This bonding protects and increases the overall strength of the tooth being restored, which a silver filling cannot do. The choice made depends on balancing appearances, longevity, strength of the tooth involved, and cost. Silver has been used as a filling for teeth for almost one hundred years. While there is mercury present in the silver filling material, called amalgam, in the past century there has been no evidence showing that silver fillings are harmful to patients. Just like the cyanide in crazy glue where the cyanide is compounded with other ingredients that make it harmless, the mercury in amalgam is compounded with silver, tin, and copper to make it just as harmless.
Silver is a strong filling agent lasting longer than comparable composite fillings.
The main argument against the use of silver fillings is esthetic. Depending on where the tooth to be filled is located in the mouth, the appearance of a silver filling may be less attractive than a more natural-looking composite filling. Also, for some patients the feeling of metal in the mouth may be displeasing. Over time, like most metals, silver fillings will eventually corrode and even leak causing decay to reoccur underneath the fillings. This compound makes a composite filling more resistant to wear, color adjustable, and easier to polish.