The<unk>  arises from political, moral, ethical, economic, and health considerations regarding the<unk>  of public<unk>  supplies. For deprived groups in both maturing and matured countries, international and national agencies and dental associations across the world support the safety and effectiveness of<unk><unk> . Proponents of<unk><unk>  see it as a question of public health policy and equate the issue to vaccination and food fortification, claiming significant benefits to dental health and minimal risks. In contrast, opponents of<unk><unk>  view it as an infringement of individual rights, if not an outright violation of medical ethics, on the basis that individuals have no choice in the<unk>  that they drink, unless they drink more expensive bottled<unk> . A small minority of scientists have challenged the medical consensus, variously claiming that<unk><unk>  has no or little cariostatic benefits, may cause serious health problems, is not effective enough to justify the costs, and is pharmacologically obsolete. Opposition to<unk>  has existed since its initiation in the 1940s. During the 1950s and 1960s, conspiracy theorists claimed that<unk>  was a communist plot to undermine American public health. In recent years,<unk><unk>  has become a prevalent health and political issue in many countries, resulting in some countries and communities discontinuing its use while others have expanded it. The<unk>  is propelled by a significant public opposition supported by a minority of professionals, which include researchers, dental and medical professionals, alternative medical practitioners, health food enthusiasts, a few religious groups (mostly Christian Scientists in the U.S.), and occasionally consumer groups and environmentalists. Organized political opposition has come from libertarians, the John Birch Society, and from groups like the Green parties in the UK and New Zealand. Proponents and adversaries have been both criticized for overstating the benefits or overstating the risks, and understating the other, respectively. Systematic reviews have cited the lack of high quality research for the benefits and risks of<unk><unk>  and questions that are still unsettled. Researchers who oppose the practice state this as well. According to a 2013 Congressional Research Service report on fluoride in drinking<unk> , these gaps in the<unk>  scientific literature fuel the<unk> . Public<unk><unk>  was first practiced in 1945, in the US. As of 2012, 25 countries have supplemental<unk><unk>  to varying degrees, and 11 of them have more than 50% of their population drinking fluoridated<unk> . A further 28 countries have<unk>  that is naturally fluoridated, though in many of them there are areas where fluoride is above the optimum level. As of 2012, about 435 million people worldwide received<unk>  fluoridated at the recommended level, of whom 57 million (13%) received naturally fluoridated<unk>  and 377 million (87%) received artificially fluoridated<unk> . In 2014, three-quarters of the US population on the public<unk>  supply received fluoridated<unk> , which represented two-thirds of the total US population.
Water fluoridation controversy
Water fluoridation by country
Waterborne disease and climate change
Human nutrition
Electronic cigarette and e-cigarette liquid marketing
Carbon nanotubes in medicine
Sports nutrition
Climate change and infectious diseases