Teeth Numbers

Teeth numbers in mouth are divergent depending on whether one is an adult or a child. The total number of teeth of an adult person is 32, comprising of 8 incisors, 4 canines, 8 premolars and 12 molars. All these are divided equally between the lower and upper part of the mouth. Children who are still in the process of developing their dentition have a total number of twenty teeth made up of 8 primary incisors, 4 canines and 8 molars; all these are also divided equally between the lower and the upper part of the mouth.

Teeth Numbers in Mouth For Adult and Children

Adult: Total 32 including 8 incisors, 4 canines, 8 premolars and 12 molars.

teeth numbers adult

Children: Total 20 including 8 primary incisors, 4 canines and 8 molars

teeth numbers pediatric


What is Teeth Numbers System?

Dentists all over the world use teeth number systems which are designed to make easy identification of teeth possible in order to facilitate dental treatment. Although, teeth are named according to their anatomic shape or letter or number, dentists prefer using numbers or coding rather than making use of names. As a result of this, dentists have developed different dental notation systems among which are: ISO Notation System (FDI); Universal Numbering System; and Palmer Notation Method.

 teeth numbers in mouth

Universal Numbering System

To make adult and pediatric dental care effective and easy, dentists use Universal Numbering System to identify teeth in the mouth. The American Dental Association approved this system of identification. This system assigned numbers to each of the teeth in the mouth. Tooth number 1 is located in the upper jaw (maxillary) and it is the upper third molar in the right side of the mouth. These numbering proceeds towards the front and across to the last molar tooth back on the top left side which is number 16. This numbering system goes on by giving numbers to the teeth in descending order to the lower left third molar which is number 17 and goes down to the lower jar up to the farthest tooth back on the bottom in the right side of the mouth which is given number 32.

Pediatric teeth numbering is also accorded importance, hence, this system assigns number to each tooth. Children have twenty primary teeth which are numbered from 1 to 20. However, to differentiate it form adult teeth numbering small letter “d” accompanies the numbers to show that it is deciduous or primary teeth. Although giving numbers to teeth is the convention, the universal Numbering System has been modified especially for children teeth numbering. Rather than using numbers, dentists nowadays use uppercase letter to identify primary teeth. Letters A to T are used. Letter A represents the child’s upper right second molar and letter T is designated the lower right second primary molar.

World Dental Federation Notation

Another widely accepted teeth numbering system is the FDI World Dental Federation System which is also recognized as 150-3950 notation. The arrangement of human teeth in the mouth is symmetrical hence; the mouth is divided into quadrants with 8 different teeth allocated to each of the quadrant is located horizontally and vertically to the other quadrant s. to make easy identification possible each of these 8 teeth is given a number ranging from 1 to 8, beginning from the center front tooth (central incisor) and counting backwards to the third molar which is number 8. In addition, a number is given to each of the quadrant ranging from 1 to 4 for permanent adult teeth and number 5 to 8 for primary teeth in children. These two numbers are combined (i.e. quadrant code number and tooth code number). This numbering system is often referred to as Two-Digit World Dental Federation Notation or FDI notation system. The FDI Two –Digit teeth numbering system is from the view point of the dentist.

However, there is a process through which teeth are numbered or named. This is based on four different characteristics, which are:

  • Teeth are numbered or named according to the jaw they are located e.g. upper jaw (maxillary) or lower jaw (mandibular).
  • The side of the face where the teeth is located (i.e. right or left).
  • The type of tooth e.g. canine, incisor, molar and premolar.
  • Teeth types can appear more than once in each of the quadrant of the mouth and this is used to give them names, for example, central and lateral for incisors; first and second for premolars; first , second, third for molars.

Palmer Notation Method

This teeth numbering system was originally called Zsigmondy system after the Hungarian dentist, Adolf Zsigmondy who created the idea in 1861 by using a Zsigmondy cross to record quadrants of tooth positions. Although it is relatively new compared to other systems, it is popular among dentists in the United Kingdom. It is also known as military system.

The adult teeth number according to this system ranges from 1 to 8 and the pediatric dentition is represented by a quadrant grid of roman numerals I, II, III, IV, V starting from the midline. To make it easier, less confusing and eliminating dentist interpretation error, Palmer changed the roman numerals to letters of alphabet A, B, C, D, and E. Palmer notation system make use of symbols (┘└ ┐┌) to highlight the quadrant within which each tooth is located and a number showing the position from the midline. However, these symbols are difficult to produce on normal or standard keyboard. This notwithstanding, it has the advantage of producing a vivid graphical image of dentition; tooth transpositions or edentulous spaces.

Teeth numbers system is a convenient and effective diagnostic method through which preventive and remedial dental care could be provided for patients. We have also discussed very interesting topic are teeth bones? in our previous article.