When decay gets deep enough it can infect the nerve and blood supply to the tooth called the dental “pulp”. Trauma can also cause a tooth root to die or become “non-vital”. Fortunately, teeth with infected roots can often be saved with a root canal, also called endodontic treatment. And in spite of their scary reputation the process is usually pretty simple and is usually done on an already dead tooth root, so pain is not an issue. The dentist uses very small instruments to clean out the infected tissue from inside the tooth roots and then after disinfecting this pulp chamber, it is sealed up, allowing the bone to remain healthy around the tooth.