CLEARWATER — Moderate. Sensible. Sober. That is how Pinellas County has preferred to think of its local government for decades. But many say that image cracked a year ago, when the commission voted to end fluoridation, making it the largest county in Florida to reject the practice, and drawing national ridicule.

One year later, the board has reversed the decision. On Tuesday, the Pinellas County Commission voted to begin fluoridating its drinking water again.

The switch, which will cost the county about $185,000 to carry out, was inevitable. Over the summer and into the fall, fluoride had become a political weapon, used successfully by Democratic candidates to oust two Republican commissioners who had opposed the policy. Both blamed the mineral for their defeat.

Normally confined to the sterile rooms of a dental clinic, fluoride was slapped on campaign posters and dominated stump speeches. Dentists donated to the Democrats, Charlie Justice and Janet Long, and urged their patients to vote for the candidates, both of whom promised to restore fluoridation.

And in the intervening months, the cities of Pinellas Park and Tarpon Springs voted to begin adding fluoride to their water. Other cities, such as St. Petersburg, Gulfport, and Belleair, had already been doing so.

Though it was clear on Tuesday that a majority of commissioners supported fluoride, their 6-1 vote was preceded by three hours of public testimony, dominated by fluoridation opponents. Many of them accused the commission of trying to medicate or poison them. Supporters included a handful of dentists and public health advocates.

“I’m glad we got it done,” Long said. “It has moved our county to a place where thoughtful and deliberate discussion and conversation can take place and you can make decisions based on scientific evidence.”

Though fluoride is now county policy again, it will be several months before the roughly 700,000 people affected by the commission’s vote will feel its effects. Robert Powell, the county’s director of water, said that fluoridation will begin on March 1, giving county staff enough time to alert residents through fliers in their water bills.

Fluoride occurs naturally in trace amounts but not at the level recommended by the U.S. Department of Health and Human Services to prevent tooth decay.

In October 2011, the commission eliminated fluoride in a 4-3 vote that took many, including some of the commissioners, by surprise.

At a workshop meeting, the commission was swamped by tea party members and others who view fluoridation as an unnecessary, even malevolent, form government intervention. Many of the same people attended the meeting on Tuesday, overflowing the 150-seat commission hearing room so that 20 people had to watch the proceedings from the building’s lobby.

Opponents railed against the commission. Some accused the board of trying to medicate them into submission; some warned that fluoridation was a Nazi policy designed to kill off undesirables; and some claimed that their skin ailments and other medical problems stemmed from fluoride.

Others simply wanted the government out of their faucet.

“I don’t have the choice of not getting city water,” said Vicki Hass, a Clearwater resident and mother of two.

“What I take and what I give my kids should be my choice,” she said. “I can’t afford to install a $6,000 water filtration system to take out the fluoride.”

“This is terrorism at the highest,” said Yvette Capetillo, a Tampa resident who said she often visits Pinellas beaches with her son. At home in Tampa, which also adds fluoride to its drinking water, Capetillo only drinks bottled water.

But this time the commission sided with the dentists.

“This is about this commission’s responsibility for public health,” said Commissioner Ken Welch, running down a long list of federal agencies and officials who support fluoridation.

“What we’re doing has been done in the United States for more than 50 years,” he said. “It is safe and effective.”

One commissioner disagreed. Norm Roche, who opposed fluoridation a year ago and recently told the Tampa Bay Times that he had changed his view and would support the practice, reversed course again.

On Tuesday, he was the lone vote against adding fluoride back into the water system. His view had never changed, he said.

“It is very clear here today that there are questions, and if there are questions it (fluoride) should not go into our public drinking water supply,” he said.

More than anyone, Commissioner John Morroni has embodied the board’s shift since 2011, when he joined Roche and former Commissioners Nancy Bostock and Neil Brickfield in rejecting fluoridation.

Looking back on the vote, he said that he had been deluged with emails and phone calls from residents who opposed the practice, making it seem like it was a popular decision. But after the election, his outlook changed.

On Tuesday, he voted in favor of fluoridation. Driving to work that morning, he had passed a neighbor who stopped him to say that she had just bought fluoride pills for her children.

“We’re voting it back in today,” he told her.