Fluoride-free drinking water in Calgary leads to rise in kids' tooth decay, study indicates

University of Calgary study shows rise in decay worst in baby teeth

A new study indicates tooth decay in children's baby teeth has increased since Calgary stopped adding fluoride to its drinking water supply. (iStock

Tooth decay in children in Calgary has worsened since the city stopped adding fluoride to drinking water in 2011, according to a new study.

The study, published Wednesday in the journal Community Dentistry and Oral Epidemiology, compared Grade 2 students in Calgary and Edmonton, which still adds fluoride to its drinking water.

Lindsay McLaren, the researcher with the University of Calgary's Cumming School of Medicine who led the study, told the Calgary Eyeopener's David Gray that there were more cavities in both Calgary and Edmonton over the period of the study, but "it got worse in Calgary, where fluoridation was stopped, than in Edmonton."

No fluoride 'most important factor'

McLaren said the study is clear about the cause and effect at play.

"We designed the study so we could be as sure as possible that [the increased tooth decay] was due to [fluoride] cessation rather than due to other factors," she told the CBC.

"We systematically considered a number of other factors ... and in the end, everything pointed to fluoridation cessation being the most important factor."

Coun. Druh Farrell was among the 10 on council who voted to stop adding fluoride to Calgary's drinking water in 2011. (Evelyne Asselin/CBC)

Health Canada notes that provincial and territorial governments regulate the quality of drinking water in their jurisdictions, with the fluoridation of drinking water supplies decided by each municipality, in collaboration with the province or territory and possibly in consultation with residents.

Calgary's city council voted 10-3 in 2011 to stop adding fluoride to the drinking water.

Ward 7 Coun. Druh Farrell was one of those in favour of removing it, arguing that helping families who couldn't afford fluoridated toothpaste would be a better idea than giving it to the entire population.

Why Calgary stopped

Ward 3 Coun. Jim Stevenson also voted to remove fluoride from Calgary's water, saying there was insufficient medical proof that keeping it would have any benefit.

"We as a council have to show some leadership here," he told the CBC in 2011.

"I would really question our right to put [fluoride] in, but … I don't question at all our right to remove it."

The study compared Grade 2 students in Calgary and Edmonton, which still adds fluoride to its drinking water. (Alex Dental Health Bus)

One of the arguments in favour of fluoride removal was its availability in sources other than drinking water, such as toothpaste.

McLaren said fluoride given by dentists is one source, but not everybody has access to such care.

"Our findings, and others, suggest that community fluoridation continues to have an effect above and beyond these other sources of fluoride," she said.

McLaren said the tooth decay increase found in her study is more significant in children's baby teeth than in adult teeth, and she added there is a need to continue to monitor the trend.