There are three layers to the tooth. The outside layer is a thin layer called the enamel. The second layer is under the enamel consists of a hard substance called dentin. The inside of the tooth is called the dental pulp, which is made up of arteries, veins, nerves and connective tissue. 

A tooth can be traumatized in various manners. Tooth trauma and/or a fracture or break can have enamel and dentin missing, pulp exposure with and without bleeding, a dark discolored tooth, a loose tooth or facial swelling over the root of a damaged tooth. Any portion of the root or crown can be broken or damaged. A tooth can even be knocked from its socket (avulsion). 

In cats, tooth fracture can be related to hit-by-car incidents, a fall from a high place, such as out a window, facial trauma from an animal attack or a fractured jaw resulting in tooth fracture. Resorptive lesions, which are destructive lesions in the tooth that cause loss of dentin, can also weaken a tooth leading to fracture. A fractured tooth can occur below the gum line, vertically or horizontally in the tooth. The level (locations or depth) at which the root is fractured helps determine if the tooth can be saved.

Fractured teeth are painful even if the cat does not show much pain. The tooth, facial area, jaws and head can be sensitive and painful. The cat can be head shy or purposely avoid having facial or head contact with the owner. He may drop his food while chewing, not pick the food up properly, or chew properly. Difficulty chewing can lead to inadequate nutrition.

What to Watch For

• Changes in the tooth shape, color or position
• Localized facial swelling or pain
• Reduced biting pressure during play or aggression training
• Reluctance to eat or refusal of food, especially hard or fibrous food. 

Diagnosis of a Fractured Tooth in Cats
Veterinary care should include diagnostic tests and subsequent treatment recommendations. A tooth fracture should be treated as an emergency. If there is pulp exposure, then there probably is increased sensitivity and much pain. A pulp exposure may lead to bleeding and then infection of the pulp inside of tooth. The tooth is usually treated for infection and trauma. Diagnostic tests are needed in tooth trauma cases. Tests may include:

• a complete medical history and physical examination needs to be completed by your veterinarian. Examination for other evidence of trauma should be completed. Jaw and skull fractures can accompany fractures of the teeth;
• dental radiographs (X-rays) may be completed, while under general anesthesia;
• physical examination/evaluation of each tooth may be done with a periodontal probe, a blunt-tipped instrument used to probe under the gums;
• blood chemistries, a complete blood count (CBC), and urinalysis may be suggested to determine the general health of the patient. These tests are also recommended prior to anesthesia

Treatment of a Fractured Tooth in Cats

Treatments for tooth trauma may include one or more of the following:

• if only the dentin is exposed and not the dental pulp, then a fluoride or bonding sealant, the material dentists apply to children's molars at age six and eight that prevents cavities, can be applied. This reduces sensitivity and prevents bacterial invasion of the pulp cavity;
• severely damaged teeth may need to be extracted; 
• more advanced stages of pulp damage require root canal therapy and crown restoration (cast metal crowns). Some teeth will require root canal therapy if the fracture has involved the pulp and there will be redness or bleeding of the pulp. Root canal therapy is superior to extraction in almost all cases. Root canal therapy of functional teeth is much less painful than extractions. Extractions that involve bone loss may require eight to 12 weeks to heal and then the cat is without tooth function;
• early tooth fractures may be treated with direct or indirect pulp capping, designed to save the health of the tooth;
• tooth fractures in the line of jaw fractures, should be left in place if they contribute to fracture stability and after the jaw heals a root canal should be performed;
• an avulsed tooth, or a tooth displaced from the socket, should be repositioned as quickly as possible. Place in whole milk for temporary preservation while waiting for re-implantation by your veterinarian.