# 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.  