Why do milk teeth fall out?

This morning, Na showed Cú Bông her wobbly front tooth. It rocked whenever she touched it with her tongue.

Cú Bông worried that the tooth had a cavity. But up close it was spotless, with no sign of decay.

Na's mum said a new tooth was waiting underneath. Na stared into the mirror and saw nothing, because it was still inside her jaw.

By about the age of three, most children have all 20 milk teeth. Inside the jaw, some of the new teeth have already begun to form.

As a milk tooth is due to be replaced, its root usually dissolves over time. The root usually gets shorter, so the tooth may loosen and fall out. This often starts between about 5 and 7, as the teeth loosen and fall out one by one.

Slide through the stages to watch one front tooth being replaced. These are drawn stages, not a timetable by age; everyone changes teeth at their own pace.

You might not know

Milk teeth have roots too. By the time one falls out, most of its root has dissolved.
By about 12 or 13, most children have lost all their milk teeth.
Grown-ups can have up to 32 teeth, though some have 28.

As a milk tooth is due to be replaced, its root usually dissolves; the tooth loosens and falls out. A new tooth takes its place.

The chapter's sources

Everything this chapter tells you rests on at least two trustworthy sources, retold in the book's own words.

Your Teeth (for Kids) — Nemours KidsHealth
Teeth development in children — Better Health Channel, Victoria State Government
Where do the roots on baby teeth go? — The Naked Scientists
Why do we lose our baby teeth? — The Conversation, Curious Kids (a dental researcher answers)