Signs of Dental Disease in Dogs and Cats to Watch For

Most owners notice when a pet stops eating or starts limping. Dental pain is harder to spot, because dogs and cats instinctively hide discomfort. A cat with a sore tooth may keep eating, only a little more carefully. A dog may simply seem a bit quieter.

That’s why dental disease is so often found late. Veterinary sources commonly describe it as one of the most frequent health problems in both species, and many pets show some signs by middle age. The encouraging part is that it’s largely preventable, and early signs are easy to catch if you know what to look for.

The short answer

Persistent bad breath, red or bleeding gums, tartar, and changes in how your pet eats are the main warning signs. Bad breath is not normal, and it’s often the first sign. If you notice any of the signs below, book a vet check. Don’t wait for your pet to stop eating.

What is dental disease?

It starts with plaque, a sticky film of bacteria that forms on teeth after eating. Within days, plaque can harden into tartar (also called calculus), which can’t be brushed off. Bacteria then irritate the gums, causing gingivitis, which is reversible with cleaning. If it continues, the infection reaches deeper tissues and the bone that holds the teeth, causing periodontal disease, which is not reversible, though it can be managed.

Advanced disease can mean pain, loose or lost teeth, abscesses, and bacteria entering the bloodstream. Vets are increasingly concerned about the link between severe dental disease and problems in other organs, though the details are still studied.

Signs in both dogs and cats

Early signs (often missed):

• Bad breath that is strong or doesn’t go away
• Yellow or brown tartar along the gumline, especially on the back teeth
• Slightly red gums along the edge of the teeth

Moderate signs:

• Red, swollen or bleeding gums, particularly when eating or being touched
• Drooling more than usual, sometimes with blood
• Dropping food, or chewing on one side
• Pawing or rubbing at the mouth or face
• Reluctance to eat hard food, or preferring soft food
• Reluctance to have the face or mouth touched

Advanced signs:

• Loose, broken or missing teeth
• Swelling of the face, especially below the eye, which can mean a tooth root abscess
• Pus or a bad-smelling discharge from the mouth
• Weight loss or refusing food
• Pain behaviours, such as hiding, irritability, or reduced grooming in cats
• Nasal discharge or sneezing, which can be linked to a tooth root problem

Signs that are more specific to cats

Cats are especially good at hiding dental pain, and they have some conditions that dogs rarely do:

• Tooth resorption. A common condition where the tooth structure gradually breaks down, often starting at or below the gumline. It can be very painful, and may be visible only on dental X-rays. Signs include drooling, chattering the jaw, or eating strangely.
• Stomatitis. Severe, painful inflammation of the gums and mouth. Signs include a very red mouth, drooling, bad breath, and refusing food. It often needs specialist treatment.
• Reduced grooming. A sore mouth makes grooming painful, so a cat’s coat may become greasy, matted or unkempt. Our guide to grooming a long-haired cat covers coat changes.
• Subtle eating changes. Eating on one side, dropping kibble, or favouring wet food over dry.

A cat that stops eating for more than a day or so needs to see a vet. Cats can become seriously ill quickly when they don’t eat.

Signs that are more specific to dogs

• Broken teeth from chewing hard objects such as bones, antlers or hard nylon chews, which can expose the sensitive inside of the tooth
• Chewing less enthusiastically on toys or treats
• Bad breath that smells sour, or very unpleasant
• Heavy tartar buildup, which is especially common in small breeds
• Facial swelling or a draining sore under the eye or along the jaw

Small dogs are particularly prone to dental disease because their teeth are crowded into small jaws. Our guide to the best food for small dogs covers dental care for small breeds.

What causes dental disease?

• Plaque and tartar that isn’t removed
• Lack of regular brushing and dental checks
• Breed and anatomy. Small and toy breeds, and flat-faced breeds with crowded teeth, are at higher risk
• Age. Disease becomes more common as pets get older
• Hard chews, which can break teeth
• Other health conditions, such as diabetes, which can affect the mouth
• Genetics and individual differences

Does food affect dental health?

