Your dog’s mouth can look fine and still be in trouble. By the age of three, 80% to 90% of dogs already have some form of gum disease, and the earliest stages hide below the gumline where you cannot see them. The good news is that dental disease follows a predictable path, and vets have a simple map for it.
That map is a five-stage grading system. Knowing which stage your dog is in tells you two things that matter: whether the damage can still be undone, and how urgent treatment is. This guide walks through all five grades in plain language, shows you how vets actually measure them, and explains what to do at each point.
The short version
Dog dental disease is graded from 0 to 4 using the American Veterinary Dental College system. Stage 0 is healthy and Stage 1 is gingivitis, which is fully reversible. From Stage 2 onward the disease is periodontitis, meaning the support around the tooth starts breaking down for good. Stage 2 is early (under 25% loss), Stage 3 is moderate (25% to 50%), and Stage 4 is advanced (over 50%), where teeth loosen and often need to come out. The stage can only be confirmed with probing and dental x-rays under anesthesia, because roughly 60% of the disease is invisible to the naked eye.
Jump to a section
- The five stages at a glance
- Grade 0: a healthy mouth
- Grade 1: gingivitis, the reversible stage
- Grade 2: early periodontitis
- Grade 3: moderate periodontitis
- Grade 4: advanced periodontitis
- How vets actually pin down the stage
- Treatment and cost by stage
- How to keep your dog at grade 0 or 1
- Common questions
The five stages at a glance
Vets around the world stage gum disease using the same framework, published by the American Veterinary Dental College (AVDC). It runs from PD0 to PD4, where “PD” stands for periodontal disease. The dividing line that matters most sits between Stage 1 and Stage 2, and this chart shows why.
| Stage | What is happening in the mouth | Attachment or bone loss | Can it be reversed? |
|---|---|---|---|
| Grade 0 (PD0) Healthy |
Clean, pink gums with no inflammation. Nothing wrong. This is the goal. | None | Already healthy |
| Grade 1 (PD1) Gingivitis |
Red, puffy gums caused by plaque. The bone and tissue holding the tooth are still fully intact. | None yet | Yes, the only fully reversible stage |
| Grade 2 (PD2) Early periodontitis |
Attachment starts to break down below the gumline and small pockets form around the tooth. | Up to 25% | No, but it can be stopped |
| Grade 3 (PD3) Moderate periodontitis |
Deeper pockets, visible bone loss on x-rays, and gum recession. Roots begin to lose support. | 25% to 50% | No, damage is permanent |
| Grade 4 (PD4) Advanced periodontitis |
Loose or painful teeth, exposed roots, infection, and often abscesses. Extractions are common. | More than 50% | No, usually means tooth loss |
Attachment loss is the key measurement here. It refers to how much of the tissue and bone anchoring a tooth to the jaw has been destroyed. A little is bad. More than half is often the end of the line for that tooth. Now let us walk through each grade one at a time.
A healthy mouth
Stage 0 is exactly what it sounds like. The gums are pink and firm, there is no inflammation, and the bone under the gumline is intact. There is no periodontal disease to speak of.
Very few adult dogs stay here without help. Plaque, the sticky bacterial film that starts the whole process, begins forming within hours of a cleaning. Left alone, it hardens into tartar and irritates the gums. Keeping a dog at Grade 0 is less about luck and more about routine home care and regular professional cleanings, which we cover further down.
Gingivitis, the reversible stage
This is the single most important stage to understand, because it is the last one you can completely undo. Gingivitis means the gums are inflamed, red, and maybe a little swollen or prone to bleeding. But crucially, there is no attachment loss yet. The bone and ligaments holding each tooth in place are still normal.
Because nothing structural has been lost, a professional cleaning followed by consistent home care can return the gums to full health. That is a genuine reset. Persistent bad breath is often the first thing owners notice at this stage, and it is worth taking seriously rather than writing off as normal doggy breath.
The line that matters: everything before Stage 2 can be reversed. Everything from Stage 2 on cannot. If your dog is going to have gum disease, this is the stage where you want to catch it.
