Why do I need a filling?

Tooth structure and integrity can become compromised by decay which softens the tooth substance and results in a cavity. Other reasons why tooth structure can become compromised are due to tooth wear, cracks or breaks due to excessive forces during function or even trauma for example due to a knock to the teeth during an accident.

A filling is used to build up a tooth to its original natural size and shape in order to revive the function and appearance of the missing tooth structure.

Types of filling


Amalgam fillings are silver coloured. They are made by combining mercury and a silver alloy.
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.

Are there any risks with this type of filling?

Mercury in dental amalgam is not poisonous once it is combined with the other materials in the amalgam 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 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 the filling can take up stains.

Glass ionomer

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.

What is the procedure to have a filling?

The dentist will first usually numb the tooth in question. The tooth is then cleaned to remove any decay and shaped so that the filling will fit in nicely. Next the filling material is prepared. This is then placed into the prepared tooth and the tooth is built up before the material sets hard. The advantage of fillings is that they usually set quickly and can be carried out in a single procedure.

Are there any alternatives to fillings?

There are alternatives such as veneers, crowns, inlays and onlays although they will usually cost more.

What are inlays and onlays?

These can be used in most areas of the mouth. An inlay is used within the biting surface of the tooth. An onlay can cover a larger area of the tooth. Materials that can be used include gold, porcelain, composite and ceramics.

Your dentist will usually take an impression of the prepared cavity and send it to the laboratory for the technician to make the inlay or onlay. In the meantime a temporary filling will be placed in the cavity. After the inlay or onlay has been made, your dentist will fix it in place with dental cement. This type of filling is more expensive.

For further information, ask your dentist about Fillings or speak to the receptionist by calling us on 01902 763200.