Periodontal Disease Stages in Cats: AVDC Grading

Last updated: May 4, 2026

How Veterinarians Grade Feline Gum Disease

The periodontal disease stages cats progress through follow the same American Veterinary Dental College (AVDC) grading scale used for dogs — grades 1 through 4, from reversible gingivitis to severe attachment loss. What makes feline mouths different is that classic periodontitis often coexists with two other very common conditions: tooth resorption and stomatitis. The same cat may have all three problems at once, and they require different management.

Cats are also masters at hiding oral pain. A cat with a severely diseased mouth may still purr, accept petting, and eat enough to maintain weight. By the time owners notice obvious signs, disease is usually advanced. This guide explains each AVDC grade, where feline-specific complications fit in, and what diagnostic workup is required to truly know what is happening in the mouth.

If you suspect anything off — bad breath, drooling, chewing on one side, a sudden food preference change — book a veterinary dental exam. Visual inspection alone, without sedation and dental X-rays, misses most of the disease.

Grade 1: Gingivitis Only

At grade 1, the gums are inflamed — red, slightly swollen, possibly bleeding when brushed or probed — but no attachment has been lost. The bone holding the teeth is still intact, the periodontal ligament is unaffected, and the disease is fully reversible.

This is the only stage where consistent home care plus a professional cleaning can return the mouth to baseline. Owners who catch this early give their cat the best long-term outcome. For more on the early stage in cats, see our guide to gingivitis in cats.

Visible signs are subtle: a thin red line at the gum-tooth junction, mild bad breath, occasional pink saliva on a toy or food bowl. Most cats at grade 1 act completely normal at home.

Grade 2: Early Periodontitis

Grade 2 marks the threshold where damage becomes permanent. By definition, less than 25 percent of the tooth’s supporting attachment has been lost. There may be very early gum recession around individual teeth and shallow periodontal pockets that a probe can detect under sedation.

Dental X-rays are essential here because the bone changes happen below the gum line and cannot be seen with a flashlight. The same applies in dogs — see our companion piece on periodontal disease stages in dogs for the parallel grading.

Treatment focuses on a thorough scaling above and below the gum line, polishing, and aggressive home care to prevent further loss. With consistent maintenance, many grade 2 mouths can be held there for years.

Grade 3: Moderate Periodontitis

Grade 3 means 25 to 50 percent attachment loss. Pockets are deeper, gum recession is visible to the naked eye, and individual teeth may show slight mobility. Bad breath becomes consistent and noticeable to owners.

Some teeth at this grade can still be saved with advanced periodontal therapy, but selective extractions of the worst-affected teeth are common. The decision depends on which teeth are involved, how much of each root is still supported, and the cat’s overall mouth health.

Cats at grade 3 are in real pain even if they are eating. Subtle behavior changes — preferring softer food, chewing on one side, less grooming, irritability when the face is touched — often only get recognized in retrospect after treatment.

Grade 4: Severe Periodontitis

At grade 4, more than 50 percent of attachment is gone. Roots may be exposed, mobility is significant, abscesses form, and some teeth fall out on their own. The mouth is painful, the breath is foul, and chronic bacteremia stresses other organs.

Treatment is almost always extraction of the affected teeth. Cats handle this well. Most are eating normally within a few days and visibly more comfortable once the source of chronic pain is removed.

Skipping treatment at grade 4 is not an option that protects the cat. The chronic infection burdens the kidneys (already a concern in many older cats — see chronic kidney disease in cats), and the daily oral pain takes a real toll on quality of life.

Tooth Resorption: A Cat-Specific Complication

Tooth resorption is a process where a cat’s own cells dissolve the structure of its own teeth, often starting at or below the gum line. It is not classic periodontitis but it frequently coexists with it, and it can affect cats with otherwise excellent gum health. Estimates suggest a substantial fraction of adult cats develop at least one resorptive lesion in their lifetime.

The lesions are intensely painful — many cats with resorption show a characteristic jaw chatter when the lesion is touched during exam. Diagnosis requires dental X-rays; many lesions are entirely hidden under the gum line. For details, see our guide to tooth resorption in cats.

Treatment is extraction or, in select cases, crown amputation. There is no medical management that reverses or stops resorption. Once a tooth has been affected, it is a question of when, not whether, it needs to come out.

Stomatitis: Severe Immune-Mediated Inflammation

Feline chronic gingivostomatitis, often just called stomatitis, is a severe inflammatory disease that goes well beyond the gum line into the soft tissues at the back of the mouth. Cats with stomatitis are in significant pain — many drool, refuse hard food, lose weight, and stop grooming.

It is not the same disease as periodontitis, though periodontal disease can worsen it. Treatment is often full-mouth or near full-mouth extraction, which sounds extreme but is the most effective long-term therapy. Our deep dive on stomatitis in cats covers diagnosis, medical management, and surgical outcomes.

