Dental disease, and why bad breath is not normal
4 min read · Updated
Sixty-one of the breed profiles on this site mention teeth, and small breeds and flat-faced breeds get their own warning every time. Periodontal disease is the commonest diagnosed condition in dogs and cats, most animals have it by three, and almost none of them show it — because an animal in pain keeps eating.
What is actually happening
Plaque — a film of bacteria — forms on the teeth within hours of cleaning. Left there, minerals in saliva turn it into tartar, which is hard, rough, and gives more plaque somewhere to stick.
The bacteria at the gum line cause gingivitis: red, swollen gums that bleed easily. That part is reversible.
What follows is not. The inflammation spreads below the gum, destroying the ligament and bone that hold the tooth in place. The tooth loosens, the root becomes exposed, abscesses form, and eventually teeth are lost. That is periodontitis, and it does not go back.
The visible tartar is the least of it. Most of the damage is below the gum line, where nothing can be seen without dental radiographs — which is why a proper assessment happens under anaesthesia with x-rays rather than by looking in the mouth.
Why nobody notices
Animals do not stop eating because their mouth hurts. Eating is not optional, and a dog or cat with severe dental pain will chew on the other side, swallow food whole, or simply push through it.
So the signs are indirect, and each is easy to explain away. Bad breath, which is very often dismissed as normal — it is not. Dropping food. Chewing on one side. Pawing at the face. Drooling, sometimes with blood in it. Reluctance to have the head touched. A cat that has become grumpy or withdrawn.
Weight loss and going off food are late signs.
The most common thing owners report after a dental procedure is that the animal became noticeably brighter and more playful — which tells you what it had been living with.
Cats have a problem of their own
Tooth resorption affects a large proportion of adult cats — figures between a third and a half are commonly reported — and it is not caused by plaque.
The body begins to resorb the tooth itself, from the root inward. The crown eventually breaks away, and the exposed nerve is intensely painful. A red spot at the gum line where it meets the tooth is often the only visible clue.
It is diagnosed on dental radiographs and treated by extraction. There is no way to prevent it, and no way to find it by looking.
This is the strongest argument for a proper dental assessment in an older cat even when the mouth looks reasonable.
What actually works
Brushing is the only thing that reliably removes plaque before it hardens, and it has to be near-daily to beat the timeline — plaque mineralises within a couple of days.
Use a pet toothpaste. Human toothpaste is not safe: fluoride is not meant to be swallowed in these quantities, and any product containing xylitol is dangerous to dogs even in small amounts.
Start young and go slowly. A week of just letting the animal lick paste off a finger, then a few teeth, then more, builds something that lasts fifteen years. Starting on an adult is harder but entirely possible.
Dental diets, water additives and chews help at the margins. Look for products carrying the Veterinary Oral Health Council seal, which means they were actually tested rather than merely marketed.
And hard chews cut both ways. Antlers, bones, hooves and hard nylon toys are a common cause of fractured teeth — the slab fracture of a large upper premolar is a classic. If it does not flex under a thumbnail, it is hard enough to break a tooth.
The thing to avoid
Anaesthesia-free dental cleaning is offered in salons and at pet shops and it is not a substitute for veterinary dentistry.
It scrapes visible tartar from the crown, which is the part that looks bad and matters least. It cannot clean below the gum line, where the disease is, and it cannot take radiographs to find resorptive lesions or root abscesses. The animal is left with teeth that look better and disease that is unchanged, and the owner is reassured.
It also involves restraining a conscious animal while sharp instruments are used in its mouth, which the veterinary dental colleges have been clear about.
Anaesthesia is the common objection, and it is understandable. Modern protocols with pre-anaesthetic bloods, intravenous fluids and monitoring are far safer than they were, and for most animals the risk of leaving painful infected teeth in place is meaningfully higher than the risk of the anaesthetic.