Universal Numbering System

The Universal Numbering System, sometimes called the "American System", is a dental notation system commonly used in the United States.

Most of the rest of the world uses the FDI World Dental Federation notation, accepted as an international standard by the International Standards Organization as ISO 3950. However, dentists in the United Kingdom commonly still use the older Palmer notation despite the difficulty in representing its graphical components in computerized (non-handwritten) records.

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 ("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.