When the blood or nerve supply of a tooth (often known as the ‘pulp’) becomes damaged through injury, infection, or decay, it can cause the nerve of the tooth to die. Years ago this would have meant that the tooth would have to be removed entirely before the whole area became infected. However, thanks to root canal treatment, it is now possible to save teeth that are at risk from the damaged pulp. An infection that starts in the pulp can quickly spread through the entire root canal system and if left untreated, could grow to form an abscess. If this happens, bacteria-filled pus will collect under the gums, causing them to swell and become hot and potentially extremely painful. The main goal of root canal treatment is to remove all of the infection from the root canal in order to save the original tooth.