Resorption Lesions in Cats
Can be extremely painful and can spread very rapidly

Resorption lesions in cats are extremely painful, and as a result, your pet will lose their appetite and in most all cases, refuse to eat at all.

As the pain increases with this very painful condition, your cat will become both very irritable as well as very aggressive.

They may also start to bleed orally as well as begin to salivate excessively.

Excessive salivation is common in certain breeds of dogs, but it is extremely rare in cats and is a real warning sign that something very sinister is happening.


Resorption lesions in cats is also known by another name; FORLs. This stands for Feline oral resorption lesions, and it is a very painful dental disease.

Although it is not as well-known as other common dental disease in cats, it occurs a lot more often than most owners are aware of.

In fact, it is estimated that between 30 and as high as 65 percent of all cats will suffer this disease at some point in their lifetime.

Mean green eyes in catsThe actual cause of Resorption lesions in cats is still not fully understood

It can attack any breed of cat at any age, but it does seem to favor certain age groups and breeds.

It most commonly affects cats that are older than four years of age, and it also seems to be more common in purebreds.

The most common breeds affected are Siamese and Abyssinian's, but in recent years it appears to be spreading in the general cat population.

Even though it is relatively unknown, it is believed to be the number one cause of tooth loss in cats.

Your cats teeth are made up of six basic components; the pocket, hyperplasia, pulp chamber, enamel, dentin, and the gum area. When resorption lesions in cats develop, several things occur with their teeth.

Your cats affected tooth, or teeth if it is severe enough, will basically lose its structure.

It starts by attacking the outer surface enamel and in most every case it is right at or below the gum line, making very difficult for an owner to spot.

What is important for an owner to understand is that these are lesions, not cavities, and the result is the loss of tooth enamel.

Once this start to occur, it will eventually spread to what is called the dentin in your cats tooth, and will than make its way to the pulp canal.

The pulp canal in your cat’s teeth contains blood vessels as well as the nerves to the tooth.

If it becomes severe enough, the entire crown of your cats tooth will simply disappear.


What makes resorption lesions in cats so potentially dangerous is that it is extremely progressive and although it can affect only one tooth, this is seldom the case.

In most cases, it affects several teeth at the same time.

This disease can be lingual, which means that it is on the side where your cats tongue is, or it can be buccal, which means that it will develop on the side where the cheek is located.

These lesions can be visible in some cases, but in the majority of cases they will be hidden either under plaque or the swollen gums of your cat.

Because of this, in order for your veterinarian to properly identify it, your cat must be anesthetized so they can examine the entire structure of every tooth in your cat.

Resorption lesions can occur in your cat’s canine teeth as well as the incisors.

However they are much more likely to affect the much larger multi-rooted teeth; the molars and premolars, and will attack in stages.


Resorption lesions in cats will appear in a series of five stages, and begins with the loss of enamel in the teeth.

In this first stage, the disease will extend only about 0.5 mm into the affected tooth or teeth.

In stage two, the lesion begin to extend into the dentin, and in stage three they begin to extend into the pulp canal.

Although this disease is now getting progressively worse, there is still a lot of good tooth structure intact.

In stage four, the disease extends even deeper into the pulp canal, but now there is an extensive amount of loss occurring in the structure of the affected teeth.

In stage five, the crown of the tooth is now missing, but the roots are still present.

It is in stages three through five that the pain is now becoming quite severe for your cat and the symptoms will rapidly start to surface.

As the resorption lesions start to develop in stage two, you will begin to see some very obvious signs in your cat that something is terribly wrong with them.

The first sign that you will see is your cat becoming very irritable for no apparent reason.

As the disease progresses, this irritability starts to turn into aggression for one simple reason; they are now in a lot of pain.

By this stage, your cat has lost their appetite because it is becoming painful for them to eat.

The next signs will begin to tell you that your cat has a real problem; they will begin to completely change their eating habits.

They are now experiencing extreme difficulty in chewing and if the food is not moist and very soft, it will start to fall out of their mouths because they cannot hold it, let alone chew it.

At this stage, if you attempt to touch their jaw area, they may bite as it is very painful.

As it progresses, your cat will demonstrate a symptom that should stop the hearts of any cat owner; excessive salivation.

All cats will salivate slightly at times, but if it is excessive, it is a real warning sign.


Resorption lesions in cats are extremely frustrating, primarily because there is to this date, no known actual cause of the disease.

There are several theories in the medical community as to the actual cause, but they are just that; theories.

The first theory is that they are caused by inflammation stimulated by plaque.

It is believed that plaque in your cat may stimulate cells that are referred to as odontoclasts. These cells are believed to eat the enamel from your acts teeth.

Another theory is that it is an autoimmune disorder that actually changes the pH content in your cats mouth, but it is also believed that it may be the result of some type of viral infection.

There are also some in the medical community that believe that it is caused by a nutritional disorder, but no one is exactly sure which nutrient is deficient.

Diagnosis and Treatments

Resorption lesions in cats are very difficult to properly diagnose, unless the lesions are actually visible. However, in the vast majority of cases, they are not.

Because of this, the only way your veterinarian can properly diagnose this very painful disease is to put you cut under during the process.

Once this is done, they will have to examine each tooth in detail for the disease.

In this process, they will also have to remove any calculus that has built up on your cat’s teeth to properly identify it.

The actual treatment of this disease is just as controversial as the actual cause.

If it is only in stage one, it can be treated with a sealant that will help the tooth, but it may not stop the progression.

However, if it is in stage two and progressing, the tooth will in most all cases have to be taken out.

If the destruction has been severe and gone into the later stages, the root will also have to be removed which is now a very expensive process.


Resorption lesions in cats are an extremely painful and dangerous disease, as well as a very challenging one.

Because there is no known actual cause, this makes it even more important to have your cats teeth checked at least every six months.

If you cat has any history at all with this disease, you may need to have them checked even more frequently.

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