Tooth numbering

The accordance of a unique number to each tooth.

The Universal/National System for permanent (adult) dentition (1-32) includes: (1) is the patient's upper right molar and follows around the upper arch to the upper left third molar (16), descending to the lower left third molar (17) and follows around the lower arch to the lower right third molar (32).

The Universal/National System is used primarily in the United States whereas the International Standards Organization System is used in most other countries.

(American Dental Association 'Current Dental Terminology Third Edition, 1999)