Periodontal Disease in Dogs: Signs, Stages and Treatment

By Dr Joe Inglis BVSc MRCVS · Published 2026-10-09

Periodontal disease is an infection of the gums and the structures that hold a dog's teeth in place. It is the most commonly diagnosed health problem in UK dogs, and it is often painful, even though most dogs show few obvious signs. Caught early, it can be reversed. Left untreated, it causes permanent bone loss, infection and tooth loss. This guide explains how periodontal disease develops, how to recognise it, its four stages, and how it is treated.

What is periodontal disease in dogs?

Periodontal disease is inflammation and infection of the periodontium, the group of tissues that support each tooth. These are:

• The gums (gingiva), which seal around the neck of the tooth
• The periodontal ligament, which attaches the tooth root to the jaw
• The cementum, a thin layer covering the root
• The alveolar bone, the part of the jaw that holds the tooth socket

The disease has two phases. Gingivitis is inflammation of the gums only, and it is reversible. Periodontitis is when the infection has spread deeper, destroying the ligament and bone. This damage is permanent.

The word "periodontal" simply means "around the tooth". It's a useful reminder that this disease mainly affects the tissues around and below the tooth, rather than the visible crown.

How common is periodontal disease in dogs?

Periodontal disease is the most commonly diagnosed disorder in UK dogs. A Royal Veterinary College (RVC) VetCompass study of 22,333 dogs attending 784 UK vet practices found that 12.5%, about 1 in 8, were diagnosed with periodontal disease in a single year. The next most common problems, ear infections (7.3%) and obesity (7.1%), were far behind (RVC VetCompass).

The true number is very likely higher. The same study found insured dogs were 30% more likely to be diagnosed than uninsured dogs, suggesting that many cases go unnoticed simply because nobody looks closely. Most periodontal disease is below the gumline and can only be fully assessed under anaesthetic with dental X-rays.

What causes periodontal disease?

Periodontal disease is caused by bacteria in plaque, and by the dog’s response to them. It develops in a predictable sequence:

• Plaque forms. Within hours of eating, a sticky film of bacteria called plaque coats the teeth.
• Plaque hardens into tartar. If not removed, plaque mineralises into tartar (calculus) within a few days. Tartar's rough surface attracts even more plaque.
• The gums become inflamed. Bacteria along the gumline cause gingivitis: red, swollen gums that may bleed.
• Bacteria move below the gumline. Plaque spreads into the gap between tooth and gum, where it can't be reached by chewing or brushing.
• The supporting tissues break down. The dog's immune response to the bacteria, together with bacterial toxins, destroys the periodontal ligament and bone. Pockets form, or the gums recede, and the tooth gradually loses its support.

Tartar itself is not the main problem; it is a sign that plaque has been allowed to build up. The real damage is done by bacteria below the gumline, which is why a dog can have serious disease even if their teeth look fairly clean.

Which dogs are most at risk?

Any dog can develop periodontal disease, but the RVC VetCompass study found that age, size and breed all make a big difference (RVC VetCompass).

• Older dogs. Dogs aged 8 and over were more than three times as likely to be affected as young adult dogs aged 2 to 4.
• Smaller dogs. Dogs under 15 kg were 2.5 times as likely to be affected as dogs weighing 30 to 40 kg. Small jaws often mean crowded teeth, which trap plaque.
• Certain breeds. Some breeds were strongly predisposed:

Other factors that increase risk include crowded or misaligned teeth, retained baby teeth, and a lack of regular tooth brushing. If your dog falls into a higher-risk group, regular dental checks are especially worthwhile.

Signs of periodontal disease in dogs

Dogs rarely show obvious pain from periodontal disease, and most keep eating normally. Owners often put the signs down to old age. Look out for:

• Bad breath that persists between meals
• A red line along the gumline, the first visible sign of gingivitis
• Bleeding gums, or blood on chew toys or in water bowls
• Tartar build-up, yellow or brown deposits, especially on the back teeth
• Receding gums, making teeth look longer or exposing roots
• Loose or missing teeth
• Reluctance to chew, chewing on one side, or dropping food
• Drooling, sometimes stained with blood
• Pawing at the mouth or rubbing the face
• Facial swelling or a discharging wound below the eye, which can mean a tooth root abscess
• Nasal discharge or sneezing, which can happen when disease around an upper tooth breaks through into the nose

The absence of these signs doesn't mean your dog's mouth is healthy. Early and even moderate periodontitis is often invisible without a full examination under anaesthetic.

The stages of periodontal disease

Vets grade periodontal disease from PD0 to PD4, based on how much of a tooth's supporting tissue has been lost. Each tooth is staged individually, so one dog can have healthy teeth alongside badly affected ones. Staging requires probing and dental X-rays under anaesthetic.

Two things matter most for owners. First, only stage 1 is fully reversible. Second, the stage you can see from the outside often underestimates what's happening below the gumline.

Can periodontal disease affect the rest of the body?

Yes. Periodontal disease is not just a mouth problem. Its effects can reach well beyond the teeth.

