A group of Calgarians supported by dentists are asking their city councillors to once again add fluoride to the public water supply in order to prevent tooth decay.

The group, calling itself Calgarians for Kids’ Health, includes parents like Carmen Davison, who told reporters at a news conference Monday that she blames lack of fluoride for cavities so severe that her daughter required surgery.

“It was very traumatizing for my husband and I to take a child into a surgery,” she said.

Decades of research has shown that fluoride added to drinking water hardens tooth enamel, thereby reducing cavities. Many Canadian communities have been adding it to their supplies since the 1940s. Calgary began in 1989, but removed it in 2011 citing costs and health concerns.

At least one city councillor who voted to remove fluoride now says she’ll reconsider. “We have done harm, actually, by removing it,” said Diane Colley-Urquhart. Several others told CTV Calgary they would still vote against fluoride.

Alberta’s provincial health authority reviewed the science and concluded in January that water fluoridation “offers significant benefit with very low risk.”

Health Canada also took a close look at the issue in 2010 and said fluoride in drinking water up to twice the recommended amount was “unlikely to cause any adverse health effects including cancer, bone fracture, immunotoxicity, reproductive/developmental toxicity, genotoxicity, and/or neurotoxicity.”

However, one recent study renewed concerns by connecting fluoride to lower IQ. Investigators at the University of Toronto, McGill University and the Harvard School of Public Health studied 287 pairs of mothers and children in Mexico City and found a correlation between fluoride levels in mother’s urine during pregnancy and lower intelligence in their children.

The researchers adjusted their analysis for other possible factors that might have impacted the children’s neurodevelopment, such as the mothers’ smoking history, IQ and lead exposure, but couldn’t find another explanation.

That said, one of the researchers told CTVNews.ca that fluoride may be “a proxy of some other real actor that’s playing a role” in the neurodevelopment, and that more research is needed to confirm the link.

Calgary dentist June Dabbagh said she believes other factors that weren’t tested for could explain the correlation.

According to Dabbagh, the science is clear and fluoride is safe. “There is no debate,” she said. “We just need to make sure that the public gets it.”

With a report from CTV Calgary’s Brad MacLeod