(WVLT) As you heard from us yesterday, the South Blount Utility District is the latest in East Tennessee to approve the addition of fluoride to their water supply.

It's a decision that's rarely met without at least some opposition.

There's a lot of information out there about the health effects of fluoride exposure.

Volunteer TV's Jessa Goddard has more.

Dr. Larry Tragesser opened his family dentistry practice in Knoxville 28 years ago.

Just six years after the city of Knoxville added fluoride to its water supply.

"The difference in people in their level of decay at that time in about 1979 when i started versus today, it's reduced by at least 90 percent."

Tragesser says cavities used to be a fact of life.

But during the past few decades, tooth decay has been reduced dramatically, and the reason is fluoride.

Fluoride is a mineral that occurs naturally in all water sources, but is often added to the drinking water supply to reduce cavities and repair the early stages of tooth decay.

"We used to see decay on almost every young person and certainly multiple areas of decay on many. Today, it's not uncommon that we can take a person through his teens without any decay."

Now, a group called the Fluoride Action Network is calling attention to an online action petition calling on congress to stop water fluoridation until hearings are conducted.

The group cites new scientific evidence that fluoridation is not only ineffective, but has serious health risks.

"Anytime people have something put in their drinking water that appears to be a chemical in nature, I suppose they have concerns about that."

Dr. Tragesser and the American Dental Association, for that matter, contend fluoride is not only extremely effective, and inexpensive but also safe at recommended levels for the vast majority of the population.

Children who ingest higher than recommended levels of fluoride may be at increased risk of mild to permanent discoloration of their developing teeth.

Your county health department should be able to tell you the fluoride content of the water you receive.