgams (sometimes referred to as "high-copper" amalgams) contain approximately equal parts 50% of liquid mercury and 50% of an alloy powder containing:

• > 40% silver (Ag)
• < 32% tin (Sn)
• < 30% copper (Cu)
• < 2% zinc (Zn)
• < 3% mercury (Hg)

The possible difference in toxicology between the two has not been studied conclusively. Amalgams continue to be used today because they are hard, durable and inexpensive.