Fluoride And Cavities

I read Joe Shields's letter suggesting that socioeconomic status might affect dental health and be a statistical factor that could be a confounding variable with regard to the preventative effects of fluoride in potable water on dental caries (C&EN, Dec. 7, 2009, page 5).

A study that eliminated socioeconomic factors was performed in England back in the 1970s. In this study, 386 15-year-old children from West Hartlepool were examined by a dentist under standardized conditions, and the DMF (decayed, missing, or filled) scores were recorded. The same dentist also examined 381 15-year-olds in York and recorded the DMF scores. The children from the two cities were of the same age, had comparable socioeconomic backgrounds and the same general health status; the only difference was that the drinking water in West Hartlepool was naturally fluoridated, containing 1.5–2.0-ppm fluoride, whereas York water contained only 0.15–0.25-ppm fluoride.

There was a marked and statistically significant difference in DMF scores: Children in fluoridated West Hartlepool had a DMF score of 5.0 ± 3.1, whereas those in nonfluoridated York had a DMF score of 9.0 ± 3.9 (p < 0.001). In other words, the difference in decay rates was wholly attributable to the presence of fluoride in drinking water, a finding that was not confounded by socioeconomic factors.

J. A. von Fraunhofer
Baltimore