How does the numbering of the teeth take place in dentistry?

Numbering of teeth in our dentistry

A visit to the dentist can turn into a surprise when you hear the doctor’s diagnosis. The fact is that each tooth has the number assigned to it, with two-digit value, for example, “39”, “48”.

Naturally, it causes a bit of surprise at patients because everyone knows that a healthy person should have from 28 to 32 teeth. To understand the doctor’s diagnosis, let’s see, what teeth are there and what do those mysterious numbers used by a dentist.

Why there is such a need?

Teeth, despite the outward similarity, differ from each other. Each of them is unique and fulfills its function.

Numbering in dentistry is necessary for optimizing the patient’s mouth diagnosis. Precise designations allow to shortly note data in the outpatient card.

It is important to note the use of a single numbering system. If you change the dentist, another doctor needs to understand what diseases have you had and how they were treated. If every dentist uses his or her own system of notes, it will violate the history of diseases of the patient.

The differences in the numbering still exist. Designation of permanent teeth differs from the numbers that are given to the numbering of milk teeth.

Designation of units and ordinal numbers

Despite the symmetry of the dentition, its own number is assigned to each tooth. To understand why it is done, we will consider the types of them and find out what are their functions.

By origin, the teeth are divided into permanent and temporary. Numbering starts from the middle of the dentition. We consider the structure of the jaw in an adult:

  • Incisors. Here refer the first and second teeth, both on the lower and upper jaws. Counting is carried out from the middle, in general, there are 8 pieces. They have a flat form and are required to capture food or to bite it.
  • Canines. A Number “3” is assigned to them. Similar to the fangs of a predator, they perform their natural function – to tear or cut solid pieces of food. They are also required for its retention. There are 4 canines in a mouth cavity.
  • Premolars. Their serial numbers are “4” and “5”. On the outer surface, they have two tubercles, intended for crushing food.
  • Molars. They are called the “six” and “seven”. They have four tubercles that effectively chew various food. “Sixes” also have the function of limiting the jaw when closing. A wisdom tooth is also called a molar, or the “eight”.

In adults

numbering of teeth in adultsHow do you know that you have the canine ache on the upper jaw, but not on the lower? To do this, the division of the jaws into 4 segments is performed. The countdown starts with the upper incisor, which is located on the right, then move further in a clockwise direction. Each of the parts has its name:

  • The first segment is called tens. It begins with the upper incisor on the right side and is denoted by the number “11”. This part ends with the seventh molar, or “eight” and is numbered “17” or “18”.
  • The second part is called twenties. It starts with the incisor of the upper row on the left. Thus, the second segment has a value from “21” to “28”.
  • The third part is thirties. Moving further clockwise, we are on the lower jaw on the left side. As always, we count from the center. As a result, a canine will be denoted by the number “33”, and the fifth molar – “35”.
  • The final segment is called forties. It begins from the mandibular incisors to the right. This part includes designations of “41”. Counting ends with the number “48”.

In order to easily memorize segmentation, it is sufficient to determine the starting point of counting, and move farther clockwise.

It remains to find out how many teeth should be in a healthy person, and at what age. Full formation of permanent teeth ends in about 13 years. Since then, the mouth has 28 pieces.

In the period from 17 to 31 years the “eights” should appear in a person. Thereafter, the mouth has 32 teeth – 16 on the upper and lower jaws which are arranged symmetrically to each other.

How does the changing take place?

To understand how the calculation will hold teeth in children or adolescents, it is necessary to know how the change of temporary teeth on the root.

This process begins at the age of 6 or 7 years. During this period, there are the first molars, in other words – “Six”, as well as cutters, located on the lower jaw. Considering the process by age:

  • at the age from 7 to 8 years, on the upper jaw there appear central and lateral incisors under numbers “32” and “42”.
  • A nine-year-old child says goodbye to the upper lateral incisors.
  • At the age of ten, there is a change of the lower canines.
  • From 10-11 years, there is a change of “fours” on the upper jaw.
  • Up to 12 years of age, upper “fives”, lower “fours”, upper canines, and premolars “35” and “45”.
  • In adolescence, from 12 to 13 years of change in the permanent molars “17”, “27”, “37” and “47”.

