A filling replaces part of a tooth that has been lost either to decay or impact fracture and white fillings are used predominantly in the front teeth to restore and cover unsightly areas.
White fillings are virtually invisible and as they are glued into place they are less invasive than traditional fillings. They can be used in the back teeth, although where there is a large amount of tooth loss they may not be as durable as other materials.
Amalgam silver fillings are strong and hard-wearing and have an excellent life span, often being used in the molar teeth at the back of the mouth where aesthetics is not a major concern and where there is heavy wear from chewing.
Inlays and onlays are used where the amount of tooth structure lost is too great to place a filling but where a crown is not required. They are often used where a tooth needs a larger filling that extends over the corner, called a cusp. Normally they are made of porcelain on a model from the patient’s mouth, and preparing a tooth for an onlay takes away less of the natural material than a crown does, while still protecting it.
An inlay or onlay is constructed in the laboratory and then cemented into a pre-prepared cavity in the tooth. They are especially useful in areas where heavy chewing occurs, and give a strong, hard-wearing restoration.
When making a filling the dentist will use a local anaesthetic to numb the area around the tooth to be filled before a drill or air abrasion instrument is used to remove the decayed area; the choice of instrument depends on the location and extent of the decay. Once the decay has been removed, the dentist will prepare the space for the filling by cleaning the cavity of bacteria and debris and if the decay is near the root they may put in a liner to protect the nerve.