Cat dental disease: tooth resorption, gum disease and what home care can do

Quick answer

A comfortable cat: mouth closed, no drool line on the chin, coat smooth because it is still grooming itself.

Dental disease is the most common untreated painful condition in pet cats, and the reason it goes untreated is that cats keep eating.

There are three separate problems, and they need different answers. Gum disease is driven by plaque and is partly preventable at home. Tooth resorption is not caused by plaque and cannot be prevented by brushing. Gingivostomatitis is an immune overreaction and is in a category of its own.

• Halitosis is not "cat breath". It is the earliest sign most owners get, and it warrants an examination.
• Purring does not mean a cat is comfortable. Cats purr in pain and in fear as well as in contentment.
• Most feline dental disease sits below the gumline, so it cannot be assessed by looking, only by radiographs under anaesthesia.
• Brushing is the only home measure with real evidence behind it, and it has to be near daily to matter.
• Cats eat well after extractions, including dry food, and most owners report a livelier cat afterwards.

Decide in 60 seconds

Three diseases, not one

Periodontal disease.

Plaque is a bacterial biofilm that forms on teeth continuously. Where it sits at the gum margin it provokes inflammation, which is gingivitis: a red line along the edge of the gum, reversible if the plaque is removed.

If plaque persists it mineralises into calculus, which is rough and holds more plaque, and the inflammation extends deeper. The attachment between tooth and bone breaks down, the bone recedes, and the tooth loosens. That is periodontitis, and unlike gingivitis it does not reverse.

This is the one that home care genuinely influences.

Tooth resorption.

The cat's own odontoclast cells begin destroying the tooth, usually starting below the gumline. The defect fills with granulation tissue, which is why owners sometimes see what looks like a red spot of gum growing onto a tooth, most often on a lower premolar.

Dentine contains microscopic tubules that connect to the nerve inside the tooth. Once resorption exposes dentine, the tooth is painful, even if the crown still looks reasonably normal.

There is no filling for this. The treatment is removal of the affected tooth. Radiographs decide how: some resorbing teeth still have a normal root and periodontal ligament and must come out completely, while in others the root has been progressively replaced by bone, and removing the crown alone is the appropriate procedure. Guessing between those two without radiographs causes unnecessary trauma in one direction and retained painful root fragments in the other.

The cause is not known. That matters practically, because it means brushing will not prevent it, and an owner who does everything right can still have a cat that needs extractions.

Feline chronic gingivostomatitis.

Severe inflammation that extends past the gums into the tissues at the back of the mouth. It is thought to be an exaggerated immune response to plaque antigen rather than a simple infection.

These cats are in serious pain. They drool, often with blood in the saliva, have marked halitosis, stop grooming, lose weight, and may show the characteristic behaviour of running to the food bowl hungry and then flinching away from it.

The treatment with the best evidence is extraction of the teeth in the affected areas, often most or all of them. Medical management alone usually fails over time. Cats that have full-mouth extractions frequently do strikingly well, and the transformation in behaviour afterwards is a fair measure of how much pain they had been in.

Feline calicivirus and retroviral status are relevant, so expect testing to be discussed.

Why owners miss it

Cats eat through pain. A cat with severe dental disease will keep emptying its bowl, often by swallowing kibble whole with minimal chewing. An empty bowl is taken as evidence that the mouth is fine.

Purring is not a comfort signal. Cats purr when content, and also when frightened, injured or in pain. A purring cat at the vet is often a stressed one.

The changes look like ageing. Sleeping more, playing less, being less tolerant of handling, and a coat that has become unkempt all read as "getting old". Each of them is also what a cat with a sore mouth looks like.

Nothing is visible. The crowns can look reasonably clean while there is significant resorption and bone loss underneath. Lifting the lip is a useful habit, but it does not rule anything out.

The signs, in the order they usually appear

Halitosis. Usually the first thing an owner notices. Bad breath in a cat is not normal and is not a species characteristic.

A red line at the gum margin. Easy to see if you lift the lip in daylight and know what you are comparing against.

Chattering or a jaw shudder. A quick tremor of the lower jaw when the cat eats, or when a specific area is touched, is closely associated with resorptive lesions.

Chewing on one side. Turning the head to chew, dropping food, or leaving one side of the bowl.

A change in food preference. A cat that switches from dry to wet, or that starts leaving anything hard, is telling you something.

Drooling. Particularly persistent, one-sided, or blood-tinged drool. A permanently damp chin with stained fur is significant.

Pawing at the mouth or face rubbing.

Reduced grooming. The coat becomes scurfy, greasy or matted, worst over the back and hindquarters where the cat has to reach furthest.

Behaviour change. Hiding, less interaction, irritability, resenting being touched around the head.

Weight loss. Late, and often the point at which the cat is finally presented.

What it might be instead

The point of this table is not to diagnose at home. It is to explain why the vet will want to examine and test the whole cat rather than only the mouth.

What changes with age and breed

Kittens and young cats. Some cats, particularly certain purebreds including Maine Coons, Siamese, Somalis and Abyssinians, develop severe gingivitis around the time the adult teeth come in. It is not a plaque problem in the usual sense and it needs early veterinary involvement rather than waiting.

Adults. Tooth resorption becomes progressively more common with age and is frequently found in cats that have never shown a clear sign.

