Endodontics is a specialized branch of dentistry that deals with the complex structures found inside the teeth. Endodontic treatment (or root canal therapy) is performed to save the natural tooth. Many people need a root canal after a deep cavity has grown down into the root of the tooth. In this situation, the decay needs to be removed as soon as possible so the tooth can be saved. In spite of the many advanced restorations available, most dentists agree that there is no substitute for healthy, natural teeth.