The mood is sombre around the horseshoe-shaped table at the centre of the South Taranaki District council chambers. Their decision-making is under scrutiny by concerned locals just a couple of metres away in the public gallery.
Queen Elizabeth II, Prince Philip and Maori King Tuheitia Paki gaze down sternly from the white walls.
It has been two hours since the council began deliberating on the emotive question of whether fluoride should be added to water supplies in the small towns of Waverley and Patea.
Already, some residents have stormed out with disappointment at what they are hearing.
More than 508 people and organisations in the South Taranaki district have filed submissions, 68 per cent of them opposing the introduction of fluoride.
Over five weeks, decision-makers have read submissions, attended information evenings and listened to experts on both sides of the argument. The 12 councillors and the Mayor are not health experts. But it is up to them to decide what chemicals are put in the region's water supply. And their decision to disregard the weight of public submissions, and add fluoride to their district's water supply, will see them taken to court.
The question of whether to fluoridate public water supplies, seemingly settled by science and the demands of health in the 1980s, is once more an open question.
This month, advocacy group New Health New Zealand lodged an application in the High Court at New Plymouth for a judicial review of the council's decision.
The society says it seeks to protect the "best interests and health freedoms of consumers". Director David Sloan argues everyone has the right to refuse to undergo medical treatment under the NZ Bill of Rights Act. He also argues councils have not had the authority to fluoridate water supplies since the Local Government Act 2002 was enacted.
South Taranaki District Council chief executive Craig Stevenson says the case could set a precedent for all councils in New Zealand that fluoridate water supplies.
Fluoride is a natural element in our water that helps strengthen teeth and prevent decay - but the levels at which it naturally occurs are not enough to fully protect people's teeth. In 1954, New Zealand became the second country in the world to introduce fluoride to some of its water supplies.
Hastings was the first region to copy the Americans, who discovered a lack of fluoridation contributed to higher rates of tooth decay.
A Commission of Inquiry was held in 1957, and by 1968 fluoridated water reached 65 per cent of the population.
More than 84 municipal water supplies are now topped up with manufactured fluoride called hydrofluorosilicic acid, sodium fluoride or silicofluoride. About 52 per cent of New Zealanders currently have access to fluoridated water through council supplies and food.
The New Zealand Drinking-Water Standards recommend optimum fluoride levels of 0.7 to one part per million in tap water.
Fluoride is also added to toothpaste at a much higher level of 1000 parts per million. However, this is used only as a topical solution and can be harmful when swallowed.
Over the past 60 years, scientific studies argued about the health effects of fluoridated water. The debate has been a factor in convincing some councils, including Waipukurau and Northland, to stop adding fluoride. Others, like the towns of Waverley and Patea in South Taranaki, have been persuaded to introduce fluoride.
Advocates say adding fluoride to the water is a safe and cost-effective way to reduce tooth decay, particularly in low socio-economic groups.
Opponents claim it is a poison that triggers adverse health effects, not to mention a gross breach of individual rights. Those opponents have been derided as paranoid, tinfoil hat-wearers in the past - but now they're back with a glint in their eyes.
Local government elections loom in October, and several councils are considering whether to continue fluoridating their water.
Whakatane and Hastings will hold referendums with their elections. Hamilton City Council is revisiting the issue, despite spending $100,000 on a binding referendum five years ago. That referendum reported 70 per cent support for fluoridation, but the 30 per cent who opposed it have dug in their heels. Their 177 post-referendum submissions have forced a tribunal hearing.
Further north, the Thames-Coromandel District Council recently voted to retain fluoride in water.
However, the community board has been researching the possibility of allowing residents to "opt out" of fluoride. This would involve installing $800 water tanks, at the ratepayer's expense, for each family that does not want fluoridated water.
Almost $200 million was spent on dental treatment and education last year - 6 per cent higher than in the previous year.
The Ministry of Health says most dental treatments were related to tooth decay, particularly in areas that didn't have fluoridated water.
In 2009, Sathananthan Kanagaratnam, the clinical director of Auckland Regional Dental Health, researched the teeth of 612 9-year-old children.
