A child's first teeth are called baby or primary (deciduous) teeth. Primary teeth are present deep in the gums at birth. These teeth start to come in between 4 and 18 months of age. In most children, all 20 baby teeth are in place by age 3. Taking good care of them helps the adult teeth develop correctly.
At age 6 or 7, baby teeth begin to fall out. They are replaced by adult (permanent) teeth. Most adult teeth are in place by the time a child is in their early teens. Permanent teeth are the ones a child will have for the rest of their life.