The flouride debate is heating up, as several American cities consider banning it from the water supply. Opponents of flouride say it's toxic and bad for the environment. Supporters say it saves kids' teeth, especially poor kids who can't afford to go to the dentist on a regular basis. 75 percent of us are drinking water that has it. Should we be concerned? HuffPost Live's Janey Varney hosted a segment digging into both sides of the argument.