Universal Numbering System
Definition
The North American standard. Permanent teeth are numbered 1-32 running clockwise from the maxillary right third molar. Deciduous teeth are lettered A-T in the same clockwise order.
- Region
- North American standard
- Permanent teeth
- Numbered 1 to 32, clockwise
- Starting point
- Maxillary right third molar
- Deciduous teeth
- Lettered A to T, same clockwise order
Common questions
How does the Universal system differ from the FDI two-digit system?+
FDI uses a two-digit code where the first digit identifies the quadrant and the second the tooth position within it, while the Universal system assigns a single running number or letter across the whole dentition, which can cause confusion when comparing records from different countries.
Why does the numbering start at the maxillary right third molar specifically?+
It is simply the convention fixed by the American Dental Association when the system was adopted, giving a consistent, unambiguous starting reference point that every chart using the system follows.
Related terms
- FDI Notation
- The two-digit system published by the Federation Dentaire Internationale. The first digit (1-4 for permanent, 5-8 for deciduous) encodes the quadrant; the...
- Midline
- The anatomical midpoint of the dental arch dividing it into left and right halves. In notation systems, position 1 is always the...
- Palmer Notation
- A grid-based system where a bracket symbol indicates the quadrant and a number 1-8 (or letter A-E for deciduous) indicates position from...
- Quadrant
- One of four sections of the dentition: upper right, upper left, lower left, lower right. The midline divides left from right; the...