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FRLS- Feline Oral Resorptive Lesions

Feline Oral Resorptive Lesions

Feline Resorptive Lesions, or RLs, are erosions of the enamel from the surface of the tooth, at or below the gum line. The cause is, at this point, unknown. Mummified cats in Egyptian tombs have these lesions on their teeth but the problem is much more common today than it was then. Even 30 years ago cats did not commonly get these lesions, but no one knows what has changed to cause them to occur so frequently today. It may be a result of environmental changes, toxin exposure, a virus or a nutritional deficiency that we are unaware of. Unfortunately, they are currently being seen in as many as 60% of domestic cats, and if a cat has one RL there is a 72% chance the cat has or will develop additional ones.

Resorptive lesions begin as a small erosion in the enamel. The overlying gums may become swollen and inflamed. One or more teeth may be affected at a time causing much discomfort to the cat. The lesions progress, growing larger and deeper, eroding more and more of the tooth. Once the enamel is eroded enough to expose the dentin layer underneath, the tooth becomes painful. The affected tooth may fracture, or the gums may grow up onto the side of the tooth, and eventually the tooth will be lost. RLs are even more painful to your cat once the pulp of the tooth is exposed.

The most commonly affected teeth are the small lower premolars – the first teeth behind the fang (canine) teeth (see pictures below). It can be hard to see these teeth because there’s a little fold of lip in the way. Most cat owners don’t notice problems in the mouth until the lesions are quite severe and their cat is in a lot of pain. Sometimes the hole in the tooth is on the tongue side and can’t be seen at all until the cat is anesthetized, or it’s below the gum line and can’t be seen without dental x-rays. (This is why we recommend full mouth dental x-rays.)

Extraction of the affected tooth is the best course of treatment that we have today. Attempts to repair these lesions with a filling rarely slows the destruction of the tooth. The lesion grows in size, the filling falls out, and the cat is in pain once again. Today’s state of the art pain medications along with a course of antibiotics help cats recover quickly from extractions, so they can return to pain-free living.