Tooth Abscess in Dogs

A tooth abscess in a dog is an infection at the tip of a tooth root. It usually starts when bacteria get in through a broken tooth or from advanced gum disease.¹ The classic sign is a swelling just below the eye, from an infected upper carnassial tooth, the large tooth at the back of the upper jaw, but abscesses can also cause swelling along the jaw, a draining sore on the face, or chewing on one side.^2,1 Antibiotics alone won't cure it. The tooth needs to be removed or given a root canal.^1,2 See your vet the same day if your dog's face swells.

Signs of a Tooth Abscess in Dogs

• Swelling below the eye, on the cheek or along the lower jaw
• A draining sore on the face or in the mouth, sometimes mistaken for a bug bite
• Chewing on one side, dropping food, or eating only soft food
• Pawing at the face, flinching when the face is touched, or drooling
• Bad breath, red gums, or a broken or discolored (pink, gray or purple) tooth
• Fever, low energy, poor appetite or swollen lymph nodes under the jaw

Some dogs show no signs at all, and the gums over an abscessed carnassial tooth can look completely normal.^2,1

Why a Dog's Face Swells Under the Eye

The upper fourth premolar, or carnassial tooth, is the largest tooth in a dog's mouth. Its three roots extend up toward the area just in front of the eye. When one root becomes infected, pus can build up under the eye, causing a firm swelling that may burst and drain onto the cheek. Carnassial teeth are the teeth most often involved in abscesses.^2,1 Swelling near the eye can also come from other causes, such as an allergic reaction or a tumor, so it always needs a vet exam.

Is a Tooth Abscess an Emergency?

It's painful and should be seen promptly, usually the same day or the next. Go urgently if the swelling is growing quickly or near the eye, if your dog has a fever, won't eat or drink, or is very lethargic, or if the swelling spreads to the face or neck.^1,2 Untreated infection can spread to the jaw bone and, rarely, further. Sudden facial swelling with hives or trouble breathing is an allergic emergency rather than a tooth problem; see hives in dogs.

Broken Teeth in Dogs

Between 20 and 27 percent of dogs have at least one broken tooth, most often a canine or a carnassial.^5,3 A common injury is a slab fracture, where a flat piece of the outer surface of the upper carnassial shears off when a dog bites down hard on something.¹ Antlers, bones, hooves, hard nylon or plastic toys, ice and rocks are common culprits.^3,6,5

If a fracture exposes the pink or dark center of the tooth (the pulp), the tooth will die and become infected if it isn't treated, even if your dog seems fine. Waiting to see what happens isn't appropriate; at minimum the tooth needs X-rays.^4,3 A recently broken tooth is time sensitive: in young dogs, a procedure called vital pulp therapy can sometimes keep the tooth alive, with the best results within about 48 hours.^7,3

The fingernail test: If you can't make a small dent in a chew with your fingernail, it's too hard for your dog's teeth.^6,5

Diagnosis

Your vet will examine the mouth and face, then take dental X-rays under general anesthesia, where an abscess shows as a dark area around the root tip. Bloodwork and a urine test are usually done first to check that anesthesia is safe.^1,2

Treatment: Extraction or Root Canal

Antibiotics and pain relief can calm the infection for a while, but they don't cure an abscess. The signs come back once the medicine stops, because the infected tooth is still there.^1,2 There are two lasting treatments:

Root canals usually cost more and require a specialist, but they're less invasive than removing a large tooth, most dogs eat normally within a day or two, and follow-up X-rays check that the tooth stays healthy.⁴ Extraction is always a reasonable option and removes the problem for good.⁷ Treatment with extractions commonly costs $800 to $3,000 in the US, depending on the tooth and what else is needed.¹

Prevention

• Avoid antlers, bones, hooves, hard nylon toys and ice cubes.
• Have any broken or discolored tooth checked promptly, even if your dog seems comfortable.
• Brush daily and keep up with professional cleanings to prevent periodontal (gum) disease.⁸

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