Somehow, the fluoride debate keeps getting uglier.

Opponents of the push to fluoridate Portland's water supply are suggesting the Oregon Health Authority might have colluded with pro-fluoride groups to withhold results of a 2012 survey of students' dental health. In a news release today, anti-fluoride political action committee Clean Water Portland announced it's called on the OHA to answer whether or not it purposefully witheld figures—obtained by several news organizations—that show cavities are down in Oregon.

Results of the 2012 "Smile Survey" had been expected earlier this year, but the OHA recently indicated they might not be available until after the election. It released a draft of the report following a series of records requests.

The delay "has raised questions about OHA’s motivations in withholding the cavity data and whether fluoridation proponents have known about this data," Clean Water Portland said in today's release.

The survey shows 52 percent of Oregon children between the ages of 6 and 9 experienced cavities. That's down from 64 percent in the 2007 survey and 57 percent in 2002. Untreated cavities are down, too. So is "rampant decay," defined as when "a child has 7 or more teeth with treated or untreated cavities or tooth decay in the primary or permanent teeth."

It's not just a statewide trend. In unfluoridated Multnomah County, the survey found kids who'd experienced cavities (51 percent) and kids who had untreated cavities (21 percent) were both down.

From the Clean Water Portland release:

Clean Water Portland posed the following two questions to the OHA and asked for an immediate response: 1) Was the delayed release of the 2012 Smile Survey in any way related to influencing the water fluoridation ballot measure in Portland? 2) Did OHA share the results of the survey data with fluoridation promoters before releasing it to the media or public? If OHA’s answer to these questions is “no” it should be quick and clear. Clean Water Portland also filed an Oregon Public Records Act request with the OHA seeking emails, phone records and other public records from the OHA related to the Smile Survey results.

The new Smile Survey also highlighted the familiar disparities often cited in this debate. Decay is most-prevalent in rural areas, and among minority children and children in low-income families, the report found. Black and Asian students actually saw an increase in cavities. So did kids who don't speak English at home.

"Decay rates for Black/African American, Hispanic/Latino and Asian children have remained higher than those for White children and have not improved as much since 2007," the document says.

The new numbers will probably be trumpeted by fluoride opponents and proponents alike in the run up to May 21, when voters will decide Measure 26-151. While opponents say the report is evidence the state doesn't have the dental health crisis advocates claim, the OHA says the numbers are still far too high, and that fluoride would help.

By the way, if you plan on voting in the May election but aren't yet registered, today's your last chance.

UPDATE, 1:50 p.m.: A representative from pro-fluoride political action committee Healthy Kids, Healthy Portland says the group had no idea what the 2012 numbers were until their release.

The campaign also sent along an official response to the numbers. It quoted Mel Rader, a co-director of Upstream Public Health, a pro-fluoride lobbying group: "These latest statistics reinforce the need for community water fluoridation. Multnomah County is doing a lot worse in every measure of dental health than both Seattle and the nation as a whole. We can and should be doing a lot better. Water fluoridation is a proven solution that can substantially decrease the pain and suffering of Portland’s kids.”