Which is only ten times more expensive.
Hopefully you're buying toothpaste anyway, so the relevant number is the difference in price between fluoridated toothpaste and non-fluoridated. I think it's more or less zero. In fact, non-fluoridated toothpaste is likely to be some all-natural all-organic fancy expensive thing :-)
A post from Gregory Cochran's and Henry Harpending's excellent blog West Hunter.
The commenter Ron Pavellas adds:
The Wasserman Test.