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How are teeth named and numbered?

Teeth Names & Numbers

Dentists refer to a specific tooth using a number or coding more usually than using teeth names. There are several teeth numbering systems: the Universal Numbering System (used in US), FDI World Dental Federation notation, and the Palmer Notation Method. However, for patients it is easier to identify and remember the different teeth by using more descriptive teeth names instead of numbers or other coding.

Universal tooth numbering system

The Universal Numbering System is a simplified method of identifying teeth that is approved and adopted by the American Dental Association.

Adults

In the universal tooth numbering system, tooth number 1 is the patient's upper right third molar, on the right side of the mouth in the upper (maxillary) jaw. Numbering of teeth continues along the upper teeth toward the front and across to the last molar tooth back on the top left side (number 16). The tooth numbering continues by assigning teeth numbers descending to the lower left third molar (number 17) and follows the lower (mandibular) jaw up to the tooth farthest back on the bottom right side of the mouth (number 32). All teeth that should be there are numbered, including those teeth that have been removed for any reason or have not erupted yet (e.g. wisdom teeth).

Children

In the original system, children's 20 primary teeth are numbered in the same order (from 1 to 20), except that a small letter "d" follows each number to indicate deciduous (primary) teeth.

However, most dentists today use a modified version of the Universal Numbering System for children, with letters instead of teeth numbers. The primary teeth are designated by upper case letters A through T, with A being the patient's upper right second primary molar and T being the lower right second primary molar.

Universal tooth numbering system
Teeth numbering chart for adult teeth
upper left upper right
Teeth Numbers - Universal Tooth Numbering System
lower left lower right
Orientation of the Universal tooth numbering chart is traditionally "patient's view", i.e. "left" and "right" on the chart correspond to the patient's left and right, respectively.
- tooth number diagram 1a -
Universal tooth numbering system
Teeth numbering chart for deciduous (primary) teeth
upper left upper right
Teeth Numbers - Universal Tooth Numbering System for primary teeth
lower left lower right
- tooth number diagram 1b -

FDI World Dental Federation Two-Digit Notation (international)

The second system, developed by the Fédération Dentaire Internationale (FDI), World Dental Federation notation is also known as ISO-3950 notation.

The human teeth are symmetrically arranged in the mouth. Each quadrant of the mouth has 8 different teeth that are mirrored horizontally and vertically to the other quadrants. In the FDI notation each one of these 8 teeth is assigned a number from 1 to 8, starting from the center front tooth (central incisor) and moving backwards up to the third molar (number 8). Each quadrant is also assigned a number, from 1 to 4 for the adult (permanent) teeth or 5 to 8 for the baby (primary or deciduous) teeth.

Quadrant codes Tooth codes
Adult teeth Baby teeth
1 - upper right 5 - upper right 1 - central incisor 5 - 2nd premolars
2 - upper left 6 - upper left 2 - lateral incisors 6 - 1st molars
3 - lower left 7 - lower left 3 - canines 7 - 2nd molars
4 - lower right 8 - lower right 4 - 1st premolars 8 - 3rd molars

The combination of these two numbers (Quadrant code number & Tooth code number) specifies how are teeth numbered. This tooth numbering system is called, the Two-Digit World Dental Federation Notation or FDI notation system.

Adults
FDI tooth numbering system
Teeth numbering chart for adult teeth
upper right upper left
FDI Tooth Numbering System - chart for adult teeth
lower right lower left
Orientation of the FDI two-digit tooth numbering chart is traditionally "dentist's view", i.e. patient's right corresponds to tooth chart's left side. The designations "left" and "right" on the chart, however, correspond to the patient's left and right.
- tooth number diagram 2a -
  Children
FDI tooth numbering system
Teeth chart for primary teeth
upper right upper left
FDI Tooth Numbering System - chart for baby teeth
lower right lower left
- tooth number diagram 2b -

How are teeth named and numbered?

Teeth names are created by a combination of 4 different characteristics:

  1. The jaw where they are located: upper and lower (alternatively the terms maxillary and mandibular can be used)
  2. The side of the face: left and right
  3. The type of tooth: incisor, canine, premolar, and molar
  4. A secondary name for the teeth types that appear more than once in each quadrant of the mouth e.g. central and lateral for incisors, first and second for premolars, first, second, and third for molars.

Based on these characteristics, the teeth names for the permanent dentition are the following (starting from the upper right back tooth and moving anti-clockwise):

Next to its tooth you can see the tooth number based on:
     a) the Universal Numbering System (UNS) used in the United States and b) the FDI notation (FDI)

Permanent Teeth Names & Numbers


Permanent Teeth UNS FDI   FDI UNS  
Upper left third molar 16 28   18 1 Upper right third molar
Upper left second molar 15 27   17 2 Upper right second molar
Upper left first molar 14 26   16 3 Upper right first molar
Upper left second premolar 13 25   15 4 Upper right second premolar
Upper left first premolar 12 24   14 5 Upper right first premolar
Upper left canine 11 23   13 6 Upper right canine
Upper left lateral incisor 10 22   12 7 Upper right lateral incisor
Upper left central incisor 9 21   11 8 Upper right central incisor
             
Lower left central incisor 24 31   41 25 Lower right central incisor
Lower left lateral incisor 23 32   42 26 Lower right lateral incisor
Lower left canine 22 33   43 27 Lower right canine
Lower left first premolar 21 34   44 28 Lower right first premolar
Lower left second premolar 20 35   45 29 Lower right second premolar
Lower left first molar 19 36   46 30 Lower right first molar
Lower left second molar 18 37   47 31 Lower right second molar
Lower left third molar 17 38   48 32 Lower right third molar

Left and Right on the chart correspond to the patient's left and right respectively (patient's view).

Primary (Baby or Deciduous) Teeth Names & Numbers

For primary teeth, most dentists in United States use a modified version of the Universal Numbering System, with each primary tooth assigned a letter (from A to T) instead of a number.

Primary Teeth UNS FDI   FDI UNS  
Upper left second molar J 65   55 A Upper right second molar
Upper left first molar I 64   54 B Upper right first molar
Upper left canine H 63   53 C Upper right canine
Upper left lateral incisor G 62   52 D Upper right lateral incisor
Upper left central incisor F 61   51 E Upper right central incisor
             
Lower left central incisor O 71   81 P Lower right central incisor
Lower left lateral incisor N 72   82 Q Lower right lateral incisor
Lower left canine M 73   83 R Lower right canine
Lower left first molar L 74   84 S Lower right first molar
Lower left second molar K 75   85 T Lower right second molar

Left and Right on the chart correspond to the patient's left and right respectively (patient's view).

Other teeth names

Other common teeth names:

  • Cuspids: Another name for canines
  • Bicuspids: Another name for premolars
  • 6 year molar: Another name for first permanent molar
  • 12 year molar: Another name for second permanent molar
  • Wisdom Teeth: A popular name for the third molars
  • Anterior Teeth: The teeth in the front of the mouth including central incisors, lateral incisors, and canines.
  • Posterior Teeth: The teeth in the back of the mouth including premolars and molars.
  • Mandibular Teeth: The teeth on the lower jaw
  • Maxillary Teeth: The teeth on the upper jaw
  next page -> Tooth Formation and Development • How Teeth Grow?

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