Why Baby Teeth Fall Out: The Science of Root Resorption

As a permanent tooth develops beneath a primary (baby) tooth, it triggers root resorption—a natural process where specialized cells (osteoclasts) gradually dissolve the baby tooth’s root.

Once most of the root is resorbed, only the crown and a tiny root remnant remain. The body then reabsorbs this fragment, the tooth becomes loose, and the erupting permanent tooth pushes it out completely.

This orderly sequence ensures space for adult teeth and typically begins around age 6, continuing into the early teens.