Effects in and around the mouth

• Chronic pain, which dogs often hide
• Tooth root abscesses, causing facial swelling
• Oronasal fistulas, holes between the mouth and nose caused by bone loss around the upper canine teeth, leading to sneezing and nasal discharge
• Jaw fractures, particularly in small breeds, where disease can weaken the thin lower jaw so much that it breaks with little force

Effects on the wider body: Infected, inflamed gums allow bacteria and inflammatory substances into the bloodstream every time a dog chews. Research has linked periodontal disease with changes in organs such as the kidneys, heart and liver (RVC VetCompass). Exactly how much it contributes to these conditions is still being studied, but reducing a long-term source of infection and inflammation is good for your dog's overall health.

How is periodontal disease diagnosed?

A vet can often spot gingivitis and tartar during a conscious check. To diagnose and stage periodontitis properly, three things are needed, all done under general anaesthetic:

• Periodontal probing. A thin, blunt probe with millimetre markings is gently placed between each tooth and the gum. In a healthy dog it goes in only 1 to 3 mm. Deeper pockets, gum recession, bleeding, and loss of bone between roots all show disease.
• Full-mouth dental X-rays. X-rays show the bone around each root, which can't be seen any other way. They reveal how much bone has been lost, whether there is infection at the root tip, and whether a tooth can be saved.
• Dental charting. Every finding, tooth by tooth, is recorded on a dental chart. This gives an accurate picture of your dog's mouth, guides treatment, and provides a baseline for future checks.

A conscious examination can only show the visible part of the problem. It's very common to find more disease under anaesthetic than was visible beforehand.

How is periodontal disease treated?

Treatment is always carried out under general anaesthetic, with pain relief, and depends on the stage of disease in each tooth.

For all stages, treatment includes

• Scaling above the gumline to remove plaque and tartar from the visible tooth
• Cleaning below the gumline (subgingival scaling), the most important step, as this is where disease does its damage
• Polishing to smooth the tooth surface and slow plaque build-up

For moderate disease, treatment may also include

• Root planing, smoothing the root surface inside periodontal pockets so the gum can re-attach
• Local antimicrobial gels placed into cleaned pockets
• Periodontal surgery, where the gum is lifted to clean deep pockets under direct view, in suitable cases where the owner can commit to daily home care

For advanced disease

• Extraction of teeth that are too damaged to save. Removing a painful, infected tooth is often the kindest option, and most dogs eat normally afterwards.

After treatment, daily home care and regular check-ups are essential. Without them, plaque returns within days and the disease will progress again.

A note on anaesthetic-free dentals: cleaning the teeth of an awake dog only removes visible tartar. It can't clean below the gumline, where periodontal disease happens, and can't include X-rays or probing. Veterinary dental specialists advise against it.

Can periodontal disease be reversed?

Only in its earliest stage. Gingivitis (stage 1) can be fully reversed with a professional clean followed by good daily home care. The gums heal and return to normal.

Once periodontitis has developed (stages 2 to 4), the ligament and bone that have been lost do not grow back. However, treatment can still:

• Stop the disease progressing, saving teeth that would otherwise be lost
• Remove pain and infection, by treating or extracting diseased teeth
• Protect the remaining teeth, through ongoing home care and regular checks

This is why early diagnosis matters so much. The earlier periodontal disease is found, the more teeth can be saved and the simpler treatment is likely to be.

Can periodontal disease be prevented?

Yes. Periodontal disease is largely preventable, because its cause, plaque, can be controlled. The goal is to remove plaque every day, before it hardens into tartar.

• Brush daily. Tooth brushing is the most effective way to prevent periodontal disease. Use a soft brush and a dog toothpaste, never human toothpaste. Focus on the outer surfaces and the gumline, where plaque does the most harm. Brushing a few times a week is far less effective, because plaque starts to harden within days.
• Start early. Puppies who get used to having their mouths handled usually accept brushing for life.
• Add evidence-based dental products. Dental diets, chews and water additives can help, but they support brushing rather than replace it.
• Choose safe chews. Avoid bones, antlers and other very hard items, which can fracture teeth.
• Have regular dental checks. Every 6 months, or more often for small breeds, older dogs and predisposed breeds.
• Treat early. If your vet recommends a professional clean, acting at the gingivitis stage is the best way to avoid permanent damage.

How Luna can help

Luna the Dental Vets is a UK veterinary practice group dedicated entirely to dentistry for dogs and cats. Periodontal disease is the condition we treat most often, and our approach focuses on finding it early and treating it thoroughly.

When your dog visits Luna, you can expect:

• A dental health check to assess your dog's mouth and explain what we can see
• Periodontal probing and full-mouth dental X-rays as standard with every dental procedure
• Detailed charting and staging of every tooth, so you know exactly what was found and why
• Thorough cleaning below the gumline, where periodontal disease does its damage
• Careful anaesthesia and monitoring, with pain relief tailored to your dog
• Clear home-care advice and follow-up checks to keep disease under control
• Bespoke care packages through the Luna Dental Health Club

We have clinics in Bristol, Reading and Eastleigh, with Surbiton opening soon, and we welcome both direct bookings from owners and referrals from your regular vet.

Book a free dental check