Before starting the tooth numbering it is important to give a brief overview of the human dentition. Humans have two sets of dentitions one is called Primary dentition and the second and the final set is called secondary dentition.
Primary Dentition
The primary dentition is also known as deciduous dentition, milk teeth, temporary teeth, or baby teeth. The first primary tooth erupts at the age of 8 months and the deciduous dentition is completed by the age of 3 years. In the complete primary dentition, there are twenty teeth. Ten teeth in the upper arch (Maxillary jaw) and ten teeth in the lower arch. (Mandibular jaw)
The teeth are divided into anterior teeth and posterior teeth. The anterior teeth in the deciduous dentition include maxillary and mandibular central incisors, lateral incisors, and canines. The posterior teeth are maxillary and mandibular first and second molars.
The details and names of the primary teeth are in the figure and table below.
The human complete primary dentition
Table 1: Names of Primary teeth with the age of eruption and Exfoliation
| Name of Primary Teeth | Age of Emergence (eruption age) | Age of Exfoliation (shedding of teeth) |
|---|---|---|
| Maxillary or Upper arch | ||
|
Central Incisors |
10 months | 6-7 years |
|
Lateral Incisors |
11 months | 7-8 years |
|
Canines |
19 months | 10-11 years |
|
First molars |
16 months | 9-10 years |
|
Second molars |
29 months | 10-11 years |
|
– |
||
| Mandibular or Lower Arch | ||
|
Central Incisors |
8 months | 5-6 years |
|
Lateral Incisors |
13 months | 6-7 year |
|
Canines |
20 months | 8-9 years |
|
First molars |
16 months | 9-10 years |
|
Second molars |
27 months | 10-11 years |
Permanent Dentition
The permanent dentition is also known as secondary dentition. The first permanent tooth erupts at the age of six years and eruption of permanent dentition is completed by the age of twenty-one years. In the case of congenitally missing third molars, the permanent dentition is completed by the age of thirteen years. From the six years until eleven years the deciduous teeth are also present in the oral cavity and this period is known as transitional or mixed dentition period.
The details and names of the permanent teeth are in the figure and table below.
The human complete permanent dentition
Table 2: Names of Permanent teeth with the age of eruption.
| Name of Permanent Teeth | Age of Emergence (eruption age) |
|---|---|
| Maxillary or Upper arch | |
|
Central Incisors |
7-8 years |
|
Lateral Incisors |
8-9 years |
|
Canines |
11-12 years |
|
First Premolars |
10-11 years |
|
Second Premolars |
10-12 years |
|
First Molars |
6-7 years |
|
Second molars |
12-13 years |
|
Third Molars |
17-21 years s |
|
Lateral Incisors |
|
| Mandibular or Lower Arch | |
|
Central Incisors |
6-7 years |
|
Lateral Incisors |
7-8 years |
|
Canines |
9-10 years |
|
First Premolars |
10-12 years |
|
Second Premolars |
11-12 years |
|
First molars |
6-7 years |
|
Second molars |
11-13 years |
|
Third molars |
17-21 years |
Tooth Types or Families
In both the deciduous and permanent dentitions there are three tooth forms or families and those are:
Incisiform teeth
The incisiform teeth are central and lateral incisors their main function is cutting as the incisal ridges have are blade-like structure.
Caniniform teeth
The canini form teeth are the canines. The main function of canine is tearing and piercing of food.
Molariform teeth
The molariform teeth are molars and premolars (premolars only present in permanent dentition). These teeth have grinding functions as these teeth have a wide occlusal surface and they possess cusps.
Introduction to Tooth Numbering Systems
Several tooth numbering systems are in use around the world for the recording of data in dental practice and dental research. The three most popular tooth numbering systems are:
- The universal tooth numbering system
- Palmer tooth numbering system
- FDI tooth numbering system
These tooth notation systems serve as an abbreviation that makes the recording of data and communication convenient.
