Causes of Periodontal Disease in Dogs and Cats

Causes of Periodontal Disease in Dogs and Cats
expert or vet photo
vet verified PetCareRx Staff Veterinarian DVM

Periodontal disease is caused by a number of things, from bacterial build-up to tooth loss. Learn more about this oral disease here.

The conditions that lead up to periodontal disease take some time to build up, but once the initial infections begin, the disease can progress quickly. If allowed to advanced, periodontal disease will cause an entire new set of problems and health risks that could be fatal for your cat or dog. The good news is you can most often avoid serious periodontal disease by taking care of your petโ€™s teeth from a young age and avoid these issues altogether.

Bacterial Buildup

Just as in humans, periodontal disease in cats and dogs is an infection caused by bacteria in the mouth. The root of the problem is poor oral hygiene. If bacteria isnโ€™t washed away from your petโ€™s teeth (through brushing or, in some instances, chewing on appropriate toys and food) it leads to a buildup of plaque and hard tartar on the surfaces of teeth around the gums. Plaque releases toxins that damage bone and tissue surrounding the teeth. In addition, this buildup in the mouth stimulates an immune response that will help destroy the bacteria, but, the same process that eradicates the bad bacteria can damage the attachment of the tooth.

Gum Infections

The rise of bacteria also leads to the development of deep pockets between the teeth and the gums. These get deeper as time passes. The oral pockets may also become infected, which will cause your petโ€™s gums to soften and become mushy. The gums will begin to recede, exposing more and more of each tooth in an affected area of the mouth. Pus may ooze from these infected gums as well. In this state, your petโ€™s breath may have a fetid odor. Also, chewing can be extremely painful for your pet, leading to malnutrition and other health issues.

Tooth and Bone Loss

As the oral pockets deepen, they trap more bacteria and the cycle continues. In the last stages of periodontal disease, your pet will begin to lose teeth and may suffer jaw bone loss. In some small breeds, there may also be fractures resulting from these conditions.

Whoโ€™s At Risk?

Any dog or cat can develop periodontal disease, but small dogs may have a greater risk because they usually donโ€™t chew on toys for play as often (which helps to fights plaque buildup). Small dogs may also have more tooth crowding above the gum, which promotes tartar buildup; this is especially an issue for round-headed breeds such as Pugs, Boston Terriers, Boxers, and Bulldogs.

Cats often face the same dental problems as small breed dogs. Cats are also more likely to develop periodontal disease if they only eat canned food that is soft versus dry food that can require more chewing.

Symptoms of Periodontal Disease in Dogs and Cats

Itโ€™s estimated that 80 percent of dogs and 70 percent of cats show signs of oral disease by age three, although problems can start at a much younger age. While there are several different oral diseases that can affect your pet, periodontal disease is the most common in dogs and cats. Also known as gum disease, periodontal disease can be extremely painful and debilitating. It can also lead to serious health problems in other parts of the body. To avoid complications, you should be aware of these key symptoms, signs that your dog or cat may need periodontal treatment.


Animals are naturally predisposed try to mask pain (a trait thatโ€™s important to survival in the wild but a disadvantage for domesticated pets). This means that you may miss the earliest symptoms of periodontal disease, pain or discomfort. Thus, your pet may not whimper or cry when food or pressure irritates the affected area in the mouth. You may notice, however, that a pet only chews food on one side, refuses to eat, or drops food from the mouths while trying to chew. You may also find that some pets with periodontal disease, especially cats, will have an aversion to hot or cold foods. If you see these signs, check your petโ€™s gums for inflammation, bleeding, and sensitivity.

Bad Breath

You may assume that itโ€™s normal for pet breath to be a bit foul. Whatโ€™s known as โ€œdog breathโ€ or โ€œcat breath,โ€ though, is usually a sign of dental disease. If you notice that pets have bad breath even when they havenโ€™t eaten anything that would cause a bad smell to linger (garbage, feces, unusual food, etc.), you should consider having a veterinarian evaluate your pet.

Other Symptoms to Watch

The pain and inflammation associated with periodontal disease can cause other changes in your petโ€™s appearance and behavior, including:

  • Bleeding along the gum line (especially after you brush your petโ€™s teeth)
  • Vomiting whole pieces of food that werenโ€™t properly chewed
  • Poor grooming in cats
  • Lethargy and lack of playfulness


Without proper treatment and, in some cases, lifestyle changes, your dog is at risk for tooth loss. Also, because periodontal disease weakens bones in the mouth, pets may suffer a jaw fracture. This is most likely to occur in small breed dogs of advanced age. Pets with this condition are also at risk for sepsis, an infection of the bloodstream that can be life threatening.

Studies are increasingly showing that poor oral hygiene can impact a petโ€™s overall health. Periodontal disease may contribute to infections of the heart, lungs, or kidneys; cancerarthritis; and heart failure. It may also aggravate diabetes.

This information is for informational purposes only and is not meant as a substitute for the professional advice of, or diagnosis or treatment by, your veterinarian with respect to your pet. It has, however, been verified by a licensed veterinarian for accuracy.

Was this article helpful?
Periodontal Disease Bad Breath (Halitosis)

You May Also Like

Image for All About Liver Disease in Dogs and Cats
All About Liver Disease in Dogs and Cats

A Serious Condition With Many Causes

Read More