As reported on NPR, the Department of Health and Human Services (HHS) recently changed its recommendation for the amount of fluoride in community water systems. The new recommendation is 0.7 milligrams of fluoride per liter of water. The previous recommendation, adopted in 1962, ranged from 0.7 to 1.2 milligrams, based on outdoor air temperature of geographic areas.
The new recommendation notes that “the optimal concentration of fluoride in drinking water is the concentration that provides the best balance of protection from dental caries while limiting the risk of dental fluorosis.” Dental fluorosis is a cosmetic condition characterized by changes in the appearance of tooth enamel caused by excessive fluoride intake.
The HHS recommendation is advisory only. The department first proposed the new level in 2011, but did not finalize that recommendation until April.
As noted by NPR, fluoridation opponents argue that the new standard doesn't go far enough, and should be lowered further to avoid possible health risks due to excessive fluoride. By contrast, the article notes that the American Dental Association supports the new recommendation.