The universal tooth numbering system
The American dental association (ADA) recommends the universal numbering system. This tooth notation system is also known as the American tooth numbering system. In this notation system, every tooth has a unique alphabet or a number and there is no need to use any symbols as in some other numbering systems (Palmer tooth numbering system).
Deciduous dentition
The Universal system for tooth notation uppercase alphabets is used for deciduous teeth. The tooth notation in the universal system in deciduous teeth begins from the right maxillary second molar with alphabet A and the last alphabet in the maxillary arch is J for the left maxillary second molar. In the mandibular deciduous teeth, the universal notation begins with alphabet K for the mandibular left second molar and ends with letter T for the right mandibular second deciduous molar. The universal tooth notation system for entire deciduous dentition is presented in the following picture.
A universal tooth notation system for primary teeth
Permanent dentition
In the universal notation system for permanent dentition, the teeth are numbered. The numbers begin with 1 for the right maxillary third molar and in the maxillary arch end on 16 for the left maxillary third molar. In the mandibular arch, the numbers begin with 17 for the left mandibular third molar and end on number 32 for the right mandibular third molar.
The following picture designates the universal tooth notation system for entire permanent dentition.
The universal tooth numbering system for permanent teeth
Palmer tooth numbering system
The palmer tooth notation system was first introduced by Adolf Zsigmondy for the permanent dentition and later modified for deciduous dentition. The system is widely known as the Palmer notation system and less commonly as the Palmer Zsigmondy notation system. This notation system uses symbols to designate the quadrants with the alphabets (deciduous teeth) or numbers (permanent teeth) to designate a particular tooth.
Deciduous dentition
In this notation system the maxillary and the mandibular arches are divided into the quadrants the central incisors are represented by A through E for the second deciduous molar. In this notation system, the important thing is the symbol that is used together with the upper case alphabet, and that symbol indicates the arch (Maxillary or mandibular) and the quadrant (right or left). The Palmer tooth notation system (together with symbols use to designate arch and quadrant) is presented for entire deciduous dentition in the following picture.
Palmer tooth notation system for deciduous teeth (observe the symbols used)
Permanent dentition
The palmer notation system for the permanent dentition the arches are also divided into quadrants represented by symbols. In the palmer notation system for the permanent teeth, the teeth are represented by a number instead of alphabets that were in use in deciduous dentition.
The Palmer numbering system in each quadrant begins with 1 for the central incisor to 8 for the third molar. The symbols that are used along with these numbers indicate the arch and the quadrant where the tooth is present.
The following picture explains the palmer tooth notation system for the entire permanent teeth.
Palmer tooth notation system for permanent teeth (observe the symbols used)
FDI tooth numbering system
The Fédération Dentaire Internationale (FDI) proposed a two-digit tooth numbering system known as an FDI tooth numbering system. This tooth numbering system is adopted by the major organizations around the world such as the World Health Organization (WHO) and the International association for dental research (IADR).
Deciduous dentition
The first digit in this numbering system indicates quadrant and the second digit indicates the tooth number, for example, the deciduous maxillary right central incisor is designated as 51. The first number that is 5 indicates the maxillary right upper quadrant and 1 indicates central incisor. In this numbering system, the correct pronunciation is five-one, not fifty-one. The FDI tooth numbering system for entire deciduous teeth is presented in the following picture.
FDI tooth numbering system for primary teeth
Permanent dentition
Similar to the deciduous dentition in the permanent dentition there are two digits the first indicates the quadrant and the second digit indicates the tooth. For example, the permanent right maxillary central incisor in the FDI numbering system is indicated as 11 (one-one not eleven). The first 1 indicates the right maxillary quadrant and the second 1 indicates the tooth number. The FDI tooth notation system for the entire permanent teeth is presented in the following picture.
FDI tooth numbering system for permanent dentition
The type of teeth is designated by the alphabet and the quantity in each side of the upper and lower jaw is designated by a number.
