<P> Tooth development or odontogenesis is the complex process by which tooth form from embryonic cells , grow , and erupt into the mouth . For human teeth to have a healthy oral environment , all parts of the tooth must develop during appropriate stages of fetal development . Primary ( baby ) teeth start to form between the sixth and eighth week of prenatal development , and permanent teeth begin to form in the twentieth week . If teeth do not start to develop at or near these times , they will not develop at all , resulting in Hypodontia or Anodontia . </P>
<P> Tooth development or odontogenesis is the complex process by which tooth form from embryonic cells , grow , and erupt into the mouth . For human teeth to have a healthy oral environment , all parts of the tooth must develop during appropriate stages of fetal development . Primary ( baby ) teeth start to form between the sixth and eighth week of prenatal development , and permanent teeth begin to form in the twentieth week . If teeth do not start to develop at or near these times , they will not develop at all , resulting in Hypodontia or Anodontia . </P>
when do the first signs of tooth development begin
when do the first signs of tooth development begin
between the sixth and eighth week of prenatal development
between the sixth and eighth week of prenatal development