Numbering systems have been developed in order to have a standard way of referring to particular teeth (there are more than 32 different systems). Two are commonly in use in the US today:

  • the Universal Numbering System has been adopted by the American Dental Association and is in use by most general dentists today, and
  • the Palmer Notation Method is used by some orthodontists, pedodontists (child dental specialist), and oral surgeons (originally called the Zsigmondy system after an Austrian dentist of that name who developed the idea in 1861).

Internationally the two-digit FDI World Dental Federation notation is widely used.


Universal Numbering System

Adults

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 this system, the teeth that should be there are numbered.  If you are missing your wisdom teeth, 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.

Children

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

Adults

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.

Children

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.


FDI Two-Digit Notation

Adults

In the FDI (Fédération Dentaire Internationale) World Dental Federation ISO-3950 notation 1s are central incisors, 2s are laterals, 3s are canines, 4s are 1st premolars etc., up through 8s which are 3rd molars.  The permanent teeth  quadrants are designated 1 to 4 such that 1 is upper right, 2 is upper left, 3 is lower left and 4 is lower right, with the resulting tooth identification a two-digit combination of the quadrant and tooth (e.g. the upper right central incisor is 11 and the left is 21).  The lower left permanent first molar is 36; however, it is not said thirty-six, but rather three six.  11 is one one, not eleven.

The currently accepted convention to view the FDI notation chart is from the perspective of the patient’s right on the left:

 

Permanent Teeth

FDI Two-Digit Notation

upper right upper left
18 17 16 15 14 13 12 11 21 22 23 24 25 26 27 28
48 47 46 45 44 43 42 41 31 32 33 34 35 36 37 38
lower right lower left


Baby Teeth*

FDI Two-Digit Notation

upper right upper left
      55 54 53 52 51 61 62 63 64 65      
      85 84 83 82 81 71 72 73 74 75      
lower right lower left


Children

In the deciduous dentition the numbering is correspondingly similar except that the quadrants are designated 5,6,7 and 8.

Thanks to Dr. John Webster BDS, Australia for his clarification on the FDI notation system.


Specific Teeth

 

Permanent Teeth, Universal Numbering System

Tooth Tooth Notation
3rd molar (wisdom tooth) 1, 16, 17, 32
2nd molar 2, 15, 18, 31
1st molar 3, 14, 19, 30
2nd bicuspid 4, 13, 20, 29
1st bicuspid 5, 12, 21, 28
cuspid 6, 11, 22, 27
lateral incisor 7, 10, 23, 26
central incisor 8, 9, 24, 25


Baby Teeth*, Universal Numbering System

Tooth Tooth Notation
2nd molar A, J, K, T
1st molar B, I, L, S
cuspid C, H, M, R
lateral incisor D, G, N, Q
central incisor E, F, O, P



Comparison of Tooth Numbering Systems

The orientation of the teeth below is merely for comparison (e.g. the accepted orientation for the FDI Two-Digit system is as above:  patient’s right on the left).
 

Permanent Teeth

Universal Numbering System

upper left upper right
16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
lower left lower right
                               

Palmer Notation

8
7 6 5 4 3 2 1 1 2 3 4 5 6 7
8
                               
8
7 6 5 4 3 2 1 1 2 3 4 5 6 7
8
                               

FDI Two-Digit Notation

28 27 26 25 24 23 22 21 11 12 13 14 15 16 17 18
38 37 36 35 34 33 32 31 41 42 43 44 45 46 47 48


Baby Teeth*

Universal Numbering System

upper left upper right
      J I H G F E D C B A      
      K L M N O P Q R S T      
lower left lower right
                               

Palmer Notation

     
E
D C B A A B C D
E
     
                               
     
E
D C B A A B C D
E
     
                               

FDI Two-Digit Notation

      65 64 63 62 61 51 52 53 54 55      
      75 74 73 72 71 81 82 83 84 85      

*baby teeth, aka primary teeth, deciduous teeth, or milk teeth