McKINNEY — In some ways, this latest fight over fluoridated water echoes back to the 1950s and ’60s, when adding fluoride to drinking water was either a panacea for the problems of tooth decay or a ploy to poison the American water supply.

The language is far more civil now, and few call fluoridation a communist plot. But at a recent City Council meeting in McKinney, passions ran high on both sides, with the applause from partisans so frequent that Mayor Brian Loughmiller cautioned that clapping for every speaker would only lengthen a hearing that ultimately ran more than two hours.

If the council ultimately decides it doesn’t want fluoride in the water — the issue is on the agenda for a work session in early April — it’s only a tiny first step. McKinney is just one of 13 member cities in the North Texas Municipal Water District, and ending fluoridation requires that all 13 reach the same decision.

“If all 13 cities agreed, they would send in letters supporting stopping fluoridation and we’d put a memorandum together for our board, and then we would take action on it,” said Denise Hickey, the water district spokeswoman. “That’s how this originated back in the early ’80s.”

Council member Ray Ricchi, the point person in the ongoing debate, argues that when fluoridating water swept the country decades ago, it was seen as the best way to protect people, particularly children, from future dental problems. But that was before fluoride was added to toothpastes and mouthwash, and before dentists began dabbing pharmaceutical-grade fluoride on their patients’ teeth.

The fluoride in water, Ricchi said, is anything but pharmaceutical-grade.

McKinney’s water comes from the North Texas Municipal Water District. And like most water suppliers in the U.S., the North Texas district uses fluorosilicic acid, also called hydrofluorosilicate, largely produced as a byproduct of manufacturing fertilizer, according to the U.S. Centers for Disease Control and Prevention.

Opponents call fluorosilicic acid “toxic.” But proponents argue that it’s perfectly safe at the concentrations used in water, and say that many substances seen as vital to human health, including vitamins D, B6, A and E, are also considered toxic in concentrated forms.

The Environmental Protection Agency allows water systems to add fluoride to a maximum of 4 milligrams per liter, or 4 parts per million. The North Texas district uses far less, though, officials say.

Hickey said the water supply has some fluoride in it naturally, between .2 and .5 milligrams per liter, and the district adds fluoride to raise the level to a total of .7 to 1.2 parts per million.

The EPA is considering lowering the maximum level of fluoride, but the district will still be below that level, she said.

Ending fluoridation would save money, but not a tremendous amount, Hickey said. In 2012, the district spent $371,575 on fluorosilicic acid, “which is like .03 to .05 percent of our budget,” she said.

Proponents of fluoridated water, particularly area dentists and the American and Texas dental associations, say fluoride’s benefits far outweigh its risks, which they say are primarily the appearance of brown spots on tooth enamel.

“I’ve been to many, many fluoride hearings, and it’s usually a small group that has concerns,” said Dr. John Findley, a past president of both associations and a dentist who has practiced in Plano for 42 years. “I don’t pretend to be an expert in chemistry, but anecdotally over 42 years of practice, I’ve seen very little harm to teeth from fluoride.”

The CDC has described fluoridated water as “one of the 10 great public health achievements of the 20th century.” Findley described dental disease as “the most common chronic disease we face in the United States, and in many cases, it’s answered by that little bit of fluoride.”

And since many people don’t see a dentist on a regular basis, fluoride ensures that they have some protection against dental problems, he said. It also has the advantage of providing some protection to the surface of the teeth, and internally as children’s new teeth are formed, Findley said.

But the critics dispute that, and maintain that people get plenty of fluoride from other sources. And they point to studies that say children get more fluoride — much of it through formula or juices made with tap water — than they need or can adequately process.

For Ricchi, fluoride use should be a personal decision, not medication done on a mass scale.

“Tell me the truth about fluoride, and let me make my own decision,” he said. “You need to educate people, and then it should be their choice.

“Unfortunately, we don’t have a choice.”