Australasian Science: Australia's authority on science since 1938

Fluoridation Benefits Adults, Too

By Stephen Luntz

Drinking fluoridated water reduces tooth decay, even as an adult, a study by the Australian Research Centre for Population Adult Health has found.

Published in the Journal of Dental Research, the authors considered two cohorts: one born before 1960 and therefore not exposed to fluoridated water as children, and the other born between 1960 and 1990. The 3779 participants were asked the postcodes in which they had lived for more than

6 months, allowing the researchers to calculate the proportion of their lives in which they had drunk fluoridated water.

All those participating in the study had their mouths examined to check for decayed, missing and filled teeth. Comparisons were done for each age cohort between those who had fluoridated water for more than 75% of their life versus less than 25%.

The findings were unambiguous: those exposed to fluoride had markedly less tooth decay, although Prof Kaye Roberts-Thompson says the amount depended on the measure of tooth decay used. “If you count decayed teeth the difference was 10–11%, but if you look at tooth surfaces fluoridation produced a 30% reduction pre-1960 and 21% for those born after. Under the traditional measure you might have one small filling at the back of a tooth and that is counted the same as several fillings on different surfaces.”

Opponents of fluoridation claim the benefits, at least for adults, are due to topical contact of fluoride in water flowing over teeth rather than by ingesting fluoride. However, Roberts-Thompson says the situation is more complex than this. “None of these things are totally systemic or totally topical. If you ingest fluoride you will have some in your saliva and this will have a topical effect.”

Water fluoridation arouses passion as few other subjects do. Asked whether she had hostile feedback Roberts-Thompson merely says: “I’ve had some responses”.