What Is the Universal Numbering System for Teeth?

From the amount of time you spend sitting to the opening and spitting when told, the dentist’s chair can be a pretty uneventful place. However, the more informed you are, the more interesting the experience can be.

Dental Quadrants 

Everybody has a different approach when it comes to passing time in the dentist’s chair. Some people curiously examine dental handpiece gaskets and other related equipment placed around the room. There are others who instead try to close their eyes and relax or watch the television in the corner. However, if you learn some of the code language spoken between the dentist and the hygienist, you might find yourself entertained by what they have to say about your teeth.

Your mouth is divided into four quadrants, also known as sections. There is the upper right, upper left, lower right and lower left.  They are numbered beginning with the upper right, which is the first quadrant. Then the upper left is second, the lower left is third, and the lower right is fourth. The different naming and numbering systems of the teeth all follow the same quadrant structure to make tooth identification easier to understand.

The Universal Numbering System

The American Dental Association follows what is known as the Universal Numbering System. This is the preferred method of tooth identification used by dentists in the United States because of the sequential pattern that makes it easy to understand. 

The numbering begins with the most posterior tooth of the upper right quadrant and then counts forward and around to the posterior tooth of the upper left quadrant. It then drops down to continue at the posterior tooth of the lower left quadrant and counts forward and around before finishing at the posterior tooth of the lower right quadrant. Each quadrant has the same eight teeth from posterior to front:

  • Third molar
  • Second molar
  • First molar
  • Second bicuspid
  • First bicuspid
  • Cuspid
  • Lateral Incisor
  • Central Incisor

Understanding the quadrants and numbering system that your dentist uses can give you a little extra insight going into your next appointment.