International numbering system, FDI numbering system, FDI notation
- A tooth numbering system where the centrals of each quadrant are number 1 and the third molars are number 8. The quadrants are numbered from 1 through 4: upper right, upper left, lower left and lower right. Teeth are charted with the quadrant number followed by the tooth number. In this system, the upper right central would be tooth 1-1, or sometimes abbreviated to 11, while the lower left third molar would be 3-8 or 38.