Dental charting is a standardized process used to accurately document, track, and communicate a patient’s oral health status. Because every tooth is unique in its position and function, a numbering system provides a universal language for precisely identifying a specific tooth among the 32 permanent teeth an adult may have. This system is fundamental for clear record-keeping, effective treatment planning, and seamless communication between dental professionals.
The Universal Numbering System (UNS)
The Universal Numbering System (UNS) is the standard method used by most dental professionals throughout the United States and is formally endorsed by the American Dental Association (ADA). This system assigns a unique number from 1 to 32 to each permanent tooth in the adult mouth. The numbering sequence begins with the upper right third molar (number 1) and proceeds along the upper arch to the upper left third molar (number 16). The sequence then drops to the lower jaw, starting with the lower left third molar (number 17), and continues along the lower arch, concluding with the lower right third molar (number 32).
The FDI World Dental Federation Notation
The Fédération Dentaire Internationale (FDI) World Dental Federation Notation is the most widely adopted system globally and is used by the World Health Organization. Unlike the Universal system’s single number, the FDI uses a two-digit code. The first digit specifies the quadrant, and the second digit denotes the tooth’s position within that quadrant. For permanent teeth, quadrants are numbered 1 through 4: upper right (1), upper left (2), lower left (3), and lower right (4). The second digit is numbered 1 (central incisor) through 8 (third molar). For example, the upper left second molar is designated as 27, where ‘2’ indicates the upper left quadrant and ‘7’ indicates the second molar position.
Charting Primary (Baby) Teeth
Both the Universal and FDI systems adapt their notation to accommodate the 20 primary teeth found in children, which lack premolars compared to permanent teeth.
Universal System
The Universal Numbering System switches from numbers to uppercase letters (A through T). The path mirrors the permanent system, starting with the upper right second molar (‘A’) and moving across the upper arch to the upper left second molar (‘J’). The count then continues on the lower arch, starting with the lower left second molar (‘K’) and finishing with the lower right second molar (‘T’).
FDI System
The FDI system maintains its two-digit structure for primary teeth but substitutes the permanent quadrant numbers 1-4 with 5-8. The quadrant numbers are:
- Upper right quadrant is 5.
- Upper left quadrant is 6.
- Lower left quadrant is 7.
- Lower right quadrant is 8.
The second digit uses numbers 1 (central incisor) through 5 (second molar). For example, the upper right central incisor is 51, and the lower left second molar is 75.
Specialized Use: The Palmer Notation Method
The Palmer Notation Method (PNM) is a third system utilized in specific dental fields, particularly in the United Kingdom, and is often preferred by orthodontists and oral surgeons. This system is considered visually intuitive because it uses a number paired with a simple graphical symbol to indicate the tooth’s location. The teeth in each quadrant are numbered 1 (central incisor) through 8 (third molar). The quadrant is identified by an angle or bracket symbol placed around the number, which represents a corner of the mouth. For example, the upper right first molar is designated as 6 with a right angle symbol below it, and the lower left central incisor is 1 with a left angle symbol below it. For primary teeth, PNM uses the letters A through E combined with the quadrant symbol.