To understand endodontic treatment, it helps to know something about the anatomy of the tooth. Inside the tooth, under the enamel and a hard layer called the dentin, is a soft tissue called pulp. The pulp contains blood vessels, nerves and connective tissue, and creates the surrounding hard tissues of the tooth during development.
The pulp extends from the crown of the tooth to the tip of the roots where it connects to the tissues surrounding the root. The pulp is important during a tooth's growth and development. However, once a tooth is fully mature it can survive without the pulp, because the tooth continues to be nourished by the tissues surrounding it.
Endodontic treatment is necessary when the pulp becomes inflamed or infected. The inflammation or infection can have a variety of causes: deep decay, repeated dental procedures on the tooth, or a crack or chip in the tooth. In addition, an injury to a tooth may cause pulp damage even if the tooth has no visible chips or cracks. Most endodontically treated teeth last as long as other natural teeth.