Water Fluoridation More Useful in Preventing Tooth Decay Than Thought

A new study shows that the fluoridation of drinking water also improves the dental health of adults that didn't drink fluoridated water as children, which until now was thought a prerequisite.

"It was once thought that fluoridated drinking water only benefited children who consumed it from birth," explains study leader Gary Slade, professor and director of the oral epidemiology PhD program at University of North Carolina at Chapel Hill.

"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."

Basis for the study was national survey data from 3,779 adults aged 15 and older selected at random from the Australian population between 2004 and 2006 that was analyzed by the researchers.

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.

This enabled the researchers to determine the percentage of each participant's lifetime in which the public water supply was fluoridated.

Comparing the dental health of the upper and the lower quartile showed that adults who spent more than 75 percent of their lifetime living in fluoridated communities had significantly less tooth decay (up to 30 percent less) than adults who had lived less that 25 percent of their lifetime in such communities.They published their results online in the Journal of Dental Research,

"At this time, when several Australian cities are considering fluoridation, we should point out that the evidence is stacked in favor of long-term exposure to fluoride in drinking water," says Kaye Roberts-Thomson, a co-author of the study.

"It really does have a significant dental health benefit."