A new study has found that the protective shield fluoride forms on teeth is up to 100 times thinner than previously believed, raising the question about whether it actually works.
Fluoride changes the main mineral in tooth enamel, hydroxyapatite, into a more decay resistant material called fluorapatite, but the new research found that this fluorapatite layer is only 6 nanometers thick, meaning it would take10,000 such layers to span the width of a human hair, which has scientists questioning whether a layer so thin, which is quickly worn away by ordinary chewing, can really can protect teeth from decay at all?
Frank Muller et al., Elemental Depth Profiling of Fluoridated Hydroxyapatite: Saving Your Dentition by the Skin of Your Teeth? Langmuir, 2010; 26 (24).
Another new study shows that exposure to fluoride in drinking water lowers children's intelligence. About 28 percent of the children in the low-fluoride area scored as bright, normal or higher intelligence compared to only 8 percent in the 'high' fluoride area ... in the high-fluoride city, 15 percent had scores indicating mental retardation compared with only 6 percent in the low-fluoride city.
San-Xiang Wang et al., Arsenic and Fluoride Exposure in Drinking Water: Children’s IQ and Growth in Shanyin County, Shanxi Province, China Institute for Prevention and Treatment of Endemic Disease, Linfen, Shanxi Province, People’s Republic of China.