PEER REVIEWED
Diagnosis & Treatment of
Brook A. Niemiec, DVM, FAVD, Diplomate AVDC
Crown fractures are very common, especially in large-breed dogs.
T 18
Crown Fractures
ooth fractures are defined as complicated or uncomplicated:1 U Uncomplicated crown fractures have direct dentin but no pulp exposure U Complicated crown fractures have direct pulp (nerve) exposure.
TOOTH ANATOMY
Teeth are essentially comprised of 3 layers: enamel, dentin, and pulp. t Pulp: The innermost layer is the endodontic system (root canal or pulp). The endodontic system contains nerves, blood vessels, and connective tissue that nourish the tooth. The blood and nervous supply enter the tooth through the very tip (or apex) of the root.
t Enamel: The outer layer of the tooth crown is enamel. It is virtually all (97%) calcium and phosphorus and is the hardest substance in the body. Enamel has no nervous or circulatory system. It is applied in a very thin layer (< 1-mm thick) over the tooth surface during development. Once tooth eruption occurs, enamel cannot be naturally replaced or repaired.
t Dentin: The central layer, which is the vast majority of the tooth structure in mature patients, is dentin. Dentin has roughly the same mineral content as bone. It has a nervous supply and responds to stresses. Running at right angles to the root canal are dentinal tubules. Each dentinal tubule contains an odontoblastic process, which is basically a nervous supply that is limited to sensory function and can only report changes as pain.
Today’s Veterinary Practice July/August 2011