How Dentists Number Your Teeth: A Comprehensive Guide to Dental Numbering Systems

Reviewed by Dr. Joe Dental, DDS

Table of Contents

Introduction: The Universal Language of Your Smile

I’ve sat in the dentist’s chair more times than I’d like. Every time, my dentist would glance at my records and say things like, “Number 19 has a small cavity,” or “let’s keep an eye on number 32.” I had no idea what those numbers meant. Was I expected to know what “number 19” was? Should I be worried when they talked about “number 32”? After a while, I got curious (and maybe a little nervous) and finally asked, “How do you number my teeth?”

Maybe you’ve wondered the same thing after visiting the dentist or looking at your dental chart. Knowing how dentists count your teeth is more than just a fun fact. It helps you talk with your dentist, understand your care, and take better care of your smile. In this article, I’ll share what I found out—explaining the most common tooth numbering systems, why they’re important, and how they help dentists all around the world (and make things easier for us, too).

Understanding Your Dentition: Primary vs. Permanent Teeth

Not all teeth are the same, and when it comes to counting them, the difference between baby and adult teeth is important. Dentists see our mouths as having two kinds of teeth—primary (baby) teeth and permanent (adult) teeth. Each type is counted in its own special way.

Primary (Baby) Teeth

My child’s first lost tooth was a big deal in our house, and we paid close attention to every one. Most kids have 20 primary—or “baby”—teeth. These small teeth help kids eat and save space for adult teeth that grow in later. Dentists use certain numbers—really letters, not numbers—to make sure baby teeth are counted differently from adult ones.

• Total: 20 teeth
• Where: Ten in the top jaw, ten in the bottom
• Use: Biting, chewing, and holding space for permanent teeth

From experience, knowing what system your child’s dentist uses makes checkups much less confusing.

Permanent (Adult) Teeth

When my wisdom teeth grew in, I reached my “full set” of 32 permanent teeth (including the wisdom teeth, which are those often-problem teeth in the very back). These are the teeth you use for the rest of your life—unless you need a replacement tooth from a china dental lab.

• Total: Up to 32 (with four wisdom teeth)
• Where: 16 in the top, 16 in the bottom
• Types: Front teeth, eye teeth (canines), pre-molars, and molars

Knowing which teeth are permanent (and which ones the dentist is talking about) helps you follow along during your visit, especially if a tooth is giving you trouble!

The Major Dental Numbering Systems Explained

Here’s something that surprised me: dentists around the world don’t always use the same “tooth number” language. Depending on what country you’re in—or even what kind of dentist you visit—your teeth might be counted in different ways. Let’s look at the three most common systems. Once I understood these, I understood my dental appointments a lot better!

1. The Universal Numbering System (Most Common in the USA)

This is the main system I saw growing up in America. The Universal Numbering System is what most US dentists use. It numbers every adult tooth from 1 to 32, starting in the upper right and moving along to the left, then moving down to the lower teeth and going back to the right.

• Where to start: The upper right last molar (number 1)
• How it goes: Across the top to number 16 (upper left molar), then down to 17 (lower left molar) and across to number 32 (lower right molar)

So, if my dentist says “tooth 19,” that’s my lower left first molar. For baby teeth, dentists use letters A through T, instead of numbers.

Example:

• Tooth #3: Upper right first molar
• Tooth #9: Upper left front tooth
• Tooth #19: Lower left first molar
• Tooth #32: Lower right wisdom tooth

This system makes it really easy to know which tooth the dentist means if you’re in the US.

Primary (Baby) Teeth:

• A through T
• Starts on the upper right (A), goes to upper left (J), then lower left (K), to lower right (T)

If you’re not sure, ask your dentist to show you your tooth chart. This system is pretty simple when you see it for yourself.

2. The FDI World Dental Federation System (International Standard)

When I talked to a friend overseas, I found out they use a totally different way: the FDI World Dental Federation system (sometimes called ISO 3950). It’s popular in Europe, Asia, and lots of other places.

The FDI system uses two numbers:

• First number: Which quarter of your mouth (1–4 for adult teeth; 5–8 for kids’ teeth)
• Second number: The tooth’s place from the middle (1 is your front tooth, 8 is your wisdom tooth)

Example:

• Tooth 11: Upper right front tooth
• Tooth 36: Lower left first molar
• Tooth 48: Lower right wisdom tooth

For baby teeth, the quarters go from 5–8, and the second number is 1–5.

