🦷 The Science of Dog Teeth

🔢 42 Teeth — And Each One Has a Job

An adult dog has 42 permanent teeth — ten more than an adult human's 32. These teeth are not random; each type is precisely shaped for a specific function that reflects the dog's evolutionary past as a predator and scavenger.

✂️ The Carnassial Teeth — Nature's Scissors

If you had to pick the most impressive teeth in your dog's mouth, it would be the carnassial pair. These are the upper fourth premolar and the lower first molar on each side — four teeth in total that work together as a shearing mechanism found only in the order Carnivora. Humans don't have anything like them.

When a dog chews, the carnassial teeth slide past each other in a scissor action rather than meeting flat like human molars. This is why dogs tilt their heads when they chew — they are positioning the food onto the carnassials for maximum shearing efficiency. These teeth can slice through muscle, tendon, and even small bones with remarkable ease.

The carnassial teeth also generate the highest bite force in the mouth. Research published in Frontiers in Veterinary Science measured bite forces at different tooth positions and found that the carnassials produced forces ranging from 310 to over 3,400 Newtons — significantly more than the canine teeth at the front.

🐶 Dog Teeth vs Human Teeth

Although dog and human teeth are made of the same materials (enamel, dentine, pulp, and cementum), the differences in shape, number, and chemistry are striking.

🛡️ Why Dogs Almost Never Get Cavities

Cavities (dental caries) affect nearly 90% of adult humans at some point in their lives. In dogs, the figure is less than 5%. This isn't luck — it's chemistry, anatomy, and diet working together.

• Alkaline saliva: Dog saliva has a pH of around 7.5–8.0, compared to human saliva at 6.5–7.0. This more alkaline environment neutralises the acids produced by bacteria that would otherwise dissolve tooth enamel. It's a built-in buffer system
• Tooth shape: Most dog teeth are conical and pointed. Cavities need flat surfaces where food residue can sit and bacteria can colonise. Dog teeth simply don't provide those surfaces — with the exception of the flatter molars at the back, which is where the rare dog cavity almost always occurs
• Wider spacing: Dogs have much more space between their teeth than humans. Food doesn't get trapped and rot in the gaps the way it does in our tightly packed teeth
• Low sugar diet: Dogs don't eat processed sweets, fizzy drinks, or starchy carbohydrates in the quantities humans do. The bacteria that cause cavities need fermentable sugars to produce acid — and a typical dog diet provides very little of that
• Low amylase: Dog saliva contains very little amylase, the enzyme that breaks down starch. In humans, amylase starts digesting starchy food while it's still in your mouth, creating a sugar-rich environment. Dogs skip this step entirely

💪 Bite Force — How Hard Can Your Dog Bite?

Bite force is measured in PSI (pounds per square inch) or Newtons. It varies enormously between breeds, primarily based on skull shape, jaw muscle mass, and the size of the zygomatic arch (cheekbone) — which is where the major jaw muscles attach. Bigger cheekbones mean bigger muscles and a stronger bite.

🐾 The Puppy Teeth Timeline

Dogs go through teething much faster than humans. A child takes years to lose their baby teeth; a puppy does it in a matter of weeks. Here's what happens and when:

🐶 Breed Differences — When 42 Teeth Don't Fit

Every dog, from a Chihuahua to a Great Dane, has the same 42 adult teeth. But not every dog has the same amount of space for them.

Brachycephalic Overcrowding

Flat-faced breeds — Pugs, French Bulldogs, English Bulldogs, Boston Terriers, Shih Tzus — have been bred to have dramatically shortened skulls. But their teeth haven't shrunk to match. The result is 42 full-sized teeth crammed into a jaw that may be half the length of a typical dog's. This causes overlapping, rotation, and impaction, all of which trap food, accelerate plaque buildup, and significantly increase the risk of gum disease.

Retained Deciduous Teeth

Sometimes a baby tooth doesn't fall out when the adult tooth pushes through, resulting in a "double tooth" — two teeth occupying the space meant for one. This is called a persistent or retained deciduous tooth. It's most common in small breeds: Yorkshire Terriers, Maltese, Pomeranians, and Chihuahuas are particularly prone. The most frequently retained teeth are the upper canines, followed by the lower canines, then the incisors.

Retained baby teeth are not just cosmetic. They cause overcrowding, trap food between the two teeth, and can force the adult tooth to erupt in the wrong position, leading to a misaligned bite (malocclusion). If your vet spots a retained baby tooth, they will usually recommend extraction under anaesthetic.

⭐ Fascinating Teeth Facts

• Dogs don't chew their food properly — they are designed to tear food into chunks small enough to swallow. The grinding action humans use is largely absent. Watch your dog eat: it's tear, gulp, done
• Enamel doesn't regrow — once a dog's enamel is damaged or worn, it's gone for good. Dogs only get one set of adult teeth and no dental fillings on the NHS
• Dogs can crack their own teeth on bones — research has shown that some commonly given chews produce fracture forces higher than what the upper fourth premolar can withstand. Antlers, weight-bearing bones, and nylon chews are the most common culprits
• Tooth colour tells a story — a healthy adult tooth is white. A pink or purple tooth has internal bleeding (pulpitis). A grey or brown tooth is likely dead. A yellow tooth may have enamel defects from illness during puppyhood
• Dogs can favour one side — if a dog consistently chews on one side, it may indicate pain or a cracked tooth on the other side. Many dogs do this long before showing obvious signs of discomfort
• The "corn on the cob" nibble — when your dog gently nibbles at their leg, your arm, or a blanket using their front incisors, this is called "cobbing." It's a natural grooming behaviour and a sign of affection, not a dental problem
• Wolves and dogs have identical tooth counts — 42 teeth in the same arrangement. The difference is that wolves' teeth are larger and their carnassials are proportionally bigger, reflecting a diet of large prey rather than kibble

🔗 Related Pages on DogLens

Now you know the science behind your dog's teeth, you might want to explore how to keep them healthy:

• 🦷 Dental Health — practical guide to brushing, dental chews, professional cleaning, and spotting problems early
• 👃 The Dog's Nose — the other end of the muzzle and its 300 million olfactory receptors
• 🧬 How Breeds Are Created — including the health consequences of extreme skull shapes
• 🍖 Feeding Guide — what goes into the mouth matters as much as the teeth themselves

Sources: Lindner et al., Frontiers in Veterinary Science (2018) — bite forces and their measurement in dogs and cats; Hale (2009), PMC/NIH — dental caries in the dog; International Veterinary Dentistry Institute — dental caries diagnosis and treatment in dogs; VCA Animal Hospitals — persistent deciduous teeth in dogs, platelet-rich plasma; Purina UK — cavities in dogs; Petz Park — canine tooth facts and variations; Vetster (2024) — can dogs get dental cavities; Safarivet — diagnosis of pet dental disease and malocclusion.