Tooth Resorption in Cats: Causes, Symptoms, & Treatment

Melina Grin / Cats.com

Tooth resorption is known by different names to vets, such as feline odontoclastic resorptive lesions (FORLs), cervical lesions, or neck lesions. Regardless of the name, tooth resorption is a common dental problem that affects 30–60% of cats.

Other Names: Feline odontoclastic resorptive lesions (FORLs), Neck lesions, Cat caries, Cervical line lesions

Common Symptoms: Difficulty eating or eating on one side, drooling, pain, chattering jaw

Requires Ongoing Medication: No

Vaccine Available: No

Treatment Options: Monitoring in rare cases, extraction in most cases

Home Treatment: Regular vet checks, monitoring eating habits

It can be a painful, debilitating condition and needs immediate veterinary treatment. In this article, we’ll discuss what tooth resorption actually is and the common signs and treatments of this uncomfortable condition.

What Is Tooth Resorption in Cats?

The first tooth behind the upper canine tooth in this photo has a small red spot near the gumline. This is a typical appearance of an early resorptive lesion. Chris Vanderhoof / Cats.com

Tooth resorption is a painful condition that involves the destruction of a tooth. It is caused by the breakdown and loss of dentin, which is the hard part of the tooth beneath the enamel. The dentin is worn away or attacked by cells called odontoclasts.

This vital structure wears away and exposes the sensitive pulp cavity underneath, which contains nerves and blood vessels. It can occur on the root, the crown (tooth above the gum line), or both.

It’s important to realize that these lesions are not the same as cavities. Cavities, or dental caries as they are medically called, occur when bacteria and enzymes eat away at the outer layers of the tooth. This usually occurs on the flat surfaces of the teeth, making dental caries very rare in cats. While less well understood, tooth resorption is a very different process.

A resorptive lesion on the crown, visible on the surface, can be extremely painful and cause severe discomfort to your cat. Lesions on the root aren’t thought to be painful and aren’t visible without performing a dental x-ray.

There are two types of tooth resorption in cats;

• Crown resorption: This involves the destruction of the crown, often with a visible defect on the tooth. The root remains relatively normal, with a visible periodontal ligament on dental X-rays. Some cases present with a fractured crown and a root remaining in the jaw. This is also called a Type 1 lesion.
• Root resorption: These involve lesions on the root. On dental X-rays, the root will look like it’s blending into the bone and won’t be as distinguishable. This is also referred to as replacement resorption, or a Type 2 lesion.

There is also a Type 3 lesion which incorporates a combination of both Type 1 and Type 2. For example, the crown and one root of a tooth may show signs of resorption while the second root appears unaffected.

Tooth resorption commonly affects the lower mandibular premolars first and may occur in other teeth afterward. The progression of tooth resorption is unknown and is different in every cat. In some cats, multiple teeth be develop lesions at the same time, which is extremely painful. In others, only one may occur and a cat may not develop any more.

Regardless of how many a cat has, the resorption process affecting an individual tooth will progressively involve more and more of the tooth. Over time, the entire tooth will essentially dissolve and disappear below the gumline. The roots themselves typically also resorb, becoming part of the jaw bone.

This process however, is not fast. It often takes months for one tooth to go through the process of resorption, causing the cat more pain as more and more of the crown of the tooth is involved.

Causes of Tooth Resorption in Cats

The causes of tooth resorption in cats remain a bit of a mystery. There are many hypotheses for why this occurs, including;

• Periodontal disease
• Unique populations of normal flora bacteria and the immune system’s response to them
• Another immune-mediated stimulus triggering the resorption process
• Vitamin D level in food
• Abfraction injuries (forces on the jaw)
• Soft tissue inflammation in the mouth
• Age
• Genetic predisposition

Unfortunately, none of these are proven and why cats get tooth resorption is still unknown. Cats are thought to be more likely to get resorptive lesions as they age. However, plenty of young cats get them as well, even with quite clean-looking teeth. Cats who develop one resorptive lesion are likely to get more over time.

