Dental amalgam is a silver-coloured filling material. It is made of mercury, silver, copper, zinc and tin. It has been used as a filling material to fix teeth for over 150 years and has one of the longest life-expectancies of dental filling materials. Over time, it has also been the subject of extensive research.
Amalgam was commonly used by dentists in the 1990’s. These days it is used less commonly with some dental practices no longer using it at all. Amalgam is strong and long-lasting, however more tooth structure needs to be cut away to fix the tooth with an amalgam filling. This is because the amalgam is held in place by the shape of the cavity that is cut into the tooth. Amalgam does not stick to the tooth surface like white filling materials, such as composite resin.
This filling material is silver in colour and can appear darker over time. Some people claim that mercury in dental amalgam can cause negative health consequences, however research has shown that the mercury in amalgam fillings is poorly taken up by the body. Small amounts of mercury from amalgam do get into the blood but are removed by the kidneys and passed out of the body in urine. The only two proven side-effects of amalgam:
- Lichen planus, involving small sores on the gum or inside of the cheek.
- An allergic reaction affecting the soft tissues near the filling. Signs of an allergic reaction can include swelling, redness, and itching, but these are rare.
The use of amalgam in dental clinics has reduced over time, however this is not due to concerns directly related to human health but concerns about the environment. Mercury from dental clinics can make its way into the environment. To combat this, dentists have created policies and installed equipment for the safe disposal of amalgam waste to limit the amount released into the environment.
A dental amalgam filling in a molar tooth. Getty Images.