Older cats. The likelihood of significant disease is high, and this is exactly where owners are most reluctant to pursue treatment because of anaesthetic worry.

Brachycephalic breeds. Persians and Exotics have crowded and rotated teeth because the jaw is shortened while the teeth are not, which accelerates periodontal disease.

Outdoor cats. More fractured canines from falls and fights, and more cat-bite abscesses that can be mistaken for dental swellings.

The anaesthesia question in an older cat

"He is too old for an anaesthetic" is the most common reason a painful mouth is left untreated, and it deserves a proper answer rather than reassurance.

Age is not a disease. What matters is what else is going on: kidney function, heart function, thyroid status, blood pressure and body condition. Those are assessable, and a modern feline anaesthetic protocol is tailored around them.

The comparison to make is not "anaesthetic risk versus no risk". It is "anaesthetic risk once versus chronic untreated pain, ongoing infection and reduced eating for the rest of the cat's life". Chronic oral infection is not neutral for an older cat with kidney disease.

Ask specifically about pre-anaesthetic bloods, blood pressure measurement, intravenous fluids during the procedure, temperature support, local nerve blocks and the pain relief plan for the days afterwards. A practice that answers those questions readily is giving you the information you need to decide.

What home care can and cannot do

A well-kept coat is indirect evidence of a comfortable mouth. Grooming is one of the first things a cat gives up when it hurts.

Brushing works, and only if it is frequent.

Plaque re-forms within a day and mineralises within days. Weekly brushing does very little. The target is daily, or as close to it as you can sustain.

Build it slowly, over weeks. Start by letting the cat lick a pet-specific enzymatic toothpaste off your finger. Then touch the outside of the cheek. Then lift the lip briefly. Then one or two teeth with a soft brush or a finger brush. The outer surfaces of the upper teeth are where it matters most, and the tongue handles much of the inner surfaces.

Never restrain the head. A cat that is held still learns to avoid the whole procedure, and you will lose the habit permanently.

Never use human toothpaste. It is not intended to be swallowed, some contain fluoride at levels unsuitable for a small animal, and some sugar-free varieties contain xylitol.

Diets and chews can help, with caveats.

Some dental diets use a fibre structure that makes the kibble shear rather than shatter, so the tooth passes through it instead of breaking it. Some products use a coating chemistry that reduces calculus formation. Look for an independent veterinary oral health accreditation on the packaging rather than a marketing claim.

They reduce plaque and calculus. They do not treat existing periodontitis, and they do nothing at all for tooth resorption.

Water additives and gels. Convenient, and the evidence is weaker than for brushing. Reasonable as an addition, not as a substitute.

What does not work. Raw bones, which fracture cat teeth. Hard treats and dry food alone, which is a persistent myth: dry food is not a toothbrush. Scraping calculus off yourself. Anaesthesia-free scaling.

What the vet will do, and what to bring

The conscious examination in the consulting room is a screening step. It shows the crowns, the gum margins and the obvious lesions, and it misses most of what is going on.

The full assessment happens under general anaesthetic: probing around every tooth to measure attachment loss, charting each tooth, and full-mouth dental radiographs. Radiographs are the part that changes decisions, because they show root resorption, bone loss, retained roots from previous extractions and abscessed roots that are invisible from above.

Expect the treatment plan to be made during the procedure rather than before it, because until the radiographs are taken nobody knows what is there. Expect local nerve blocks, and expect to go home with pain relief.

After a dental: what to expect

Cats go home the same day in most cases, sore and subdued, and improve over the following days.

Soft food for a period, as instructed, then usually back to normal. This surprises owners: cats with all their teeth removed eat dry food perfectly well, because they mostly swallow it whole anyway and their tongue and gums manage the rest.

Give every dose of pain relief on time, and never substitute anything from a human cupboard. Paracetamol is lethal to cats.

The change most owners report is behavioural: a cat that plays again, grooms again, comes downstairs again. That change is the most honest measure of what was being tolerated before.

What never to do

Never dismiss bad breath. It is the sign you get earliest and the one that is easiest to act on.

Never accept anaesthesia-free scaling as a treatment.

Never give human painkillers. Paracetamol, ibuprofen and aspirin are all dangerous to cats, and paracetamol is fatal in small amounts.

Never give raw bones or hard chews to clean teeth. They fracture teeth, and a fractured tooth with an exposed pulp is a new painful problem.

Never restrain a cat's head to brush its teeth.

Never conclude that an eating cat is a comfortable cat.

Never leave a broken canine because the cat "seems fine". An exposed pulp is an open route to the root and the bone.

When to get help

The realistic outcome of treating a painful mouth: a cat that rests comfortably, grooms itself, and engages again.

Contact the practice the same day for a cat that has stopped eating entirely, for blood-tinged drooling, for a facial swelling, or for a cat crying when it tries to eat.

Book within the week for halitosis, red gums, jaw chattering, drooling, dropping food, a change in food preference, a coat that has become unkempt, or any lump or asymmetry in the mouth or face.

Book a routine dental assessment as part of every annual health check, and every six months once the cat is older. Feline dental disease is progressive, largely invisible, and painful throughout, and the only way it gets found early is because someone looked for it rather than waited for the cat to complain.

Comfort is the outcome to aim for, and in older cats it is far more often a dental question than owners expect.