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'.
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.
After the bacteria have been removed, the root canal will be filled and the tooth sealed with a filling or crown. In most cases, the inflamed tissue at the end of the tooth will heal naturally.