If your cat shows mouth pain disproportionate to what their teeth look like on the outside, ask about stomatitis specifically. The diagnosis is often missed at general physicals because the cat refuses a thorough oral exam while awake.

Why Anesthesia and Dental X-Rays Matter So Much in Cats

More than half of feline dental pathology lives below the gum line. Resorptive lesions, root abscesses, retained roots, jaw bone loss — none of it is visible without radiographs taken under anesthesia. A clean-looking mouth on a flashlight exam can hide significant disease.

This is why anesthesia-free dental cleaning is opposed by veterinary dental specialists for both cats and dogs. See our breakdown of the anesthesia-free dental cleaning debate for the specifics.

Healthy cats handle modern anesthesia safely with appropriate pre-anesthetic bloodwork, IV fluids, intubation, and trained monitoring. The risk of a properly run anesthetic is small; the risk of leaving severe oral disease untreated is much larger.

Home Care Realities for Cats

Daily brushing with a feline enzymatic toothpaste is the gold standard, but cats are notoriously harder than dogs to brush. Many owners settle for finger brushes, dental wipes, or VOHC-approved products as a more sustainable compromise — see VOHC-approved dental products for an overview of what carries the seal.

Whatever you choose, consistency matters more than the specific product. A small daily habit beats a heroic monthly effort. Even thirty seconds of finger-rubbing along the outer gum line with toothpaste, done daily, makes a measurable difference over time.

None of this reverses attachment loss that has already happened. Home care is about preserving what your cat still has and slowing further progression.

Connecting Oral Health to Overall Health in Cats

Older cats are at meaningful risk for several systemic conditions where oral health intersects with general health. Chronic bacteremia from periodontal disease can stress the kidneys at a life stage when many cats are already developing kidney compromise. Diabetic cats heal more slowly and have higher infection risk if oral disease is left untreated. Cats with hyperthyroidism may have heart changes that complicate anesthesia for needed dental work.

This is why feline dental care is woven into broader senior wellness rather than treated as a stand-alone concern. Annual or twice-yearly veterinary visits with bloodwork catch systemic issues early, and dental assessment under sedation reveals what the awake exam cannot. The combined approach gives older cats their best shot at comfort and longevity.

For cats adopted from rescues, the dental starting point is often unknown — many shelter cats come with established disease that has gone untreated. An early veterinary dental assessment after adoption, through resources like our adoption hub, establishes a baseline and identifies what work, if any, needs to be done before home care becomes effective maintenance.

Putting the Grading System in Context

The AVDC grading scale directly drives treatment decisions. Grade 1 mouths get a routine cleaning under anesthesia and a home care plan. Grade 2 mouths get the same plus closer monitoring. Grade 3 mouths often face selective extractions, particularly when complicated by resorptive lesions. Grade 4 mouths typically need extensive extractions to relieve pain and remove chronic infection sources.

Cats add an extra layer of complexity because resorption and stomatitis can coexist with classic periodontitis. A cat may have grade 2 periodontal disease on most teeth plus active resorptive lesions on a few. The treatment plan addresses each condition. Knowing the full picture requires sedation, probing, and dental X-rays — the same workup any thorough feline dental visit includes.

If your veterinarian hasn’t graded your cat’s mouth, ask. The grade should be in the medical record after every dental visit. Owners who track their cat’s grade over time can see progression or stability clearly and adjust home care and cleaning intervals accordingly. Periodontal disease in cats is dynamic; periodic reassessment matters.

Frequently Asked Questions

Are periodontal disease and stomatitis the same thing in cats?

No. Periodontitis is bone and ligament loss around teeth driven by plaque bacteria. Stomatitis is severe immune-mediated inflammation of the mouth tissues, often requiring full-mouth extractions. They can coexist in the same cat.

What is tooth resorption and how is it different?

Tooth resorption is the cat’s own cells breaking down its own teeth. It is extremely common, often hidden below the gum line, and only diagnosed reliably with dental X-rays. Treatment is extraction.

How often should my cat have a professional dental cleaning?

Most adult cats benefit from a thorough oral exam at every annual wellness visit, with cleanings under anesthesia roughly every twelve to twenty-four months depending on individual disease. Cats prone to resorption or stomatitis may need more frequent attention.

My cat is eating normally — does that mean the mouth is fine?

Not at all. Cats hide oral pain extremely well and will eat through severe disease. Visible signs only show in advanced cases. A sedated oral exam with X-rays is the only reliable assessment.

Is anesthesia safe for older cats?

Healthy seniors with normal pre-anesthetic bloodwork tolerate modern dental anesthesia well. Age itself is not a contraindication. The risk of untreated oral disease typically outweighs the anesthetic risk.

What signs should make me book a dental visit?

Persistent bad breath, drooling, chewing on one side, dropping food, pawing at the mouth, weight loss, jaw chatter when touching the face, or any change in eating habits. Sudden changes are particularly important.