Moderate severity

Periodontal Disease

The slow, progressive destruction of the tissues that hold a tooth in place — gum, ligament and bone — driven by plaque and tartar building up along and under the gumline. It is the most common disease of adult cats, largely painless-looking until it is advanced, and by middle age most cats have some degree of it.

⚠️ Common symptoms

Bad breath (halitosis), often the first thing an owner noticesRed, swollen or bleeding gums, especially a red line where gum meets toothYellow-brown tartar built up on the teeth, worst on the back cheek teethDropping food, chewing on one side, or pawing at the mouthDrooling, sometimes tinged with bloodA reluctance to eat hard food, or going off food altogetherLoose, discoloured or missing teeth in advanced casesA dull coat from grooming less because the mouth hurts

The most common disease in cats — and the easiest to miss

By the age of three, the majority of cats already have some degree of periodontal disease, yet most owners never suspect it. Cats are experts at hiding oral pain: they keep eating, keep grooming, and give almost nothing away until the disease is well advanced. The mouth, meanwhile, is quietly being damaged one tooth at a time.

How it develops

Everything begins with plaque, the invisible film of bacteria that coats teeth within hours of a cleaning. Where plaque meets the gumline it provokes inflammation — this early, reversible stage is gingivitis, seen as a red, sometimes bleeding margin along the gum. If the plaque is not removed it mineralises into tartar, a hard brown crust the tongue and dry food cannot dislodge. Bacteria then work their way beneath the gum, and the body's own inflammatory response begins to dissolve the ligament and bone holding the tooth. This deeper, irreversible stage is periodontitis. Bone lost here does not come back; the goal from that point is to stop the loss going further.

Why it matters beyond the mouth

Advanced periodontal disease is genuinely painful and can make a cat eat less, lose weight and groom poorly. The chronic infection is not sealed off in the mouth either — the bacteria and inflammation can burden the kidneys, liver and heart over time, so dental health is part of whole-body health, not a cosmetic extra.

What treatment involves

Because most of the damage is below the gumline, a proper assessment needs a general anaesthetic, full-mouth dental X-rays and probing of every tooth — the same standard of care a dentist would give. Tartar is scaled away above and below the gum, teeth are polished, and any tooth too far gone is extracted. Owners often worry about extractions, but a cat with a few sore teeth removed is a cat relieved of constant pain, and they eat happily afterwards, dry food included.

The part that is up to you

No cleaning lasts if plaque simply rebuilds. Daily brushing with cat toothpaste is the single most powerful home defence, and it is worth persevering with a slow, treat-led introduction. Where a cat truly will not tolerate a brush, VOHC-accepted dental diets, chews and water additives are a real second-best. Paired with a yearly vet check to catch gingivitis while it is still reversible, this routine is what keeps a cat's mouth comfortable for life.

🔍 Causes

It starts with plaque — a sticky film of bacteria that forms on teeth constantly. Within days plaque mineralises into hard tartar that brushing cannot shift, and the bacteria at the gumline trigger inflammation (gingivitis). Left there, the inflammation spreads below the gum and begins destroying the ligament and bone anchoring the tooth (periodontitis). Feeding soft food only, crowded or misaligned teeth, a flat-faced breed's crammed jaw, and simply getting older all speed it up, as does any illness that lowers the immune response. Some cats also suffer tooth resorption alongside it, which is separate but often found at the same cleaning.

🛡 Prevention

Daily toothbrushing with a pet toothbrush or finger brush and cat-specific enzymatic toothpaste (never human toothpaste, which is toxic to cats) is by far the most effective thing you can do — it physically removes plaque before it hardens. Introduce it slowly and make it rewarding. Where brushing is not possible, veterinary dental diets, dental treats, and water or food additives carrying the VOHC (Veterinary Oral Health Council) seal of acceptance genuinely help. Routine annual vet checks catch gingivitis while it is still reversible, and prompt professional cleanings stop it progressing. Prevention is easier, cheaper and kinder than treating advanced disease.

💊 Treatment

Periodontal disease is diagnosed and treated by your vet, and the cornerstone is a professional dental cleaning under general anaesthetic — the only way to clean below the gumline, take dental X-rays and probe each tooth, because much of the damage is hidden under the gum. Tartar is removed by scaling, the teeth are polished, and any teeth too diseased to save are extracted; cats generally cope very well and are far more comfortable once painful teeth are gone. Early gum inflammation (gingivitis) can be reversed at this stage, but bone already lost to advanced disease does not grow back, so the aim then is to halt further loss. Your vet may prescribe pain relief or a short course of antibiotics around the procedure. The real treatment is what happens afterwards: daily home care to keep plaque from rebuilding.

When to see a vet: Book a vet check if you notice bad breath, red or bleeding gums, visible tartar, drooling, or any change in how your cat eats — dropping food, chewing on one side or going off hard kibble. Cats hide oral pain remarkably well, so waiting for a cat to 'act painful' means waiting far too long; by the time a tooth is loose the disease is advanced. A mouth that smells or bleeds is never normal and always warrants a professional dental assessment.

⚕️ Medical disclaimer

  • This information is educational only and is not a substitute for veterinary advice.
  • Symptoms overlap between conditions — only a vet can diagnose accurately.
  • Never withhold treatment or self-medicate based on information found online.
  • When in doubt, call your vet. Early intervention almost always leads to better outcomes.

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