[ZenGum]

By all means keep your kids' teeth.

You'll be able to use them later for magic spells and stuff, when they run away from home and you need to use clairvoyance to find them, and mind-control spells to draw them back.

But make sure you explain to the kids that the money is only for teeth that fall out naturally. Every now and then there is a story in the media about some young kid who figures that at $5 per tooth, he's got a new skateboard right there in his mouth, and all he needs is twenty minutes alone with some pliers...