Dr. Chris Vanderhoof shares about his three cats who all developed resorptive lesions. “My three cats Teach, Bart, and Annie, all developed multiple resorptive lesions before they were four years old. This always suggested to me that genetics or the farm environment they grew up in early on as kittens may have played some part,” says Dr. Vanderhoof. “While we don’t know the exact cause for FORLs, we do know that the development of gut and oral flora and the immune system occurs a lot in the first several months of life.”

Symptoms of Tooth Resorption in Cats

Tooth resorption can be very painful, especially when eating. Signs of discomfort may include drooling, eating on one side, dropping food, vocalizing during meals, avoiding food, jaw chattering, blood in the mouth, and reduced grooming. Melina Grin / Cats.com

Tooth resorption can be extremely painful, especially if more than one resorptive lesion is present. Affected cats may show signs of discomfort, particularly when eating. Monitor your cat closely for signs such as;

• Drooling
• Eating on one side of their mouth
• Dropping food when eating
• Vocalising when eating
• Running away from their food or swatting their food bowl
• Jaw chattering/quivering
• Blood from mouth (as drops or in saliva)
• Not grooming themselves

If your cat shows some of the above signs, schedule them for a veterinary examination as soon as possible. Cats showing these signs are in a great deal of discomfort, usually with either a severe resorptive lesion, multiple ones, or another serious concern with their mouth.

But don’t be fooled. Cats often try to hide their pain, making it harder to detect this condition. In cases where only one resorptive lesion is present, as in the earlier photo, cats may show no visible signs of discomfort or trouble eating. These may not be detected until your veterinarian finds one during an exam.

Dr. Vanderhoof recalls what it was like to realize his own cats had this condition. “Annie was the first to develop them noticeably. Over time she became withdrawn with less energy, taking longer than her brothers to finish her meals. As a naive student at the time, I believed these changes were just a sign of her getting older. I can identify a great deal with cat owners not being able to detect this condition because their cats try to hide it.”

Diagnosis of Tooth Resorption in Cats

In this dental x-ray, the cursor points to the back root of a bottom molar, which is in the process of resorbing into bone. You can also see the back of the tooth’s crown is concave and irregular. This is an example of Type 3 tooth resorption, where the crown and root are both affected, while another root is not yet noticeably affected.

For cats that show signs of tooth resorption at home, this will often be diagnosed by arranging an oral examination with your vet. Cats that are suffering silently may not be diagnosed until they have a routine veterinary check-up.

Crown resorptive lesions are often diagnosed through a visual examination by your veterinarian. There will likely be a visible lesion on your cat’s tooth, just like in the earlier photo.

Lesions that affect the tooth root won’t be visible on physical examination and need to be diagnosed with dental radiographs. These are usually done under general anesthetic and should be done in all feline dentals, especially when tooth resorption is suspected.

Your vet may recommend blood and urine testing if your cat is over a certain age to rule out underlying causes of pain and disease.

Treatments for Tooth Resorption in Cats

The only treatment for tooth resorption is surgical extraction of the tooth. Antibiotics and pain relief will only provide temporary relief and there is no way to save the unhealthy tooth. The resorption process cannot be reversed or stopped.

It’s important to realize that a resorptive lesion is not the same as a cavity, which can be drilled out and filled. These are entirely different things, and cats do not typically get cavities, also called dental caries.

Extraction is needed to treat this condition and the extraction needed depends on the type of resorption. For crown lesions, where the root is relatively untouched and clearly visible on x-rays, the full tooth needs to be extracted. This is usually done with a gum flap, removal of bone surrounding the roots, careful removal of the affected roots, and the gum flap sutured back in place.

Root lesions, where the root isn’t clearly visible on x-rays and becoming absorbed into the bone, may have an extraction called a crown amputation. This involves extraction of the crown only, the part of the tooth above the gumline. The root can be left in place as it’s already disappearing into the bone. This can only be done if it has been confirmed on dental x-ray that the root is severely affected by resorption.

In cases of Type 3 resorption where one root is affected and another is not, the entire tooth still needs to be removed, especially if the crown of the tooth is involved. Part of the tooth cannot be left behind.

