TORONTO — Canadian dental experts defended the use of fluoride in drinking water Thursday as some environmental activists claimed international studies show the chemical can cause brain damage in children and called for an end to the “60-year experiment.”

Environmental groups said their experts looked at studies from India, China, Brazil and other countries documenting what they consider the dangers fluoride poses to human health, and the minimal benefits it provides for dental care.

“Studies are showing that the addition of fluoride to municipal water supplies is having little effect on oral health,” Karen Buck of Citizens for a Safe Environment told a news conference at the Ontario legislature.

“Instead, the recent studies provide mounting evidence that fluoride can adversely affect the neurological development of children.”

Other environmentalists complained that Canada has not taken the time to conduct its own scientific studies on the possible adverse affects of fluoride on people’s health, especially on children who are still developing.

“The proper toxilogical studies have not been done,” said Cindy Mayor of People for Safe Drinking Water.

” So technically we’re still in the experimental stage after 60 years.”

Dr. Paul Connett, director of the Fluoride Action Network, said the fluoridation debate “has been controlled for far too long by the dental lobby” in many countries, including Canada.

“They’re preoccupied by one tissue, the teeth, whereas the opponents of fluoridation, like myself, see the body slightly differently,” he said.

“I believe Health Canada is not giving the citizens the truth on this issue.”

Canada has neglected to take a scientific look at fluoride’s effects on the brain and other organs, or at studies that suggest it can lead to lower IQs in children, Connett said.

“No studies have investigated a possible relationship between fluoridated water and lower IQs in children, arthritic symptoms in adults, underactive thyroid (glands), increased bone fractures in children and earlier onset of puberty,” he complained.

“The science has not been done (in Canada). If you don’t look, you don’t find.”

Health Canada’s chief dental officer, Dr. Peter Cooney, has been under fire of late from anti-fluoride groups for what they consider a dismissive attitude towards their concerns. Cooney did not return calls Thursday.

Dr. Vyvyan Howard of the University of Ulster in Ireland, who is in Toronto for a conference on fluoride in drinking water, said just a five-point drop in IQ levels could lead to a 50 per cent increase in the number of mentally disabled people and a similar decline in the number of “gifted” people.

“I think there is a very strong case for the precautionary removal of this mass medication from our drinking water,” Howard said.

“There are studies which show changes in IQ from populations exposed to fluoride (in drinking water). The thing is if you look at an individual, you never really know that they may have been five points higher on the IQ scale.”

Health Canada recently recommended that municipalities lower the fluoride levels in water, but not because of any links to brain damage.

It suggested a slight lowering of maximum fluoride levels — from 0.8 parts per million to 0.7 ppm — to counter a problem known as fluorosis, a mottling of children’s teeth.

The Canadian Dental Association said there was no evidence to support the claims that fluoride in drinking water can lead to lower IQs in children.

“We rely on science and expert reports from around the world,” said CDA spokesman Dr. Euan Swan.

“So while we at the CDA have not ourselves conducted research on the IQ of children in Canada, based on studies from around the world, the UK and the United States, we feel very confident in supporting water fluoridation.”