Early periodontitis, the point of no return
Once gingivitis is left untreated, the inflammation spreads below the gumline and the disease crosses into periodontitis. At Stage 2, up to 25% of a tooth’s attachment has been lost. Small pockets form between the gum and the tooth, trapping bacteria and debris that are impossible to brush away.
The word “early” can be misleading. Early periodontitis is still permanent. You cannot regrow the lost attachment. What you can do is stop the disease in its tracks with a thorough cleaning below the gumline and diligent home care afterward. Early radiographic signs of bone change also start to show up at this stage, which is one reason x-rays matter so much.
Moderate periodontitis
At Stage 3, between 25% and 50% of the tooth’s support is gone. Pockets are deeper, gum recession becomes visible, and x-rays show clear bone loss. Some teeth may start to feel slightly loose, and the mouth is often painful even if the dog hides it well. Dogs are very good at masking oral pain and will keep eating through significant disease.
Treatment gets more involved here. On top of a deep cleaning, a vet may perform advanced periodontal therapy to try to save teeth, or recommend removing the ones that are too far gone. The goal shifts from full recovery to preserving what is still healthy.
Advanced periodontitis
Stage 4 is the most severe grade, defined by more than 50% attachment loss. Teeth are loose, roots are exposed, and infection is common. At this point a tooth has lost most of what holds it in the jaw, and the most humane and effective option is usually extraction. Left in place, these teeth are a source of chronic pain and infection.
Advanced disease also brings complications. A common one is a tooth root abscess, a painful pocket of infection at the base of the tooth. In small dogs, severe bone loss in the lower jaw can even raise the risk of a jaw fracture. The bacteria involved can also enter the bloodstream, which research has linked to strain on the heart, liver, and kidneys.
How vets actually pin down the stage
You cannot accurately stage gum disease by peeking into an awake dog’s mouth, and neither can your vet. That surprises a lot of owners, so it is worth explaining why.
Roughly 60% of dental disease sits below the gumline, out of sight. A dog with bright, clean-looking teeth can still have advanced bone loss underneath. To get the real picture, a vet does two things: they gently probe around each tooth to measure pocket depth, and they take full-mouth dental x-rays to see the bone. Both require the dog to be still and calm, which is why staging is done under general anesthesia.
This is also why the professional consensus is firmly against so-called anesthesia-free cleanings. Scraping the visible surface of a tooth on an awake dog cannot reach below the gums, cannot include x-rays, and cannot actually stage or treat the disease that matters. It makes teeth look cleaner without addressing what is happening underneath. You can read our full breakdown of whether dog teeth cleanings are safe for more on how modern anesthesia is monitored.
Why the numbers look scary: studies that stage dogs by looking only at the awake mouth find gum disease in roughly 9% to 18% of dogs. Studies that examine the same kind of dogs under anesthesia with x-rays find it in 44% to 100%. The disease was always there. The awake exam just could not see it.
Treatment and cost by stage
Treatment scales with the stage, and so does the bill. Catching disease early is not just better for your dog, it is dramatically cheaper. Here are typical 2026 ranges in the United States.
| Situation | Typical 2026 cost |
|---|---|
| Routine cleaning, no extractions (Grade 0 to 2) | $300 to $700 |
| Cleaning with simple extractions (Grade 3 to 4) | $600 to $1,300 |
| Severe case, many extractions | $2,000 to $4,000 |
| Per-tooth extraction (simple to surgical) | $150 to $1,200 |
| Pre-anesthetic bloodwork (common add-on) | $80 to $150 |
The pattern is hard to miss. A dog treated at Stage 1 or 2 usually needs a straightforward cleaning. A dog that reaches Stage 4 may need multiple extractions, longer anesthesia, and specialist care, which is where costs climb fast. Dental work is a big part of why vet bills feel so expensive, and it is largely preventable spending.
One more note for multi-pet homes: cats follow the very same AVDC staging system, though they get some conditions dogs rarely do. If you have a cat too, our guide to cat dental disease covers the feline side.
How to keep your dog at grade 0 or 1
The whole point of understanding the stages is to stay near the top of the list. You cannot reverse periodontitis, but you have real control over whether your dog ever gets there. Four habits do most of the work.
