A dental chart is a map of your dog's mouth, one box for every tooth, so a vet can write down what each one is doing. An adult dog has 42 permanent teeth and a puppy has 28 baby teeth. To keep them straight, vets give every tooth a three-digit number using the modified Triadan system, set out by Floyd in 1991 and still the standard today.
Once you know how the numbering works, a line like "extracted 208" stops being code. Below is the full set of numbers for a dog, and how to read the chart your vet hands back after a dental. A chart is where dental disease in dogs gets recorded tooth by tooth, so it helps to know what the numbers point to. It also pairs with our dog mouth anatomy guide, which covers what each tooth is and what it does.
How vets number a dog's teeth
The modified Triadan system gives each tooth a three-digit number. The first digit says which corner of the mouth the tooth is in. The last two digits say where it sits in that corner, counting back from the front.
The last two digits mean the same thing in every quadrant, and in most species. The canine is always 04 and the first molar is always 09. So 104 and 404 are both canines, one top right and one bottom right, and a vet reading 309 knows it is a lower first molar without counting along the jaw.
The four quadrants
Face your dog and split the mouth into four, left and right, top and bottom. The adult quadrants are numbered one to four, starting at the dog's upper right and going clockwise as you look at it.
| First digit | Quadrant | Numbers |
|---|---|---|
| 1 | Upper right | 101 to 110 |
| 2 | Upper left | 201 to 210 |
| 3 | Lower left | 301 to 311 |
| 4 | Lower right | 401 to 411 |
Baby teeth get their own four quadrants so they are never confused with the adult set. They run five to eight in the same order, upper right 500s, upper left 600s, lower left 700s, lower right 800s.
Finding any tooth from its number
To place a tooth, read the first digit for the corner, then count back from the midline for the rest. Position 01 is the central incisor next to the midline, 02 and 03 are the incisors beside it, 04 is the canine, 05 to 08 are the four premolars, and 09 onward are the molars.
Two landmarks make this quick. The canine is the fourth tooth from the front, so it carries 04 in every quadrant. The first molar is the ninth position, so it carries 09. Find either of those and you can count along the jaw in both directions.
The big shearing teeth, the carnassials, are worth knowing by number because they break more than any other tooth. The upper carnassial is the fourth premolar, 108 and 208. The lower carnassial is the first molar, 309 and 409. Our guide to the carnassial teeth explains why those four take the most force and crack the most often.
A dog is numbered straight through with no gaps. A cat skips a few numbers because it has fewer teeth, so a cat has no 105 or 205, but a dog fills every slot its jaw has room for.
The full dog dental chart
The upper jaw has three incisors, one canine, four premolars and two molars on each side. The lower jaw has the same front teeth but three molars on each side, which is why the bottom quadrants end one number higher, at 311 and 411.
| Quadrant | Incisors | Canine | Premolars | Molars |
|---|---|---|---|---|
| Upper right (1) | 101, 102, 103 | 104 | 105, 106, 107, 108 | 109, 110 |
| Upper left (2) | 201, 202, 203 | 204 | 205, 206, 207, 208 | 209, 210 |
| Lower left (3) | 301, 302, 303 | 304 | 305, 306, 307, 308 | 309, 310, 311 |
| Lower right (4) | 401, 402, 403 | 404 | 405, 406, 407, 408 | 409, 410, 411 |
That is 20 teeth up top and 22 along the bottom, 42 in all.
Puppy teeth use the 500s to 800s
A puppy's 28 baby teeth follow the same idea, with one difference in the premolars. Each baby quadrant has three incisors, one canine and three premolars, so seven teeth, and seven across four quadrants makes 28.
Baby premolars are numbered 06, 07 and 08, not 05, 06 and 07. There is no baby 05. The adult first premolar comes through on its own with no baby tooth before it, so the three baby premolars line up with the adult teeth they will be replaced by. A puppy's upper right baby teeth are 501, 502, 503, 504, 506, 507 and 508. If a chart shows you a puppy 505, it is wrong.
This matters when a baby tooth refuses to fall out. A retained baby canine sitting next to its adult replacement is the easiest retained tooth to spot. Our guide to when puppies lose their baby teeth covers the six-month check and which tiny breeds hold on to baby teeth the longest.
Reading the chart at your vet
On the chart itself, the number only names the tooth. The marks written beside it are the findings, and that is the part worth asking about. A vet might note gum recession in millimeters, a wobble graded for mobility, a fracture, a gap where a tooth is missing, or a pocket depth from the probe that runs around each tooth. Different practices use slightly different shorthand, so it is fair to ask what a symbol means.
The chart records which teeth were treated and what the vet saw. What a finding means for your dog is a question for your vet. Some findings have their own guide. A swelling below the eye above an upper carnassial often turns out to be a dog tooth abscess. If a tooth is marked for removal, read when a tooth needs pulling. A tooth flagged for a change in color is explained in a tooth that changes color.
If your dog is dropping food, chewing on one side, pawing at its mouth or has breath that has turned, see your vet, even if no chart exists yet.
Questions owners ask
How many teeth does an adult dog have?
Forty-two permanent teeth, 20 in the upper jaw and 22 in the lower. A puppy has 28 baby teeth and no molars, with the adult set fully in by about seven months.
What is the modified Triadan system?
It is the three-digit numbering vets use for teeth. The first digit is the quadrant of the mouth and the last two are the tooth's position counting back from the front, so every tooth has a short, unambiguous name.
What does a tooth number like 208 mean?
The 2 puts it in the upper left quadrant. The 08 is the eighth position back, the fourth premolar. So 208 is the upper left fourth premolar, one of the large carnassial teeth.
Why do puppy teeth have different numbers?
Baby teeth use quadrants five to eight so they are never mixed up with the adult set. A puppy also has no first premolar, so its baby premolars are numbered 06, 07 and 08.
Is a dog's dental chart the same as a human's?
Only the idea of splitting the mouth into quadrants is shared. Human dentists use their own numbering systems, not the Triadan one, and people have 32 adult teeth to a dog's 42, so the charts are not interchangeable.
References
Floyd MR. The modified Triadan system, nomenclature for veterinary dentistry. J Vet Dent. 1991;8(4), 18-19.
American Veterinary Dental College. Triadan tooth numbering system. https://avdc.org/PDF/Triadan_Tooth_Numbering_System.pdf
Merck (MSD) Veterinary Manual. Dentition and dental nomenclature of animals. https://www.msdvetmanual.com/digestive-system/dental-development-and-anatomy/dentition-and-dental-nomenclature-of-animals