A root canal is a treatment used to repair and save a tooth that is badly decayed or becomes infected. During a root canal procedure, the nerve and pulp are removed and the inside of the tooth is cleaned and sealed. Without treatment, the tissue surrounding the tooth will become infected and abscesses may form.
An abscess occurs when the infection spreads all the way past the ends of the roots of the tooth. In addition to an abscess, an infection in the root canal of a tooth can cause:
Swelling that may spread to other areas of the face, neck, or head
Bone loss around the tip of the root
Drainage problems extending outward from the root. A hole can occur through the side of the tooth with drainage into the gums or through the cheek with drainage into the skin.