Teeth names and numbers: a simple chart of adult and baby teeth

Your dentist says "tooth 36", your X-ray report mentions "48", or a dentist abroad talks about "tooth number 19": it is not always easy to follow. This guide gives the names of the teeth, explains what each group of teeth does, and shows the two numbering systems you are most likely to meet: the FDI system, used in Morocco and in Europe, and the Universal system, used in the United States. It is here to inform you; it does not replace an examination.

There is also an interactive chart of the 32 teeth, where you can touch a tooth to see its name and number: the interactive teeth chart (in French).

How many teeth do humans have?

• Adults have 32 teeth: 16 in the upper jaw and 16 in the lower jaw. This includes the 4 wisdom teeth; many people have 28 because their wisdom teeth have not come in, have been removed, or never formed.
• Children have 20 baby teeth (also called milk teeth, primary teeth or deciduous teeth).

The mouth is divided into four quarters (quadrants): upper right, upper left, lower left and lower right. "Right" and "left" are always the patient's right and left, not those of the person looking at the mouth.

The names of the teeth

In each quarter of an adult mouth, from the middle towards the back, there are:

1. Central incisor: the big front tooth.
2. Lateral incisor: next to it, a little smaller.
3. Canine: the pointed tooth at the corner of the smile.
4. First premolar.
5. Second premolar.
6. First molar: often called the "6-year molar".
7. Second molar: the "12-year molar".
8. Third molar: the wisdom tooth.

So each quarter has 2 incisors, 1 canine, 2 premolars and 3 molars: 8 teeth, and 8 × 4 = 32.

The front teeth are the incisors and canines; the back teeth (or "cheek teeth") are the premolars and molars.

What does each type of tooth do?

• Incisors (8 in total) have a thin, flat edge, like a blade: they cut food. They play a big part in your smile and in pronouncing sounds such as "f", "v" and "th".
• Canines (4) are pointed and have the longest root of all the teeth: they tear food and guide the movements of the jaw when you slide your teeth from side to side. The upper canines are sometimes called "eye teeth".
• Premolars (8) have two points (cusps): they crush and tear, halfway between canines and molars. They are often the teeth removed when braces need space.
• Molars (12, including the wisdom teeth) are large and wide, with several cusps and roots: they grind food.
• Wisdom teeth (up to 4) are the last molars. They come in, when they do, from the late teens; they often lack room. See the guide on wisdom teeth.

Tooth numbering: the FDI system (Morocco, Europe)

In Morocco, as in most countries, dentists use the FDI two-digit system (from the World Dental Federation). An article in a dental education journal describes it as used throughout the world except in the USA, and as the only system that makes visual, cognitive and computer sense (Peck and Peck, 1993, PubMed).

Every tooth has two digits, read separately ("three-six", not "thirty-six"):

• the first digit is the quarter: 1 upper right, 2 upper left, 3 lower left, 4 lower right;
• the second digit is the tooth, counted from the middle: 1 central incisor to 8 wisdom tooth.

So 11 is the upper right central incisor, 36 the lower left first molar, and 18, 28, 38 and 48 are the four wisdom teeth.

Tooth numbering: the Universal system (United States)

In the Universal system, used in the United States, the adult teeth are simply numbered from 1 to 32: you start with the upper right wisdom tooth (1), go along the upper jaw to the upper left wisdom tooth (16), then drop to the lower left wisdom tooth (17) and come back along the lower jaw to the lower right wisdom tooth (32).

In the United Kingdom, some dentists also use the Palmer notation: a number from 1 to 8 inside a small corner symbol that shows the quarter.

Teeth numbers chart: FDI and Universal side by side

The first number in each box is the FDI number; the number in brackets is the Universal number. If you have treatment in Morocco after treatment in the United States, or the reverse, check which system your records use: "tooth 14" is not the same tooth in the two systems.

Baby teeth and adult teeth

A child has 20 baby teeth: in each quarter, 2 incisors, 1 canine and 2 molars. Baby teeth have no premolars: later, the adult premolars take the place of the baby molars.

Numbering baby teeth:

• in the FDI system, the quarters become 5 (upper right), 6 (upper left), 7 (lower left) and 8 (lower right), and the teeth go from 1 to 5: for example 51 is the upper right baby central incisor and 85 the lower right second baby molar;
• in the Universal system, baby teeth are given letters from A to T: from A (upper right second baby molar) to J (upper left second baby molar), then from K (lower left second baby molar) to T (lower right second baby molar).

When do they come in? The first baby tooth, usually a lower central incisor, most often comes in between 6 and 12 months, and most children have all 20 by about 2 and a half or 3 years. The timing varies a lot: in a review of 42 studies (42,109 children), the first tooth came in at about 6 months on average in the North American studies and at 13.5 months in the Asian ones (Muthu et al., 2023, PubMed).

When are they replaced? Baby teeth start to become loose at about 6 years old, and the changes usually go on until about 12. In general:

A review of 80 studies on adult teeth found that they tended to come in earlier in girls and earlier in the lower jaw, with differences between populations (Vandana et al., 2024, PubMed).

The 6-year molar comes in at the back without any baby tooth falling out: it is often mistaken for a baby tooth, when it is an adult tooth that must last a lifetime. Brush it carefully, and ask your dentist whether a fissure sealant is useful (see the guide on tooth decay).

When should you see a dentist?

• A knocked-out adult tooth after an injury, especially in a child or teenager, is an emergency: see a dentist straight away. A knocked-out baby tooth is not put back, so as not to damage the adult tooth underneath, but the child should still be seen the same day.
• No tooth at all by about 18 months, a baby tooth lost very early without an injury, or an adult tooth that is still missing long after the baby tooth fell out: have it checked; a panoramic X-ray may be useful.
• An adult tooth coming in behind a baby tooth that is not loose, a tooth that turns grey, pain or a pimple on the gum.
• Swelling of the face, fever, or difficulty swallowing or breathing: go to the emergency department straight away.

Booking an appointment

Consultations take place in Rabat, Monday to Friday from 9 am to 6 pm and on Saturday from 9 am to 2 pm; the address is given when you book. The easiest way is to send a WhatsApp message stating the patient's age and the reason (for example "check-up for my 7-year-old"). See the appointment section. If you bring records from abroad, mention which numbering system they use.

Frequently asked questions

How many teeth do humans have?

Adults have 32 teeth, including 4 wisdom teeth, but many have 28 because their wisdom teeth have not come in or have been removed; children have 20 baby teeth.

What are the names of the teeth?

From the middle to the back of each quarter of the mouth: central incisor, lateral incisor, canine, first and second premolars, then first, second and third molars, the third molar being the wisdom tooth.

Which tooth is number 36?

In the FDI system used in Morocco and Europe, 36 is the lower left first molar, the "6-year molar"; in the Universal system used in the United States, the same tooth is number 19.

What are the wisdom teeth numbers?

They are 18, 28, 38 and 48 in the FDI system, and 1, 16, 17 and 32 in the Universal system.

What are canine teeth?

The canines are the four pointed teeth at the corners of the smile, one in each quarter of the mouth; they have the longest roots, tear food and guide the movements of the jaw; the upper ones are sometimes called eye teeth.

Do baby teeth have numbers?

Yes: in the FDI system they are numbered 51 to 55, 61 to 65, 71 to 75 and 81 to 85, and in the Universal system they are named with the letters A to T.

What are deciduous teeth?

It is the medical name for baby teeth: the 20 teeth that come in during early childhood and are replaced by adult teeth, usually between about 6 and 12 years old.