水道水フッ化物添加
Dental caries remains a major public health concern in most industrialized countries, affecting 60–90% of schoolchildren and the vast majority of adults. Water fluoridation reduces cavities in children, while efficacy in adults is less clear. A Cochrane review estimates a reduction in cavities when water fluoridation was used by children who had no access to other sources of fluoride to be 35% in baby teeth and 26% in permanent teeth. Most European countries have experienced substantial declines in tooth decay without its use. Recent studies suggest that water fluoridation, particularly in industrialized countries, may be unnecessary because topical fluorides (such as in toothpaste) are widely used and caries rates have become low. For this reason, some scientists consider fluoridation to be unethical due to "the debilitating effects of fluoride toxicity" and the lack of informed consent.