How long do silver fillings last?

A Finnish study published in 2001 found that silver fillings, also known as amalgam fillings, last approximately 12 years. They can, however, last much longer.

Amalgam fillings are actually made from a mixture of mercury, silver, zinc and other metals. According to Colgate, a manufacturer of oral health products, amalgam fillings are often used on the back teeth because they are strong and can withstand the forces involved in chewing. Some people are concerned that the mercury content in amalgam fillings is toxic to people; however, Colgate, in conjunction with the Columbia University College of Dental Medicine, says that the mercury levels are not high enough to harm humans and that mercury is only a risk for those who have an allergy to the metal.