Cat Cavities or Feline odontoclastic resorptive lesions
The feline odontoclastic resorptive lesion (FORL) is a common feline dental problem. A majority of the cats affected are older than five years. These resorptions have also been called cavities, neck lesions, external or internal root resorptions, and cervical line erosions. FORLs are located usually where the gum line meets the tooth. The most common teeth affected are the lower premolars, however, FORLs can be found anywhere on any tooth. The cause is unknown.
Patients affected with FORLs may drool, bleed, or have difficulty eating. A portion of affected cats do not show clinical signs. Most times, it is up to the owner or veterinarian to diagnose the lesions on oral examination. Diagnostic aids include a periodontal probe or cotton-tipped applicator applied to the suspected FORL. The lesion often erodes into the sensitive dentin, causing the cat to show pain with jaw spasms when the FORL is touched.
FORLs can present in many stages:
Initially, in the class one FORL, an enamel defect is noted. The lesion appears like a chipped tooth and is minimally sensitive because it has not entered dentin. Therapy for the defect usually involves thorough cleaning, polishing, and daily tooth brushing with a fluoride paste.
In class two, lesions penetrate enamel and dentin. Affected teeth used to be treated with glass ionomer restoratives, which release fluoride ions to desensitize exposed dentin, strengthen enamel, and chemically bind to tooth surfaces. The long-term effectiveness of restoration is questionable and the decision to extract the affected teeth at this time should be considered.
Radiographs are essential to determine if the lesions have entered the pulp (class 3), lesion. These teeth must be extracted.
In the class four FORL, the crown has been eroded or fractured. Gum tissue grows over the root fragments, leaving a painful lesion that bleeds when probed. Treatment of choice is flap surgery, crown amputation, or extraction of the root fragments when the tissue surrounding them appears inflamed or painful to the patient.
Dental x-rays are extremely helpful in making a diagnosis and for treatment planning. We feel those patients diagnosed with a FORL should have a complete mouth series of x-rays to identify any other, possibly hidden, lesions. This allows us to perform any needed extractions or under the same anesthetic.