Last updated on January 17, 2021
What do the numbers dentists call out actually mean? There are two things that dentists use numbers for:
- tooth numbering (i.e. which tooth they’re referring to) and
- periodontal (gum) charting.
We’ve got a separate page on BPE scores (gum scores) and what they mean. On this page, you can find all common tooth numbering systems.
Tooth Numbering Systems
Letters and numbers system
This system is very popular in the UK and Ireland. The 4 quadrants of the mouth are:
- UR – upper right
- UL – upper left
- LR – lower right
- LL – lower left
Within each quadrant, the teeth are numbered from 1 to 8 going from the front tooth to the wisdom tooth:
For example, UR1 is the upper right central incisor, and LL8 is the lower left wisdom tooth.
U.S. Tooth Numbering Chart (“Universal” system)
The American system of numbering teeth from 1 to 32 can hardly be described as elegant… but this handy tooth chart explains it all:
ISO System by the World Health Organisation (based on FDI Two-Digit Notation system)
The first digit denotes the quadrant and the second digit, like the Palmer method, denotes the type of tooth:
Palmer Notation Method
The mouth is divided into 4 quadrants (upper left, upper right, lower left, lower right), and as in the Letters and Numbers system, teeth are numbered 1-8 going from the front tooth to the wisdom tooth in each quadrant. Right angles symbols are used to denote which quadrant is being referred to:
