Possibly it was inspired by having executed a similar strategy when it sacked the Canterbury Regional Council in 2010 and installed a commissioner to ensure environmental concerns did not prevent dairy giants greening the blasted plains by sucking the braided rivers dry.
Fluoridation is official Ministry of Health policy and DHBs are stacked with government appointees so any elected DHB member wishing to represent constituents by preventing water fluoridation would need to be either extraordinarily persuasive or possessed of a superior grasp of standing orders. Even then they're doomed because there is a provision for appointed Crown monitors to step in should any deviation from the party line prevail.
So much for democracy; and thus the outlook is equally grim for urban water supplies.
Fluoridation of public water supplies became official US policy in 1951 after research into a local population with notably mottled teeth but few cavities indicated higher levels of naturally occurring fluoride in their environment.
Fluoride is thought to operate in the mouth by creating low levels in saliva, which reduces the demineralisation of tooth enamel and increases remineralisation in the early stages of tooth decay in children. Efficacy in adults is less clear. Alleged benefits are solely from topical application in the mouth.
Studies indicate reduction in tooth decay in populations where fluoridation has been introduced. However, studies also show substantial declines in tooth decay in places where public water supplies are not dosed with fluoride.
Some attribute the latter to topical use of fluoridated toothpaste although changes in brutal invasive dental treatment regimes since the 1950s - when children's teeth were drilled and filled mercilessly and extractions and dentures were common rites of passage for adults - could well play a part.
Incredibly, no randomised controlled trials of long-term side effects of public water fluoridation on general population health appear to exist.
However, independent scientists have conducted many studies which indicate swallowing and ingesting fluoride may be linked with dental and skeletal fluorosis, developmental neurotoxicity affecting learning and behaviour, Alzheimer's disease, thyroid dysfunction, arthritis, hip fractures, low IQ, impaired visual/spatial organisation, infertility and bone cancer.
Consequently, many countries have voted to cease fluoridation.
While any doubt over the safety of fluoridation exists, it seems extremely unwise to override inconvenient democracy to impose non-targeted, untested mass medical treatment in uncontrolled doses on general populations.
Better to err on the side of caution.
DHBs had better watch their backs, too.
Recent history is strewn with substances once considered perfectly safe by confident experts - for example, thalidomide, asbestos, 245T, lead and tobacco - and with their downstream suffering and ongoing costly legal proceedings.
