Hamilton residents have voted for fluoride to be returned to their water supply.
Newly released Hamilton City Council community referendum results show 23,000 people voted in favour of water fluoridation, and 10,000 voted against.
The overwhelming support did not surprise the Waikato District Health Board (DHB), which cited a previous fluoridation referendum in 2006 that returned similar results.
"The positive result is absolutely what we would have expected being that the decision to remove fluoride was lobbied by an active minority rather than the average ratepayer going about their business," Waikato DHB chief executive Craig Climo said.
The referendum result did not include votes from ratepayers in the south and west of the Waikato District, who also receive water from Hamilton City Council.
However, a Waikato District Council survey conducted in the area found 2500 residents also supported having fluoride in their water.
Mr Climo said a Hamilton City Council tribunal earlier this year on water fluoridation was disappointing, with councillors voting 7-1 to remove fluoride.
The issue should never had come to tribunal in the first place, he said.
Waikato DHB spent $47,000 on its pro-fluoride campaign, $8000 of which went towards billboards and banners, Mr Climo said.
Four councillors who were also on the Waikato DHB did not participate in the tribunal vote.
Waikato DHB medical officer of health Dr Felicity Dumble urged the local council to learn from the results.
Ultimately, the results and those from 2006 should be used as an "example as to why it's not a good idea to use tribunals which grossly overrepresent the position of small interest groups, when it comes to making public health decisions for the whole city," she said.
Water fluoridation was particularly important for the protection of the teeth of low socio-economic New Zealanders, she said.
The Waikato DHB would be supporting any other communities which had fluoride removed from the water, such as Taumarunui and Morrinsville.
Mr Climo said those communities should raise the issue with their local councillors.