Jan. 7, 2011 --The recommended level of fluoride in U.S. drinking water supplies should be lowered to prevent dental problems, 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 current 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 said it will review the maximum amount of fluoride that will be allowed in drinking water, looking at the most recent research.

''Today's announcement is part of our ongoing support of appropriate fluoridation for community water systems, and its effectiveness in preventing tooth decay throughout one's lifetime," says HHS Assistant Secretary for Health Howard K. Koh, MD, MPH, in a news release.

The HHS recommendation comes in the wake of data finding that excess fluoride consumption during the tooth-forming years in children age 8 and younger may lead to dental fluorosis, a condition in which teeth can become streaked or spotty due to excess fluoride.