An FDI number refers to the FDI World Dental Federation notation (also known as the ISO 3950 notation), which is the most widely used dental notation or tooth numbering system globally.
In simpler terms, it's a standardized way to identify each tooth in the mouth, allowing dentists worldwide to communicate clearly and avoid confusion. This system uses a two-digit number to designate each tooth, making it easier to record and track dental treatments.
Here's a breakdown:
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The first digit indicates the quadrant of the mouth:
- 1 = Upper right quadrant
- 2 = Upper left quadrant
- 3 = Lower left quadrant
- 4 = Lower right quadrant
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The second digit indicates the tooth's position within that quadrant, counting from the midline (central incisor):
- 1 = Central incisor
- 2 = Lateral incisor
- 3 = Canine
- 4 = First premolar
- 5 = Second premolar
- 6 = First molar
- 7 = Second molar
- 8 = Third molar
For example, tooth number 11 represents the upper right central incisor, while tooth number 36 represents the lower left first molar. This numbering system is universally recognized and avoids the ambiguity that can arise from using different naming conventions. It is used for both permanent and deciduous (baby) teeth. For deciduous teeth, the quadrant numbers are 5, 6, 7, and 8, respectively, instead of 1, 2, 3, and 4.
Using FDI numbers ensures consistent and accurate dental records worldwide.
