Dental Abscesses in Cats

Key Takeaways

Dental abscesses in cats are severe infections around the root of a tooth caused by bacteria entering the pulp cavity, usually through tooth injury and dental decay. The pocket of infection around the tooth root often opens and drains, either along the gumline or through the skin of the face. 

• Dental abscesses may be asymptomatic; if present, symptoms include a visibly broken tooth, facial swelling with or without draining pus, and red gums around the affected tooth

• The most commonly affected tooth is the upper 4th premolar, also called the carnassial tooth

• Tooth root abscesses are diagnosed by thorough oral exam, dental x-rays, and possibly biopsy

• Treatment is either extraction or root canal of the affected tooth, with pain management and potentially antibiotics

• Prognosis is excellent with appropriate treatment

A Closer Look: What are Dental Abscesses in Cats?

Tooth root abscesses are common in cats. A bacteria enters through the exposed root canal of the tooth in cats with enamel that has chipped or worn away, exposing the dentin or pulp of the tooth. Once the bacteria gains entry, it can spread around the gums, inflaming the affected area and potentially killing the tooth. The outer enamel layer that protects cats’ pulp cavity is only 0.1-0.3 mm thick, much thinner than humans’, and is therefore more easily fractured. They are not life-threatening, but symptoms are painful and require prompt veterinary intervention. If left untreated, tooth root abscesses can spread and lead to complications such as osteomyelitis (bone infection) and sinus/nasal inflammation.

Risk Factors

Symptoms may be absent and sometimes the abscessed tooth is only discovered during a dental procedure. 

If the abscessed tooth is near the eye, symptoms can include

• Bulging of the eye (exophthalmos)

• Eye discharge

• Red, inflamed tissue around the eye

• Elevated third eyelid (nictitans)

In cases of more severe infection, symptoms can include:

• Lack of appetite • LethargyWeight loss

In cases where the infection has spread to the surrounding areas, the following symptoms may be seen:

FeverEnlarged lymph nodesSneezing

Nasal discharge • Bloody nose (epistaxis)

Possible Causes

The most common cause of tooth root abscesses in cats is a broken tooth. The canine teeth and upper 4th premolars are the most commonly fractured teeth. A common type of fracture is called a slab fracture, in which a slab or flake of the tooth is broken off. This allows bacteria to access the tooth pulp, where they cause pain, inflammation, and infection. Rarely, a systemic infection may concentrate around the root of a tooth, causing an abscess.

Main Symptoms

Some cats with dental abscesses may be asymptomatic. When symptoms are present, they include:

• Unilateral facial swelling, with or without draining pus

• Visibly broken tooth

Redness and swelling of the gums around the tooth

• Chewing only on one side of mouth

• Swallowing food without chewing

• Rubbing the face on the affected side

Halitosis (bad breath)

Testing and Diagnosis

The first step to diagnose a possible tooth root abscess is a physical examination including a thorough oral exam (sedation may be necessary). A fully anesthetized dental procedure for diagnosis and treatment may be recommended. Blood work is typically recommended prior to the anesthetic event. During the procedure, dental x-rays may be taken to confirm the diagnosis of a dental abscess. In some cases, such as those with associated complications, advanced imaging (CT, MRI) may be indicated. Additional diagnostics can include biopsies of the affected tissues and bacterial culture to aid in antibiotic selection.

Steps to Recovery

Most commonly, the affected tooth is extracted. When saving the crown of the tooth is a priority, referral to a specialist for a root canal procedure may be elected. Medications may include antibiotics and pain medications.

With either root canal therapy or tooth extraction, the outcome of treatment  is expected to be very good.


Dental abscesses are not contagious. Regular veterinary visits can help detect symptoms early. Dental fractures can be prevented by not allowing cats to chew on hard objects and by keeping them indoors to avoid trauma. Scheduling annual dental prophylactic procedures (full general anesthesia to clean and monitor teeth) is helpful to catch injured or decaying teeth before they can abscess.

Are Dental Abscesses Common in Cats?

Dental abscesses are common in cats, but much more common in dogs, who have a greater tendency to chew hard objects.

Typical Treatment

• Tooth extraction or root canal (specialist may be needed)

• Antibiotics

• Analgesia (pain relief)

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