NEW YORK — For about 50 years, adding cavity-preventing fluoride to drinking water was a popular public health measure in Yorktown, a leafy town north of New York City. But in September, the town’s supervisor used his emergency powers to stop the practice.

Here's everything you need to know about the benefits and the risks of this common but controversial natural element.

The Washington Post and other media noted that medical organizations responded by calling Kennedy’s assertions unfounded at the levels of fluoridation used in drinking water. But many of them have also noted that in an NBC interview, Trump said possible action against fluoridation of water “sounds OK to me ... You know, it’s possible.”