The crown and roots
A tooth has two main regions. The crown is the portion visible above the gumline. The root or roots extend below the gumline and are supported by the surrounding bone and periodontal tissues.
Beneath the enamel is a hard layer called dentin. Inside the dentin is a central space containing the pulp—soft tissue with nerves, blood vessels, and connective tissue. The narrow spaces running through the roots are the root canals.
How the pulp becomes damaged
The pulp can become inflamed or infected because of deep decay, repeated dental procedures, a large or leaking restoration, a crack or fracture, periodontal disease, or trauma. An injury can damage the pulp even when the tooth does not appear visibly broken.
How endodontic treatment preserves the tooth
When the pulp cannot heal, root canal treatment removes the damaged tissue, cleans and disinfects the internal canal space, and seals it. The root and supporting tissues remain in place, allowing the tooth to continue functioning after it receives an appropriate final restoration.
A mature tooth can function without its pulp because the tissues surrounding the root continue to support and nourish it.