When diagnosing children, an adult numbering system is not enough, since both permanent and temporary teeth may be in the mouth. Therefore, for milk teeth another numbering system was made up.

In children

milk teethThe anatomical features of children’s jaws leave their print on the numbering system. Sequence numbers are the same as in adults. Up to six years, there should be 20 temporary teeth cut through. The first of them begin to appear beginning from 6 months of age, at the same age, dental germs of permanent teeth begin to grow.

X-ray of a child under the age of 6 years will not only show milk teeth, but also molars.

To distinguish between them, conventional division into segments is also carried out. Thus, the calculation is held beginning from the middle of the oral cavity assigning numbers “1” to “5”. The following division turns out:

  • First part. It starts from the top right side. Milk teeth from “51” to “55”.
  • The second segment. As in the adult system, moving clockwise. We get the cutter under the number “61” and end with a molar number”65″.
  • The third part. Next, let’s move to the lower jaw, where to an ordinal number “seventies” are added.
  • The fourth segment. It rounds out the numbering, and for this purpose “eighties” are added. As the result, we get numbers from “81” to “85”.

Using schemes and systems

There were invented more than 20 systems. The most popular of them are:


It is based on the square-cell counting system. Adopted in 1876, still today it is used when diagnosing children and adults.

To calculate the permanent teeth, Arabic numerals (1-8) are used, and for the temporary teeth – Roman (I-V). This calculation system is mainly used by orthodontists and maxillofacial surgeons.

Haderup system

The point of application of the system is reduced to adding characters “+” or “-” to the segments. The segments are separated as follows:

  • “+” sign is added to the first part after the number;
  • for the second segment plus is posed before ordinal numbers;
  • for the third part, a minus is used, which is set in front of the numbers;
  • the fourth segment – numbers, after which a sign “-” is set.

For the calculation of the milk systems “0” is added. As a result, the values from 01 to 05 are used. As the division into segments by analogy with the adult scheme plus and minus signs are used.

Viola system

The two-digit international system was adopted in 1971. It is considered to be the most common, as most dentists use it worldwide.

Its essence lies in the use of sequence numbers 1 to 8 for adults and from 1 to 5 for children. Next to these numbers tens are added, thus getting values from “11” to “75”.

The popularity of Viola system is linked to a simple principle of calculation, which does not need complicated formulas. It is convenient to transfer information over the phone, email, or take notes in a medical card using this system.

system of the teeth numeration

Universal system

For numbering teeth, the system uses a combination of numbers and letters. It was adopted by American Dental Association, which uses the following values as dental units:

  • I – refers to all the incisors;
  • C – this letter indicates the canines;
  • P – is for premolars;
  • M – refers to the molars 10 or 12, if you have wisdom teeth.

Such a system of calculation is applied in adult dentistry, when observing kids, doctors use the same literal values. Capital, not small letters are used (i, c, p, m).

To determine what kind of tooth is questioned, American dentists use numbers that are at the bottom of letters. They are assigned according to the type of a tooth. For incisors – “1”, canines “2”, premolars “3”, and molars “4”. A segment number is added to these values, so they acquire a two-digit number.

In practice, the Americans use a very simple calculation system, assigning for each tooth a separate number. The countdown starts from the upper jaw on the right side. To do this, the number “1” is assigned to the wisdom tooth.

The calculation is held in a clockwise direction; it ends with number “32”. Milk teeth are named with Latin letters from «A» and moving further clockwise end with “T”.

Understanding numerology used in dentistry can help you talk to a doctor in the same language. Many people feel safer when they understand the meaning of the treatment and can decipher the diagnoses listed on the medical card.

Knowledge of the structure of the jaw and understanding individuality of any tooth will lead to the realization that each of them is necessary, therefore, their treatment should be carried out well in advance.

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