The Teeth Human grow two sets of teeth. The first set serves during infancy and childhood. These teeth are known as the primary, mil, temporary, or deciduous teeth. They are gradually replaced by a second set. These are secondary, adult, or permanent teeth.
All teeth develop from cellular buds inside the jaws.
The buds of both the primary teeth and the permanent teeth form long before the baby is born. From the bud, the crown develops first. This is the hard, enamel-covered part which will later become visible in mouth. When the crown is fully grown and hard, the root starts to develop. The crown is complete and the root about two third formed when the tooth erupts, or pushes through the gum.