Could my Cat have a FORL?

According to information presented at the American Veterinary Dental Forum, if your cat is over five years old, there is a 72% chance he or she has a painful feline odontoclastic resorptive lesion (FORL). These dental resorptions once called cat cavities or neck lesions can occur in any tooth. The most commonly affected teeth are the lower premolars.

Unlike cavities in humans, which are the result of bacterial enzymes and acids digesting the teeth, the cause of FORLs are unknown. Specifically, cells known as odontoclasts are found in the defects causing the tooth structure to dissolve. What triggers this reaction has not been determined for certain but a reaction to plaque on the teeth seems to be the major factor.

Cats affected with FORLs may show hypersalivation, oral bleeding, or have difficulty chewing. A majority of affected cats do not show obvious signs but are in pain. A cotton tipped applicator applied to the suspected FORL causes pain with jaw spasms when the FORL is touched.

The FORL can present in many stages -- initially (Stage I) an enamel defect is noted. The lesion is usually minimally sensitive in because it has not entered the dentin. Therapy of this defect usually involves thorough cleaning, polishing, and smoothing the defect with a dental drill.

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Class 2 FORL

In Stage 2, lesions penetrate the enamel and dentin. These teeth may be treated with glass ionomer restoratives, which release fluoride ions to desensitize the exposed dentin, strengthen the enamel, and chemically bind to tooth surfaces. The long term (greater than two years) effectiveness of restoration of Stage 2 lesions have not been proven.

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Grade 3 FORL

X-rays are essential to determine if the lesions have entered the pulp chamber (Stage 3) requiring either root canal therapy or extraction. Here the lesion it is not only painful, but bacteria in the mouth now have easy access to the tip of the tooth root where an abscess can develop. Tooth root abscesses have been well documented as chronic sources of infection that can lead to infections on the heart valves, in the liver, kidneys, spleen, joints, bones and central nervous system.

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Stage 4 FORL

In Stage 4 FORL, the crown has been eroded or fractured. Gum tissue grows over the root fragments leaving a sometimes painful bleeding lesion upon probing. Treatment requires extraction of the root fragments if they appear inflamed or painful to the patient.

At least monthly examine your catís mouth for FORLs. Take a Q-tip and gently place it against the area where the tooth meets the gum. If there is pain or bleeding a trip to the veterinarian is in order. Your best friend will thank you.


This page last updated on October 31, 2000
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Jan Bellows, DVM
All Pets Dental Clinic
17100 Royal Palm Blvd.
Weston, FL 33326
(954) 349-5800