Sixty-one percent of Portlanders voted against putting fluoride in the city’s water supply last year. When the idea was floated to Wood Village residents last fall, the small town made an even more emphatic statement: 100 percent of those who responded said no.

But there’s a catch: Just 10 people — eight of the city’s almost 4,000 residents and two non-resident business owners — voiced an opinion.

This also was not a ballot but merely an informal question included in the city’s October newsletter. Still, public sentiment was strong enough that when councilors saw results last month, they took the issue of adding fluoride to the city’s water supply off their agendas for the foreseeable future.

Fluoride is a naturally occurring compound that already is in water supplies in some parts of the world but often added elsewhere to promote oral health.

Several prominent health organizations regard the practice as a safe way to help prevent tooth decay. The U.S. Centers for Disease Control considers water fluoridation to be one of the 10 greatest public-health achievements of the 20th Century.

Opponents regard water fluoridation as a form of “mass medication” that robs individuals of a choice in their health-care decisions and could have adverse health effects for some people.

City councilors in Wood Village opened discussion last year on whether they should be fluoridating water as a public health benefit.

“What public response we had was overwhelmingly negative,” said Bill Peterson, administrator of the city bounded by Fairview, Gresham and Troutdale.