FDI Notation
Definition
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 second (1-8) encodes the position from the midline. FDI 11 = maxillary right central incisor.
- Publisher
- Federation Dentaire Internationale
- Format
- Two-digit code
- First digit
- Quadrant, 1-4 permanent / 5-8 deciduous
- Second digit
- Position from midline, 1-8
Common questions
How does FDI notation avoid confusion between permanent and deciduous teeth using the same numbering logic?+
The quadrant digit does the work: quadrants 1 through 4 are reserved for permanent dentition and 5 through 8 for primary (deciduous) dentition, so a tooth coded 11 is unambiguously a permanent maxillary right central incisor, while 51 would be its deciduous predecessor.
Why is FDI notation preferred internationally over the Universal or Palmer systems?+
It is unambiguous across languages and avoids the symbol-based quadrant markings of the Palmer system, which do not transmit well in plain text or across different charting software, making it the system mandated for international identification work such as INTERPOL DVI forms.
Related terms
- 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...
- Universal Numbering System
- The North American standard. Permanent teeth are numbered 1-32 running clockwise from the maxillary right third molar. Deciduous teeth are lettered A-T...