Tooth Numbering Systems

You go to the dentist and you hear numbers and sometimes letters called out. It sound like a secret code but it has some meaning for the dentist which makes it easy to make notes and later communicate findings and treatment to the patient, staff, other dentists and insurance companies.

There are 32 teeth in the adult dentition, and each tooth has a number. In the United States, the number starts at 1 in the back on the upper right. That tooth is the wisdom tooth, the upper right third molar. The uppers go from 1 to 16, from the wisdom tooth on the right side to the wisdom tooth on the left side. The lowers start on the lower LEFT, being tooth number 17, and going around to the other lower molar, number 32. When a patient is referred to have his wisdom teeth taken out at the oral surgeon, I will write “please take out teeth number 1, 16, 17 and 32.”

In Canada and most of the rest of the world, a different numeric system is used. . The first number represents which quadrant (quarter of the mouth) the tooth is in. So, 1=upper right, 2=upper left, 3=lower left, and 4=lower right. The second number indicates which tooth it is, starting in the front.  These go from 1-8.

In Canada, if you refer a patient to the oral surgeon to have the wisdom teeth removed, the dentist would write “please take out teeth number 18,28,38, and 48.

There is another system that is in use and not keyboard friendly using quadrant markings. That is used less as people rely more and more on computers.