Brush the teeth regularly
Brushing is the single most effective thing you can do at home, because it removes plaque before it hardens into tartar. Daily is ideal, but a few times a week still helps a lot. Use toothpaste made for dogs, never human toothpaste.
Use vet-accepted dental products
Dental chews, water additives, and diets that carry the Veterinary Oral Health Council (VOHC) seal are tested to actually slow plaque and tartar. They are a useful backup, not a replacement for brushing.
Book professional cleanings
A cleaning under anesthesia removes what brushing cannot, especially below the gumline, and gives your vet the chance to x-ray and catch trouble early. How often depends on your dog’s breed, age, and mouth.
Watch for the early warning signs
Persistent bad breath, red or bleeding gums, yellow-brown tartar, drooling, or a reluctance to chew are all reasons to book a dental exam. The earlier the stage, the cheaper and more reversible the fix.
Small and toy breeds deserve extra attention. Their teeth are crowded into a smaller jaw, which traps more plaque and speeds the disease up, so they tend to move through the stages faster than larger dogs.
Common questions
What are the stages of dog dental disease?
Vets use the American Veterinary Dental College’s five-stage system, PD0 through PD4. Stage 0 is a healthy mouth. Stage 1 is gingivitis, which is gum inflammation with no lasting damage. Stage 2 is early periodontitis with up to 25% attachment loss. Stage 3 is moderate periodontitis with 25% to 50% loss. Stage 4 is advanced periodontitis with more than 50% loss, loose teeth, and likely extractions.
Can dog dental disease be reversed?
Only gingivitis (Stage 1) can be fully reversed. A professional cleaning plus good home care can return inflamed gums to healthy. Once the disease reaches Stage 2, the tissue and bone that hold the tooth in place start breaking down, and that loss is permanent. You cannot rebuild it, but you can stop it from getting worse with treatment and consistent home care.
How do vets know what stage my dog’s dental disease is in?
By measuring, not just looking. A vet gently probes each tooth for pocket depth and takes full-mouth dental x-rays to see bone loss below the gumline. Roughly 60% of dental disease lives under the gums where it is invisible to the naked eye, so this work is done under anesthesia. A visual look at an awake dog consistently underestimates the true stage.
What stage of dog dental disease means teeth have to be pulled?
Extractions usually come into play at Stage 4, when more than half of a tooth’s support is gone and the tooth is loose, infected, or painful. Some individual teeth at Stage 3 may also need to come out if they cannot be saved. A vet decides tooth by tooth based on x-rays and probing depths, not on the dog’s overall stage alone.
Is bad breath a sign of dental disease in dogs?
Often, yes. Persistent bad breath is one of the earliest things owners notice, and it usually comes from the bacteria driving gum disease. Doggy breath is not supposed to be foul. If it is, that is a reason to book a dental exam rather than something to wait out.
How much does it cost to treat dental disease in dogs?
In 2026, a routine cleaning with no extractions typically runs $300 to $700. A cleaning that includes simple extractions usually lands around $600 to $1,300. Severe cases with many extractions can reach $2,000 to $4,000. Pre-anesthetic bloodwork often adds $80 to $150. Catching disease at Stage 1 or 2 is almost always cheaper than treating Stage 4.
How fast does dog dental disease progress?
Faster than most owners expect. Studies show most dogs have some periodontal disease by age two to three, and one longitudinal study found the large majority of young dogs already had early periodontitis in at least one tooth before their first birthday. Small and toy breeds tend to progress faster because their teeth are crowded in a smaller jaw.
The bottom line
Dog dental disease is not a single event, it is a slow slide through five predictable grades. The most valuable thing you can do is know where the line sits: Stage 1 gingivitis is fully reversible, and everything after it is not. That makes early attention less of a nicety and more of a money-and-pain saver.
Because most of the disease hides below the gumline, the only way to truly know your dog’s stage is a proper exam with probing and x-rays under anesthesia. If your dog has bad breath, red gums, or has not had a dental check in a while, that is your cue to book one.
