In the debate over fluoridating Portland’s water, the two sides trying to persuade voters can agree on one thing: Low-income children aren’t getting the dental care they need and deserve. And each side says its position offers the best hope for helping those kids.

But for one side in the battle—Clean Water Portland, which opposes fluoridating the city’s water supply—that argument is getting little traction with groups that say they represent low-income and minority Portlanders.

None has sided with anti-fluoridation forces.

Meanwhile, Healthy Kids, Healthy Portland, the backers of a May 21 ballot measure to authorize fluoridation, has lined up more than 80 local organizations that have endorsed its campaign, including the African American Health Coalition, Causa, the Latino Network, and the Asian Pacific American Network of Oregon.

Kimberly Kaminski, executive director of Clean Water Portland, says she won’t disclose in detail what her group has done to reach out to low-income or minority groups.

“We have offered to meet with most, if not all, of the groups within the communities of color that have spoken out in favor of fluoridation to hear their perspective and share ours,” Kaminski wrote in an email to WW. “Our volunteers have also recently met with both groups and individuals. These conversations are ongoing and the response has been mixed, with some clearly supporting and others clearly opposing fluoridation.”

But Kaminski won’t name a single group that has endorsed Clean Water Portland’s position. “We’re not prepared to give out that information at this time,” she says.

Organizations that have backed the fluoridation efforts say Healthy Kids, Healthy Portland reached out to them early—in some cases, they had been part of a pro-fluoridation coalition in the past.

“Healthy Kids, Healthy Portland arose with communities of color at the grassroots level,” says the Rev. Joseph Santos-Lyons, executive director of APANO. “With Clean Water Portland, there isn’t really leadership at the table from communities of color, so they have to do more external, after-the-fact outreach.”

The debate highlights the wide gulf in perceptions and political approaches between the two political campaigns so far. Healthy Kids, Healthy Portland left opponents trying to break into an established political circle and pry away groups that had already expressed support.

For decades, experts have said adding fluoride to drinking water cuts down on tooth decay, especially in children. But Portland has resisted fluoridation for years: Voters defeated fluoridation ballot measures in 1956 and 1962; they approved a fluoridation measure in 1978, but overturned it in 1980.

Supporters launched a swift, quiet strike last fall, getting then-Commissioner Randy Leonard and other City Council members to approve a plan for a fluoride plant. The fluoridation facility would cost $5 million to build, and $500,000 annually to operate. So far, the Water Bureau has spent $152,657 on plans for the facility.

Opponents of fluoridation—who say the dangers of adding the chemical to drinking water outweigh any health benefits—collected more than 33,000 valid signatures to put the question on the 2014 general election ballot. The council instead referred the issue to voters this spring.

But backers of Measure 26-151 say there is no meaningful evidence that fluoridated water poses health risks. Many Healthy Kids, Healthy Portland coalition members say fluoridation opponents don’t understand the inequities that Portland’s underserved communities face in accessing dental care.

“The anti-fluoridation people have access to fluoride; one of the most common arguments I’ve heard is, ‘Why don’t you just take your child to the dentist?’” says Nichole Mahar, president of Northwest Health Foundation. “It shows, I think, a basic misunderstanding of what low-income people are going through.”

Opponents point to studies that say too much fluoride can lead to fluorosis, which creates spotting on the teeth, and that young children and infants are at risk, especially if they consume infant formula and other foods mixed with too much fluoridated water.

“Fluoridation is not the silver bullet that will fix everything,” Kaminski says. “Putting a toxic waste byproduct into our drinking water and calling it good is an insult, I think, to families and poor kids who are suffering the effects of lack of access to dental care.”

Frances Quaempts-Miller, one of the chief petitioners of the anti-fluoride referendum, says Clean Water Portland has found plenty of opposition to the city’s plan, but many organizations who support it don’t necessarily reflect the views of people they represent.

“Many members within Portland’s communities of color that I have spoken with were never asked about their feelings regarding water fluoridation,” Quaempts-Miller wrote in an email to WW. “Minority leaders and community members don’t necessarily agree on this issue.”