Eruption of Teeth

Eruption of Teeth 

the gradual appearance of dental crowns on the surface of the alveolar process of the jaw and gums. Eruption ends with the appearance of the entire crown of the tooth (up to its neck) on the surface of the gums.

Teeth erupt twice in humans; the first eruption begins when the child is six months old and ends by the time he is 24 to 30 months old. During this time, 20 temporary, or milk, teeth appear—eight incisors, four canines, and eight molars. From five to 14 years of age, the dental alveoli and roots of the milk teeth are resorbed and replaced by 20 permanent teeth—eight incisors, four canines, and eight bicuspids. During the second eruption, another eight to 12 molars develop. The third molars, or wisdom teeth, appear between 17 and 25 years of age or do not erupt at all. The first permanent teeth to erupt are the first molar teeth and the last are the third molars.

Sometimes, for example, with rickets, the time and order of tooth eruption are disrupted. The pathology of the eruption of wisdom teeth is frequently observed and is usually the result of the improper position of the wisdom teeth. There have been rare cases of children born with one or two erupted milk incisors. In the second half of the 20th century, the developmental period has become noticeably shorter; consequently, dental eruption begins earlier. This is believed to be the result of a general acceleration of development.

REFERENCES

Kolesov, A. A. Stomalologiia detskogo vozrasta. Moscow, 1970.
Rudenko, A. T. Patologiia prorezyvaniia zubov mudrosti, 2nd ed. Leningrad, 1971.

G. D. OVRUTSKII