FDI Tooth Numbering: A Clear Study Guide

Read the quadrant, then the position

The FDI notation system identifies a permanent tooth with two digits. The first digit identifies the quadrant: 1 is upper right, 2 upper left, 3 lower left and 4 lower right when viewed from the patient perspective. The second digit counts from the midline toward the back of that quadrant.

That pattern makes the notation easier to decode than memorising thirty-two separate labels. For example, 36 is in quadrant 3 and is the sixth tooth from the midline, so it identifies the mandibular left first molar. The same position in the upper left is 26.

• Read the first digit as a quadrant.
• Read the second digit as a position from the midline.
• Say the arch, side and tooth type aloud before checking the model.

Use tooth type as a second check

Positions 1 and 2 are incisors, 3 is the canine, 4 and 5 are premolars, and 6 through 8 are molars. This quick pattern catches common reversal errors. If the second digit is 7, you are looking for a second molar, regardless of the quadrant.

Numbering systems are conventions, so a correct number does not replace identifying anatomy. Pair each number with crown shape, roots and neighbouring teeth. That makes it easier to move between FDI, Universal and Palmer notation in a clinic or classroom.

Use a short 3D recall loop

Choose one quadrant at a time. Name each tooth in FDI, rotate it in the model, and locate the adjacent and opposing teeth. Then repeat the same sequence from the other side. Short, repeated recall is more useful than passively scanning a number chart.

Dent3D lets learners isolate each permanent tooth and inspect the surrounding jaw. Use it as an anatomy reference alongside course material, not as a diagnostic or treatment resource.

Questions learners ask