Why man milks teeth?
A person’s teeth break twice. First time – dairy (DENTES LACTEI). They function before replacing constant, so the other name is temporary, drop-down (DENTES decidui). In the first set there are eight cutters, four fangs and eight molars (indigenous) – only 20 teeth. A permanent bite consists of eight incisors, four fangs, eight premolars and from eight to 12 molars.
Why is the "dairy kit" less, why a person is a cheese-boron with a change of teeth, as and when the replacement for permanent?
The main reason for the need for replacement is the growth of the child and, in particular, the growth of the jaws.
A child is born with a small head, toothless (although the laying of the teeth is happening during the intrauterine development). Approximately half a year, the demand for teeth in the infant is almost absent, since breast milk is the main food for it. Then follows the transition to mixed nutrition and the need to chew more coarse food appears.
In a healthy child, the process of teething the first teeth ends to two, two and a half years, some longer – for another one and a half years. But this age there should be 20 teeth. Dairy period lasts up to six, six and a half years.
All this time, the baby grows, his head grows, together with her jaws – under the milk teeth there is a permanent.
In the first period (from the moment of the formation of up to three and a half years old), the teeth are arranged tight, without intervals, the spun of them is invisible. In the second (from three and a half to six and a half years old) during the growth of the jaws there is advocate, gaps between the teeth occur, their significant sparking occurs. Rapid roots of dairy teeth. When the "shortened" root can no longer hold the milk tooth in the hole, it falls. So gradually, one by one, temporary teeth "fly out", freeing the place permanent. Change usually ends by 12 years.
One of the most important destinations of dairy teeth is that they "indicate" a constant space for cutting. In the case when milk drops ahead of time (or when it is necessary to delete), the constant "deprived of the landmark" and may grow curly.
In a set of permanent teeth, there is a set that is missing in a set of dairy. These are two pairs of premolars on each jaw. They are between fangs and indigenous.
Teeth of wisdom rubs the last, approximately 17-21 years. By the way, if the jaw is small and seats for the teeth of wisdom on it, they may not appear at all and the person lives with a set of 28 permanent teeth.
Interesting: the number of teeth in humans has decreased over time. There is information that the ancient people had more than 50. They served a person not only for chewing food, but were an instrument of protection and attack. Then some of the functions themselves disappeared. In addition, the dental dental contributes to more processed, soft food, for chewing, which requires less effort.