Fluoridation Directives provide no evidence of effectiveness

In July 2022 the then Director-General of Health (DGH), Ashley Bloomfield, sent 14 councils a directive to start fluoridation at one or more of their water supplies.

The DGH is allowed to do this under the Amendment to the Health Act 2021 which gives the DGH the ability to direct councils to fluoridate or not to fluoridate. In making a decision to direct councils to fluoride the DHG must:

1. Provide evidence of the effectiveness of fluoridation.

2. Have determined the benefits outweigh the financial costs.

3. Confer with the Director General of Public Health. 

To meet these requirements the then DGH, Ashley Bloomfield, said he relied on the following data to come to the decision that fluoridation was effective:

1. The Cochrane Collaboration 2015 Review of Water Fluoridation 

2. The NZ 2009 Oral Health Survey

3. The New Zealand Community Dental Health Statistics. 

An examination of these three pieces of data show that the only conclusion that can be drawn is that there is no evidence that fluoridation is effective.

1. The Cochrane Collaboration said in its conclusion “The available data …indicate that water fluoridation is effective at reducing caries levels in both deciduous and permanent dentition in children”. However, this statement is then negated by the following caveats that they give:

• No evidence that cessation of fluoridation led to an increase in dental decay rates
• No evidence that fluoridation reduced inequalities between rich and poor
• No evidence that fluoridation benefited adults
• 97% of the studies they examined were biased
• An estimate that 40% of people will have dental fluorosis when water is fluoridated at 0.7ppm
• An estimate that 12% of people will have dental fluorosis that could cause concern over appearance when water is fluoridated at 0.7ppm

3. The New Zealand Community Dental Health Statistics is the data collected by all the school dental clinics of each child and how many decayed, filled or missing teeth they have. The MoH provide this data on their website collated into each DHB area, age and fluoridation status. Plotting the data since 2001 up to 2021 (last complete set) shows there is no major difference between fluoridated and non-fluoridated areas.