Numbering systems

Question 1

What is the purpose of numbering teeth?

Answer 1

To identify specific teeth

Question 2

What are the three tooth numbering systems?

Answer 2

• Universal/National Numbering System (American)
• International Standards Organization (ISO) / Federation Dentaire Internationale (FDI) (Canadian)
• Palmer Notation System (older)

Question 3

How does the Universal Numbering System work?

Answer 3

Permanent teeth are numbered 1 to 32, starting on the maxillary right side (Q1). If a patient is missing wisdom teeth (third molars), we start by counting the second molar as 2. Primary teeth are denoted by letters A to T, starting in the maxillary right and moving through to the mandibular left

Question 4

How does the ISO/FDI Numbering System work?

Answer 4

Uses a two-digit tooth recording system where the first digit indicates the quadrant and the second indicates the tooth. Quadrants are as follows:
-Q1: maxillary right
-Q2: maxillary left
-Q3: mandibular left
-Q4: mandibular right
Numbering is from the midline toward the posterior

Question 5

How is the ISO/FDI Numbering System used in primary teeth?

Answer 5

The quadrants are 5,6,7,8 instead of 1,2,3,4, respectively.

Question 6

How does the Palmer Notation System work?

Answer 6

Each of the four quadrants is given its own tooth bracket made up of a vertical line and a horizontal line. This system is a shorthand diagram of the teeth as if the patient’s teeth were being viewed from the outside. Ex: the teeth in the right bracket have the vertical line to the right of the tooth numbers or letters, since the midline is to the right of the teeth

Question 7

How does the Palmer Notation System work on primary teeth?

Answer 7

The teeth are instead labeled as A-E in each quadrant, same as the would be 1-8.