A painful mystery in cats

As we finish off pet dental health month, it seems important to provide some information on a condition that we see very commonly in cats that the general public knows little about… feline ‘tooth resorption’.

Greater than half of all cats older than three years old will have at least one tooth affected by resorption (it affects dogs much less frequently).  Over the years these tooth defects have been called many things by veterinarians: feline cavities, ‘neck lesions’, external or internal root resorptions, feline odontoclastic resorption lesions (FORLs), and ‘cervical line erosions’. Our doctors may refer to them by any or all of these names.

The main reason that veterinarians cannot agree on a name for this condition is that the cause of these lesions is unknown; theories supporting an autoimmune response, calicivirus, and metabolic imbalances relating to calcium regulation have all been proposed. Unfortunately, our poor understanding of why these lesions occur not only causes confusion, but it also means that we have no way to prevent this painful condition.

The process of tooth resorption starts with erosion of the tooth (usually starting at or just below the gumline where it cannot be easily seen) and continues with progressive loss of tooth structure. This eventually results  in the exposure of the sensitive portions of the tooth, which is what makes this condition so painful.

Many cats will show no obvious signs of pain unless and until a lesion is actually touched. Sometimes an affected cat will drool, have difficulty eating or owners will notice bleeding at the gumline. Occasionally there can also be vomiting of unchewed food, behavior changes and bad breath.  Most often it is up to an observant pet owner or a veterinarian to diagnose this problem in a cat’s mouth.

Our doctors may be able to identify teeth with suspected resorption during a physical examination, however, dental  radiographs (x-rays) are essential to evaluate all the teeth to determine the best course of therapy when tooth resorption is suspected.  Our hospital is equipped to take these x-rays when necessary and we will often call owners to discuss such x-rays when cats are in for dental assessments under anesthesia. Depending on what is seen in those intraoral x-rays, treatment for tooth resorption involves either extraction of the entire tooth and roots, or a partial tooth extraction. 

Once a tooth with resorption has been identified in a cat's mouth, it is very common for additional lesions to occur. We recommend rechecks every 6-12 months for a cat with a history of tooth resorption so that we can assess if the cat may be developing further damage to remaining teeth.

As our understanding of feline medicine continues to advance, we hope that this is one of the conditions that we will begin to understand better. Please let us know if you have any questions about your cat's dental health, particularly if you see any warning signs of dental disease at home.