Fillings are used to repair holes (or cavities) in your teeth. These cavities are most commonly caused by decay, but can also be caused by teeth fracturing / breaking or wearing down.
There are several different materials that are used to fill teeth.
Amalgam fillings are silver coloured. They are made by combining mercury and a silver alloy (50% mercury, 35% silver, and 15% tin, copper and other metals). Amalgam is strong and hard wearing and has been used in fillings for at least 150 years. They are generally long lasting - it is not unusual for an amalgam filling to last 15 to 20 years.
This kind of filling is usually used on the back 'chewing' teeth. Before the filling can be placed, the dentist must prepare the area by removing all the decay and shaping the cavity in a particular way in order to hold the filling in place.
The mercury in dental amalgam is not poisonous once it is combined with the other materials in the filling. Its chemical nature changes so that it is harmless.
Research into the safety of dental amalgam has been carried out for over 100 years. So far, no reputable ‘controlled' studies have found a connection between amalgam fillings and any medical problem.
Composite fillings are tooth coloured fillings made from powdered glass quartz, silica or other ceramic particles added to a resin base. They are strong, but may not be as hard wearing as amalgam fillings. However, there are now new materials available that are comparable to silver amalgam, and these are proving to be very successful.
Composite fillings can be used on both front and back teeth. The dentist can choose a shade to match your own teeth and so highly aesthetic results can be achieved.
As composite fillings bond directly to the tooth, the cavity does not have to be prepared in the same way as with an amalgam filling. Hence they don't require as much tooth tissue removal which is better for the tooth.
Glass Ionomer Fillings
Glass ionomer fillings are another type of tooth-coloured filling. They release fluoride, which helps to prevent further tooth decay. This type of filling is fairly weak. Because of this, they are usually only used on baby teeth and ‘non-biting' surfaces such as around the ‘necks' of the teeth. Little preparation is needed as the filling bonds directly to the tooth by forming a chemical link with the tooth.