There are a number of different fillings including:
Amalgam fillings are silver coloured. They are made by combining mercury and a silver alloy (50% mercury, 35% silver, 15% tin, copper and other metals). Amalgam is long lasting and hard wearing and has been used in fillings for at least 150 years. It is economical to use and it is not unusual for an amalgam filling to last 15 to 20 years. This kind of filling is normally used on the back 'chewing' teeth. Before the filling can be placed, the area must be prepared by removing all the decay and shaping the cavity to hold the filling in place. If the tooth is badly broken, your dentist may need to place a small stainless steel pin to help secure the filling.
Composite fillings are strong, but may not be as hard wearing as amalgam fillings. Composite fillings are tooth coloured and are made from powdered glass quartz, silica or other ceramic particles added to a resin base. After the tooth is prepared, the filling is bonded onto the area and a light shone onto it to set it. The dentist will choose a shade to match your existing teeth, although over time staining can happen.
Glass ionomer fillings form a chemical link with the tooth. They may also release fluoride, which helps to prevent further tooth decay. This type of filling is fairly weak and, because of this, is usually limited to use 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.