Universal Numbering System


The Universal Numbering System also called the "American System", is a dental notation system for associating information to a specific tooth, commonly used in the United States.
In the rest of the world, a different International Standard ISO 3950:2016 is used.

Left and right

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.

Universal numbering system

Although it is named the "universal numbering system", it is also called the "American system" as it is only 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 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.

Tooth numbering

Permanent teeth and their assigned numbers
Upper right
Upper left
Lower left
Lower right