Root Canal  

If the nerves and blood vessels of a tooth have been irreparably damaged, rather than extracting the tooth, a dentist may attempt to save it by performing root canal treatment. 

Root canal treatment typically requires a series of appointments.  At the first appointment, the dentist will drill a small hole through the crown, and remove the infected pulp tissue.  The pulp chamber and root canals are then cleaned out and disinfected to remove all of the infection causing bacteria. 

If there is an abscess, then the dentist may place a temporary seal on the tooth, provide you with antibiotics, and schedule a follow-up appointment. 

If there is no evidence of remaining infection at the next appointment, then the canals are packed using a paste and inert rubber like material called gutta percha.   Depending on the condition of the tooth, the access opening is either filled with cement, or a crown is placed on the tooth.

Occasionally, if an abscess has formed at the base of the tooth, it will be necessary to perform an apicectomy.  This is a minor surgical procedure in which the tissue at the base of the root is removed.

Risks?
If root canal therapy is suggested by a dentist, then is important to have a tooth treated as soon as possible.  An infection that is allowed to continue, will likely result in the formation of an abscess at the root of the tooth.   This will lead to destruction of the underlying bone tissue an may make it impossible to save the tooth; in addition, the infection can spread to adjacent teeth, and could result in blood poising, fever, swelling in the face and neck, and a general feeling of unwell.