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Tooth Numbering

Numbering systems have been developed in order to have a standard way of referring to particular teeth.

The Universal Numbering System has been adopted by the American Dental Association and is in use by most general dentists today.

The Palmer Notation Method is used by many orthodontists and oral surgeons.

In this system, the teeth that should be there are numbered. If you are missing your wisdom teeth (the molars farthest back in your mouth), your first number will be 2 instead of 1, acknowledging the missing tooth. If you've had teeth removed or teeth are missing, the missing teeth will be numbered as well.

Universal Numbering System

The Permanent Arch


1. 3rd Molar (wisdom tooth)
2. 2nd Molar (12-yr molar)
3. 1st Molar (6-yr molar)
4. 2nd Bicuspid (2nd premolar)
5. 1st Bicuspid (1st premolar)
6. Cuspid (canine/eye tooth)
7. Lateral incisor
8. Central incisor
9. Central incisor
10. Lateral incisor
11. Cuspid (canine/eye tooth)
12. 1st Bicuspid (1st premolar)
13. 2nd Bicuspid (2nd premolar)
14. 1st Molar (6-yr molar)
15. 2nd Molar (12-yr molar)
16. 3rd Molar (wisdom tooth)
17. 3rd Molar (wisdom tooth)
18. 2nd Molar (12-yr molar)
19. 1st Molar (6-yr molar)
20. 2nd Bicuspid (2nd premolar)
21. 1st Bicuspid (1st premolar)
22. Cuspid (canine/eye tooth)
23. Lateral incisor
24. Central incisor
25. Central incisor
26. Lateral incisor
27. Cuspid (canine/eye tooth)
28. 1st Bicuspid (1st premolar)
29. 2nd Bicuspid (2nd premolar)
30. 1st Molar (6-yr molar)
31. 2nd Molar (12-yr molar)
32. 3rd Molar (wisdom tooth)


ADA classifiaction of permanent teeth 

Palmer Notation Method
Universal Numbering System


In this system:

  • Tooth number 1 is the tooth farthest back on the right side of your mouth in the upper (maxillary) jaw.
  • Numbering continues along your upper teeth toward the front and across to the tooth farthest back on the top left side (which is number 16).
  • The numbers continue by dropping down to the lower (mandibular) jaw. Number 17 is the tooth farthest back on the left side of your mouth on the bottom.
  • Numbering continues again toward the front and across to the tooth farthest back on the bottom right side of your mouth (which is number 32).


    In the original system, children's 20 primary teeth are numbered in the same order, except that a small letter "d" follows each number to indicate deciduous (primary) teeth. So, a child's first tooth on the upper right would be 1d and the last tooth on the lower right would be 20d.

    However, most dentists and insurance companies now use a modified version of the Universal Numbering System for children. This version uses the letters A through T instead of the number 1 through 20. So, a child's first tooth on the upper right would be A and the last tooth on the lower right would be T.

    Palmer Notation Method


    In this system, the mouth is divided into four sections called quadrants. The numbers 1 through 8 and a unique symbol are used to identify the teeth in each quadrant. The numbering runs from the center of the mouth to the back.

    In the upper right section of the mouth, for example, tooth number 1 is the incisor (flat, front tooth) just to the right of the center of the mouth. The numbers continue to the right and back to tooth number 8, which is the wisdom tooth (third molar.)

    The numbers sit inside an L-shaped symbol used to identify the quadrant. The "L" is right side up for the teeth in the upper right. The teeth in the upper left use a backward "L." For the bottom quadrants, the "L" is upside-down. The quadrants may also be identified by letters, such as "UR" or "URQ" for the upper right quadrant.


    In children, the Palmer Notation System uses uppercase letters instead of numbers. Following the same order as for adult's teeth, children's 20 primary teeth are lettered "A" through "E" in each quadrant. The same symbol is used to identify the quadrants.



    Adult Teeth

    An adult has 32 permanent teeth. The incisors and canine teeth tear and cut food, and premolars and molars are used to grind and crush. The four back teeth are called the wisdom teeth (or third molars).

    Adult Teeth

    Internal Structure of Teeth

    The three main parts of a tooth are the crown, neck and root. The crown (the part of the tooth you see - above the gums) is covered by a protective, bony layer of enamel, and the root of the tooth is covered by a sensitive, bonelike substance called cementum.

    A hard substance known as dentin surrounds the pulp, which contains nerves (sensing heat, cold, pain, and pressure) and blood vessels (nourishing the tooth).

    The gums (or gingiva) fit around the teeth, and the roots of the teeth fit into sockets in the jawbone. Lining the sockets is a tissue called periodontium.

    Structure of Teeth


    Types Of Teeth
    The shapes of animals' teeth give clues to the type of diets they eat. Meat eaters have sharp, pointed teeth to pierce and tear. Plant eaters have broad, flat teeth to crush and grind. Humans are no exception. As a species, we eat both meats and plants, so we have different types of teeth to handle both types of food.
    • Incisors — The four front teeth in both your upper and lower jaws (a total of eight) are incisors. The pair of teeth at the center of your mouth, top and bottom, are called the central incisors. And the teeth on each side of the central incisors are the lateral incisors. All the incisors are broad, flat teeth with a narrow edge good for cutting or snipping off pieces of food. They have a single root.
    • Canines — On both sides of your upper and lower incisors are the canines (a total of four). Sometimes called eyeteeth or cuspids, canines are the longest and most stable teeth in the mouth. They are thick and come to a single sharp point, ideal for ripping and tearing at foods that might be tough, such as meat, and for piercing and holding. They have a long single root.
    • Premolars — Next to each canine are two premolars (a total of eight). Also called bicuspids, premolars are a cross between canines and molars. They have sharp points for piercing and ripping, but they also have a broader surface for chewing and grinding. On the upper jaw, the first premolars (directly next to the canines) have two roots, and the second premolars have one root. On the lower jaw, all premolars have one root.
    • Molars — The last three teeth on both sides of your mouth, upper and lower, are the molars (a total of 12). They are numbered first, second or third molars depending on their location. The first molars, also called 6-year molars, are those closest to the front of the mouth, directly next to the second premolars. The third molars, also called the wisdom teeth, are the last teeth, farthest back in the mouth on all sides. In between are the second molars, also called 12-year molars. Molars are large teeth with broad surfaces designed for crushing, grinding and chewing food. On the upper jaw, the molars have three well-separated roots; on the lower jaw, the molars have two roots.

    Types Of Teeth