The nation is abuzz once again over whether the fluoridation of tap water should be expanded to the entire country for the sake of public health.

The issue came to a head as the Ministry of Health and Welfare announced on Tuesday that adding fluoride to tap water at a density of 0.8 ppm has proven effective in preventing dental cavities in children.

A research team from Wonkwang University studied 9,000 elementary school students divided into two groups ? one group living in areas with fluoridated tap water and the other living in areas without it. They found that those living with fluoridated tap water had a cavity average of 0.54 per child, compared to an average of 0.91 for children in non-fluoridation areas.

For a demographic pool of 8-year-olds, the cavity prevention rate stood at 61 percent in fluoridated areas, according to the research, compared to 48 percent for those living in non-fluoridated areas.

“The wealthier and more educated the children’s families were, the more effective the tap water fluoridation was,” the team said.

Health authorities said that should fluoridation be conducted throughout the nation, the country could save up to 1.7 trillion won ($1.46 billion) a year in dental care.

The report lays an academic foundation for the government plan to expand fluoridation. Currently, 25 out of 539 water filtration plants nationwide add 0.8 ppm of fluoride to their distilled water. The fluoridation rate is limited by high costs and faces strong opposition from environmentalists, civic activists and others. They claim that constant exposure to and possible intake of fluoride could trigger osteoporosis and other side effects.

Some overseas reports also say that those exposed to fluoridated water had a higher level of lead in their blood than those living in non-fluoridated areas.

As a result, fluoridation has become an international hot potato. While the U.S. government hails it as one of the greatest achievements in public health, opponents stand against forced “medication.” Currently water fluoridation is used in various degrees in Australia, Brazil, Chile, Ireland, Malaysia and Vietnam.

“Fluoride is the reduced form of fluorine as an ion bonded to another element. It coats the surface of the teeth and slows decay by germs, acid and other factors,” Dr. Seo Jong-chul of Samsung Medical Center told The Korea Herald.

He said that drinking water containing approximately 1.0 ppm of naturally generated fluoride causes fewer dental cavities and can reverse tooth decay by enhancing remineralization.

“But it is a toxin, so how much it has been diluted matters. Therefore, people need to use it carefully,” he added.

“People will be upset if the government pushes a nationwide fluoridation forcibly, because it deprives them of the right to refuse fluoridated water. People should be given options,” a civic group activist against the fluoridation said. “Unless we can be 100 percent confident about its safety, the government should not supply fluoridated water for all,” she added.

“Under the current law, the health minister is authorized to expand the fluoridation project, but in reality, the minister will face a horde of opponents in doing so,” a ministry official said.