Permanent dentition
At the age of 6 years the first permanent molar breaks through. Since it appears behind the last milk tooth, it is still considered by many as a milk tooth, because no milk tooth falls out. This cheek tooth, which is also called 6-year molar because of its appearance, is the first tooth of the 2nd dentition.
The tooth change takes place over a period of about 8 years. It begins between the 6th and 7th year of life. After the breakthrough of the first molar, the change starts again with the lower middle incisors and ends with the second upper molar.
The third cheek tooth plays a special role in the upper and lower jaw. This tooth is called the wisdom tooth, it appears only around the age of 20 In some people it gets stuck in the jaw or it is not attached at all. The non-apposition is a consequence of evolution. The proof can be provided by an X-ray. X-rays can also be used to determine whether teeth are doubled or misaligned.
Marking of the individual teeth
Various schemes have been introduced for the exact determination of the individual teeth. The most common is the FDI (Federation Dentaire International) formula for teeth. The teeth are divided into 4 quadrants, which are marked with the numbers 1,2,3, and 4.
It starts with the upper right quadrant, followed by the upper left, the lower left and finally the lower right quadrant. The teeth are counted from 1 to 8 from the center. This results in the following picture for the permanent teeth: top right top left 18 17 16 15 14 13 12 11 21 22 23 24 25 26 27 28.
Center: 48 47 46 45 44 43 42 41 31 32 33 34 35 36 37 38 bottom right bottom left. In the case of the 20 milk teeth, the quadrants are marked with the numbers 5,6,7 and 8. This results in the following scheme: 55 54 53 52 51 61 62 63 64 65.
Center: 85 84 83 82 81 71 72 73 74 75. Another scheme is the angular system. Here, the corresponding teeth are entered in angles that indicate the corresponding quadrant, e.g. for the upper left quadrant. Milk teeth are marked with Latin numbers such as I, II, III, IV or V, permanent teeth with the Arabic numbers 1 to 8.
