Cat Teeth Numbering: 4 Essential Rules Made Easy

Cat teeth numbering uses a three-digit code called the modified Triadan system. The first digit names the part of the mouth, and the last two name the tooth. So "104" means the upper right canine, and "409" means the lower right first molar.

This guide explains the numbers on your cat's dental chart. If you want the tooth count and formula first, read our cat dental formula guide. Here, we focus on reading the numbers your vet writes down.

What Is Cat Teeth Numbering?

The American Veterinary Dental College (AVDC) says the modified Triadan system is presently the tooth numbering system of choice in veterinary dentistry. See the AVDC nomenclature.

In this system, every tooth gets a three-digit number, so cat teeth numbering is exact. Wikivet notes that each tooth is allocated a three-digit number on a dental chart. As a result, a vet can record a problem on one exact tooth. Read Wikivet on dental charts.

Why vets use cat teeth numbering

First, AAHA defines a dental chart as a written and graphical record of the mouth, with space to note problems and procedures. See the AAHA definitions.

A journal guide on feline extractions also advises using the modified Triadan system. So when your vet says "tooth 307 has a lesion," every vet who reads the chart later knows exactly which tooth that is. Read the J Feline Med Surg guide.

In short, cat teeth numbering turns a busy mouth into a clear map.

The Four Quadrants in Cat Teeth Numbering

In cat teeth numbering, the first digit tells you the quadrant. Wikivet explains that quadrants are numbered 1 to 4, starting with the right upper jaw. See the Wikivet Triadan page.

The MSD Veterinary Manual adds that the numbering runs clockwise when you look at the animal from the front. The upper right quadrant is labeled 100. Read the MSD page.

Also, remember that "right" and "left" mean the cat's right and left, not yours. So when you face your cat, the 100s are on your left side.

Similarly, the AVDC chart PDF shows the same cat teeth numbering layout. It lists the upper teeth as 100s and 200s and the lower teeth as 400s and 300s. See the AVDC chart.

Two Landmarks in Cat Teeth Numbering: 04 and 09

The last two digits give the tooth position. They count from the front of the mouth backward, starting at 01 for the middle incisor.

However, two positions never change. Wikivet says canines are always 04, and the first molar is always 09. Ohio State's vet handbook gives the same two landmarks. See the Ohio State handbook.

Because of this, you can find your way in any mouth. First, find the long canine tooth, which is 04. Then count back to the last big cheek tooth, which is 09 in cats.

The last premolar is 08

Wikivet also notes that the last premolar is always 08. So in cats, 108, 208, 308 and 408 are the last premolars before the molar.

MSD also adds that cats have only one molar in each quadrant. That is the first molar, so it is numbered 109, 209, 309 or 409.

Why Cat Teeth Numbering Skips Some Numbers

To start, cats have fewer teeth than the full mammal pattern. However, the system keeps each position number fixed. So missing teeth leave gaps.

The AVDC explains that gaps are left in the numbering where there are missing teeth. Its example is clear: the first premolar in a cat's upper left jaw is numbered 206, not 205.

Indeed, Wikivet puts it simply: there is no 105 in the cat. Likewise, the AVDC chart shows that 305 and 306 are absent in the lower jaw.

This is why cat teeth numbering can look odd at first. Once you know the gaps, though, the chart is easy to follow.

Full Adult Cat Teeth Numbering Chart

First, adult cats have 30 teeth. Ohio State's handbook gives the formula as 2 times (I3/I3, C1/C1, P3/P2, M1/M1). VCA notes that 16 teeth are in the upper jaw and 14 in the lower jaw. See VCA on cat teeth.

Here is how those 30 teeth map to the numbers, based on the AVDC chart:

MSD notes that the tooth right behind the upper canine is the second premolar, 106 or 206. In other words, cats have no first upper premolar in this pattern.

A quick way to count

For example, each side of the upper jaw has 3 incisors, 1 canine, 3 premolars and 1 molar. That makes 8 per side. Each side of the lower jaw has 3 incisors, 1 canine, 2 premolars and 1 molar, so 7 per side. Together, that equals 30.

Kitten Teeth and Cat Teeth Numbering

In cat teeth numbering, baby teeth use quadrants 5 to 8. The AVDC chart lists 500s and 600s for the upper jaw and 800s and 700s for the lower jaw.

Also, the MSD owner manual says most cats have 26 baby teeth and 30 adult teeth. It notes the baby incisors begin to erupt at 2 to 4 weeks of age. Read MSD on dental development.

Then, VCA says baby teeth are usually all in by 6 to 8 weeks. By 6 to 7 months, most kittens have all 30 adult teeth. See VCA on retained baby teeth.

Retained baby teeth on a chart

Sometimes, though, a baby tooth stays after the adult tooth comes in. VCA calls this a persistent tooth. On a chart, your vet may note both the baby tooth number and the adult tooth next to it.

So if you see a 500-series number on your kitten's chart, it refers to a baby tooth. Our kitten gums guide explains teething signs to watch for.

