Cat Teeth: Not All Holes Are Not Cavities

Sasha the beautiful fluffy Himalayan cat had been hiding under the bed more than normal, and when she was out she could sometimes be found sitting, staring at the wall. She had been eating fine, so it couldn’t be a problem with her mouth… or could it?
Cats only have 30 teeth compared to a person’s 32 (and a dog’s 42!), but the species’ differences do not end there. A cat’s teeth are designed more for puncturing, slicing, and tearing, rather than the chewing that we humans do. While cats and people both get cavities, they are usually in totally different ways, and with completely different results.
Image via www.catster.com.
Cats, dogs and humans all develop tartar and plaque on their teeth over time. Brushing the teeth, eating properly and routine dental care helps to slow this process. In people, bacteria in this tartar and plaque can eat away at the tooth wall, eventually leading to a cavity, or hole in the tooth. While cats develop tartar, their “cavities” are typically not related to tartar and bacteria, but rather spontaneously occur. These “cavities” are more accurately called Feline Odontoclastic Resorptive Lesions, or FORLs, and are surprisingly common. They usually appear on the tooth at the gum line, and can erode the tooth enamel until the nerve root is exposed, which can cause severe pain. FORLs left untreated eventually eat away at so much of the structure of the tooth that the tooth spontaneously shatters. This process can cause discomfort for months or years.
FORL in lower third premolar- it’s a dramatic hole in the tooth!
While we know that tartar and plaque alone are not the cause of FORLs, we do not know what does cause these cat cavities. Some have theorized it is related to cat food, although skeletons of our pet cat’s ancient ancestors show evidence of FORLs thousands of years ago, long before cat food was developed. There does seem to be a genetic component, since FORLs are more common in certain purebred breeds, such as Siamese and Himalayans. 
Unlike human cavities, FORLs typically do not respond well to fillings or even root canals. Usually, the affected teeth have to be extracted. While this may seem as though it would be uncomfortable, these teeth are so painful that removing the tooth is a huge relief. While FORLs are common, they are not the only dental problem a cat can have, so a proper diagnosis is vital; dental x-rays may be needed to fully analyze the tooth roots.
Gum tissue is trying to fill in the FORL in the cat canine (the fang)
Thanks to the American Veterinary Dental Society
Many astute owners miss that their cat has FORLs. Even the best pet owners have difficulty looking at the rear teeth, and this is even more true if the mouth is uncomfortable. Sometimes, tartar or a swollen gum may obscure the FORLs. While difficulty eating would seem to be an obvious sign, many cats with painful teeth simply choose to chew on the other side of their mouth, or not chew much at all. Since a cat’s teeth are designed to tear rather than chew, many cats swallow small pieces of food whole, so a difficulty chewing may go completely unnoticed. Often cat owners report that cats with FORLs seem more reserved and quiet, drool slightly, or only vomit more often (since they are swallowing their food whole). They may hide more often, or stare at a blank wall; these can be signs of discomfort in a cat, and should not be ignored. 
Cat FORLs can be very frustrating; with no known cause, and no real treatment except tooth removal, the options can be very limited. Hopefully, continued research in cat dentistry will reveal a way to prevent, or at least treat, this painful cat disease.

Originally published in the Tampa Bay Weekly Newspapers August, 2012