Fluoride (FLOOR-ide) is an essential trace mineral found in bones, teeth, and body fluids. If it's present when bones and teeth develop, it makes them more resistant to decay and to diseases such as osteoporosis (ah-stee-oh-puh-ROE-sus). Fluoride also maintains the structure of bones and teeth after they're formed. Fluoride occurs naturally in some sources of drinking water, and it's added to others. Fluoridation is one ofthe most thoroughly studied community health measures. People who live in areas where the drinking water contains fewer than one part per million of fluoride have more dental decay and osteoporosis. Children raised in areas where the water is fluoridated have 50 percent fewer cavities than children who don't drink fluoridated water. Areas where the natural fluoride concentration is high may result in teeth that appear slightly spotted, but the condition doesn't seem to be harmful, and those teeth are very resistant to decay. Opponents of fluoridated water claim it increases the incidence of cancer, birth defects, and other health problems, and that the medical research is contradictory. If you're concerned about fluoride in your drinking water, you can filter it out by using a water purification system. However, you may want to consider giving growing children supplemental fluoride to protect their teeth. Contact a dentist or other healthcare professional for more information.