A root canal is the space within the root of a tooth. It is part of a naturally occurring space within a tooth that consists of the pulp chamber (within the coronal part of the tooth), the main canal(s), and more intricate anatomical branches that may connect the root canals to each other or to the surface of the root.
The smaller branches, referred to as accessory canals, are most frequently found near the root end (apex) but may be encountered anywhere along the root length. There may be one or two main canals within each root. Some teeth have more variable internal anatomy than others. This space is filled with a highly vascularized, loose connective tissue, the dental pulp.
The dental pulp is the tissue of which the dentin portion of the tooth is composed. The dental pulp helps complete formation of the secondary teeth (adult teeth) one to two years after eruption into the mouth. The dental pulp also nourishes and hydrates the tooth structure which makes the tooth more resilient, less brittle and less prone to fracture from chewing hard foods. Additionally, the dental pulp provides a hot and cold sensory function.
Root canal is also a colloquial term for a dental operation, endodontic therapy, wherein the pulp is cleaned out, the space disinfected and then filled.