This document discusses different tooth numbering systems used in dentistry. It describes the human dentition, which includes 20 primary teeth and 32 permanent teeth. Tooth numbering systems allow dentists to identify and communicate about individual teeth. The three main systems described are the Zsigmondy/Palmer system, American Dental Association system, and Federation Dentaire Internationale system. The Zsigmondy/Palmer system divides the mouth into quadrants and numbers teeth within each quadrant. The FDI system uses a two-digit numbering where the first digit indicates the quadrant and second the tooth. The universal system uses letters for primary teeth and numbers for permanent teeth.