Overview We sometimes refer to resorptive lesions as "cat cavities", because, like cavities is people, resorptive lesions in cats are loss of tooth substance. The process by which the tooth substance is lost in cats is quite different from what it is in people; in that sense, cavities is not a very accurate term.
Resorptive lesions (RLs) can occur in dogs and other species, but for reasons that are not well understood, cats have particular trouble with them. RLs are common: at least 50% of cats 5 years or older have at least one tooth affected with RLs. They can occur in any age cat.
RLs can occur in one or more teeth, and involve any of the teeth. They are always progressive (more and more of the tooth structure is lost) but the speed of the progression is variable. At any one time a cat can have multiple resorptive lesions at various stages of progression.
We can often diagnose RLs on the awake exam of the cat's mouth, but sometimes they are so effectively covered up with tartar and swollen gum tissue that we do not know they are present until the anesthetized exam. Even then, we do not know the true extent of them without dental x-rays.
Cause The cause of resorptive lesions is unknown. We do know they are not caused by tartar build-up or the cat's diet.
Signs Many cats with RLs do not have obvious signs, but a significant small percentage do. When the RL progresses through the enamel into the deeper layers of the tooth it becomes painful. Signs seen at this point include: swollen, inflamed and bleeding gums, excessive salivation and drooling, difficulty chewing, picking up and dropping food, hissing at the food, bruxism (grinding teeth and jaws), and jaw twitches or spasms.
Treatment We believe RLs are always painful, even though some cats do not obviously act that way, so we recommend treatment. The only reasonable and practical treatment option is extraction. We base our decision on whether or not to extract teeth on many, many factors, including, but not limited to: the physical extent of the RL in an affected tooth, the cat's level of pain, and the owner's level of interest, desire and financial ability to pursue the problem with extractions. Our most common recommendation for a cat with RLs is to have a dental cleaning and exam once a year (sometimes more often) and, at that time, have any teeth with advanced RLs extracted.
Prevention Unfortunately, there is no way to prevent RLs. And once a RL begins there is no way to stop it, and there is no way to restore the tooth. That said, we still consider routine dental care, including some type of homecare and an annual professional cleaning a vital part of a cat's overall health care.