Portal:Dentistry/Selected article/2
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Tooth development is the complex process by which teeth form from embryonic cells, grow, and erupt into the mouth. Although many diverse species have teeth, non-human tooth development is largely the same as in humans. For human teeth to have a healthy oral environment, enamel, dentin, cementum, and the periodontium must all develop during appropriate stages of fetal development. Primary (baby) teeth start to form between the sixth and eighth weeks in utero, and permanent teeth begin to form in the twentieth week in utero. If teeth do not start to develop at or near these times, they will not develop at all.
A significant amount of research has focused on determining the processes that initiate tooth development. It is widely accepted that there is a factor within the tissues of the first branchial arch that is necessary for the development of teeth. Tooth development is commonly divided into the following stages: the bud stage, the cap, the bell, and finally maturation. The staging of tooth development is an attempt to categorize changes that take place along a continuum.
Enamel formation occurs after the initiation of dentin formation. Cementum begins to form late in the development of a tooth. Supporting structures of teeth must also develop during this time. Tooth eruption occurs when the teeth enter the mouth and become visible. Baby teeth start to appear at about eight months of age, and permanent teeth appear at six years of age.
