Randy Davis, manager of the Machias Water Co., rests his hand on the lid of the fluoride tank at the plant. He said the plant adds 0.7 parts per million of fluoride to the water. "It's a white powder. It almost looks like flour or salt," he said.

The use of fluoride in public drinking water is a scientifically supported public health approach. After 75 years of communities using fluoride to promote dental health, studies cited by the U.S. Centers for Disease Control and Prevention show a 25 percent reduction in tooth decay in children and adults.

Importantly, Maine municipalities can choose whether to add some fluoride — a mineral that occurs naturally at some level in most water sources, and is found in some processed food and drinks — to community water systems in order to bolster dental health. According to the Maine Center for Disease Control and Prevention, more than 60 municipalities have chosen to do so ( some communities on the CDC list, which is from 2013, have since decided not to use fluoride in their water).

“Fluoride added to community drinking water has been shown to be a safe, inexpensive and extremely effective method of preventing tooth decay,” reads the Maine CDC website.

The Orono-Veazie Water District has used fluoridation since 1962. In June, voters in both towns will decide whether or not to continue this longstanding practice, which the Surgeon General calls “one of the most practical, cost-effective, equitable, and safe measures communities can take to prevent tooth decay and improve oral health.”

Setting aside the demonstrated dental health benefits of fluoride for a moment, we simply cannot ignore how this issue began its path to the ballot in these two towns.

A few years ago, an Orono businessman accidentally swallowed fluoride while his dental student niece practiced a procedure on him. He said he felt sick to his stomach and experienced a “severe mental fog.” He now avoids fluoride completely, and is asking Orono and Veazie to do the same when it comes to the public water supply.

Respectfully, this man’s experience isn’t a cautionary tale about fluoride in our drinking water or even in dental practice. It is, however, a cautionary tale about ingesting way too much of any substance — and perhaps, about the risks of volunteering to be a practice subject in someone’s medical education.

“It’s the dose that makes the poison. Anything can be a problem,” Northern New England Poison Center director Karen Simone told the BDN.

The U.S. Department of Health and Human Services provides a recommended optimal concentration for fluoride in public water supplies, currently at 0.7 milligrams per liter. According to officials, The Orono-Veazie Water District follows that recommendation, which is well below the Environmental Protection Agency’s maximum amount of fluoride allowed in public water systems, 4.0 milligrams.

It’s true that the federal government lowered the recommended optimal concentration from a range of 0.7 to 1.2 milligrams per liter in 2015, in part because of the availability of fluoride in other sources and because of concerns about dental fluorosis. This condition impacts tooth enamel and occurs when children with developing teeth are exposed to too much fluoride.

There are real and proven risks that come with overexposure to fluoride — just as there are with countless other minerals. That doesn’t mean fluoride is inherently unsafe, or that it should be abandoned as a public health tool. That’s why setting and monitoring the level of fluoride to ensure safety is key — an ongoing.

The Orono man who swallowed too much fluoride said he doesn’t dismiss its dental health benefits. Rather, he wants the public to learn about possible risks of fluoride when ingested in large amounts, citing a study published in 2012 by Harvard researchers. That study suggested high levels of fluoride exposure could have an adverse effect on neurodevelopment in children, but it’s own authors later clarified that their findings “do not allow us to make any judgement regarding possible levels of risk in exposure typical for water fluoridation in the U.S.”

We’re all for communities keeping up to date on scientific research and having the fullest picture possible when it comes to public health. As the 2015 federal revision to fluoride recommendations show, there’s room for reassessment and, when appropriate, readjustment. But we do not see evidence that supports a complete departure from fluoridation.

“This isn’t a new issue … This is a public health practice [that] has been studied for years and decades that we know is safe,” Simone, the poison center director, said.

Dental care is health care, and Maine municipalities should not abandon the proven practice of strengthening community dental health by using recommended levels of fluoride in public drinking water.