Diet can play a supporting role, but it can’t replace brushing and vet care.

• Most kibble doesn’t clean teeth reliably. Many pets swallow it with little chewing.
• Some dental diets and treats are tested for plaque and tartar reduction. Look for specific, evidence-backed claims, such as the Veterinary Oral Health Council (VOHC) seal, and not general words like “dental” on the packaging.
• A complete and balanced diet supports overall health, including the gums. Our guide to reading a pet food label shows what to check, and you can browse our pages on dry food and fresh food.
• Chews and treats add calories, so count them in your pet’s daily food. Our guides to the cost of feeding a dog and how much to feed your cat show how.

Don’t change your pet’s food to treat a dental problem without asking your vet. If a mouth is painful, the answer is treatment, not a different kibble.

How vets diagnose and treat dental disease

A vet will start by examining your pet’s mouth, but much of a tooth lies below the gumline, where you can’t see it. A full assessment usually involves a dental procedure under general anaesthesia, so the vet can:

• Clean above and below the gumline
• Examine every tooth and probe the gum pockets
• Take dental X-rays to check the roots and bone
• Treat or extract damaged or diseased teeth
• Give pain relief

Anaesthesia always carries some risk, and vets assess each pet beforehand, often with bloodwork, particularly for older pets or those with health conditions. Ask your vet about the risks and benefits for your pet.

A note on “anaesthesia-free” dental cleaning. You may see it offered. Many veterinary dental organisations advise against it, because it can’t properly clean below the gumline or find hidden disease, and it can give a false sense of security. Ask your vet what they recommend.

Treatment costs vary widely by region, clinic and the work needed, so ask your vet for an estimate. Pet insurance policies often treat dental care differently, so check what yours covers.

How to prevent dental disease

1. Brush your pet’s teeth.
It’s the most effective step you can take at home. Our guide on how to brush a dog’s teeth shows a gradual, reward-based method, and cats can often be trained the same way with cat toothpaste and a small brush. Use only toothpaste made for pets, never human toothpaste, which can contain ingredients such as xylitol that are dangerous to pets.

2. Ask your vet for regular dental checks.
Include a mouth check at every routine visit, and ask how often your pet needs a professional dental assessment.

3. Choose chews carefully.
Avoid very hard items such as bones, antlers and hard nylon. Look for products with the VOHC seal, and ask your vet which are safe for your pet.

4. Consider dental diets or treats if your vet agrees.

5. Start early.
Get puppies and kittens used to having their mouths handled, with treats and patience.

6. Know your pet’s risk.
Small breeds, flat-faced breeds, and older pets may need more frequent checks.

Check your pet’s mouth at home

Once a week, or while brushing:

1. Lift the lip gently and look at the teeth and gums.
2. Healthy gums are usually pink, though some pets have dark pigmentation, so know what’s normal for yours.
3. Look for tartar, redness, swelling, broken teeth or sores.
4. Smell the breath. A strong, unpleasant smell isn’t normal.
5. Stop if your pet is in pain or objects. Don’t force it, and ask your vet to look.

When to see a vet

Book a vet visit if you notice:

• Persistent bad breath
• Red, swollen or bleeding gums
• Heavy tartar
• Changes in eating, dropping food or chewing on one side
• Drooling or pawing at the mouth
• A broken, loose or missing tooth

See a vet urgently if:

• There is swelling of the face or a draining sore
• Your pet won’t eat for more than a day (cats) or is clearly in pain
• Your pet has blood or pus from the mouth
• Your pet is very lethargic, or the mouth injury is severe

Final thoughts

Dental disease develops quietly, and pets rarely show pain the way we would. Regular brushing, mouth checks at home, and routine vet exams catch problems early, when treatment is simpler. If your pet’s breath has changed, or eating looks different, ask your vet, since the cause is often fixable. For more on choosing a complete and balanced food, see how our reviews work.

Frequently asked questions