ENDODONTIC DISEASE

The endodontic system is the pulp tissue (blood vessels, nerves, and connective tissue) that are in the root canals and pulp chambers in our and our patients' teeth. This system supplies the living tooth with all components it needs to live and mature. The blood supply for the teeth arises from the mandibular and maxillary branches of the blood vessels. Nervous supply comes from the branches of the trigeminal nerve. Endodontic disease refers to any inflammation to this organ which is called pulpitis. Depending on the severity of the insult, the pulpitis may be reverseable or irreverseable. Reverseable pulpitis is usually caused by a lesser trauma, and the tooth will survive the insult. Irreversable pulpitis is due to significant pulpitis and will result in the death of the tooth. The most common cause of this is a fractured tooth where the endodontic system is exposed to the oral cavity for any length of time.

Fracture of the maxillary fourth premolar results in pulp exposure. This tooth needs endodontic care.

Broken teeth are a very common occurrence in dogs and cats. They can break due to trauma (hit by a car, ball, or rock) or due to chewing on hard objects. Any tooth can break, however some teeth are fractured more than others. The most common teeth that are broken are the canine (fang) teeth in the dog and the cat, and the upper fourth premolar (large tooth on the top in the back) in dogs. 

Teeth with severe damage may benefit from placement of a crown.

After the tooth is fractured, bacteria from the mouth will gain access to the pulp (root canal) and infect the tooth. Eventually, the tooth will die and become a bacterial haven. The bacteria will then leak out through the apex (or bottom) of the tooth, and infect the bone in that area. Eventually, the bacterial byproducts and white blood cell enzymes will cause bone destruction around the root tip. Next, the blood vessels in the area will pick up the bacteria and spread it to other areas of the body. Most specifically, to the liver and kidneys which filter the blood, and possibly to the heart valves. They will form micro-abscesses on the organs, and over time will decrease the efficiency of these vital organs.

These infected teeth are painful, as anyone who has needed a root canal can testify to. Unfortunately, only very rarely will our animal patients show discomfort, as they prefer to suffer in silence. This allows owners and veterinarians alike to ignore the problem, as “it doesn’t seem to bother him”. But we now know that these animals are being affected locally as well as systemically, and ignoring the problem is not a viable option. I have had numerous clients who have told me that the pet is not bothered by the broken tooth when it is discovered tell me that the pet acts “5 years younger” just two weeks after the problem is fixed. In addition, I have had innumerous patients that have had elevated liver enzymes at the time of dental work go back to normal within two weeks of surgery.

Occasionally, the abscess at the root tips will get so bad that the abscess will break out through the skin. This most commonly occurs with a fracture of the upper fourth premolar in dogs, and it is known as a carnassial abscess. It can also occur secondary to an abscessed canine as well as most other teeth. In cats, the abscess will usually be due to a fractured canine, but due to the shortness of the nose will open below the eye as well. Antibiotics will usually cure the problem for a while, but invariably the problem will reoccur if the offending tooth is not dealt with. 

There are three options for dealing with a fractured tooth, and ignoring it is NOT one of them. The first and best option for a fractured tooth that is otherwise healthy (no periodontal disease or root fracture, etc.) is standard root canal therapy. This is where the infected pulp is removed and the canals filled with mendicants to discourage future bacterial contamination. This is most commonly done in canines in dogs and cats, and the upper fourth premolars and lower first molars in dogs. However, any tooth can be done in a dog. A vital pulpotomy can be performed if the fracture is fresh and not yet severely infected; this procedure is especially useful in fractures of immature teeth (dogs and cats less than 18 months of age).

Completed root canal therapy in a  maxillary fourth premolar.

A final option, depending on the tooth involved, degree of fracture, and any other disease present, is extraction of the offending tooth. For the canine tooth in dogs and cats, and the upper fourth premolar and lower first molar in dogs this is the last option. There are several reasons we prefer to avoid this procedure when possible. First, as it is painful due to the size of the roots in our animal patients. The root of the canine is twice as long and wider than the crown (the part you can see). It is oral surgery and not a simple extraction in canines especially. Secondly, the patient looses the function of the tooth, which can be very important for chewing in some cases. In addition, you can see orthodontic problems secondary to the loss of the tooth. We try to avoid this in cases of otherwise healthy teeth.