U.S. has lowered the recommended fluoride levels in drinking water. The optimal fluoride level in drinking water to prevent tooth decay should be 0.7 milligrams of fluoride per liter of water.

These new levels fall at the bottom of the previously recommended fluoridation range of 0.7 to 1.2 milligrams per liter, which was issued in 1962.

Americans today have access to more sources of fluoride including toothpaste and mouth rinses then they did when municipal officials first began adding the mineral to water supplies across the U.S.

According to the U.S. Centers for Disease Control and Prevention, more people are exposed to too much fluoride and are suffering from fluorosis, which are white stains in the enamel of their teeth caused by too much fluoride. It can take on the appearance of scattered white flecks, frosty edges or lacy chalk-like lines on teeth. In extreme cases the surface of teeth become rough and pitted.

Federal health officials say the new recommended levels of 0.7 milligrams of fluoride per liter of water will maintain the protective benefits of water fluoridation and reduce the occurrence of dental fluorosis.