FDI Tooth Numbering System App

A brief description of the FDI Tooth Numbering System

The FDI dental notation is a two-digit tooth numbering system, widely used by dental professionals in many countries to easily identify teeth in a patient’s mouth. Developed by the Fédération Dentaire Internationale (FDI) World Dental Federation, this system is also referred to as the ISO 3950 notation.

The FDI chart takes a traditionally ‘dentist's view’ with the patient's right corresponding to the left of the chart. Left and right on the chart correspond to the patient's left and right.

The first number in the two digits (1 - 4) represents the quadrant: That is, teeth in the upper right are identified as 1, upper left teeth as 2, lower left teeth as 3, and lower right teeth as 4. The second number from the two digits (1 – 8) represents the tooth starting from the midline of the face. Accordingly, central incisors are 1, lateral incisors are 2, canines 3, first premolars 4, second premolars 5, first molars 6, second molars 7, and third molars 8. This numbering system makes it easy for dentists to share information with each other for closer cooperation.