Explanation

Humans usually have 20 primary (deciduous, “baby” or “milk”) teeth and 32 permanent (adult) teeth. Most people know these teeth as baby teeth, though they are also sometimes called milk teeth or primary teeth. In all, children have 20 baby teeth – 10 on the top and 10 on the bottom. These teeth act as placeholders for the adult teeth that grow in after the baby teeth fall out.