[rotrux]

A)Teeth are sorta like regular ol' bones 'cept they're on the outside of your body and their purpose is to grind things. B) You don't really need all of them to survive + evolution. C) Humans live a really long time now and we just expect our mashy-grinders to keep up? D) Enamel doesn't like sugar which is in everything.

Bam. Scientific American here I come.