Do you remember your first loose tooth? Your friends may have started losing teeth and gaining goofy smiles in the process. But your teeth were firmly set in your mouth. Until that one day when you felt a tell-tale wiggle and…yes!...your first loose tooth.

Did it fall out right away? Or did you have to wiggle it for several days? Did it fall out on its own? Or did you have to resort to tying a string around it and pulling?

Once it was out, what did you do with it? If you're like most kids, you probably placed it under your pillow for the Tooth Fairy to find. In the morning, you immediately checked under your pillow to find your loose tooth replaced with cold, hard cash. Ka-ching!

But have you ever stopped to WONDER why you lose your baby teeth in the first place? Why don't those baby teeth just grow up into permanent teeth without all the rigmarole of falling out and growing new teeth?

Baby teeth — also known as deciduous teeth, primary teeth, or temporary teeth — are your first set of teeth, and they're just as important as your permanent teeth. In addition to helping young children chew and speak, baby teeth hold spots along the jaw for the permanent teeth that are still growing under the gums.

Baby teeth usually begin to appear between the ages of six months and one year. Most kids have a full set of 20 baby teeth by the time they turn three years old.

Around the age of six, baby teeth will begin to loosen and fall out on their own to make room for the permanent teeth that will replace them. Girls tend to lose baby teeth earlier than boys. This process goes on for several years. Most kids will have lost all their baby teeth by the time they turn 12 or 13.

And what if you lose a permanent tooth? Does a new one regenerate in its place? Nope. We only get two sets of teeth, so it's important to take care of them your whole life.

Wonder What's Next?

All aboard! Tomorrow’s Wonder of the Day will take you for a ride on one of the most famous railroads of all time…with no tracks in sight.