Hawaii’s children have the most pervasive tooth decay in the nation.

Particularly hard hit are low-income families, whose children need urgent dental care at a rate five times higher than that for higher-income peers, according to a first-of-its-kind survey through which Hawaii’s Department of Health compared data with other states.

Among the fix-it strategies in the “Hawaii Smiles 2015” report: expand community-based prevention programs, step up screening and referral services and, advocate for restorative dental care. Such efforts can make a big difference, no doubt. But compared to improvements that would come with adding fluoride to drinking water, they’re little more than a drop in the bucket.

“If we put the fluoride in the water, we’d see a 50 percent reduction in decay” within about 10 years, said Dr. Steve Wilhite, president of the Hawaii Dental Association. “This is preventable,” he said, referring to the survey’s finding that more than 7 out of 10 third-graders (71 percent) here are affected by tooth decay. The national average is 52 percent.

Hawaii ranks 50th among states for population percentage on fluoridated public water systems (11.7 percent), with the treated water used only on military properties in the state. Nationwide, nearly three-quarters of the overall population gets fluoridated tap water, according to the U.S. Centers for Disease Control and Prevention.

So, what’s stopping the Aloha State from funneling the cavity-fighting chemical into its community water systems? Well, it goes beyond just dental health.

“Many people like pure things, without chemicals,” said Honolulu City Councilmember Ann Kobayashi, who voted in favor of a measure that banned fluoridated water from Oahu’s public system. The first paragraph of the ordinance passed in 2004 states: “Drinking water should not be used as a means for delivery of chemicals for medical or dental purposes when other alternatives are available.”

Kobayashi said she hasn’t changed her mind over the past 12 years. “We shouldn’t force people, because you can always add it — get fluoride drops and add it to your drinking water.”

On the flip side of that take, state Sen. Karl Rhoads said, “I think the default should be the other way around. … I just feel that the tap water should be fluoridated. If you don’t want to drink it, buy bottled water that’s not fluoridated.”

Rhoads, who has served as a legislator for the past decade, has introduced bills seeking statewide fluoridation, but none has secured even a hearing. “You have a passionate minority that thinks this is the end of the world,” he said.

The mineral fluoride occurs naturally in water, but usually its level in groundwater is not enough to prevent tooth decay.

In 1945, Grand Rapids, Mich., was the first city to add fluoride to its water system. Community water fluoridation, according to the CDC, is the process of testing the water supply for fluoride and adjusting it to the right amount to prevent cavities. Over the past seven decades, hundreds of cities have started community water fluoridation.

Citing its contribution to a large drop in cavities over the decades, the CDC named community water fluoridation as one of the “10 great public health achievements of the 20th century,” alongside vaccination, motor vehicle safety and control of infectious diseases, among other feats.

Some critics of fluoridation, however, contend that the tasteless, odorless chemical has killed houseplants and koi in backyard ponds and caused serious health ailments. Proponents maintain there’s scant evidence to back up most claims.

Rhoads said there are likely rare cases of chemical sensitivity, akin to a bad reaction to vaccination, but overall health benefits to the population outweigh small risks. “The scientific evidence is overwhelming. It’s a cost-effective, safe way to prevent an illness for lots of people.”

In addition, he said, it saves money. According to the American Dental Association, Rhoads said, the average lifetime cost per person to fluoridate a water supply is less than the cost of one dental filling. For most cities, every $1 invested in water fluoridation saves $38 in dental treatment costs.

But some water systems, such as Honolulu’s Board of Water Supply, express concern about costs.

In January 2015, BWS officials estimated an initial capital investment of $15 million to fluoridate Honolulu’s water system, with a $2.7 million annual operating cost. The city agency would have to install equipment across the island at more than 190 facilities to add fluoride to the drinking water. Also, BWS officials would have to continually monitor fluoride levels as an inadvertent over-dosage of the chemical could cause mottling of the teeth.

Sen. Rosalyn Baker, chairwoman of the Commerce, Consumer Protection and Health Committee, who has listened to both supporters and typically more vociferous opponents at the state Capitol, does not expect to see a fluoridation law taking shape any time soon.

“My sense is that unless there’s clear and and convincing evidence that there’s no other way to achieve good oral health,” other than by fluoridating water, “it’s not going to happen,” Baker said.

During a news conference last month to announce the Hawaii Smiles survey’s findings, state Health Department officials and others said they don’t anticipate lobbying for fluoridation after having had many proposals defeated over the years.

Matthew Shim, DOH’s Acting Family Health Services Division Chief, echoed that sentiment last week.

“We believe fluoridation must ultimately be a community-based decision,” Shim said. “The Hawaii Department of Health has introduced the idea of fluoridation for a limited geographical area in the past, but this met strong community opposition.”

No plans are in the works to push for fluoridation “in the near future because of the tremendous amount of time and energy required to promote such an initiative,” he said. Instead, “We are pursuing other ways to address the immediate oral health needs of Hawaii’s children.”

For example, the DOH will continue forging public-private partnerships such as a pilot teledentistry project called the Virtual Dental Home, which is underway on Hawaii island. It aims to provide greater access to dental care for children who live in rural areas of West Hawaii — without having to physically go to a dentist office.

The project is a partnership that includes DOH, Pacific Center for Special Care, University of Pacific, School of Dentistry, West Hawaii Community Health Center and Hawaii Dental Service.

Baker (D, West Maui-South Maui) supports the strategy. She also backs its scope as detailed in the Hawaii Smiles report, which directs dental and medical caregivers to zoom in on disease prevention efforts for families with children younger than 2 years old. “So many people apparently don’t understand that it’s not OK to let the baby teeth decay and fall out,” she said, adding that adult teeth surfacing in an infected mouth are susceptible to dental troubles.

The Hawaii Smiles survey obtained a baseline assessment of the oral health of the state’s children. It screened a total of 3,184 third-graders in 67 public elementary schools on six islands during the 2014-15 school year. Third-grade children were selected because the CDC and national organizations recommend states conduct third-grade surveillance as part of the National Oral Health Surveillance System, which is conducted by each state.

The study was funded by the CDC and the U.S. Department of Health and Human Services, with additional local funding from the HDS and the Kaiser foundations.

Among the survey’s other findings: almost 1 out of four third-graders (22 percent) has untreated tooth decay; while the need for urgent dental care was 13 percent among children from low-income families it was 2 percent for higher-income peers; and more than 60 percent of children in Hawaii do not have protective dental sealant on molars.

“What we want to do is shine a light on the need for better oral health”and strengthen the “link between good oral health and good general health,” Baker said. “We think there are possibilities for changing behavior and changing attitudes.”

Still, eyeing possibilities for changing state law, Rhoads said he will probably introduce another fluoridation bill during the Legislature’s 2017 session.

“A lot of people think we’re drinking water straight from the aquifer or lava rock, and that’s not true,” he said, pointing out that all four of the state’s counties add chlorine to drinking water to kill bacteria and viruses.

Chlorination and fluoridation are similar processes. “I think if people realize just how closely these two chemicals are (related in properties) … and that we’ve been drinking the one” with virtually “no ill effect,” he said, “maybe it wouldn’t be such a jump.”

Rhoads, who is moving from his seat in the House (D, Chinatown-Iwilei-Kalihi) after winning election to the Senate (D, Downtown-Nuuanu-Liliha) this month, said: “I may be getting off on the wrong foot politically but … the evidence is just so overwhelming.” He added, “For me it’s a social justice issue, too. It’s the poor kids who don’t have the good dental care.”