# Fédération Dentaire Internationale (FDI) notation

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.

#### 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
- 1 premolar = 4
- 2 premolar = 5
- 1 molar = 6
- 2 molar = 7
- 3 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
- 1 molar = 4
- 2 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