The teeth in humans grow twice during life. The first teeth are called dairy, while others are permanent teeth.
Dairy teeth has a total of 20, 10 in each jaw. They begin to form around the thirtieth week before the birth. Most children grow out first lower incisors. They usually grow when baby has 6 months.
Between 6 and 13 months appear and other dairy teeth. Dairy teeth in each jaw has a 10: 4 incisors, 2 canines and 4 molars. After six years, dairy teeth fall out and are replaced by permanent teeth.
Of the 32 permanent teeth, 28 usually grow between six and fourteen. Other 4 teeth, third molars and wisdom teeth, grow between seventeen and twenty-first year of life. Permanent teeth in each jaw has 16; 4 incisors, 2 canines, 4 premolars and 6 molars.
The permanent molars do not replace any of the milk-teeth. Jaws are growing and get bigger and molars grow from the first or dairy teeth. Premolars of permanent teeth, however, replace the molars of dairy teeth.
Read also How do Braces Straighten Teeth
Did you know, dairy fours and fives remain very long in the mouth, so to them should be given extra attention, because these teeth are very important for keeping the place for permanent successors.
Each dairy tooth keeps the place to his successor, and therefore in the case of premature loss of the dairy tooth reduces the free space in which to be placed permanent tooth.