The dental health benefits of adding fluoride to drinking water may be smaller now than before fluoride toothpaste was widely available, an updated Cochrane review has found.
The team of researchers from the Universities of Manchester, Dundee and Aberdeen reviewed the evidence from 157 studies which compared communities that had fluoride added to their water supplies with communities that had no additional fluoride in their water. The research is published in the Cochrane Database of Systematic Reviews.
They found that the benefit of fluoridation has declined since the 1970s, when fluoride toothpaste became more widely available.
The contemporary studies were conducted in high-income countries. The impact of community water fluoridation in low- and middle-income countries is less clear, due to the absence of recent research.
Results from studies conducted after 1975 suggest that the initiation of water fluoridation schemes may have led to slightly less tooth decay in children’s baby teeth. Analysis of these studies, covering a total of 2908 children in the UK and Australia, estimate that fluoridation may have led to an average of 0.24 fewer decayed baby teeth per child.
However, the estimate of effect comes with uncertainty, meaning it’s possible that the more recent schemes have no benefit. By comparison, an analysis of studies with 5708 children conducted in 1975 or earlier estimate that fluoridation reduced the number of decayed baby teeth, on average by 2.1 per child.
The same contemporary studies (conducted after 1975) also looked at the number of children with no decay in their baby teeth. The analysis found that fluoridation may have increased the number of children with no tooth decay by three percentage points, again with the possibility of no benefit.
The review was only able to draw conclusions about the impact on children’s teeth, with similar findings across both baby and permanent teeth. There were no studies with adults that met the review’s criteria.
“The evidence suggests that water fluoridation may slightly reduce tooth decay in children,” co-author Dr Lucy O’Malley said.
“Given that the benefit has reduced over time, before introducing a new fluoridation scheme, careful thought needs to be given to costs, acceptability, feasibility and ongoing monitoring.”
Advocates have suggested that one of the key benefits of water fluoridation is that it reduces oral health inequalities. This updated review sought to examine this question and did not find enough evidence to support this claim, although this doesn’t necessarily mean there is no effect.
Original article online at: https://www.bitemagazine.com.au/water-fluoridation-found-to-be-less-effective-now-than-in-past/