WATERLOO — The great fluoride debate launched Thursday with civility, passion, and total disagreement.

About 60 people watched four panellists duke it out for 90 televised minutes over the merits of adding fluoride to drinking water as a way to prevent cavities.

Panellists disagreed about everything, using arguments that have changed little in decades.

There was passion but speakers were civil and everyone behaved, including the audience. This left the police officer in attendance with little to do except listen along.

Waterloo has been fluoridating its water since the 1960s. Residents have twice endorsed the practice by referendum and will be asked Oct. 25 to vote on it again.

Two dentists, Dr. Ira Kirshen and Dr. Harry Hoediono, promoted fluoridation against critics Paul Connett, a retired chemistry professor, and Peter Van Caulart, who trains Ontario water workers.

To sum up: Proponents said the credible science shows that adding fluoride limits cavities with no known health risks. Critics claimed the chemical used to fluoridate water is a threat and alleged various health risks. Both sides disputed the science of the other side, in a debate that also touched on personal rights.

“It’s a bad medical practice,” said Connett, who also called it unethical and risky. “Don’t be confused by scare tactics,” Hoediono countered. “Water fluoridation in the right amount is safe and effective.”

Fluoridation is common in Ontario and endorsed by public health authorities. But in this region only Waterloo fluoridates its water, which also flows to Elmira and St. Jacobs.

Kitchener residents have twice rejected fluoridation, the last time in 1967. Still, a public health survey found that about one-third of Kitchener residents wrongly believe their water is fluoridated.

Thursday’s panel debate, which included questions from the audience, was broadcast live by Rogers TV. Two more debates are scheduled leading up to the referendum.