The recommended level of fluoride in U.S. drinking water supplies should be lowered to prevent dental troubles, according to a joint announcement today by officials from the Department of Health and Human Services (HHS) and the Environmental Protection Agency (EPA).

The HHS is recommending that water supplies contain 0.7 milligrams of fluoride per liter of water, replacing the present recommended range of 0.7 to 1.2 milligrams.

That recommendation won't go into effect immediately. It will be published in the Federal Register, followed by a period of comment from the public and others for 30 days.

In other action today, the EPA told it will review the maximum amount of fluoride that will be allowed in drinking water, looking at the most latest research.