Patient-friendly definition from the DentistsDirectory.org dental glossary.
Dental amalgam is a filling material composed of roughly 50% elemental mercury bound with a powdered alloy of silver, tin, and copper. Despite containing mercury, amalgam has been used safely for more than 150 years and is considered safe for most adults and children over six by major health organisations including the FDA and WHO. The mercury in amalgam is chemically bound into a stable alloy and behaves very differently from the forms of mercury — elemental liquid or methylmercury — that are associated with health risks.
Amalgam's silver-grey appearance makes it conspicuous in the mouth, and most patients today prefer tooth-coloured composite resin for visible teeth. However, amalgam is exceptionally durable, less moisture-sensitive during placement, and less expensive than composite. For large fillings in back molars that endure heavy chewing forces, many dentists still consider amalgam the most reliable long-term material. The choice between the two is largely clinical — your dentist can explain which suits the specific tooth and situation.
Most dental and health organisations do not recommend removing intact, well-functioning amalgam fillings purely out of concern about mercury content. The removal process itself releases more mercury vapour than leaving a stable filling in place. If an amalgam filling cracks, fails, or needs replacement for legitimate dental reasons, it can be swapped for composite at that time. If you have concerns, discuss them with your dentist — they can review your specific situation and the current evidence with you.