MONCTON, N.B. -- Restoring fluoride to drinking water is a no-brainer, say dentists in one New Brunswick city, citing a dramatic increase in tooth decay since fluoride use ended there in 2011.

Suzanne Drapeau-McNally of Moncton says she has seen the startling change among patients at her clinic over the last five years.

"The first thing (patients) say is 'What happened? We haven't changed anything,' and I have to tell them the only thing that has changed is there is no fluoride in your water anymore," she said.

Drapeau-McNally said the biggest increase in tooth decay has been among young children.

"They've come in for check-ups and never had any cavities, and all of a sudden they come in and have a higher number of decays. That's why we're approaching the city to try to get the fluoride brought back."

A five-year moratorium on fluoride use ends on Dec. 31, and Moncton dentists and hygenists are urging the city to start adding fluoride to the water again.

Drapeau-McNally says people should not be concerned about the practice because the concentration is only 0.7 parts per million.

Fluoride is a natural element that protects tooth enamel against the acids that cause tooth decay.

"I just know that it is beneficial. I have no studies that show negative impact to 0.7 parts per million of fluoride," Drapeau-McNally said.

New Brunswick's Chief Medical Officer of Health and the Board of the New Brunswick Dental Society both support the fluoridation of public drinking water supplies in the province.

"The value of water fluoridation should not be underestimated. The studies are clear and unequivocal and the benefits of fluoridation are well documented for all individuals in the community regardless of age, education, or socio-economic status," they wrote in a joint statement.

"More than 90 national and international professional health organizations including Health Canada, the Canadian and American Dental Associations, the Canadian Medical Association, the World Health Organization and the Food and Drug Administration of the United States endorse the use of fluoride at recommended levels to prevent dental caries," they wrote.

Despite the science, the debate over whether to fluoridate is not a new one across Canada.

The city of Calgary also stopped adding fluoride in 2011, and just last month its city council voted against any effort to re-open that debate.

Opponents argue not enough is known about what they say are possible health risks such as cancer, bone disease and fluorosis, in which too much fluoride causes teeth to discolour.

While federal and provincial governments set guidelines for fluoridation, the decision to use fluoride is left up to municipalities.

Brantford, Ont., became the first Canadian community to add fluoride in 1945 and many others followed. Health Canada reported in 2009, the last time it counted, that about 45 per cent of the population was drinking fluoridated water.

Big cities including Toronto, Hamilton, Ottawa, Halifax and Winnipeg fluoridate. Montreal and Vancouver don't, along with Waterloo and Windsor in southern Ontario.

City council in Saint John, N.B., voted against fluoride in 2014.

Drapeau-McNally said Moncton dentists and hygenists will make a closed-door presentation to Moncton city council on Oct. 24.

She said they will ask that fluoride be added to the city's water supply again as soon as possible.

"I'd like it started again tomorrow. The sooner the better," she said.