What is a tooth root abscess?

A tooth root abscess is an infection that develops in the root of a tooth.

What causes a tooth root abscess?

“The most common cause of a broken or cracked tooth is a traumatic injury.”

A tooth root abscess forms when bacteria enter the root canal of the tooth and set up an infection. In the dog, this most often occurs if the tooth develops a crack or part of the crown chips off, exposing the tissues that lie beneath the tooth enamel. The most common cause of a broken or cracked tooth is a traumatic injury. Sometimes a tooth root abscess can develop in association with periodontal disease, an inflammation, or infection of the tissues surrounding the tooth. For more information about periodontal disease, the most common dental problem in the dog, see our handout “Dental Disease”. 

What is the most common location for a tooth root abscess in the dog?

The most common tooth to develop a tooth root abscess is the upper carnassial tooth or 4^th premolar. This is the largest tooth in the dog’s mouth and is prone to developing a problem called a ‘slab fracture’, a condition in which a ‘slab’ of the crown of the tooth breaks away from the main tooth, exposing the inner dentin and sometimes the root canal. This gives bacteria direct access to the root and other sensitive structures of the tooth. 

What causes a slab fracture?

A slab fracture develops on the carnassial tooth (or any other tooth for that matter) when the dog bites down on a hard object at just the right angle and with just the right force to break off a flake or slab of the tooth. Objects that are hard enough to do this include bones, sticks, stones, cage bars, fences, or dog ‘treats’ made out of animal hooves. The slab that breaks off may be a small chip or a large piece of the tooth.

Can anything else cause a tooth root abscess?

Anything that exposes the inner layers of the tooth to the bacteria that are always present in the mouth can result in a tooth root abscess. This includes any sort of trauma to a tooth that causes a piece of the tooth crown to break off or periodontal disease that causes loss or damage to the bony tooth sockets.  

Are there any obvious symptoms when a dog has a tooth root abscess?

Although we know that abscessed teeth are very painful, dogs do not typically show any obvious signs of pain when they have a tooth root abscess. Instead, the dog may be reluctant to chew on its toys or may pull away when its head is touched. An observant owner may sometimes notice that their dog is eating or chewing on only one side of its mouth, or that the dog drops food if it tries chewing on the affected side of its mouth. A dog with an abscessed tooth will often have halitosis or bad breath. Sometimes the dog will paw at the affected side of its face or rub its face along the ground, and the pet owner may assume that the dog has an itch.

“If the abscessed tooth is the upper carnassial tooth, the outward signs are often mistaken for some other problem such as an eye infection or a puncture wound.”

If the abscessed tooth is the upper carnassial tooth, the outward signs are often mistaken for some other problem such as an eye infection or a puncture wound. This happens because the tooth roots are located just below the eye, and when they become abscessed the infection quickly spreads to the surrounding tissues. As the abscess enlarges, the pus builds up, and eventually, the abscess will burst through the skin so that the pus can escape. The tissue below the eye will usually become swollen and inflamed just before the abscess bursts, and the area will be warm to the touch. Once the abscess bursts, the pressure will be relieved and the tooth will often be less painful.

If you look inside the dog’s mouth, there will often be swelling and redness on the gums around the affected tooth.

How is a tooth root abscess diagnosed?

In some cases, such as when there is an obvious slab fracture or damage to a tooth that is accompanied by the presence of a discharge, the diagnosis of a tooth root abscess is simple and straightforward.  However, in all cases your veterinarian will need to take dental x-rays to determine whether the abscess has spread to the surrounding teeth, compromising their health.

What can be done to treat a shallow slab fracture?

It may be possible to save a tooth that has a shallow slab fracture, as long as it only involves a small piece of crown and does not expose the root canal. In this case, the surface of the crown can be cleaned and all the rough surfaces can be smoothed down so that tartar does not accumulate on the tooth surface. Depending on the shape of the slab fracture, it may be possible to fill the defect in the tooth with a dental filling material.

If the slab fracture is deeper and exposes the root canal, a veterinary dentist may be able to perform a root canal treatment to save the tooth if the fracture is detected within a couple of days of occurring.

What is the treatment for a tooth root abscess?

A tooth root abscess is a very painful condition and needs to be treated as soon as possible. Antibiotics will be prescribed to control the infection and either an anti-inflammatory or an analgesic will be prescribed to help with the soreness. Although this medical treatment will deal with the symptoms, it will not treat the underlying tooth injury.

There are 2 options for treatment of the abscessed tooth. One option is a root canal treatment and the other option is extraction.

The tooth may be saved if a root canal treatment is performed on it. However, the likelihood that a root canal treatment of an abscessed tooth will be successful depends on the health of the surrounding tissues and the condition of the affected tooth. Some general practitioners are comfortable performing a root canal treatment on an abscessed tooth, but most veterinarians will refer these complex cases to a veterinary dental specialist.

If the tooth that is abscessed has extensive bone loss around its socket, or if there is significant damage to the crown of the tooth, your veterinarian may recommend extraction as the best treatment. Since the upper carnassial tooth has 3 roots, it can be difficult to successfully perform a root canal treatment on this tooth, and in many cases, the tooth will need to be extracted.

Your veterinarian will be in the best position to recommend the appropriate option for your pet, depending on the severity of the abscess and the degree of damage to the tooth and surrounding structures.

What sort of follow-up care will be necessary?

If a root canal treatment is performed, your dog will need to have dental x-rays taken of the tooth on a regular basis. Most veterinary dentists recommend follow-up x-rays several times in the first year; after this, the frequency of recheck x-rays will depend on the individual case.

“Once the gums have healed over, most dogs can resume their regular diet and activity level.”

If the abscessed tooth is extracted, your veterinarian will prescribe antibiotics and pain medications for a period of time that will be determined by the severity of the condition. Your dog may or may not require a change in diet during the post-operative recovery period. Once the gums have healed over, most dogs can resume their regular diet and activity level.

All dogs should have a dental examination performed by their veterinarian on an annual basis. For a dog that has developed a tooth root abscess, your veterinarian may recommend more frequent dental examinations.