Is Periodontal Disease Contagious in Dogs? 9 Crucial Vet Tips

In our society, telling someone they have “dog breath” is a huge insult. We all know dogs have gross-smelling breath. And the older a dog gets, the more his breath stinks. But some dog owners don’t realize it’s a sign of periodontal disease. But is periodontal disease contagious in dogs? Let’s go over how they get it and how you can help them avoid it.

Is Periodontal Disease Contagious in Dogs?

There is no scientific evidence that periodontal disease is contagious in dogs. Researchers have observed transmission of oral bacteria between dogs and humans as well as between dogs. But it has never been shown that transmitted mouth bacteria leads to periodontal disease in an otherwise healthy dog’s mouth. (5, 6, 7, 2)

Technically, a contagious illness could result in a periodontal tissue lesion because the term “periodontitis” refers to any disease of the tissues around a tooth. Once more, this is quite unusual and would typically result in additional symptoms.

Contagious causes of oral lesions in dogs include viral and bacterial infections including: 

  • Distemper virus
  • Transmissible venereal tumor
  • Tularemia
  • Viral warts

Is Periodontal Disease Hereditary in Dogs?

The majority of veterinary dentists think that heredity is one of several variables that contribute to periodontal disease. Small breed dogs are more likely than medium and large breed dogs to have periodontitis.

A 2015 study discovered a link between the existence of particular genes and the propensity for a dog to have periodontal disease. (1) The hypothesis that periodontal disease in dogs is inherited needs additional scientific support.

What Is Dog Periodontal Disease?

Canine dental anatomy and human dental anatomy are very similar. The tooth and the periodontal tissues make up the primary structures. 

The tissues that encircle a tooth are referred to as the periodontium. The gums, periodontal ligament, cementum and bone immediately around the tooth make up the periodontium.

When any disease process affects the periodontal tissues, we call it periodontal disease. Some people call it gum disease. Immune-mediated processes, infectious disease and oral cancer can all affect the periodontium but these are not the most common causes of the disease in dogs. 

blonde dog lying on back (is periodontal disease contagious in dogs)
Who wouldn’t want to kiss this dog’s cute face?

What Causes Periodontal Disease in Dogs?

Accumulation of bacterial plaque is the main cause of periodontal disease in dogs. Plaque is like a slime layer on the teeth. It develops on teeth when normal bacteria in a dog’s mouth interact with food particles.

It’s normal for dogs to have a thin layer of plaque on their teeth, but as time passes it thickens and promotes the growth of troublesome anaerobic bacteria. Salivary minerals mix with the plaque and form a hard brown crust you’ve probably seen in a dog’s mouth. 

Scientists don’t fully understand how plaque leads to periodontal disease. But they believe that “bad” bacteria overwhelm “good” bacteria. The bacteria and the dog’s body produce inflammatory chemicals that collect in the area, eventually destroying the delicate tissues around the tooth. 

Interestingly, some dogs can have a lot of plaque and no signs of periodontal disease. Clearly, the presence of plaque is not the only factor in the development of periodontal disease in dogs. It’s likely a combination of genetics, general health and diet that determine whether a dog’s mouth stays healthy or gets dental disease.

Periodontal disease is more prevalent in older canines. Japanese researchers looked at a group of dogs that ranged in age from under two years old to thirteen years old. None of the dogs under the age of two had periodontal disease. Older dogs in the study had higher prevalence of periodontal disease as well as more types of pathogenic bacteria. (4)

What are the Symptoms of Dog Periodontal Disease?

It’s pretty common for dog owners to overlook their pet’s dental disease. Dogs don’t always show symptoms. Sometimes your vet needs oral radiographs and an anesthetized dental exam to make a diagnosis. 

Symptoms of dog dental disease you might be able to see: 

  • Bad breath
  • Recessed gums
  • Bleeding gums/gingivitis
  • Oral pain
  • Increased drooling
  • Hesitance to eat or only wanting soft food
  • Dropping food while eating
  • Chewing strangely or on one side only
  • Crying out while playing with a chew toy
  • Facial swelling
  • Pus seen at the gumline
  • Loose teeth
  • Missing teeth

The mere absence of any of these signs does not guarantee that your dog’s mouth is in good health. Many issues are found only with intraoral radiographs and a full dental exam on an anesthetized animal.

What are the Stages of Periodontal Disease in Dogs?

The severity of canine periodontal disease is quantified by veterinarians using a specific system. Full dental staging requires mouth radiographs and an anesthetized oral exam. A general outline of the stages of dental and periodontal disease is as follows:

Stage 0: Normal gum tissue and deep periodontal anatomy. 

