Fluoride in water cuts tooth decay in adults

A recent study has produced the strongest evidence yet that fluoride in drinking water provides dental health benefits to adults – even those who had not received fluoridated drinking water as children.

The study – carried out by researchers at the University of North Carolina at Chapel Hill and the University of Adelaide, Australia – shows that fluoridated drinking water prevents tooth decay for all adults regardless of age.

Led by UNC School of Dentistry faculty member Gary Slade, the study adds a new dimension to evidence regarding dental health benefits of fluoridation.

Gary Slade, who is director of the oral epidemiology PhD programme at UNC, said: ‘It was once thought that fluoridated drinking water only benefited children who consumed it from birth. Now we show that fluoridated water reduces tooth decay in adults, even if they start drinking it after childhood. In public health terms, it means that more people benefit from water fluoridation than previously thought.’

The researchers analysed national survey data from 3,779 adults aged 15 and older selected at random from the Australian population between 2004 and 2006. Survey examiners measured levels of decay and study participants reported where they lived since 1964. The residential histories of study participants were matched to information about fluoride levels in community water supplies. The researchers then determined the percentage of each participant's lifetime in which the public water supply was fluoridated.

The results, published online in the Journal of Dental Research, show that adults who spent more than 75% of their lifetime living in fluoridated communities had significantly less tooth decay (up to 30% less) when compared to adults who had lived less that 25% of their lifetime in such communities.

Kaye Roberts-Thomson, a co-author of the study, said: ‘At this time, when several Australian cities are considering fluoridation, we should point out that the evidence is stacked in favour of long-term exposure to fluoride in drinking water. It really does have a significant dental health benefit.’

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