Dog mouth anatomy and how dog teeth work
Last updated October 13, 2026
An adult dog's mouth holds 42 teeth, against 28 in a puppy. Around them sit the lips and cheeks, the gums, a hard palate lined with ridges, a soft palate further back, the tongue, four pairs of salivary glands and a tonsil on each side of the throat. The whole front of the face, nose and jaws together, is the muzzle.
The big difference from our mouths is what goes wrong. Cavities are rare in dogs. Plaque that hardens into tartar, and the gum disease that follows it, is the everyday problem.
What's inside a dog's mouth
Lift your dog's top lip and you're looking into the vestibule, the gap between the lips and cheeks and the outside of the teeth. In breeds with heavy, hanging upper lips, those lips are called flews. The space inside the teeth is the oral cavity proper.
The roof of the mouth has two parts. The hard palate at the front is bone covered in firm tissue, with a row of curved ridges across it. The soft palate carries on behind it with no bone at all, separating the mouth from the airway above.
The tongue's top is covered in tiny papillae, with a V of four to six larger ones at the back. Underneath, a fold of tissue called the frenulum ties it to the floor of the mouth, with a small raised bump on each side where two more salivary glands drain. The parotid gland drains through a small bump in the cheek beside the big upper cheek tooth, and the zygomatic gland opens nearby. At the very back, partly tucked behind a fold, are the tonsils.
Normal bumps and patches owners worry about
Most "what is that?" moments come from structures every dog has.
| What you see | What it usually is | Normal or vet? |
|---|---|---|
| Black or patchy dark color on the gums, lips, palate or tongue | Natural pigment, common in many dogs | Normal if it has always been there and is flat |
| A small bump just behind the top front teeth | Incisive papilla | Normal |
| A small bump inside the cheek, beside the big upper cheek tooth | Parotid papilla, where saliva comes in | Normal |
| A V of large bumps at the back of the tongue | Vallate papillae (taste buds) | Normal |
| Two small bumps under the tongue, either side of the frenulum | Where two salivary glands drain | Normal |
| Ridges across the roof of the mouth | Palate ridges | Normal |
| A new, raised or growing dark patch, or any lump | Needs a look | Vet visit soon |
Flat pigment your dog has always had is fine. Melanoma is the most common oral cancer in dogs (Polton et al., 2024). Not every melanoma is dark, so any new lump counts too. A patch that's new, raised or getting bigger should be seen by a vet rather than watched.
How many teeth dogs have
Dogs are diphyodont, which means they grow two sets of teeth in a lifetime, just as we do. Puppies have 28 baby teeth and no molars at all. Adults have 42.
| Tooth type | Puppy | Adult | Upper / lower (adult) |
|---|---|---|---|
| Incisors | 12 | 12 | 6 / 6 |
| Canines | 4 | 4 | 2 / 2 |
| Premolars | 12 | 16 | 8 / 8 |
| Molars | 0 | 10 | 4 / 6 |
| Total | 28 | 42 | 20 / 22 |
Baby teeth start coming through at 3 to 5 weeks old. The adult set starts at around 4 to 5 months, and all 42 are normally in place by 7 months. We have 32 adult teeth, so a dog has ten more.
A baby tooth should fall out before the adult tooth behind it comes through, so two teeth should never share one spot. If you see a baby canine still sitting next to the new adult one, ask your vet. A retained baby tooth is normally taken out once its replacement has started to erupt.
What each type of tooth does
The 12 incisors at the front are small and close together. Dogs use them for fine work, like nibbling at an itch or pulling a burr out of their coat.
The four canines are the long fangs for gripping and holding. Their roots run deep into the jaw, longer than the part you can see, which is why removing one is a surgical job.
Premolars are pointed and have gaps between them, so they cut and tear rather than grind. Behind them, the molars are flatter and do the crushing, with more of them in the lower jaw (six) than the upper (four). The drawing above is simplified and doesn't show the real count, which is three incisors, one canine, four premolars and three molars on each side of the lower jaw.
The carnassial tooth and why it breaks
The carnassials are a pair rather than a tooth type. The upper fourth premolar and the lower first molar slide past each other like the blades of scissors when your dog bites down on the side of its mouth. Because they sit further back in the jaw, they take higher forces than the canines (Soltero-Rivera et al., 2018). The upper carnassial is the biggest tooth on top and has three roots.
That pressure is also why it breaks. When researchers loaded upper carnassials from dogs in a lab, they fractured at an average of 1,281 newtons, roughly 130 kg (290 lb) of force. A dog's voluntary bite ranges from 13 to 1,394 newtons, depending on its size. That puts the breaking point within reach of the average dog. In 17 of the 24 teeth, the break reached the pulp (Soltero-Rivera et al., 2018). The authors' conclusion is that a rigid chew that doesn't give before that force is a fracture risk for this tooth.
A broken tooth with a pink or red dot in the middle has an exposed pulp. Call your vet the same day. In fractured canine teeth, 88% of pulps treated within 48 hours were still alive three years later, against 41% at one week (Clarke, 2001). An infected upper carnassial often shows up as a swelling just below the eye, which is easy to mistake for an eye problem. Our guide to a dog tooth abscess covers the signs.
