The Fédération Dentaire Internationale or FDI World Dental Federation notation system is a commonly used system for the numbering and naming of teeth. The system uses a two number system for the location and naming of each tooth.
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Permanent teeth
The jaw is divided into four quadrants between the central incisors and the upper and lower dental arches. The first number refers to the quadrant of a tooth:
- right upper quadrant = 1
- left upper quadrant = 2
- left lower quadrant = 3
- right lower quadrant = 4
The second number refers to the individual tooth within a specific quadrant:
- central incisor = 1
- lateral incisor = 2
- canine = 3
- 1st premolar = 4
- 2nd premolar = 5
- 1st molar = 6
- 2nd molar = 7
- 3rd molar = 8
The notation "21" would therefore refer to the permanent left upper central incisor.
Deciduous teeth
In deciduous ("baby") teeth the system is similar however in describing the quadrants the numbers 5 to 8 are used in the place of 1 to 4:
- right upper quadrant = 5
- left upper quadrant = 6
- left lower quadrant = 7
- right lower quadrant = 8
Likewise due to the absence of the premolars in deciduous dentition the numbers 1 to 5 are used only:
- central incisor = 1
- lateral incisor = 2
- canine = 3
- 1st molar = 4
- 2nd molar = 5
The notation "82" would therefore be the deciduous right lower lateral incisor.
See also
- American Dental Association Universal Numbering System, used in the United States
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