About the Diagnosis

Tooth resorption is the most common dental problem in cats. Either the tooth root (the part of the tooth under the gum line, within the jaw) or the crown (the part of tooth visible above the gum line), or both may be affected. This condition is known by several names: feline odontoclastic resorptive lesions (FORL), neck lesions, cervical line erosions, and feline caries. The tooth is eroded away beginning at the gum line and continuing into the tooth root or the crown, or both root and crown.
The cause of the condition is unknown and is under investigation. Cats over 5 years of age may be affected, and the likelihood of FORL increases as cats grow older. Cats that have dental tartar and periodontal disease may be at higher risk of developing FORL. The cheek teeth are most frequently affected, although FORL may occur in any tooth.
Affected cats often show no symptoms of the problem, even though many of the teeth are painful. Drooling, bleeding gums, and reluctance to eat hard food may be noted in some cats. The cat’s behavior may change as well; the cat may sleep more and become irritable, apparently as a result of dental pain. An examination of the mouth often reveals areas of the gums that are cherry-red in color (from inflammation) or overgrown. In advanced cases, the crowns of some teeth may be missing entirely since the eroded tooth breaks off at the gum line. If the involved teeth are touched, the cat may show pain by chattering its teeth.
Your veterinarian may have a strong suspicion of the presence of FORL after examining your cat’s mouth. However, an examination under anesthesia will be required to evaluate the extent of the problem. Even cooperative cats usually will not allow a thorough exam of the mouth, especially if painful resorptive areas are present. Anesthesia also allows x-rays of the teeth to be taken. This is an important diagnostic step to determine the extent of tooth root resorption, since this cannot be judged by external appearance.

Living with the Diagnosis

A cat that has had one tooth affected with resorption is likely to develop the problem in additional teeth. Have regular oral examinations done by your veterinarian. Periodic radiographic (x-ray) examinations allow discovery of teeth that have resorption of roots, which cannot be seen externally.


Most affected teeth need to be extracted (removed). Teeth that appear outwardly normal but have early x-ray changes may be extracted or rechecked in 6 months. This recheck should include repeat x-rays. Recommendations have been made to fill the eroded areas in teeth that have more advanced changes. Although fillings relieve the pain, this treatment does not stop the problem from progressing and therefore probably does not have long-term benefit. Therefore, all teeth with extensive involvement should be removed. Removal of affected teeth stops the pain, and treated cats often show an improvement in activity and attitude. Cats with no teeth at all have no problem eating commercial diets, even dried kibble-type foods-although this would no doubt be a problem for a cat that had to live only on mice!


• After surgery to remove affected teeth, your cat will probably be sent home with medication for pain, as well as an antibiotic. Give medicines exactly as directed.
• Return for follow-up examinations as scheduled.
• Realize that dental disease may be much more severe than meets the eye, since extensive disease may exist below the gum line and not be apparent externally.

When to Call Your Veterinarian

• If you have difficulty giving the medication(s).
• If your cat has not returned to its normal routines by the day following surgery or if it is not eating.

Signs to Watch For

• A significant improvement in demeanor (activity, alertness) is very common after removal of diseased teeth. You should expect to see a recovery period of a few days to 1 week after dental removal, after which a cat feels as good as or better than before the procedure was done.

Routine Follow-Up

• Recheck examination in 2 to 3 weeks after oral surgery to check gum healing.
• Routine reexaminations to look for new FORL in other teeth as recommended by your veterinarian.