No, it isn’t a communist plot or an inherent abuse of government power for municipalities to try to improve the public’s dental health by supplementing the water. But before we laugh off or dismiss some people’s concerns about fluoridation, we ought to look at the facts behind them.

Much to its credit, the Des Moines Water Works management and board are soliciting input on that highly fraught subject . The opinions offered so far in this newspaper suggest serious opponents of fluoridation are in a minority. Some of their claims strain credibility. But that doesn’t mean none have merit.

Fluoride is added to 70 percent of U.S. water supplies and more in Iowa. The U.S. Centers for Disease Control and Prevention calls it one of the top 10 public health achievements of the 20th century. But what exactly is fluoride? Is it as needed today as 54 years ago, when Des Moines started adding it? And why have most other developed nations rejected it? While some waterways have naturally occurring fluoride, the fluoride added to U.S. water systems is a byproduct of chemical fertilizer processing. We drink that. The Fluoride Action Network, which opposes fluoridation, says the chemicals undergo no purification, so they can contain elevated toxins.

Excessive fluoride exposure from infancy to 8 years old can also cause “dental fluorosis,” a mottling of the tooth enamel, which at its worst can leave rough, pitted surfaces. Though dentists say that’s only a cosmetic problem, it’s still a risk for infants exposed through tap water mixed with baby formula. Other at-risk groups, say opponents, are people with kidney disease or nutritional deficits and black Americans, who — for whatever reasons — have higher rates of dental fluorosis than whites.

Some African-American leaders, including former Atlanta Mayor Andrew Young, want to end fluoridation. The League of United Latin-American Citizens (LULAC), an 85-year-old, 2 million-member organization, passed a resolution in 2011 opposing fluoridation, saying it disproportionately harms low-income and minority communities. The group calls it “forcible mass medication.”

Joe Henry, the state director of Iowa LULAC, says poor families — and one-third of Iowa Latinos — live in poverty and can’t opt out with bottled water or private wells. As to those who dismiss fluorosis as an aesthetic problem, he says, “Most wealthy, successful people have white teeth.”

There’s little question that fluoridation has saved millions of teeth. While 20 percent of Americans had lost their teeth by their mid-50s in the 1960s, today fewer than a one-tenth have. U.S. Surgeon General Regina Benjamin, Steven Levy of the University of Iowa College of Dentistry and others say the benefits of fluoridation are not limited by income level, ability to get routine dental care or diet, making it very cost-effective.

But Henry says, “When you look at the possible dangers, that’s a cheap way of doing it. Fluoride should be a choice, not a mandate.”

The American Dental Association claims that fluoride reduces tooth decay by 20 to 40 percent today and that 65 years of studies have shown it to be safe. But opponents point out that you shouldn’t have to ingest fluoride to receive the benefits of topical contact with teeth.

A University of Iowa study on fluoride, beginning in the early 1990s, has been cited by both opponents and proponents of fluoridation. It monitored over 600 Iowa children from birth to adolescence at regular intervals. “Fluoride intake was found to be significantly associated with dental fluorosis, but not tooth decay,” claims the Fluoride Action Network, of a 2009 report. A 2011 report also found the water fluoride level had no significant effect on tooth decay, though greater tooth-brushing frequency did, it noted.

Asked about the group’s claims, Levy, to whom questions about the study are referred, acknowledged they were factual, but said, “As anyone would, advocating for their causes, they’ve taken it a bit out of context.”

The study found 10 to 18 percent lower cavity rates with fluoridated water. He said the object was to estimate the amount of fluoride obtained from different sources. Benefits are lower than before because there are other sources of fluoride such as toothpaste, he noted.

Levy calls fluoride safe but says, “We can never 100 percent prove something safe.”

There are cases in which Harvard researchers and Environmental Protection Agency staff have broken from their superiors or organizations in opposing fluoridation. Portland, Ore., Wichita, Kan., and Pinellas County, Fla., among other communities, have rejected fluoride. Israel, which has required fluoride since 1998, was reportedly ending its addition this year.

Maybe they’re overreacting. Then again, throughout history, small, vocal minorities have been written off for raising tough questions that cut against conventional wisdom but later proved to be right. Global warming is a case in point.

My own dentist, Debra Thorsheim, who is holistic in her outlook and in her products, thinks there would be a huge increase in tooth decay without fluoridation. “But if it is a neurotoxin, like the holistic groups say, we don’t want that either,” she sighed.

That’s why it’s good for Des Moines to have this debate. But it must include unbiased, scientific input.

Correction: This article has been updated to correct a figure on tooth loss.