Abstract

Endodontic disease refers to damage to the dental pulp. Unfortunately, endodontic disease is often untreated. At one time, veterinarians were taught "wait and see" was appropriate treatment for fractured teeth. And, when endodontic disease was diagnosed, it was often treated only with antibiotics. Consequently, many patients suffered silently as the tooth first died and then became abscessed.

Pulp tissue consists of blood vessels, nerves, and connective tissues that support the odontoblastic cells lining the pulp chamber and root canal. Throughout life the odontoblasts produce dentin that fills in the canal. As a result, the dentin layer thickens with age. Young animals have very thin-walled teeth and large pulp chambers.

Bacteria usually gain entry to the pulp chamber via a fractured tooth. The pulpal tissue becomes inflamed and edematous and dies. Bacteria move into the apical region of the tooth. In young sea lions, the apex is blunderbuss in shape and open. In older sea lions with apexes, bacteria can spread through the canals in the apical delta of the tooth, which formerly served as tunnels for the nerves and blood vessels. Once the bacteria enter the apical bone, bone can become infected. Trauma to the teeth that does not cause fracture can also cause death of the pulp tissues by pulpitis. Once the tooth dies, the dead tissue may be subject to infection through a process called anachoresis. These teeth may appear normal to casual clinical observation.

There are a number of clinical appearances of endodontically diseased teeth. All teeth that are fractured with the pulp exposed have endodontic disease. These fractures are called complicated fractures. Teeth may have chips of enamel or dentin chipped away but no pulp exposure; these are uncomplicated fractures. Uncomplicated fractures and teeth that are discolored are tougher to diagnose clinically as the pulp may or may not still be vital. Radiographic evaluation of these teeth is necessary. Other clinical signs of an endodontically diseased tooth include swelling of the tissues around the tooth, fistula on the mucus membrane and/or a draining skin lesion near the apex of the tooth.

All complicated tooth fractures require treatment, which may be extraction, or if the tooth is sufficiently developed, endodontic therapy. Treatment with antibiotics will not treat this disease as the infection resides within the dead tissues inside the tooth and in the wall of the tooth that no longer have blood supply to deliver the antibiotic.

A number of clinical cases will be presented to illustrate endodontic disease in California sea lions.