SAINT JOHN – Residents who live west of the Reversing Falls bridge will not have fluoride in their tap water for the next four to six months, a city official says.

Major work at the Spruce Lake watershed means construction workers will need to cut into fluoride lines, said Nicole Taylor, Saint John Water’s operations manager for water resources and quality.

“There’s a major capital project happening at Spruce Lake and in order to do the work safely, we need to turn off the fluoride,” she said Monday.

“It’s a temporary measure while the construction is underway.”

The city informed the Department of Health, and Dr. Scott Giffin, the medical officer of health, sent a notice out to the Saint John Dental Society.

Giffin, who supports fluoridation, said he felt compelled to inform the dentists because after the last fluoride shutdown, the dental society made it clear it wanted to be informed of any changes in fluoridation levels.

In safe doses, fluoride is beneficial for reducing cavities and strengthening tooth enamel, he said.

The issue is a sore point for Saint John dentists, who were angry that city hall failed to notify people that there was no fluoridation of water east of the Reversing Falls from June 2006 until January 2010. The removal occurred after a fire in a mechanical building damaged a feed line.

In an Telegraph-Journal commentary in January, Dr. Kelly Manning said if fluoridation is withdrawn, at-risk children in poor households would be most severely affected.

Fluoride from toothpastes doesn’t have as profound an effect on tooth enamel as small amounts of swallowed fluoride.

“In 2009, I noted a clinical difference in the incidence of decay in children who were supposed to be receiving fluoride and weren’t,” she said.

Manning wasn’t available for comment Monday.

Giffin said he agrees that fluoride is important for children, adults and the elderly, but he said it’s hard to measure how a shorter absence of fluoride would affect people’s teeth.

“If anybody was thinking of taking it out permanently, I would be very concerned,” he said.

“But I don’t know how to calculate the effect of four to six months … I would assume that some children who are in critical periods may not get the fluoride they need – but that’s just speculation.”

The issue of fluoridation has been a hot topic in municipalities across Canada, with Calgary recently voting to stop adding the chemical to drinking water.

Several Calgary councillors question the need to spend money on a program that benefits fewer and fewer people and suggest fluoridation is no longer necessary since people already get fluoride in toothpastes and mouthwashes.

Saint John has also considered removing the additive, particularly after the 2006 fire, which could have injured city workers.

It’s the main reason why the fluoride has been shut off to the west side in this case, while workers cut into the fluoride lines, Taylor said.