FDI World Dental Federation notation (also "FDI notation" or "ISO 3950 notation") is the world's most commonly used dental notation (tooth numbering system). It is designated by the International Organization for Standardization as standard ISO 3950 "Dentistry — Designation system for teeth and areas of the oral cavity". The system is developed by the FDI World Dental Federation. It is also used by the World Health Organization, and is used in most countries of the world except the United States (which uses the UNS). Orientation of the chart is traditionally "dentist's view", i.e. patient's right corresponds to notation chart left. The designations "left" and "right" on the chart below correspond to the patient's left and right.

Table of codes

Codes, names, and usual number of roots: (see chart of teeth at Universal Numbering System)

How the codes are constructed

Syntax: Sometimes a dot is inserted between quadrant code and tooth code in order to avoid ambiguity with other numbering systems, especially the UNS. Examples: