On top of that, millions of Americans rely on water supplies with what federal agencies consider more than the optimal level of the chemical.
The more severe forms of skeletal fluorosis typically are associated with long-term exposure to particularly high levels of fluoride.
The Centers for Disease Control and Prevention and its parent agency, Health and Human Services, consider fluoride concentrations in water of 0.7 parts per million, or ppm, the sweet spot – a level high enough to prevent tooth decay but low enough to avoid mild dental fluorosis or more serious problems.
CDC officials estimate that nearly 900,000 Americans receive drinking water with fluoride above 2 ppm, which they say is high enough to erode tooth enamel.
A critical National Research Council report in 2006 called for reducing that limit, saying it raises the risk of problems such as bone fractures.
“Unfortunately, it’s a very politicized issue.” For its part, the American Dental Association downplays the consequences of high fluoride concentrations in some drinking water systems.
Even so, some utilities continue to fluoridate water to above the 0.7 ppm level.
What’s more, Trader says her teeth are very fragile.
The 2006 report by the National Research Council found that 10 percent of children drinking water fluoridated to around 4 ppm suffer severe dental fluorosis.
Bottled water isn’t necessarily any better than public water supplies.