Causes and Treatment of Root Canal Disease

By Brian J. Gray, DDS, MAGD, FICOI

Why Does My Tooth Need Root Canal Treatment?

A tooth generally needs root canal treatment because the pulpal tissue inside the tooth has become irreversibly injured. The pulpal tissue is composed of elements similar to any other tissue in the body and is susceptible to injury from bacterial decay, repeated or extensive dental procedures, traumatic accidents, or advanced periodontal disease. Pulpal disease occurs in an anatomically complex space termed the root canal system. When appropriate, root canal treatment is directed towards removing inflamed or abscessed tissue, disinfecting, and preparing this space to receive a biocompatible filling material. Once the root canal system has been sealed and a protective crown placed, the tooth can be retained as a healthy and functional member of the dental arch.

What Are the Usual Events That Trigger Root Canal Disease?

Events that may trigger root canal disease include:

1. Decay: Dental decay contains bacteria that can infect the dental pulp. Decay can progress through the outer enamel surface of the tooth into the underlying dentin, which is a hard, yet porous, structure. Ultimately, decay can invade the dental pulp and cause pulpal injury, which leads to an inflammatory condition that can potentially proceed to an abscessed tooth. As dental decay and its associated bacteria invade the pulpal tissue, a patient may experience no discomfort or, in other instances, the pain may be acute.
2. Traumatic events: The dental pulp is vulnerable to trauma. A blow to the mouth may lead to a variety of dental injuries. A traumatized tooth may appear whole but exhibit root canal disease at a later date. A tooth may be only slightly chipped or it may be fractured to the extent that its clinical crown is broken off and the pulpal tissue is exposed. In severe situations, the root can be fractured within the bone or the tooth completely knocked out of the mouth, which is called an "avulsion." Frequently, these traumatic events will irreversibly damage the pulpal tissue inside the tooth by causing bacterial contamination or by interfering with the tooth's blood supply and its ability to repair. Some teeth are traumatized to the extent that they are not treatable and these teeth must be removed.
3. Repetitive or extensive dental procedures: The dental pulp is vulnerable to injury from repetitive or extensive dental procedures. Subjecting a previously injured pulp to the additional trauma of even the best planned and performed dental treatment may be enough to cause the pulpal tissue to become irreversibly inflamed and the tooth to require root canal treatment. The dentist may or may not be able to predict this outcome in advance. At times, based on the examination and treatment plan, the dentist may recommend the removal of the dental pulp before performing other planned dental procedures. In these situations, the pulp is removed so that it will not become problematic at a later date under a new, and possibly complex, restoration. At times, initiating root canal treatment through an existing restoration may compromise its integrity.
4. Periodontal disease: Infection in the gum and bone around the tooth is referred to as periodontal disease. Advanced periodontal disease may compromise the blood supply to the dental pulp and ultimately, bacteria may enter and infect the pulpal tissue in the root canal space.