Fingernail clippings could be used to determine the concentration of fluoride in the body, an international conference on fluoridation has heard.
Dr Gary Whitford, a leading US specialist, was addressing the joint conference of the British Association for the Study of Community Dentistry and the European Association of Dental Public Health at UCC.
The effects of fluoride on the body had become an important area of research, he said. Studies had suggested no effect on humans while others had suggested there might be an increased risk of bone fracture.
What was needed, Dr Whitford suggested, was a biomarker capable of identifying alterations due to fluoridation in human tissues, cells or fluids. Recent findings had shown that fingernail clippings could be used as a reliable biomarker to determine the body burden of fluoride.
Research on one individual who ingested an annual 3.0 mg of fluoride each day, in addition to his usual fluoride intake from diet and other sources, showed discernible changes in fluoride in the body over a period of less than four months. The data collected suggested that fluoride entered the nails from the growth end, and not through the nail bed.
Dr Whitford said another study was conducted in collaboration with investigators from the University of Oslo, who collected nails from Brazilian schoolchildren living in small, rural villages, each with a well as the single source of drinking water.
"There was a direct and highly significant relationship between the water and fingernail concentrations . . . Thus we think that fingernails can be used as a biomarker for chronic fluoride exposure in groups," he said.
The major research that now needed to be done was to determine the fluoride concentrations in bone, plasma, ductal saliva and fingernails obtained from the same individuals, Dr Whitford said. It was hoped, he added, that new research data in this area would be available within three years.