# Fédération Dentaire Internationale (FDI) notation

Last revised by Yuranga Weerakkody on 6 Jan 2021

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.

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.

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.

## Cases and figures

• Fig 1: orthopantomogram
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• Fig 2: CT, upper
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• Fig 3: CT, lower
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• Fig 4: dental notations (illustration)
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