The children all lived in Auckland: 310 had access to fluoridated water; 302 did not.
His research, published in the New Zealand Dental Journal, found those living in non-fluoridated areas had more tooth decay and enamel defects. However, those living in fluoridated areas had more dental fluorosis - a condition that causes white flecks on the teeth.
Kanagaratnam says the high level of fluoride in toothpaste can also cause dental fluorosis if children do not spit it out. He says dental fluorosis is nothing more than an aesthetic issue, but tooth decay can be painful and lead to other issues including low self-esteem.
"I have seen people with severe decay who can't eat, can't sleep. I have seen some pre-schoolers who have suffered so much it affected general health. They don't grow, they can't pronounce words if their teeth are affected, they cover faces when talking to people. It's a bad effect."
The outcome may seem surprising when only a tiny amount of ingested fluoride - 0.016 parts per million - is released on to the teeth through saliva.
If the amount secreted on to our teeth is so low, why bother spending taxpayers' money to put it in our water?
Kanagaratnam admits fluoride works best when applied topically. However, fluoride in water washes over the teeth, working as a topical solution to the teeth and roots: "When we drink or cook with fluoridated water it is in contact with the tooth and that is first defence against decay. Water fluoridation has added effects and additional benefits."
But Dr Bruce Spittal, psychiatrist and author of Fluoride Fatigue, claims the adverse health effects go beyond dental fluorosis. He describes the added fluoride as a poison that affects the organs, brain and skeletal system when ingested.
Spittal's claims are partly backed by a World Health Organisation study that reveals more than a million people have worse health where fluoride levels are high.
In India, more than 4 per cent of adults were reported to suffer from skeletal fluorosis in areas where the fluoride levels were higher than 1.4 parts per million. About 63 per cent suffered where the levels were six parts per million.
Although these levels are much higher than New Zealand's maximum recommended level of one part per million, Spittal questions how we monitor the amount of fluoridated water being ingested.
World Health Organisation research states: "Fluoride toxicity is dependent on a number of factors, including the quantity of water consumed and exposure to fluoride through other routes."
"It is bizarre that something toxic is being added to our water," Spittal says. "People can have healthy teeth without exposure to fluoride."
If Spittal is right and the scientific jury is still out on the health risks of fluoridation - and there is major doubt on that claim - the question around individual rights is somewhat clearer.
When are the public health benefits of fluoridation so overwhelming that they justify imposing fluoridation on unwilling individuals?
Founder of Fluoride Action Network Mary Byrne says adding fluoride to drinking water is mass-medicating communities while stripping individuals of their rights.
She claims everyone should have the right to choose what goes into their body. "Councillors would be arrested if they added anything else to someone's drink without their informed consent," Byrne says.
Waikato District Health Board's medical officer of health, Felicity Dumble, says the Government has taken a utilitarian approach to fluoride. That means they have had to weigh the public good against the private right.
Dumble says some people who live in lower socio-economic communities cannot afford toothbrushes, toothpaste and dental care. Without fluoridated water, the health of those people would be severely affected.
"It is an initiative that reduces health inequality because it is accessible to everybody," Dumble says. "If fluoride is taken out of the water there will be a significant additional cost because the dental decay will reappear."
Monique Jonas, an expert in population health at the University of Auckland, says the Government must consider the magnitude of the benefit for individuals and explore alternatives.
But the time comes when individuals recognise they have a responsibility to make sacrifices for the greater good. "We are members of society: we don't just have rights, we have responsibilities," she says. "You have to think about what you sacrifice for the good of everybody."
That will, no doubt, form part of the statement of defence that is being prepared by South Taranaki District Council's lawyers, from big-city legal firm Simpson Grierson.
Council boss Stevenson says fluoridation is a national debate and so the nation should help fund the case, expected to cost the council as much as $200,000.
He has already requested support from the Ministry of Health, district health boards, the Dental Association and Water New Zealand.
"This is an issue for the country and arguably an international issue, so it will be good to get a definitive ruling from the courts."