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Investigating effects of water fluoridation on children’s dental health

Published: 18 November 2022

Adding fluoride to water supplies may deliver a modest benefit to children’s dental health, finds an NIHR-funded study.

But, the benefits are smaller than shown in previous studies - carried out 50 years ago - when fluoride toothpaste was less available in the UK.

Researchers found it is likely to be a cost effective way to lower the annual £1.7billion the NHS spends on dental caries.

Researchers at the Universities of Manchester and Cambridge led the CATFISH study. The results published in the journal Public Health Research.

It is the first contemporary study of the effects of initiating a water fluoridation scheme in the UK since the widespread use of fluoride toothpaste in the 1970s.

Researchers assessed the dental health of almost 3,000 children in Cumbria for six years.

They studied a younger group from West Cumbria, born after authorities reintroduced fluoridation in 2013. This meant they had the full effect of fluoride.

A second cohort of older children, aged five at the time fluoride was added, were studied too. They mainly received effects for teeth already in their mouths.

The results were compared to the rest of Cumbria, which remains fluoride free.

Experts found 17.4% of the children in fluoridated areas had decayed, filled or missing milk teeth. This compared to 21.4% for children in non-fluoridated areas. This amounted to a modest 4% reduction in incidence of caries.

Meanwhile, 19.1% of the older cohort in fluoridated areas had decayed, filled or missing permanent teeth. The number was 21.9% in non-fluoridated areas.

There was insufficient evidence as to whether water fluoridation prevents decay in older children with a difference of 2.8%.

Over the last 40 years the proportion of children affected by decay has fallen dramatically. But because tooth decay still falls disproportionately on more disadvantaged groups.

Professor Mike Kelly, senior member of the research team from The University of Cambridge, said: “Health inequalities are a feature of all societies, including the UK. The poor dental health of children from the most disadvantaged communities and the excess number of children having general anaesthetics each year still needs to be addressed. We need to continually look at measures which can help prevent the unnecessary burden of pain and suffering."

Dr Michaela Goodwin, a senior investigator on the project from the University of Manchester, said: “While water fluoridation remains cost effective and has demonstrated an improvement in oral health it should be carefully considered along with other options, particularly as the disease becomes concentrated in particular groups.

“Tooth decay is a non-trivial disease which is why measures to tackle it are so important. The extraction of children’s teeth under general anaesthetic is risky to the child and is the most common reason for children between the ages of five and nine to have a general anaesthetic.

“Decayed teeth are painful and can impact on sleep patterns, learning, attention and many aspects of general health.

“But more questions remain and we hope to follow up on these children in the long term.”

Study collaborators included experts from Kings College London, Salford Royal Foundation Trust and Cumbria Community Dental Service team.

NIHR’s Public Health Research (PHR) Programme funded the study.

Read more on the CATFISH study’s project page.

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