Dental health in dogs and cats: tartar is not a cosmetic problem

Plaque is a bacterial biofilm that reforms on the tooth surface within hours of a cleaning. It is soft, colourless and sticky, and rinsing does not remove it. If it is not taken off mechanically, minerals in saliva harden it within a few days into calculus, a rough solid layer. Calculus itself does not attack the tooth: the damage is done by the plaque that keeps settling on and under it, because a rough surface holds bacteria far better than smooth enamel.

This is why removing only the visible tartar on the crown has almost no effect on oral health. What matters is hidden in the gingival sulcus, where anaerobic bacteria trigger inflammation of the tissues that hold the tooth in place: gum, periodontal ligament, root cementum and alveolar bone. Together these structures form the periodontium, and their progressive destruction is periodontal disease.

Periodontal disease is staged according to how much bone and connective attachment has been lost. The clinically decisive line is between the first stage, gingivitis, and everything after it: gingivitis is reversible, attachment loss is not. A tooth that has lost bone does not grow it back, and every later intervention slows progression rather than reversing it.

Staging is done tooth by tooth and cannot be judged by looking into the mouth from outside: it needs a calibrated periodontal probe measuring sulcus depth on every surface, and it needs intraoral radiographs to see bone. The same animal can carry healthy teeth, teeth with gingivitis and teeth that need extracting.

The first sign is almost always breath. Unpleasant breath in an adult animal is not normal and does not come from the food: it is the smell produced by anaerobic bacteria in periodontal pockets. The other signs are subtler and get read as ageing or as personality.

• Persistent breath that gets worse over time, even right after a meal.
• A bright red gum margin, or bleeding when the lip is lifted.
• Chewing on one side only, food dropping from the mouth, pieces swallowed whole.
• A sudden preference for wet or soaked food in an animal that used to eat dry.
• Discomfort when the head is touched, pawing at the muzzle, head shaking.
• Increased drooling, sometimes with traces of blood on toys or in the bowl.
• Swelling below the eye, which can point to an abscess at the root of an upper premolar.

In cats, alongside periodontal disease, two specific conditions change how checks should be planned. The first is tooth resorption, a lesion in which the hard tissue of the tooth is progressively destroyed and replaced by bone like tissue. It is common in adult cats, it is painful, and in its early phases it is invisible to the naked eye because it starts below the gum or inside the root. Only intraoral radiographs reveal it, and the classic clinical sign is a chattering of the jaw when the lesion is touched with a probe.

The second is chronic gingivostomatitis, a severe widespread inflammation of oral tissues that extends beyond the gum margin into the back of the mouth. It is painful and frustrating to treat, and the animal's own immune response to plaque plays a central role. In resistant cases the best documented treatment remains extensive extraction of the affected teeth, which sounds drastic to many owners and which in practice gives the cat back a mouth that no longer hurts.

• A cat that approaches the bowl and walks away without eating needs an oral examination, not a change of food.
• Jaw chattering during the examination is a sign of pain, not a reflex.
• Saliva staining the fur under the chin is often the first thing owners report.
• Gradual weight loss in an older cat can start in the mouth before it starts in the kidneys or the thyroid.

A complete oral hygiene session includes steps that simply cannot be done on a conscious animal: periodontal probing of every surface of every tooth, full mouth intraoral radiographs, scaling above and above all below the gum line, polishing and, where needed, extraction with closure of the site. Subgingival scaling is the therapeutic part; everything else is preparation or finishing.

Radiographs are not an optional extra. Studies comparing visual examination with full mouth radiography found clinically relevant lesions in teeth that looked normal in roughly one dog in four and roughly four cats in ten. Without imaging, a substantial share of the disease stays in the mouth after the session.

Fear of anaesthesia is understandable and deserves data rather than generic reassurance: pre anaesthetic testing proportionate to age and disease, a protocol chosen for the individual patient, fluid therapy, instrumental monitoring and temperature control, pain management started before rather than after the procedure. In an older animal a well managed anaesthetic risk is almost always smaller than the harm of a chronic oral infection left in place for years.

Brushing remains the only method with documented efficacy for removing plaque before it mineralises. Everything else reduces deposits rather than eliminating them. The obstacle is not the dog or the cat: it is the approach, because almost everyone tries to brush the whole mouth on the first attempt and ends up with an animal that runs away from then on.

1. 1

   Start with the taste only

   For a few days let the animal lick veterinary toothpaste off your finger, without touching the mouth. Human toothpaste should not be used: it contains fluoride in amounts meant to be spat out, and often xylitol, which is dangerous for dogs.

2. 2

   Then a finger on the gum

   Lift the lip and run your finger with the paste along the outer surface of the canines for a few seconds. You stop before the animal walks away, so the session always ends well.

3. 3

   Introduce the brush

   A soft bristled brush or a finger brush, angled towards the gum margin, with short strokes. The outer surface collects most of the plaque, and the inner surface can be skipped without losing much.

4. 4

   Build the daily routine

   Thirty seconds per side, every day, always at the same point in the day. Tying the habit to something already established, such as coming back from the walk, works better than any reminder.

Dental diets and chews have a real but partial effect: they work by mechanical abrasion or through additives that hinder mineralisation, and they mostly reach the back teeth. Independent bodies review the evidence submitted by manufacturers and publish lists of products that have passed efficacy testing: looking for that recognition is more useful than reading the packaging. They remain a complement to brushing, not a replacement.