A Dog's Carnassial Tooth May Cause Swelling Under the Eye

Updated on March 23, 2016

If your dog developed swelling under his eye, you may chalk it up to being some sort of temporary eye problem or perhaps you may assume it's just an insect bite. Yet, a day later, and the day after that, the swelling is still there and you now also notice some drainage, what gives? It's very common for dog owners to be fooled when they see this type of swelling. Whether there is a draining pustule under the dog's eye, a lump or an actual abscess, dog owners are often perplexed by it, especially when the area seals over and the swelling is gone for a bit, only to come back after a while, explains veterinarian Ron Hines on his website.

Some dog owners ignore the problem since their dogs continue to act happy and healthy, so they wait to mention it when they bring their dog to the vet for some other problem. So what may be going on with these dogs? Is that facial swelling just below the dog's eye some medical mystery? If it's not an eye problem or an insect bite, what is going on? Respected veterinarian Dr. Ronald Hines, has a possible explanation.

The owners often doubt me when I tell them that the actual problem is in the dog’s mouth. What has happened is that an infection has spread from an infected fourth upper premolar tooth."

— Dr. Ronald Hines
The dog's upper carnassial tooth is the largest tooth and has 3 roots. All rights reserved.
The dog's upper carnassial tooth is the largest tooth and has 3 roots. All rights reserved.

Understanding a Dog's Carnassial Teeth

Have you ever watched your dog carefully when he chews a bone? If so, you may have noticed how at some point, he'll turn his head and use his back teeth to cut through the meat or crush the bone. When he does that, he is using his carnassial teeth. What are a dog's carnassial teeth? If you take a look at the word carnassial, it comes from the French word "carnassier" which stands for carnivorous. Carnassial teeth are commonly found in meat-eating animals. Also known as shearing teeth, their main function is to allow the dog to crack bones and shear through the flesh, tendons and muscles of their prey. Your dog may not need these teeth as much as he might have in his past as a hunter, but you'll still see him put them to good use when he's gnawing on a bone, chew toy or raw meat if he's on a raw meat diet.

Where are the carnassial teeth exactly located? Well, consider that adult dogs have 42 teeth consisting of 6 incisors, 2 canines, 8 pre-molars and 4 molars in the top jaw, and 6 incisors, 2 canines, 8 pre-molars and 6 molars in the bottom one. Carnassial teeth consist of teeth pairs that work together to provide that strong shearing action carnivorous predators are known for. They comprise the dog's fourth upper premolar and the first lower molar. These teeth are known for having self-sharpening edges that work together when the dog is chewing. Basically, when the dog chews laterally with his head tilted sideways, the inside of the dog's fourth upper premolar aligns with the outer surface of the first lower molar, providing potent shearing action. Yes, just like shearing blades!

Did you know? According to Pet Education, a dog's carnassial tooth is not only the largest tooth, but it's also the only one with three roots, when the rest of the dog's other teeth have only one or two.

When Things Go Wrong

When things go well, the dog's teeth shear through meat, muscles and tendons and even crack bones with no problem. However, sometimes things don't go as planned. As dogs age, their teeth may weaken and putting tremendous force on them with strong shearing action, may predispose them to fractures. All it takes is for the dog to chew on something that is harder than the actual tooth.

Things dogs chew that may be culprits for a fractured carnassial tooth include bones (raw or cooked), cow hooves, nylon toys, rocks and the bars of cages, explains Daniel T. Carmichael, a veterinarian specializing in veterinary dentistry. However, things may also go awry when a dog sustains injury to the teeth through a vehicle accident, being kicked by an animal or even catching a flying object roughly with the mouth.

When the upper fourth premolar gets fractured, bacteria may enter through the gap and move its way along the carnassial tooth's long roots and then create an infection pocket that may generate an abscess in the dog's facial area, right under the dog's eye. Taking antibiotics for this type of abscess may sound like a good idea, but it's only a temporary measure. Since the problem tooth is still in the mouth, the problem is likely to recur sooner than later. The only way to fix the problem is to extract the problem tooth, or if you are lucky to have a vet specializing in veterinary dentistry, there may be chances the tooth can be restored through a restorative procedure such as a root canal.

Of course, swelling under a dog's eye may also be due to other conditions. An insect bite, a severe allergic reaction, an animal bite and tumors may be other culprits. If your dog has developed swelling under his eye, see your vet for proper diagnosis and treatment.

Disclaimer: this article is not intended to be used as a substitute for professional veterinary advice. If your dog has swelling under his eye, please see your vet for proper diagnosis and treatment.

Tip: to look for a veterinary dentist near you, visit the American Veterinary Dental College website.

Abscessed Pet Teeth

Questions & Answers


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        Sunni Porter 5 weeks ago

        Thx u very much for this info. It was really helpful. It’s nice to see that u are trying to help people fix the main problem instead of putting a band aid over it.

      • alexadry profile image

        Adrienne Janet Farricelli 2 years ago from USA

        Thanks AliciaC and Suhail and my dog for stopping by. Hopefully, it will be helpful for many dog owners!

      • Suhail and my dog profile image

        Suhail Zubaid aka Clark Kent 2 years ago from Mississauga, ON

        This is going to be a great resource hub for any contingency relating to my dog. I think you have done a wonderful job in writing and putting together all the information in a way that is easy to read and remember.


      • AliciaC profile image

        Linda Crampton 2 years ago from British Columbia, Canada

        Thanks for sharing this useful information. I'll keep it in mind in case my dogs develop the problem that you describe.

      • alexadry profile image

        Adrienne Janet Farricelli 2 years ago from USA

        Thanks DDE, my friend had a husky with this swelling under the eye problem and we saw several dogs with this at the vet so thought to write about this to spread awareness.

      • DDE profile image

        Devika Primić 2 years ago from Dubrovnik, Croatia

        Dogs are amazing pets and need proper care. Your helpful hubs are interesting and have useful tips.