Why does this filling need to be replaced? It doesn't hurt.

A filling may need to be replaced when something is gone wrong with the tooth in which the filling has been previously placed or with the filling material itself.

Let us first talk about things that go wrong with teeth that have already been “filled”. Teeth that have had “cavities” can still suffer from tooth decay subsequent to restoration: the word your dentist actually thinks of when he says fillings. The edges where the tooth meets the fillings are still susceptible to bacteria from the plaque that forms on teeth. Thus if not kept immaculately clean, with the passage of time a new cavity can form next to the original filling. When these “recurrent “cavities are small the individual is not even aware of their presence unless visible on front teeth. Often the best way to treat the new cavity is to replace the old filling with a new one including the spot where the new decay has formed.

Sometimes things can go wrong with the filling materials themselves. When you think about it the mouth is a violent place. Occasionally the wear and tear can result in cracks or fractures in a filling. Cracks allow decay causing bacteria easy access to the inside of a tooth resulting in a cavity underneath an old filling. Ideally such failures of filling material should be detected early and the old filling removed and replaced with a new one. Early diagnosis and treatment is of course is more likely to occur when one follows a regular pattern of visits to the dentist for thorough oral examinations. 

Dr Shawn Lee a Vernon Dentist