Overview
Broken (fractured) teeth are not uncommon in active dogs. The teeth are very hard, but rock chewing and traumatic impact commonly lead to breakage. Chewing on wire fences, cage doors, or ice cubes sometimes also result in tooth fractures.
There is a canal inside the tooth running up in the centre called the pulp chamber. When exposed, it appears as a reddish brown dot in the middle of the surface of the tooth. A tooth fracture may just involve the outer layers (enamel and dentin), but if a break results in loss of the top of the crown of the tooth, a small hole at the tip of the pulp canal is left open to the mouth and provides an entry point for bacteria. These bacteria from the oral cavity can travel down the tooth to the root, and there they can gain entry into the surrounding tissue and tiny blood vessels. From the circulation, they can travel around the body, but usually remain locally and produce infection in the tooth root (apical or periapical abscess). If a local infection occurs, or a heavy impact led to the fracture, often the tooth will lose vitality, and die. When the tooth is not alive, the normal white color is replaced by a dull grey-brown color. Infection does not always occur right away. Without X-rays to check tissues down at the tooth root mild infections may be missed, so the veterinarian will recommend an X-ray in addition to performing a visual examination of the dog's mouth.
Fracture of the Canine Tooth (or Fang)
The canine tooth or fang has a very long root below the gum line. The length of the root is about the same below the gum as it is above the gum where you can see it. Note that infections of the canine teeth of the upper arcade can extend deep into the tissues, and enter the nasal cavities that lie directly above. If this happens, a discharge from the nose may be noted. Sneezing may also occur, and sometimes blood comes out of the nostrils mixed with discharge as well. Sometimes the tooth falls out or is extracted. An oronasal fistula may then develop. Oronasal refers to the oral-nasal connection, and a fistula is a hole or tract between the mouth and the nasal cavity where the tooth root used to be, and if present, will require a surgery to close it. If not closed over, food and water and bacteria in the mouth can enter the nose causing problems.
Symptoms of Fractured Teeth
The nerve supply to the teeth of the dog and cat is similar to that of humans. If you have ever split or broken a tooth, you will know that there is significant pain. Signs of pain in dogs may include drooling, eating on the other side of the mouth away from the fractured tooth, head shaking, rubbing the face with the paws, and perhaps a reduced appetite or change in attitude. Not all dogs show obvious signs of discomfort.
Treatment
Veterinary advice should be sought regarding restorative or extraction procedures and follow-up care. If only a small tooth tip is lost, sometimes a filling of amalgam or acrylic is used to restore or cap the tooth crown. Often metal is chosen since it withstands wear and tear in the dog best. Sometimes the tooth can also be saved if a root canal procedure is done to seal and empty the pulp canal. If the tooth is just chipped on the outer surface, the veterinarian may use a dental bur or sander to smooth the sharp margins so that the ragged tooth edges do not cut the tongue.