[Andrew @ Feb 3rd 2006 7:35AM]

In my college inorganic chemistry course last semester, I had to answer a question about why flourine toothpaste works to make the enamel of your teeth incredibly strong. Basically, the elements in the 2nd to last column in the period table, the halogens [F Cl Br I], are inversely reactive depending on their state. If the element is in F2, Cl2, I2 form [2 = subscript], the most likely element to react is at the top, F. If they are in F-, Cl-, I- form, it's the inverse and F- is the worst.

So, you put F2 [Flourine] in toothpaste. It's way more reactive than the OH- in your enamel [Tooth Enamel � Ca10(PO4)6(OH)2] so it displaces the OH- and becomes F- [Flouride] which then reacts with pretty much nothing, because F- in principle sucks at reactions, where F2 rocks out.

My novice guess is that the current is used to aid the reaction between the Flourine in the gel and your tooth enamel - thus an "electrochemical reaction." How, exactly, you're supposed to stay plugged in to the wall after 8 hours of tossing and turning, I'm not sure, but it's a cool idea and I think has decent potential. My dad's teeth are yellow now, after years of living in the country, but they were stark white when he had the Flourine of the city water to help him out.

Anyways, hope that makes sense without a picture of the table. Normally I had visual aids ;)