Feeding & Nutrition

By the age of three, most dogs and cats already show some degree of periodontal disease. The overwhelming majority of them are eating dry food. Those two facts sit uncomfortably beside the oldest claim in pet nutrition, the one everybody has heard and almost nobody has questioned: that kibble scrubs the teeth on the way down.

Watch a dog eat in slow motion and you can see why the claim struggles. Standard kibble is engineered to be brittle so it can be extruded, dried and shipped without turning to dust. It shatters on first contact with the tip of the tooth, sprays crumbs, and is swallowed. Whatever contact happened, happened at the crown, well above the gum line. Periodontal disease begins at the gum line, in the narrow sulcus where plaque presses against soft tissue and the immune system starts a fight it cannot win. The part of the tooth that most needs cleaning is the part ordinary kibble never reaches. Cats are worse: many barely chew at all and swallow pieces whole.

Dry food is not completely equivalent to wet in dental terms, and there is some evidence that all-canned diets go with a little more visible calculus. But the gap is small, and it vanishes next to the difference between a mouth that gets brushed and one that does not. If your dog eats standard kibble, plan his dental care as though he were eating soup.

What a genuine dental diet does differently

There are two honest engineering routes, and a proper dental diet uses one or both.

The mechanical route makes the kibble deliberately large for the size of animal, with plant fibres aligned right through the piece so it holds together instead of exploding. The tooth has to sink into the kibble before anything gives way, and as it sinks, the fibre matrix wipes the tooth surface downward towards the gum. That is a real physical difference rather than a sentence on a bag, and it is why dental kibble looks faintly absurd when you first pour it out. The pieces are far bigger than you expect, and owners who worry the food is the wrong size are usually looking at the point of it.

The chemical route coats the kibble with polyphosphates, typically sodium hexametaphosphate. As the coating dissolves, it binds calcium in the saliva, so the soft plaque film has nothing to mineralise with and cannot harden into calculus. Useful, but be clear about what it achieves. It reduces tartar, the hard cement, rather than plaque, the living bacterial film. Plaque is what inflames the gums. A product that only holds tartar back can leave a mouth looking tidier while the disease underneath carries on quietly, which is exactly why the distinction matters on the packaging.

The only seal worth trusting

The Veterinary Oral Health Council is an independent body that reviews trial data submitted by manufacturers and awards a seal to products that meet a defined standard. Crucially, there are two separate seals, one for plaque control and one for tartar control, and a product may carry either or both. The accepted list is published free online and updated, so you can check a product in about thirty seconds before you buy it.

Nothing else on a dental product's packaging carries any guarantee whatsoever. Helps reduce tartar is a phrase anybody may print. Clinically proven, on a bag with no seal and no citation, means the marketing department liked the sound of it. The seal is not perfect, since a manufacturer has to choose to submit and pay for testing, and some decent products are simply absent. But it is the only shortcut available to an owner standing in an aisle, and it is worth taking.

One caveat that catches people out: the seal is awarded to a specific product fed as directed in the trial. Dental kibble earns its claim as the main diet, not as a handful sprinkled over something else. A dental chew earns its claim at the stated frequency, which is usually every single day. Three chews a week is a treat, not a dental programme.

What the chews cost you

Calories, mostly. A daily dental chew can account for a tenth or more of a small dog's energy needs, and two a day for a terrier is a straight path to a weight problem that will do him far more harm than his gums. Read the kilocalories on the packet, deduct them from the day's food, and weigh the rest. If a chew has no calorie figure printed anywhere, that tells you something about the company.

There is also the hardness question, briefly, because it belongs in any conversation about chewing. If you cannot dent it with a thumbnail, or you would wince at it landing on your kneecap, it is hard enough to snap a slab off an upper carnassial. A chew intended to clean teeth should flex, compress or wear down. Anything that behaves like a rock is not a dental product regardless of what the label promises.

Water additives and oral gels sit in the same category. Several carry the seal, several do not, and they can be a reasonable option for an animal who will not tolerate anything near his mouth. They are an addition rather than a replacement.

Which brings us to the honest bottom line. Brushing with a pet toothpaste, most days, is the standard everything else gets measured against, because it is the only thing that physically disrupts plaque at the gum line where the damage happens. Diet and chews are what you do on top of brushing, and they are genuinely worth doing, especially for the dog who will not let a brush anywhere near him. But no food removes calculus that has already hardened, and no food treats disease below the gum line, where most of the tooth actually lives. That needs a scale, a polish and dental radiographs under anaesthetic. Food can slow the rate at which a mouth falls apart. It has never once reversed it.