What does Tooth Scheme Mean?

The position of each individual tooth in a set of teeth can be precisely identified using a tooth scheme. Such an approach is necessary to avoid misunderstandings. It is not enough to divide the teeth according to their function. After all, every normal set of teeth has several incisors, canines and molars.

  • Tooth scheme is used to clearly identify the teeth present in the jaw.
  • In Europe, doctors use the dentition scheme of the Fédération Dentaire International.
  • The assignment is based on two digits that provide information about the jaw quadrant (1st position) and the exact position of the tooth (2nd position).
  • In order to be able to distinguish deciduous teeth from those of an adult, dentists use the digits 5 to 8 for the different quadrants of the jaw.

In Europe, the dental scheme of the Fédération Dentaire Internationale applies

Around the world there are around 40 different systems for clearly identifying or numbering the position of a tooth in the jaw. In Europe, dentists almost exclusively use the dental scheme of the Fédération Dentaire Internationale (FDI). At its annual meeting in 1970, the World Association of Dentists decided with an absolute majority to use the dental scheme developed by the Berlin dentist and university professor Joachim Viohl across national borders.

However, there are also countries where other systems are used. For example, dentists in Great Britain use the Palmer tooth scheme and dentists in the USA use the American tooth scheme.

The dentition scheme in adults: two numbers for each tooth

An adult’s dentition is usually made up of 32 teeth, which are evenly distributed over the upper and lower jaw. The FDI tooth scheme identifies each tooth using a two-digit tooth number. The first digit indicates the quadrant of the jaw in which the tooth is located. From the patient’s point of view, the teeth are divided counterclockwise. This results in the following assignment:

  • Right upper jaw: number 1
  • Left upper jaw: number 2
  • Left lower jaw: number 3
  • Right lower jaw number 4

The second digit indicates the exact position

The second digit of the tooth number names a specific tooth within the respective quadrant. Here the numbering always starts on the central incisor, which is given the number 1, and ends with the wisdom tooth. This is given the number 8. The following list shows how the systematisation looks in detail:

  • Central and lateral incisors (incisors = I): Numbers 1 and 2
  • Canines (Canini = C): Number 3
  • Small molars (premolars = P): Numbers 4 and 5
  • Molars (molars = M): Numbers 6 and 7
  • Wisdom teeth: digit 8

According to the FDI tooth scheme, the tooth numbers do not represent a total number, but rather two-digit coordinates. Therefore, the dentist always mentions both numbers individually. The canine of the right lower jaw is therefore given the designation “four-three” instead of “forty-three”.

The dental scheme of a child’s dentition

A child’s deciduous dentition consists of 20 teeth. In each jaw quadrant there are therefore five milk teeth. However, the counting method is the same as for an adult dentition and also starts with the incisors.

So that it can be seen directly in the given case that it is a dentition with milk teeth, the attending physician uses the digits 5 to 8 for the different quadrants. In principle, however, the numbering is done according to the same system:

  • Right upper jaw: number 5
  • Left upper jaw: digit 6
  • Left lower jaw: digit 7
  • Right lower jaw number 8

However, this assignment has often met with criticism, since from a chronological point of view the permanent teeth only erupt after the milk teeth.

Where does the tooth chart apply?

The dental scheme not only offers doctors the opportunity to document the dental status and findings. Dentists also use the concept in the course of drawing up treatment and cost plans . In addition, the FDI dental scheme is also used in dental studies and forensic medicine. The greatest advantage of the standardized system is that it simplifies communication between different doctors (including among themselves) and insurance companies. As a result, confusion or misunderstanding is very rare.