In dentistry a canal is the pulp filled space within the roots of the teeth. Depending upon the type of tooth, it may either contain a single root or multiple roots. The incisors, canines and the premolars have a single root, with the exception of the maxillary first premolars, which contain two roots. On the other hand, the mandibular molars usually have two roots, while the upper molars have three roots. Hence, single rooted teeth usually contain a single root canal, while teeth having two or three roots tend to have multiple root canals.

A Root canal treatment (RCT) is an endodontic procedure. It needed in case of serious infection, deep cavity, repeated cavity treatment, or in some cases of trauma. It will normally be preceded with an x-ray examination, and local anesthesia will be provided. The treatment involves opening the canal, removing the pulp (pulpectomy), cleaning the canal, filling it with artificial material, and sealing it. A steel post of the right size may also be inserted in the prepared root canal before filling. Filling is done with gutta parcha (which is a rubber like material) and the steel post provides support to it. The tooth is normally sealed temporarily for observation, and when found satisfactory, the tooth is given a permanent sealing. A crown may also be placed over it.

The root canal procedure will normally take two or more sessions. On the plus side, the root canal treatment is a lifelong treatment with a very high success rate.  However, a root canal treated tooth may require further treatment in case there is post treatment trauma, deep infection, or a loosened filling. Caution can prevent this. The patient must be advised to avoid chewing hard stuff e.g., ice, with a tooth which has received root canal treatment.  Root canal treatment may not be advisable in case the tooth is damaged beyond restoration or lacks sufficiently bone support or the affected root canal is badly damaged or inaccessible.