Feline Oral Resorptive Lesions

Feline Oral Resorptive Lesions

A common feline oral malady is the feline oral resorptive lesion (FORL). These tooth defects have been called cavities, neck lesions, external or internal root resorptions, and cervical line erosions. FORLs are usually found on the outside of the tooth where the gum meets the dental surface. The lower jaw premolars are mostly affected, however, FORLs can be found on any tooth.

What causes this problem?  While there are countless volumes of research on this topic, the cause of this disease is unknown. The research thus far has shown that FORLs are seen in cats starting at 2 years of age. The number of lesions increases with age. There is also no clear breed disposition, except that there may be a higher occurrence in purebred cats with Longhaired Persians and Siamese being at the forefront. Neutering/Spaying has not been found to be a factor. There has been an increase in the prevalence of FORLs since the 1970s. It is thought that with the domestication of the cat, which has brought changes in diet, neutering and vaccinations that this has had an influence on feline tooth development, causing the tooth surface to be less resistant to resorption.

Signs?  The resorptive lesion often erodes into sensitive dentin, causing a cat to show pain and jaw spasms whenever the lesion is touched. Patients affected with FORLs may show increased salivation, head shaking, sneezing, dropping food, outright refusal to eat or hissing and/or running from the food bowl when attempting to eat.

How is this problem diagnosed?  An accurate diagnosis and classification is achieved through a combination of a good history, visual inspection, and radiographs.  With the patient under anesthesia, the teeth can be thoroughly inspected. Plaque and dental calculus need to be removed because lesions can be hidden underneath. Radiographs must be taken in order to evaluate the extent of the disease.

Treatment? FORL is a progressive disease. At this time there is no known treatment that stops the progression.  Extraction is the treatment of choice with resorptive lesions.  It does no good to put a filling in a FORL.  The erosive process that caused them in the first place will dissolve the tooth out from around the filling, and the filling will simply fall out.  While it may seem a bit extreme to extract a tooth with a FORL, just consider the alternative:  Living daily with a very painful tooth.

There are things to know about extracting teeth with FORLs.    Look again at the radiograph above of the cat tooth with a FORL.  This time observe the roots closely.  Note that the smallest tooth has roots that seem blurry or indistinct when compared to the roots of the neighboring teeth.  This is because the roots are starting to be resorbed.  The tooth as a whole is undergoing a disease process.  Not only is there a hole eaten away in the crown (top) of the tooth, but also the roots are becoming weak and brittle.  If weak and brittle wasn’t enough, the roots also become cemented into the jaw bone.

This means that teeth with FORLs can be very difficult to extract.  The roots tend to shatter and fragment, making it difficult to get the whole root.  It is, in general, a bad idea to leave root fragments in place because they are often infected, and retained root tips can continue to be painful. 

It takes a lot of delicate work using the proper techniques and the right instruments to safely and completely remove FORL teeth.  FORL teeth must be removed surgically.  In a surgical extraction, the gums are cut, moved out of the way, the tooth is cut carefully into pieces, some of the overlying bone is removed, and the tooth is gently removed.  We must take post-extraction x-rays to be sure we got all the root tips.  Then the gums are sewn back into place.  Because this can be a very lengthy, delicate procedure, treating your cat’s FORLs can be fairly expensive.

Most cats develop FORLs in more than one tooth.  It is quite common to have to extract many teeth at a time.  Sometimes all the teeth must be removed.  However, once the healing process is over, the cats are much happier without all those painful teeth.

FORLs are a common and very painful dental condition in cats.  Many cats suffer for years in silence with very painful teeth.  Treating FORLs is not simple, but your cat will definitely thank you for the relief!

– Carolina Pets Animal Hospital