FDI dental notation, illustration. Upper and lower jaw with the teeth numbered according to the FDI tooth scheme (or two-digit system). This is a dental notation used by dentists internationally to associate information to a particular tooth. The system was first designed by Joachim Viohl, a German dentist, and was then adopted by the FDI World Dental Federation as the internationally-recognised notation for teeth. It is used by the World Health Organisation, and in most countries worldwide, except for the USA and the UK, where different notation schemes are used.