Stage 1: Gums are inflamed but there is no attachment loss of periodontal tissue from the tooth

Stage 2: 1-25% loss of periodontal tissue attachment

Stage 3: 26-50% loss of periodontal tissue attachment

Stage 4: 51-99% loss of periodontal tissue attachment

dog's mouth showing signs of periodontal disease
Be glad this photo of a dog with periodontal disease is not scratch and sniff!

How Do You Treat Periodontal Disease in Dogs?

The unfortunate fact is that periodontal disease cannot be reversed. The only option is to halt the disease’s progression once the tissues have gotten inflamed and separated from the tooth.

It’s necessary to first identify all the diseased tissue before treatment can begin. This may include tooth root abscesses and bone loss. Severely diseased teeth may not be salvageable and they are extracted so the remaining tissue can heal. 

In addition to identifying and treating diseased oral tissue, the vet will also clean the plaque and calculus from the remaining teeth. Antibiotics and other medication may be applied to stop the progression of periodontal disease. 

Ongoing home care of your dog’s teeth is a crucial part of halting periodontal disease. The best thing you can do to maintain your dog’s oral health is to brush his teeth once a day, every day. There are some additional steps you can discuss with your vet including the use of water additives and special treats to help control oral plaque.

Can You Prevent Periodontal Disease in Dogs? 

Periodontal disease in dogs is preventable in most cases. 

Brushing your dog’s teeth twice a day is the best approach to stop periodontal disease. Daily brushing removes the soft, thin layer of plaque that is constantly developing on a dog’s teeth. If it’s not removed regularly, plaque hardens into calculus that can’t be removed by brushing.

Many of my clients believe that having their dog’s teeth brushed by the groomer every three months is sufficient. It isn’t! Plaque must be removed with daily brushing.

What about giving your dog water additives and dental treats? While they may help a dog’s oral hygiene, they are not a replacement for daily tooth brushing. 

When you get into the habit of brushing your pup’s teeth daily, you’ll also be examining his mouth daily. Then you can catch problems early before tooth loss occurs.

When you take your dog to the vet for annual or semiannual exams, ask your vet how your dog’s teeth look. If they recommend a dental cleaning, do it! Timely dental care may be inconvenient but it can make a huge difference in a dog’s health and quality of life. 

Many people worry about the safety of anesthetizing their dog. While there are always some risks involved, vets have come a long way with anesthesia safety. Thousands of dogs have safe, anesthetized dental cleanings every day in this country and the rate of adverse events is low. 

Discuss your concerns with your vet. If your dog has a disease that makes anesthesia riskier, they may recommend referral to a specialist. 

How Long Can Dogs Live with Periodontal Disease?

Very few dogs die from periodontal disease. Many dogs have periodontal disease for years on end. And even when a dog loses all of its teeth as a result of disease, the situation in their mouth usually improves!  

Periodontal disease can exacerbate other illnesses. Heart, liver, and renal disorders may be influenced by ongoing inflammation and harmful bacteria. (3) Oral discomfort can also make a dog eat less, which makes it harder for them to fight infections.


Dogs and humans can transmit oral bacteria to each other through close contact. Some of these bacteria can be involved in periodontal disease. However, it is unknown whether this sharing of bacteria actually causes periodontal disease in dogs or humans. 

Most cases of periodontal disease in dogs are not contagious. I consulted veterinary dental specialists about this topic. Their opinion was that it’s unlikely a healthy dog would develop periodontal disease from bacteria transmitted from a dog with periodontal disease

There are a few rare contagious causes of inflammation of a dog’s periodontal tissues. Dogs affected by contagious diseases almost always have other symptoms besides inflamed oral tissues.

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  1. Albuquerque, C., Morinha, F., Magalhães, J., Requicha, J., Dias, I., Guedes-Pinto, H., … & Viegas, C. (2015). Variants in the interleukin-1 alpha and beta genes, and the risk for periodontal disease in dogs. Journal of genetics, 94(4), 651-659.
  2. Beikler, T., Bunte, K., Chan, Y., Weiher, B., Selbach, S., Peters, U., … & Flemmig, T. F. (2021). Oral microbiota transplant in dogs with naturally occurring periodontitis. Journal of dental research, 100(7), 764-770.
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  6. Preus, H. R., & Olsen, I. (1988). Possible transmittance of A. actinomycetemcomitans from a dog to a child with rapidly destructive periodontitis. Journal of Periodontal research, 23(1), 68-71.
  7. Yamasaki, Y., Nomura, R., Nakano, K., Naka, S., Matsumoto-Nakano, M., Asai, F., & Ooshima, T. (2012). Distribution of periodontopathic bacterial species in dogs and their owners. Archives of oral biology, 57(9), 1183-1188.