The dental health benefits of adding fluoride to drinking water may now be smaller than before fluoride toothpaste was widely available, a study suggests.
Researchers from the Universities of Manchester, Dundee and Aberdeen reviewed evidence from 157 studies comparing communities that had fluoride added to their water supply with communities that had no additional fluoride in their water.
Found the review that the benefit of fluoridation had diminished since the 1970s, when fluoride toothpaste became more widely available.
Fluoride is known to reduce tooth decay. The addition of low levels of fluoride to drinking water has long been considered one of the greatest public health achievements of the last century.
“When interpreting the evidence, it is important to think about the wider context and how society and health have changed over time,” says Anne-Marie Glenny, professor of health sciences research at the University of Manchester and co-author of the book. judgement.
“Most studies on water fluoridation are more than 50 years old, before the availability of fluoride toothpaste. Contemporary studies give us a more relevant picture of what the benefits are now.”
Results from studies conducted after 1975 suggest that water fluoridation programs may lead to slightly less tooth decay in children’s baby teeth.
Analysis of these studies, which involved a total of 2,908 children in Britain and Australia, estimates that fluoridation can lead to an average of 0.24 fewer rotten baby teeth per child. However, the estimate introduces uncertainty, meaning more recent schemes may not provide a benefit, the researchers said.
By comparison, an analysis of studies of 5,708 children from 1975 or earlier estimated that fluoridation reduced the number of decayed baby teeth by an average of 2.1 per child.
The Cochrane Review could only draw conclusions about the impact on children’s teeth, with similar findings in primary and permanent teeth. There were no studies in adults that met the review’s criteria.
“The evidence suggests that water fluoridation can somewhat reduce tooth decay in children,” said another co-author, Dr Lucy O’Malley, senior lecturer in healthcare research at the University of Manchester.
“Given that the benefit has diminished over time, before introducing a new fluoridation program, careful consideration should be given to cost, acceptability, feasibility and ongoing monitoring.”
Advocates have suggested that one of the main benefits of water fluoridation is that it reduces oral health disparities. The review attempted to investigate this but did not find enough evidence to support the claim, although the researchers said this did not necessarily mean there was no effect.
“While water fluoridation may lead to small improvements in oral health, it does not address underlying problems such as high sugar consumption and inadequate oral health behaviours,” said Janet Clarkson, co-author and professor of clinical effectiveness at the University of Dundee. . “It is likely that any preventive oral health program will need to take a multi-faceted, multi-agency approach.”
In August, a US government report concluded that fluoride in drinking water at twice the recommended limit was linked to lower IQ in children.
The 324-page report did not reach a conclusion on the risks of lower fluoride levels and said more research was needed. It also didn’t answer what high levels of fluoride can do to adults.