A filling is used to restore a tooth that is affected by decay, fractures, cracks and wear. The decayed or affected portion of the tooth will be removed using a drill and then filled with a material. Depending on the depth of decay, local anaesthetic may sometimes be used to anaesthetise the tooth during the filling process so that it will not be sensitive.
There are different materials used to restore a tooth. Your dentist will discuss the advantages and disadvantages of the materials whenever required. It is important to note that fillings are not permanent and may have to be replaced someday. This is why it is imperative to have good oral hygiene and regular dental examinations to prevent the need for fillings in the first place. There is nothing as strong as your own teeth!
When little tooth structure is left after removal of decay, your dentist might recommend a crown to protect the tooth.