Root canal treatment is a dental procedure used to treat infection at the centre of a tooth (the root canal system). It's also known as 'endodontics'. The infection is caused by bacteria that live in the mouth and invade the tooth. This can happen after: - tooth decay - leaky fillings - damage to teeth as a result of trauma, such as a fall To treat the infection in the root canal, the bacteria need to be removed. This can be done by either removing the tooth (extraction) or attempting to save it by removing the bacteria from the root canal system (root canal treatment). After the bacteria have been removed, the root canal will be filled and the tooth sealed with a filling or crown.