How to Read Cat Teeth Numbering on a Dental Chart

After a dental cleaning, many clinics send home a chart that uses cat teeth numbering. It may look busy, but you can read it in a few steps.

For example, "308 extracted" means the last premolar in the lower left jaw was removed. Likewise, "204 fractured" means the upper left canine is broken.

Common chart notes

Also, charts often use short codes for findings. Ask your vet to explain any you do not know. The AAHA guidelines and the AVDC nomenclature list many of these terms.

Finally, Wikivet notes that the chart is also used to confirm that all planned treatment was performed. So it is a useful record to keep with your cat's health files.

Cat Teeth Numbering Practice: 6 Quick Examples

Practice makes cat teeth numbering feel easy. So try these six examples, then check the answers against the chart above.

Notice the pattern. First, read the quadrant. Next, use 04 for the canine and 09 for the molar. Then count the gap rules, such as no 05 in the upper jaw and no 05 or 06 in the lower jaw.

After a few tries, cat teeth numbering becomes second nature. As a result, you can follow your vet's notes without guessing.

Common Mistakes With Cat Teeth Numbering

Even careful owners slip on a few points. Here are the most common mix-ups, so you can avoid them.

• Mixing up sides: the numbers follow the cat's right and left, so the 100s sit on your left when you face your cat.
• Counting every tooth: cat teeth numbering keeps fixed positions, so you skip missing teeth instead of counting on.
• Expecting 305: the lower jaw has no 05 or 06 in cats, so the first lower premolar is 307.
• Confusing baby and adult teeth: 500 to 800 numbers are baby teeth, while 100 to 400 numbers are adult teeth.
• Reading two digits only: always read all three digits, because 04 alone does not say which canine.

Also, remember that a chart is a record, not a diagnosis. If a note worries you, ask your vet to explain it in plain words.

In the same way, ask for dental X-ray images if a tooth was flagged. Cornell recommends full-mouth X-rays for cats with tooth resorption, so many clinics take them.

Questions to Ask Your Vet About Cat Teeth Numbering

A short chat after a dental visit helps you understand the chart. So bring a copy and ask these questions.

1. Which numbered teeth had problems, and what did you find?
2. Were any teeth removed, and which numbers were they?
3. Do any teeth need a recheck, and when?
4. Were X-rays taken, and do they show changes below the gumline?
5. What home care will help protect the remaining teeth?

Then save the answers with the chart. That way, the next visit starts with a clear history, and cat teeth numbering makes the comparison quick.

Problems Recorded With Cat Teeth Numbering

Cat teeth numbering matters most when something is wrong. Two problems show up often on feline charts.

Tooth resorption

Cornell describes tooth resorption as a process where the inner tooth tissue erodes and is eventually destroyed. It estimates that 20% to 60% of cats are affected, and close to three-quarters of cats aged five and older. Read Cornell on tooth resorption.

Because of this, Cornell says the only effective treatment is extraction of affected teeth. It also recommends full-mouth dental X-rays. The AVDC classifies resorption in stages 1 to 5, and each affected tooth gets its own number on the chart.

Periodontal disease

However, AAHA says that by three years of age, most dogs and cats have some level of periodontal disease. It defines the disease as starting with gingivitis and moving to periodontitis if left untreated. See the AAHA guidelines.

Also, a feline review in PubMed notes that periodontitis is essentially irreversible and progressive. So charting each tooth helps your vet track changes over time. See the PubMed abstract.

Overall, WSAVA notes that dental disease is one of the most common problems in small animal practice. See the WSAVA dental guideline summary.

Using Cat Teeth Numbering at Home

You do not need to memorize every number in cat teeth numbering. Still, a few habits help you use your cat's chart.

1. Keep a copy of each dental chart in one folder or phone album.
2. Note which numbered teeth were treated or removed.
3. Check those areas gently during home mouth checks.
4. Bring the old chart to the next dental visit so the vet can compare.
5. Ask the vet to point to the numbered teeth on a model or photo.

Then build a daily care routine to go with your cat teeth numbering records. Our guides on brushing kitten teeth and cat dental care at home cover the basics.

Finally, call your vet if you see drooling, bad breath, red gums or trouble eating. Those signs need an exam, whatever the chart says.

Related guides: Cat dental formula · Stages of gingivitis in cats · Juvenile periodontitis in cats

Key Terms Explained

• Modified Triadan system: The three-digit tooth numbering system vets use for dogs and cats.
• Quadrant: One quarter of the mouth; the first digit of a tooth number.
• Deciduous teeth: Baby teeth, numbered in quadrants 5 to 8.
• Maxilla and mandible: The upper jaw and the lower jaw.
• Tooth resorption: A process that slowly destroys tooth tissue, common in cats.
• Dental chart: A written and visual record of each tooth and any findings.

This article is for general education and is not veterinary advice. These statements have not been evaluated by the Food and Drug Administration. Kittysum products are not intended to diagnose, treat, cure or prevent any disease.