A filling is used to restore a tooth that is affected by decay, fractures, cracks & general wear. The decayed or affected portion of the tooth will be removed and then filled with a restorative material. Depending on the depth of decay, local anaesthetic may be sometimes used to anaesthetize the tooth during the filling process so that it will not be sensitive.
There are different materials used to restore a tooth but the most commonly used is the tooth-coloured filling (also known as composite). Your dentist will discuss the advantages and disadvantages of the materials whenever required.
When little tooth structure is left after removal of decay, your dentist might recommend a crown to protect the tooth.
Read more about crowns under the "Crowns/Bridges/Veneers" section.