Cavities in Dogs

Cavities, also known as caries, is the term for infected areas of tooth decay caused by the loss of calcium in the enamel, or coating, of a tooth. While dental disease is an overwhelming problem in dogs and over 80% of dogs three and older are affected by a dental disease, tooth decay and cavities are extremely rare in dogs.

While the shape of human’s teeth in horizontal crowns predisposes us to retain food deposits in our teeth, the cone-shaped teeth of a dog make it more difficult for cavities to form. While dental cavities are rare, with only around 5% of dogs affected with a cavity, it is a serious problem that should be watched for. No breed and neither sex are more likely to develop cavities, and cavities can develop at any age.

The only symptoms are the visual appearance of cavities themselves, so it is important to examine regularly your dog’s teeth yourself and to bring your dog in for regular dental check ups. Cavities can form in teeth that are growing too close together (between teeth) and in pockets between the teeth and gums (at the root of the tooth). The most common site of cavities in dogs is the pit of both the top and bottom maxillary first molar because it features deep grooves in the surface and pits where the bottom molar meets the top tooth. When you hold your dog’s mouth open, the maxillary first molar is the second-to-last tooth in the back. The maxillary molars are the least sharp of your dog’s teeth and the ones most closely resembling human teeth.

Cavities in dogs look similar to human cavities and can be found in two different types:

• Incipient cavities, or those about to form may be seen as a dull spot in the enamel.
• Cavities already formed will appear as a structural defect on the surface of the tooth accompanied by an area of dark, decayed dentin (the layer just below the enamel).

Oral hygiene is a constant homeostatic balance between the minerals in your dog’s tooth, enamel and the enzymes in your dog’s saliva, and the cause of cavities is retention of fermentable carbohydrates on the tooth surface, which leads to plaque and demineralization. Bacteria on the tooth surface ferments carbohydrates, causing demineralizing acids to develop and attack the tooth’s dentin and enamel. Eventually oral bacteria and white blood cells actually digest the tooth itself.

The development of cavities is caused by:

• Poor oral hygiene
• Poor diet, high in fermentable carbohydrates—which can be very poor quality dog food, or excessive feeding of high-carb table scraps like bread
• Poor overall health
• Teeth formed abnormally close together
• Gaps between the teeth and gums
• Low salivary pH
• Poorly mineralized tooth enamel

Because dental problems are so prevalent in dogs (even though cavities are not), all dogs can benefit from tooth brushing, special treats designed to clean teeth, and regularly chewing on tooth cleaning and strengthening toys. However, dogs with crowded teeth, gaps between teeth and gums carry a higher predisposition and an enhanced need for better oral hygiene. The above factors can be found in any dog; however, some small breeds and breeds with short faces are predisposed, such as:

• Brussels Griffon
• English Bulldog
• French Bulldog
• Shih Tzu
• Lhasa Apso
• Pug
• Chihuahua
• Pomeranian
• Poodle (toy, miniature, and full)
• Dachshund
• Yorkshire Terrier

Diagnosis will require a thorough dental exam, very similar to your trip to the dentist and involving visual exploration as well as tapping on possible cavities with a sharp instrument in order to see if the area remains hard or yields. An x-ray will also be taken in order to determine the extent of the cavity. Cavities may accompany other dental issues, and the veterinarian will further examine for periodontal disease (gum disease) or fractured teeth. Cavities will be diagnosed according to the following schedule:

• Stage 1: Only enamel affected
• Stage 2: Enamel and dentin affected
• Stage 3: Enamel, dentin, and pulp chamber affected
• Stage 4: Structural crown damage
• Stage 5: Majority of crown lost, roots exposed

Treatment of cavities will depend upon the stage. If you have caught a cavity before it has developed, the veterinarian may use a fluoride varnish or fluoride bonding agent in order to protect the tooth from cavity development. These cases are considered reversible, as the fluoride will encourage remineralization of the tooth until it can restore itself.

However, if a cavity or cavities have already formed, the case is considered irreversible, and treatment will depend upon the progression:

Stage 1 and 2

In the first two stages, the carious dentin and enamel surrounding it will be removed, and the crown will be restored with an amalgam filling.

Stage 3

Stage 3 cavities may be endodontic disease, in which a tooth dies as a result of blood being prevented from entering the root canal. This will be treated by a root canal, which involves removal of the diseased pulpal tissue, disinfecting and scrubbing of the root canal, filling of the root canal with inert material and the restoration and sealing of the crown. There may be cause to treat gum disease before it spreads to the bone. This will be done by treating the gum tissue itself through cleaning, rinsing, and reattaching to the tooth and root.

Stage 4 and 5

Stage 4 and 5 cavities will likely necessitate the total removal of the tooth, and a sealant may be used on surrounding teeth in order to ensure further cavities do not form. There may be cause to treat gum disease, which may have already spread to the bone. Depending upon the extent, estimated duration, and area of the bone loss, the veterinarian may open the gum flap, clean the diseased tissue and reattach it, or may remove the diseased tissue and then utilize therapy to encourage new gum tissue.

If a tooth has been removed, you will need to schedule a follow-up appointment. In any case, be sure to monitor the affected tooth or teeth yourself in order to watch for abnormalities, in addition to getting in the habit of regularly checking your dog’s oral health. Get to know your dog’s mouth, and in addition to checking the affected area, keep an eye on your dog’s entire mouth and watch for changes. Get in a regular habit, checking your dog’s mouth at the same time every week. 

The veterinarian will likely prescribe brushing with dog-specific toothpaste, and tooth-strengthening or cleaning toys and treats. Additionally, discuss your dog’s diet prior to developing cavities in order to seek the veterinarian’s advice and make sure you are adhering to a diet for your dog that ensures optimal dental health.

Cavities can be expensive to treat. To avoid high vet care expenses, secure pet health insurance today. The sooner you insure your pet, the more protection you’ll have from unexpected vet costs.