Rinse, spit … and flush.

That’s figuratively what many Nebraskans did last year with a public health effort to expand fluoridation in drinking water.

The naturally occurring mineral has been widely touted for reducing cavities, but that didn’t stop 49 of 61 communities from defeating fluoride on the ballot.

Now, at least two of the 12 towns that passed fluoridation could be headed for do-overs. Activists in the Saunders County cities of Wahoo and Yutan say they are willing to circulate petitions to block state-mandated fluoridation.

“I do think the government is trying to get it in our water,” said Mary Holbrook, a 53-year-old businesswoman from Yutan who said she has already collected more than 60 signatures seeking a re-vote. “They want to control the population.”

Fluoride supporters, and those with no opinion, might dismiss opposition leaders as misinformed, anti-government radicals. But do the same labels apply to the silent majorities who defeated fluoride measures in nearly 50 communities?

Word-of-mouth opposition could have spread in the mostly small communities. One other possible explanation: The anti-fluoride movement taps into a general distrust of government, public health agencies and conventional science.

At the very least, the ballot rejections also demonstrate how opponents used the Internet to spread arguments against adding fluoride to water.

The Fluoride Action Network, for example, turns up second in a Google search of the term. The group calls itself an international coalition that seeks to inform citizens, scientists and doctors that fluoride exposure represents a health threat rather than a benefit.

The professionally produced Web site says most people don’t know the fluoride injected into water supplies is a by-product of the aluminum and fertilizer industries. It also declares that while fluoride’s effectiveness at reducing cavities is dubious, studies have linked it to a rare bone cancer and lower IQ scores.

A fence sitter might be swayed by links to an anti-fluoridation petition signed by 2,500 doctors, scientists and lawyers and a National Research Council report recommending a lowering of what was considered the safe level of fluoride exposure.

“There’s so much evidence on the Internet,” Holbrook said.

The debate came to the fore in November’s vote, which took place because of a state law requiring Nebraska communities 1,000 and larger to fluoridate by June 1, 2010. The law allowed communities to opt out by holding public elections.

Fluoride’s widespread defeat surprised and disappointed David O’Doherty, director of the Lincoln-based Nebraska Dental Association. The organization, consisting of 1,000 dentists, figured a vote for fluoridation was a no-brainer.

“The health benefits are well established,” he said. “It’s cheap and effective.”

As for the dangers of fluoride, health professionals agree consuming too much can cause health problems, such as tooth staining and weakened bones. That’s one reason they recommend against swallowing toothpaste.

It’s also true one study linked fluoride with a rare bone cancer in laboratory rats.

But the small amounts of fluoride added to water and drunk by millions of Americans (and most Nebraskans) for decades “does not pose a detectable cancer risk as evidenced by extensive human epidemiological data,” said a 1991 government report.

Other studies have shown fluoride reduces cavity rates by 18 to 40 percent, according to the Centers for Disease Control and Prevention. The American Dental Association estimates that every dollar spent on fluoridation saves $38 in dental costs.

Finally, supporters say fluoridation reaches poor people who otherwise can’t afford dental treatments.

O’Doherty knew opposition leaders were working hard to defeat fluoride, but he figured they were a minority. Once in the voting booth, he felt sure, the silent majority would support a practice the CDC considers one of the top 10 public health successes of all time.

In most communities, the vote to block fluoride was close. Still, a remarkable 80 percent of them opted out.

“You’d think that science would win the day, but anybody hears what they want to hear,” O’Doherty said. “Emotion is a deciding factor.”

Both sides on the fluoride debate shared a dislike of the ballot language. The phrasing required by the state meant in most communities, a “yes” vote was against fluoridation and a “no” vote was for it. Both sides said the language may have skewed the results.

Fluoridation opponent Bill Miners of Wahoo said he thinks the confusion was orchestrated by fluoride supporters to get the measure passed in his town.

His opposition to fluoridation stems largely from anger over the government removing an individual’s right to decide the matter. If someone wants to use fluoride, he can easily do so by using fluoridated toothpaste or mouthwash.

“It’s a medicine,” he said. “We don’t put vitamin C in the water. It might help some people, yes, but it might hurt someone else.”

What happens in Yutan and Wahoo remains to be seen. The Yutan City Council has been asked to place the fluoride vote on the ballot, but it is awaiting a legal opinion, said City Administrator Gary Duncan.

In Wahoo, the city attorney told the council a special election would require a petition signed by a minimum number of registered voters. Just how many signatures, or even if there will be an effort to collect them, is not yet clear.

Without another vote, however, each city will have to install the equipment and buy the chemicals to treat the water by next summer.