Deep beneath the outer enamel of the tooth is an area of soft tissue called the pulp.
It carries the tooth’s nerves, veins and arteries and nourishes healthy tooth tissue.
Root canals are very small, thin divisions that branch off from the top of the pulp to
the tip of the root. Depending on its location in the mouth, a tooth has between one
and four canals.

Commonly a tooth becomes infected from deep decay, injury (due to trauma),
or fracture and can damage the nerve beyond repair. If the nerve dies, pressure
cannot be relieved from the inside of the tooth resulting in a toothache. Pain can be
spontaneous, intermittent, throbbing, dull, felt when biting down, chewing, or when
applying hot or cold food and liquids. Left untreated, the infection can lead to an
abscess and even the loss of the tooth.

Performed by either the general dentist or endodontist, depending on the difficulty
of the case, root canals are simple procedures with little or no discomfort. The patient
is given a local anesthetic to numb the area. A rubber dam is placed to isolate the
tooth and an access hole is drilled into the tooth. The pulp chamber is cleaned,
reshaped and sterilized. The root canals are filled with a biocompatible rubber
material called "gutta percha," which is placed with an antibacterial cement to
completely seal the root canals. To complete the treatment, a temporary filling is
placed in the opening of the tooth. To prevent leakage of saliva and the bacteria it
contains from recontaminating the root canals and to protect the remaining tooth
structure, the patient must return to his/her dentist to have the permanent restoration
placed on the tooth. In most cases a permanent crown is needed to support the
remaining tooth structure after root canal treatment due to the loss of blood supply
to the tooth.