Residents of a small community in Vermont were blindsided last month by news that one official in their water department quietly lowered fluoride levels nearly four years ago, giving rise to worries about their children's dental health and transparent government — and highlighting the enduring misinformation around water fluoridation.

Katie Mather, who lives in Richmond, a town of about 4,100 in northwestern Vermont, said at a water commission meeting this week that her dentist recently found her two kids' first cavities. She acknowledged they eat a lot of sugar, but noted that her dentist recommended against supplemental fluoride because the town's water should be doing the trick.

Her dentist "was operating and making professional recommendations based on state standards we all assumed were being met, which they were not," Mather said. "It's the fact that we didn't have the opportunity to give our informed consent that gets to me."

The addition of fluoride to public drinking water systems has been routine in communities across the United States since the 1940s and 1950s but still doesn't sit well with some people, and many countries don't fluoridate water for various reasons, including feasibility.

Critics argue that the health effects of fluoride aren't fully known and that its addition to municipal water can amount to an unwanted medication; some communities in recent years have ended the practice. In 2015, the U.S. government lowered its recommended amount in drinking water after some children got too much of it, causing white splotches on their teeth.