Universal numbering system (dental)

The Universal Numbering System is a dental notation system for associating information to a specific tooth, and is commonly used in the United States.

Dental charts are normally arranged from the viewpoint of a dental practitioner facing a patient. The patient's right side appears on the left side of the chart, and the patient's left side appears on the right side of the chart.

The labels "right" and "left" on the charts in this article correspond to the patient's right and left, respectively.

Although it is named the "universal numbering system", it is also called the "American system" as it is commonly used in the United States. The uppercase letters A through T are used for primary teeth and the numbers 1 - 32 are used for permanent teeth. The tooth designated "1" is the maxillary right third molar ("wisdom tooth") and the count continues along the upper teeth to the left side. Then the count begins at the mandibular left third molar, designated number 17, and continues along the bottom teeth to the right side. Each tooth has a unique number or letter, allowing for easier use on keyboards.

Permanent teeth and their assigned numbers (Universal Tooth Numbering System)

...
Wikipedia