What Is the Root Canal Space and What Is Its Significance?

By Brian J. Gray, DDS, MAGD, FICOI

To best understand the root canal space, it is helpful to think of a tooth that has been sectioned along its length. A tooth is composed of a "clinical crown" and one or more roots. The crown is that portion of the tooth that is visible within the mouth. The crown has a thin protective covering called the "enamel." The root has a thin covering called "cementum" and, in health, it is attached to the surrounding bone by the periodontal ligament. Under the enamel and cementum is a hard yet porous structure called "dentin," which is the material that comprises the bulk of the tooth. The root canal space typically runs centrally through the length of the root and extends into the clinical crown. In visualizing this space, it is helpful to think of a tree, which has a main trunk, limbs, and smaller branches. The limbs and branches may divide as they extend from the main trunk. Similarly, the root canal system usually contains a branching system that extends from the central canal and communicates laterally with the ligament space and bone along the external surface of the tooth. This internal anatomical space can be relatively straightforward or most complex.

In health, the root canal system is filled with living pulpal tissue. The dental pulp is composed mainly of connective tissue, nerve fibers, and blood vessels, similar to the composition of other tissues throughout the body. Because the tooth is highly innervated, it can become very painful when the pulp becomes diseased. The blood vessels of the pulp serve to bring nourishment from the main circulation outside the tooth to the tissues inside the tooth. Healthy pulp tissue is especially important during the formative stages of tooth development. In fact, it is interesting to note that the primary functions of the pulp tissue are to nourish the tooth and to guide the tooth's development before and during its eruption into the mouth. After the tooth is fully formed, the pulp is not necessary to sustain the health of the tooth. If the pulp becomes diseased or damaged at any stage, however, it can have significant adverse consequences for both the tooth and its supporting structures. The tooth will then require either extraction or root canal treatment.