Inside each of your teeth is a little bundle of nerves, blood vessels and tissue known as the pulp. The pulp is vulnerable, but it is normally protected by the hard outer layers of your tooth. However, if your tooth is cracked or broken, or if a cavity gets deep enough to reach the pulp, your pulp can become infected. This infection can spread and potentially cause the loss of the entire tooth.
Root canal therapy is the method used by dentists to remove the pulp from a compromised tooth and prevent infection. A small hole is drilled in the tooth, the pulp is surgically removed, and the tooth is sealed to protect the inside of the tooth.