In rare cases, mild resorption that is only affecting the roots with no visible lesions on the crown, may be monitored. This should only be done if the cat is returning for regular clinical examinations as there is a risk of the crown breaking off or fracturing. Your vet will judge this based on your cat’s dental x-rays, clinical exam, and dental probing under anesthetic.

The Dental Procedure

Extraction of teeth will require a general anesthetic. Your vet may do blood and urine testing prior to anesthesia to make the procedure safer and may require your cat to have intravenous fluids during the procedure. Dental procedures are often a same-day procedure, but your cat may be required to stay overnight if your vet advises it.

Cats will often go home with pain relief medication and they may also have antibiotics. Stitches that have been placed in the extraction site(s) will usually dissolve over time and don’t need removal. Recovery time will depend on how many teeth extractions were needed—it may vary from 1–4 weeks.

It isn’t normal for cats not to eat after dental procedures. It may indicate that they need more pain relief. Always contact your veterinarian if you’re concerned about your cat after their dental procedure.

Dr. Vanderhoof remembers how, even after having several affected teeth removed, his cat Annie felt so much better. “I recall realizing back then just how much discomfort she must have been in, even though it was very gradual and hard to notice. After her dental procedure, she was racing around the house, playing with her brothers, and eating like I hadn’t seen her do for weeks. I’ve never forgotten this experience as a student, and as a doctor, it’s made me an advocate for detecting these lesions in cats as soon as possible and before they develop a lot of discomfort.”

Complications of Having Tooth Resorption

If your cat has had one of these lesions in the past, they need to be monitored closely in the future. This is because cats that have had resorptive lesions are more likely to get them in other teeth. Some cats may show signs of dental pain but the majority don’t so regular veterinary check-ups are recommended.

Unfortunately, there is no way to predict if or when more lesions may develop. A new one may even develop shortly after a dental procedure to treat previous ones. This can be very frustrating, but currently there is no known way to predict or prevent them reliably.

Cat Care Tips

As cat owners, it’s very upsetting to see our cats in pain. If your cat is suffering from a tooth resorptive lesion or is in the post-operative period after their dental procedure, there are some tips that may help to keep them comfortable.

Offer Plenty of Wet Food

Unless advised to do otherwise by your vet, always offer plenty of soft food for your cat. This may be in the form of wet tins or pouches of complete cat food. Cats that are suffering with dental pain may find dry food too painful to eat and prefer eating softer food. If they have stitches in their mouth, your vet may recommend wet food to prevent damaging the stitches.

Offer Shallow Wide Bowls

Avoid using bowls that are narrow and deep, as your cat’s mouth may hit the sides. This could be very painful if they have a resorptive lesion or are in the post-operative period. If they don’t like their bowl, they’ll be less inclined to eat and drink.

Stick To Their Medication Schedule

If your vet has prescribed medication, ensure that you give this at the correct times. It’s important that they receive any pain relief or antibiotics that they need. If you’re finding it difficult to give your cat oral medication as their mouth is sore or their appetite may be reduced, contact your vet. Your vet may have alternatives such as liquid oral medication or injections.

Prevention of Tooth Resorption in Cats

Regular tooth brushing can help maintain your cat’s dental health. Liz Coleman / Cats.com

There is no known preventative of tooth resorption in cats because the cause is unknown. There are some thoughts that periodontal disease and inflammation in the mouth may predispose cats to tooth resorption. With this in mind, practicing good dental hygiene is advised.

Tooth brushing helps to prevent tartar and gingivitis on teeth. This may seem like a daunting task but some cats are surprisingly tolerant of this. Get advice from your vet on this and choose an appropriate toothbrush. You may also read our article on How to Brush a Cat’s Teeth for tips and guidance.

Regular veterinary check-ups, including an oral exam of your cat’s mouth, will aim to pick up any early signs of tooth resorption.

Conclusion

Feline tooth resorption is a painful dental condition in cats. It can occur on the tooth crown or on the root and treatment usually involves extraction of the tooth. There is no known cause but practicing good dental hygiene and regular veterinary check-ups will go a long way in helping this condition. Always contact your vet if you think your cat is showing signs of dental pain.