Just thought I'd share this with you, been using it for a couple weeks now and I like it
. I decided to take what I learned from ecigs and turned a cheap electric toothbrush into a 5v pass-through. The motor in it can handle more power than its given from 2 AAA's, so its a good bit better at cleaning your teeth, and no gum damage yet. 

I got a cheap $6 electric toothbrush and soldered its battery connections to a Usb cord, than hooked the usb cord to a ac>usb adapter from a old cell phone. Works a good bit louder, and you don't have to worry about changing battery's (can get kinda gross).

I got a cheap $6 electric toothbrush and soldered its battery connections to a Usb cord, than hooked the usb cord to a ac>usb adapter from a old cell phone. Works a good bit louder, and you don't have to worry about changing battery's (can get kinda gross).