Local authorities across the State have this week begun taking steps to reduce the levels of fluoride in public water supplies.
The change comes on foot of new regulations which came into effect on July 1st.
Under these, the levels of fluoride added to public water supplies have to be reduced from the current limit of 1 mgs per litre to 0.6-0.8 mgs per litre.
The change is in accordance with one of the main recommendations of a report issued five years ago by the national Forum on Fluoridation.
It said fluoridation of public piped water supplies should continue as a public health measure but levels added to water supplies should be reduced.
This recommendation arose from a slight increase in cases of questionable and mild dental fluorosis in the population.
Fluoride has been added to public water supplies in the Republic to prevent dental decay since the early 1960s. Its introduction has had a significant impact but the Green Party and a number of other organisations have staunchly opposed the practice, claiming fluoride intake can adversely impact on the population's health.
The Irish Expert Body on Fluorides and Health, which advises the Minister for Health and evaluates ongoing research on all aspects of fluoride including its safety, disagrees.
Its view is that fluoridation is safe and effective. Between 2004 and 2006 alone, the expert body reviewed and assessed 72 reference documents, research papers and health reports in relation to fluoride - both national and international.
The Department of Health said yesterday that the Fluoridation of Water Supplies Regulations 2007 were signed by Minister for Health Mary Harney and laid before the Houses of the Oireachtas earlier this year and took effect last Sunday.
A spokeswoman said the department had written to the Health Service Executive (HSE) in April advising it to take appropriate action to comply with the new regulations.
The addition of fluoride to water supplies and the subsequent testing of fluoride levels in water is carried out by county and city councils on behalf of the HSE. Calls to a number of local authorities yesterday confirmed they were aware of the new regulations and had begun to implement them.
Dublin City Council confirmed it was complying with the new regulations. So too did Cork City Council and Galway County Council.
Meanwhile, the Irish Expert Body on Fluorides and Health has developed a detailed code of practice on the fluoridation of drinking water and a national audit of all fluoridation processes in water treatment plants across the State is about to be instigated, it said.
Additionally, it said research would be undertaken to monitor the public health impact of the present reduction in water fluoridation levels.