Thin enamel and a wide pulp in young dogs
Dog teeth are tough, but their enamel isn't thick. Measured across 194 dog and cat teeth, it ranged from just 0.1 to 1 mm, thinner than ours (Crossley, 1995).
Inside the enamel is dentin, and inside that the pulp, the living core of nerves and blood vessels. Dentin keeps thickening throughout a dog's life, so the pulp is widest in young dogs and narrows with age (Soltero-Rivera et al., 2018). A small chip in a young dog's tooth is closer to the pulp than you'd think.
A hurt pulp often shows as color. A tooth that turns pink, purple or gray has usually been knocked and needs a vet, even if your dog seems fine. We explain each color in discolored teeth in dogs.
Why dogs rarely get cavities but often get tartar
Cavities do happen in dogs, but not often. Among 435 dogs seen at a dental referral practice, 23 (5.3%) had one or more, mostly on the big cheek teeth (Hale, 1998). Part of the reason is saliva. In 29 healthy dogs, saliva averaged pH 7.9, ranging from 7 to 9 (Iacopetti et al., 2017). Ours sits at 6.2 to 7.6 and averages 6.7 (Baliga et al., 2013). Cavities need acid, and a dog's mouth runs less acidic than ours.
The chart uses an earlier study's dog average of 8.5 (Lavy et al., 2012) and about 6.5 for people. Both sit inside the measured ranges. Either way, a dog's saliva is the less acidic of the two.
Plaque is the soft film of bacteria that builds up on teeth every day. It starts to harden within 2 to 12 days, as minerals from saliva settle into it (Lowe and Anthony, 2020). Once hard, it's tartar, and a toothbrush won't shift it. The rough surface then holds more plaque against the gums.
Tartar above the gumline is only the part you can see. The gum disease it feeds works below the gumline, and the American Veterinary Dental College's position is that cleaning there properly needs anesthesia. Dental, oral and jaw problems are the most common conditions vets see in small animals (WSAVA, 2026). Daily brushing is the most effective home care because it removes plaque before it has days to harden. For what red gums mean and what's still reversible, see our guide to gingivitis and periodontitis in dogs.
When something in the mouth needs a vet
- Same day: a freshly broken tooth with a pink or red dot showing, or a swollen face.
- Within a few days: a tooth that has turned pink, purple or gray, or swelling under one eye.
- Soon: a new lump, or a dark patch that is raised or growing.
- At the next visit: a baby tooth still in place next to its adult replacement, brown tartar at the gumline, or breath that has got worse.
Bleeding gums, dropping food, chewing on one side or pawing at the mouth usually mean the mouth hurts, and that's a vet visit too.
Questions owners ask
What is a dog's mouth called?
It's still called the mouth, or the oral cavity in anatomy terms. The muzzle (or snout) is the whole projecting front of the head, including the nose, mouth and jaws. Hanging upper lips are called flews.
Are dogs diphyodont?
Yes. Dogs grow two sets of teeth, 28 baby teeth and then 42 adult teeth, all in by about 7 months.
Is it normal for a dog to have black gums or a black tongue?
Yes, flat dark pigment is common and normal. A spot that is new, raised or growing needs a vet check.
How is a dog's mouth different from a human's?
Dogs have 42 adult teeth to our 32, and most of them cut and tear rather than grind. Their saliva is less acidic, so cavities are rare, but plaque still hardens into tartar within days.
References
- Baliga S, Muglikar S, Kale R. Salivary pH, a diagnostic biomarker. J Indian Soc Periodontol. 2013;17(4), 461-465.
- Clarke DE. Vital pulp therapy for complicated crown fracture of permanent canine teeth in dogs, a three-year retrospective study. J Vet Dent. 2001;18(3), 117-121.
- Crossley DA. Tooth enamel thickness in the mature dentition of domestic dogs and cats, preliminary study. J Vet Dent. 1995;12(3), 111-113.
- Hale FA. Dental caries in the dog. J Vet Dent. 1998;15(2), 79-83.
- Iacopetti I, Perazzi A, Badon T, et al. Salivary pH, calcium, phosphorus and selected enzymes in healthy dogs, a pilot study. BMC Vet Res. 2017;13, 330.
- Lavy E, Goldberger D, Friedman M, Steinberg D. pH values and mineral content of saliva in different breeds of dogs. Isr J Vet Med. 2012;67, 244-248.
- Lowe C, Anthony J. Pilot study of the effectiveness of a xylitol-based drinking water additive to reduce plaque and calculus accumulation in dogs. Can Vet J. 2020;61(1), 63-68.
- Niemiec B, Gawor J, Nemec A, et al. World Small Animal Veterinary Association global dental guidelines. J Small Anim Pract. 2026. doi 10.1111/jsap.70057.
- Polton G, Borrego JF, Clemente-Vicario F, et al. Melanoma of the dog and cat, consensus and guidelines. Front Vet Sci. 2024;11, 1359426.
- Soltero-Rivera M, Elliott MI, Hast MW, et al. Fracture limits of maxillary fourth premolar teeth in domestic dogs under applied forces. Front Vet Sci. 2018;5, 339.
- American Veterinary Dental College. Position statement on companion animal dental scaling without anesthesia. https://avdc.org/wp-content/uploads/2019/AVDC-pos-stmts/Dental_Scaling_Without_Anesthesia.pdf