But why is politicized opposition to fluoride happening now?* The process has been in use since the 1940s, and the Centers for Disease Control and Prevention (CDC) hail it as one of the top preventative public health measures of all time. It is thoroughly supported by the American Dental Association, and when it was initiated in the middle of the 20th century, rates of dental cavities fell by 50 percent or higher, arguably because of fluoride. But opposition groups, notably the Fluoride Action Network, a non-profit dedicated to fluoride-danger awareness, put forth a much darker picture. They say the effect of tap water fluoride on tooth decay is hard to pinpoint, and in a large enough quantity, fluoride is a toxin -- one that can possibly make bones fragile, lower IQ in children, and contribute to bone cancer. They insist cavities can be prevented by brushing alone.

Like many environmental issues turned political, the two opposing sides in this debate present a dichotomous, confusing picture. What should residents in a community debating the practice believe? Ask the CDC whether fluoridation is worthwhile, and the answer is a resounding yes. Ask the Fluoride Action Network, and it is a fearful no. When it comes to environmental issues, misinformation runs rampant and so does emotion. At the intersection of politics and science, it's often hard for the public to arrive at an objective truth.

A BIT OF BACKGROUND

Sugar does not rot your teeth, bacteria do.

Just as the body uses sugar as fuel, cariogenic (cavity-forming) bacteria start a feeding frenzy when you chew on a candy bar, and continue when bits of that candy get left behind. With the sugar, the bacteria create a corrosive acid, and like a drill boring into the surface of a tooth's hard enamel, they burrow their way to their desired treasure -- the teeth's inner soft tissues. A cavity forms.

Fluoride intervenes in two ways. It reacts with the minerals in your teeth and fortifies them against the corrosive acid, even re-mineralizing already decayed teeth. And it sabotages the bacteria's metabolism, limiting its ability to grow and attack the teeth.

"The beauty about fluoridation is that you come in contact with the fluoride throughout the day," says William Bailey, acting dental director at the CDC's division of public health. "That's why water fluoridation works so well, you don't have to remember to do anything. It's an ideal public health measure."

Bailey says fluoridated tap water provides 20 percent more protection against tooth decay than brushing alone and that communities risk harm by halting the process. This level of protection is more significant in low-income areas and for people who may not have regular access to dental care.

While some areas around the country have naturally occurring fluoride, others add fluoride -- typically purchased from fertilizer companies -- to their municipal water supplies. The CDC's ideal concentration for health benefits is between .7 and 1.2 ppm (parts per million, or one milligram in every liter of water), but this is only a recommendation. As made clear by Pinellas County, communities are free to fluoridate as they see fit.