The pulp of your tooth, which contains the nerve and tiny blood vessels, can become infected. The pulp has a limited ability to heal itself. This infection can be caused by a deep cavity that reaches the center of the tooth causing the pulp to die, a traumatic injury to the tooth, or an extensive preparation (drilling) of the tooth. The extensive preparation may have been done to prepare the tooth for a crown (cap) or other large preparation for a restoration. The pulp may or may not abscess immediately in these cases. It may take years for a problem to develop. The infected pulp tissue may or may not be painful. It may or may not be visible on a dental radiograph. A tooth with this type of an abscess is not usually extracted because the infection can be treated with endodontic therapy on the tooth. This routine procedure can save the tooth and enable you to avoid the harmful effects of tooth loss. It is successful in more than 90% of the teeth in which the treatment is completed.
Endodontic treatment can take from one to three appointments to complete. Teeth can have one to four canals that need to be treated. An opening is created to access the nerve, and the abscessed nerve is removed from the root or roots. The canals where the nerves had been located are then cleaned and shaped and a medication may be placed in the canal to promote better healing.
When it has been determined that the canals are free of infection, they are filled with a special rubber-like material and sealed with a cementing medium. The abscessed area associated with the tooth will then begin to heal. It may take several months before healing is completed and for the tooth to become asymptomatic, that is, for any soreness in the area to disappear.

