The decision to remove fluoride from Hamilton's water supply has divided opinion, with dental experts describing it as "disappointing".
Hamilton City Council voted seven-to-one to remove the chemical yesterday, joining a growing number of communities choosing to reduce or eliminate fluoridation.
While anti-fluoride campaigners have applauded the decision, dentists worry children and the less fortunate will suffer.
"It's a disappointing decision for public health in New Zealand," said Dr Julia Peters from the College of Public Medicine.
"Fluoridation of community water supplies is safe, it's effective, it's economic, and everybody's oral health benefits," she said.
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Fluoride is already in the water and in the food we eat, said Dr Peters, and the Government-recommended doses of fluoride simply top up the levels to be sufficient to have health benefits.
It strengthens tooth enamel and prevents tooth decay, she said.
"In combination with a number of other strategies, it is an extremely powerful tool to improve and protect the oral health of our population."
But Fluoride Action Network spokeswoman Mary Byrne said fluoride was a poison and shouldn't be in public water supply.
"It was a bit different years ago, when fluoridation was introduced, because people thought it was a nutrient, but nowawdays we know there's no bodily requirements for fluoride and it doesn't even reduce dental decay by swallowing it."
Twenty-two of the country's 67 councils sill add fluoride to their drinking water and anti-fluoride campaigners are vowing to continue their battle.
"While there's questions about the safety of fluoridation, its not good enough to continue. They need to stop it, and not reintroduce it at all, until they can guarantee safety for everyone," Byrne said.
"It's just adding a chemical, a toxic substance, to people's drinking water without their consent."
Hamilton City Council made its decision to remove fluoride based on what it heard during submissions, Dental Association board member John Boyens said, but he didn't agree with it.
Young people and those with less money would be hit by the decision, he said.
"I think the people who don't have a choice in the matter, which are the children whose teeth are forming, they are the ones who in the long term will suffer."
Dr Peters agreed. "The people who have the worst diets who can least afford to go to the dentist... they will suffer the most... particularly children."
Fluoride will be removed from Hamilton's water supply by June 21.