Wisdom teeth grow in the most extreme in the gum, i.e. the second molars (the typical "seven") and are called third molars or "eight". So far their arrangement causes a secondary role in grinding food. The primary set of teeth are necessary for chewing food is 28 teeth, so "eight" is considered "a luxury" and are called wisdom teeth.
Laid wisdom teeth when changing the last milk teeth at the root, i.e. approximately 13-15 years. However they are formed is quite long and begin to erupt only after 20 years. Such a long time their complete formation is determined by the physiological characteristics of the organism, because during the eruption of milk teeth children scratch their gums, bite the toy and thereby increase the blood flow and metabolic processes that help the teeth to emerge. And the third molars are so far away that when chewing food falls on the first and second molars, and the gum over the "eights" little is supplied and not "massaged" while chewing that prolongs the process of tooth formation.
Wisdom teeth tend to grow in stages. You can observe the discomfort in the gums, and sometimes pain for 1-2 weeks and then all signs of teeth growth subside for several weeks or even months. The growth of "eights" is influenced by hormonal surges in the body, for example, observed that during pregnancy, the growth of wisdom teeth much aktiviziruyutsya. Can provoke growth of latest teeth pronounced inflammatory processes in the body, which are accompanied by prolonged fever.
The monitoring of dentists third molars some people grow for decades, so if you have 20-22 years old there were signs of growth, "eights", this does not mean that soon you will have a 30-32 tooth. Wisdom teeth often have steam pattern in growth, ie if you got out of the upper third molar on the right, then soon expect the same tooth and on the left.
Is caused by the prolonged eruption of wisdom teeth and the fact that they often have the wrong location, i.e., can be laid at an angle with growth hitting a seven. Of course, the tooth is located in parallel with the gums, it is almost impossible to cut, so he gradually turned over. At this time, may take several years, i.e. - if you start to erupt, the tooth 21, the full formation of his visit will end around the age of 30.
Complicates the process of teething inflammation of the gums over the wisdom tooth. If you cut at least a small part of the tooth, forms a focus of infection, which includes fibre for food by germs and to clean the place hard to reach. When inflammation of the gums becomes spongy and often it formed "pockets" - more easily infected places. "Pockets" over the cutting of the wisdom tooth, the surgeon cuts, thus facilitating eruption of the tooth.
If 27-30 years you have never had symptoms of formation and eruption of third molars, then the chances of the emergence of these teeth after 30 years is negligible, because all the processes of formation in the body at this age subside, and the teeth are no exception.