Children continually get new teeth from age 3 months to the age 6 years. Most children have a full set of 20 primary teeth by the time they are 3 years old. As a child nears the age 6, the jaw grows making room for the permanent teeth. At the same time, the roots of the baby teeth begin to be resorbed by the tissues around them and the permanent teeth under them begin to erupt.

Primary teeth are just as important as permanent teeth for chewing, speaking and appearance. They also serve as placement holders for the permanent teeth. Primary teeth also provide structure to help shape the child's face.