If you move to a new country and see FDI numbers, don’t stress—just ask your dentist to explain it, and you’ll catch on quickly.

3. The Palmer Notation Method (Common in the UK & Orthodontics)

I once saw an orthodontist who used the Palmer notation. In the UK, or if you or your kids get braces, you might see this system.

Palmer splits the mouth into four parts. Each tooth in a quarter is numbered 1–8 (for adult teeth) or lettered A–E (for baby teeth). What’s different? Palmer uses symbols ┘, └, ┐, and ┌ to show each corner. So your upper right front tooth is “┐1,” and your lower left second molar is “└7.”

Permanent teeth:

• Numbers 1–8, front to back, in each quarter

Baby teeth:

• Letters A–E, front to back

Why use Palmer?

It’s very visual. Orthodontists like it because it looks like a mouth map, which is handy for braces. The symbols feel strange at first but make sense once you see them.

Why Dentists Use Numbering Systems: More Than Just Numbers

I used to wonder, “Why not just say ‘front tooth’ or ‘back molar’?” But now, I understand why using numbers is good for everyone.

Here’s what I learned:

1. Clarity and Precision

If I said I had pain in a “side tooth,” that’s not very clear. But if I say it’s tooth #19 or 36 (FDI), everyone knows exactly which one.

2. Accurate Record Keeping

Using numbers means your dental history stays neat and clear. From x-rays to treatment, having the exact tooth makes your records easy to follow, no matter who’s looking—like a digital dental lab if you ever need a tooth fixed.

3. Insurance and Billing

Insurance forms like clear information. Numbering makes sure your paperwork is right, so claims get paid faster and the right tooth gets marked for the right treatment.

4. Referrals and Consultations

Everyone—from specialists to surgeons—can quickly see which tooth they need to treat or check. It’s helpful for getting second opinions or switching dentists.

Interpreting Your Own Dental Chart

When I first looked at my dental chart, it was full of numbers, letters, and marks. It looked confusing, but it doesn’t have to be.

Here’s what helped me:

• Fillings might be shaded or have a short note.
• Crowns, bridges, or work from a crown and bridge lab might be colored or circled.
• Missing teeth: Usually an “X” or “MD” by the number.

Tip: “UR” usually means upper right, and “LL” means lower left. That can help you spot which side the chart is showing.

Common Questions About Tooth Numbering

I get a lot of questions from friends and family. Here are some answers:

What about wisdom teeth?

Wisdom teeth cause plenty of problems for adults. In the systems:

• Universal: #1, #16, #17, #32
• FDI: 18, 28, 38, 48
• Palmer: Each is the 8 tooth in the corner

They’re the last teeth at each end of your upper and lower jaws.

How are missing teeth recorded?

After one of my molars was pulled, my chart kept the old number, but drew an “X” over it (sometimes “MD” for missing). That way your dentist knows which tooth is gone, and which replacement you might need, like from a zirconia lab.

Do all dentists use the same system?

Nope! In the US, you’ll usually see Universal. But in other countries it could be FDI or Palmer. Sometimes orthodontists even use Palmer in the US. Whenever you see a new dentist, it’s good to ask about the chart style.

Why are my baby teeth labeled with letters instead of numbers?

This confused me at first, but it’s to stop mix-ups. Baby teeth are marked A–T (or numbers in FDI), so kids’ records don’t get mixed with adult records. It helps everyone keep things straight.

Conclusion: Empowering Your Dental Understanding

Looking back, learning how dentists count teeth was like cracking a secret code. Now, I always know what tooth my dentist means, and I can follow my own dental records and pictures. It helps me ask better questions and be part of my care, not just a bystander.

Always feel free to ask which numbering system your dentist uses, or what any markings mean. Dentists (like Dr. Joe Dental and the techs at dental ceramics lab) love to help patients who want to know more. That’s how you keep mistakes away and get the best care—whether it’s a cleaning, a new crown, or a big fix like an implant.

Learning about tooth numbering isn’t just a cool fact. It helps with good communication, safer care, and lets you take charge of your dental health. Every healthy, happy smile starts with knowing what your dentist is talking about. Now, when your dentist says “number 19,” you’ll know right where it is—and why it matters.

Reviewed by Dr. Joe Dental, DDS – Board-certified general dentist with over 25 years of patient care experience