[log in to unmask] writes:
 > Dental hygienists at work report that fluoride in drinking water does reduce
 > tooth decay *but* this reduction is most statistically significant amongst
 > the low-income population who tend toward more sweets and starches (and
 > possibly less tooth brushing)

I think something else is at play.  For instance, my brother and I grew up
eating sweets, junk, etc.  He had horrible brushing habits -- rarely did it
-- yuch!  And when he needed braces, the dentist kept warning him that if he
didn't improve his brushing while the braces were on, his teeth would have
lots of cavities after the braces were removed.  My brother continued his bad
dental hygiene while wearing braces and when they were removed, he had tons
of tarter build up but not one cavity.  I remember the dentist almost seemed
disappointed that he couldn't find a single cavity! To this day, neither my
brother nor I have any cavities.  PS: I use a rotodent electric brush with no
toothpaste.  If I want a minty taste, I'll brush lightly afterwards with a
regular toothbrush and Tom's of Maine fluoride-free toothpaste.