Broken (fractured) teeth are a very common occurrence in dogs and cats. Pet teeth can break due to trauma (hit by a car, ball, or rock) or due to chewing on hard objects. Any pet tooth can break, however some teeth are more commonly fractured than others, such as the canine (fang) teeth in the dog and the cat, and the upper fourth premolar (large tooth on the upper jaw in the back of the mouth) in dogs.
There are two categories of broken pet teeth: those that directly involve the root canal (termed complicated crown fractures) and those that do not extend deep enough to expose the root canal, but rather only expose the layer beneath the enamel which is called dentin (uncomplicated crown fractures). Both of these types of tooth fracture require therapy, but the treatment can be very different.
Pet teeth with direct root canal exposure are excruciatingly painful to a dog or cat. Unfortunately, only very rarely will animals show discomfort, as they are evolutionarily conditioned to mask pain fairly well, preferring to suffer in silence. This allows owners (and veterinarians) to ignore the problem, as “it doesn’t seem to bother the pet”. But we now know that these animals are suffering with consequences both locally in the mouth as well as systemically throughout the body. This means that in today’s current age of veterinary medicine, it is no longer appropriate or acceptable to ignore broken teeth in our patients. We have had numerous clients who have told us that their pet is not bothered by its broken tooth when it is discovered, that later tell us joyfully that their pet is acting “5 years younger” just two weeks after the problem is fixed.
The reason that a broken pet tooth with direct pulp exposure presents a problem is that after the tooth is fractured, bacteria from the mouth gain access to the root canal and infect the tooth. Eventually, the tooth will die and become a bacterial haven. The bacteria then leak out through the bottom of the tooth, and infect the bone in that area. Eventually, the bacteria cause bone destruction around the tips of the tooth root. Next, the blood vessels in the area pick up the bacteria and spread it to other areas of the body, including the liver & kidneys which filter the blood, and potentially to the heart valves, which damage these vital organs. In fact, infected teeth (and periodontal disease) can so greatly affect the rest of the body and its vital organs that we have had numerous patients with elevated liver and kidney enzymes found on the pre-op blood which then improve or return to normal levels within two weeks of the dental procedure.
Occasionally, the infection at the root tips will get so bad that an abscess will break out through the skin and appear as a wound on the face, often below the eye. This most commonly occurs with a fracture of the upper fourth premolar in dogs, and it is known as a carnasial tooth root abscess. It can also happen secondary to an infected canine as well as most other teeth. In cats, an abscess will usually be due to a fractured canine tooth, but due to the shortness/shape of the nose, this wound will open below the eye as well. Antibiotics will usually resolve the problem for a while, but invariably the problem will continue to reoccur if the offending tooth is not appropriately dealt with.