A filling replaces part of a tooth that has been lost because of decay or through accidental damage.
'Silver' fillings are made of amalgam - a mixture of mercury with other metals, such as silver, tin and copper. They are very strong, so they are ideal for back teeth, where there is heavy wear from chewing.
'Composite', 'glass ionomer' and 'compomer' are different types of white filling. Unlike silver (amalgam) fillings, white filling material sticks to teeth and can form edges, so it may be effectively used to repair front teeth that are chipped, broken, decayed or worn. It can also be used to cover marks or discolouration that cleaning won't remove. White fillings come in a range of shades so they can be matched to the colour of your own teeth.
The 3D model shows the placement of a white filling.
The dentist will usually numb the area around the tooth with an injection (local anaesthetic).
A drill is used to remove any decay, together with any old filling material. Then the tooth is washed and dried by blowing water and then air onto it (the dentist will be holding something which looks like a water pistol).
A mild acid is then applied to etch (roughen) the surface of the hole. It is then washed and dried again. The etching helps the filling stick better.
A layer of bonding agent is applied to the hole and acts like a cement to help hold the filling in place. It has to be set (hardened) using a bright light (called a curing light).
The filling material is then pushed into the cavity (hole), shaped and then hardened using the same bright light. A drill is used to trim and polish the filling as necessary.