Introduction

Tooth numbering systems
There are several systems in use in the world, but only a few are considered.
In 1947, a committee of the American Dental Association (ADA) recommended the symbolic (Zsigmondy/Palmer) system as the numbering method of choice.
in 1968, the ADA officially recommended the “universal” numbering system, due to difficulties with keyboard notation of the symbolic (Zsigmondy/Palmer) notation system.

1-Universal notation system:
Examples:
#11: Permanent Maxillary Left Canine
#29: Permanent Mandibular Right Second Premolar
#8: Permanent Maxillary Right Central Incisor
#22: Permanent Mandibular Left Canine
#28: Permanent Mandibular Right First Premolar
Examples:
#B: Deciduous Maxillary Right first Molar
#O: Deciduous Mandibular Left Central Incisor
#D: Deciduous Maxillary Right Lateral Incisor

2-Zsigmondy/Palmer (or tow-digit ) notation system:
It was originally termed the "Zsigmondy system" after the Hungarian dentist Adolf Zsigmondy who developed the idea in 1861, using a Zsigmondy cross to record quadrants of tooth positions.
The Palmer notation consists of a symbol (?? ??) designating in which quadrant the tooth is found and a number indicating the position from the midline.
Adult teeth were numbered 1 to 8, and the child primary dentition were depicted with a quadrant grid using Roman numerals I, II, III, IV, V to number the teeth from the midline distally.
After that, Palmer changed this to A, B, C, D, E.

3-Fédération Dentaire Internationale “FDI” notation system:
It is a two-digit system proposed by Fédération Dentaire Internationale (FDI) for both the primary and permanent dentitions. It is also known as ISO 3950 notation system.
It has been adopted by the World Health Organization “WHO” and accepted by other organizations such International Association for Dental Research.