Ask A Scientist

When a baby’s tooth falls out, how does it grow back?

Asked by: Taylor Geertgens
School: West Middle School, Binghamton School District
Grade: 6

Answer from Sara Mina

PhD Candidate, Binghamton University

Research area: Tissue Engineering
Interests/hobbies: Music, singing and cake designing

We are born with all of our teeth already forming: 20 baby teeth (or primary teeth) and 32 permanent adult teeth. Teeth begin as soft tissue, known as the bud stage. Minerals for hardness and strength are added later. Babies start out with a small number of tiny teeth to fit into their small jaws. As children grow, the larger primary teeth come in. These will all be replaced by the permanent teeth already growing underneath.

Our jaw is composed of bone (which holds the teeth in place) and gums, the pink tissue that covers the bone. As we grow and permanent teeth develop, they produce large roots; bone then forms around the root of the tooth. When the permanent teeth are fully formed, they move into place.

Most permanent teeth erupt when we are between six and twelve years old. The last to come in are the wisdom teeth, which break through the gum between the ages of 16 and 25. Our 32 permanent teeth have various shapes and sizes, some for cutting, such as incisors and canines, and some for grinding, such as pre-molars and molars. Adult teeth are not replaced because no new tooth buds are formed after birth.

It is important to take care of your teeth by brushing and flossing every day, because you want your teeth to last a lifetime.


Last Updated: 3/1/17