Thursday, 9 September 2010
CASE 024 - Water fluoridation
Water fluoridation is the controlled addition of fluoride to a public water supply to reduce tooth decay. Fluoridated water has fluoride at a level that is effective for apparently preventing cavities; this can occur naturally or by adding fluoride. The practice occurs mainly in English-speaking countries, as Continental Europe does not fluoridate public water supplies, although some continental countries fluoridate salt. Fluoridated water operates on tooth surfaces: in the mouth it creates low levels of fluoride in saliva, which reduces the rate at which tooth enamel demineralizes and increases the rate at which it remineralizes in the early stages of cavities. Typically a fluoridated compound is added to drinking water, a process that in the U.S. costs an average of about $0.94 per person-year. Defluoridation is needed when the naturally occurring fluoride level exceeds recommended limits. A 1994 World Health Organization expert committee suggested a level of fluoride from 0.5 to 1.0 mg/L (milligrams per litre), depending on climate. Bottled water typically has unknown fluoride levels, and some domestic water filters remove some or all fluoride, but they can cause male fertility, Any purported benefits of fluoridation are in scientific controversy. Studies from 50 years ago do not pass muster under today's standards for safety or effectiveness. Research from the same era also "proved" cigarettes don't cause cancer. There are many ways of filtering out these such as the ones you can buy for you're home but other than that looking for ways to harvest you're own water is a better option.