By Michael Biamonte, C.C.N.

LONDON (Reuters) – Dentists are more likely to suffer memory and kidney problems which could be due to long-term exposure to mercury in tooth fillings, doctors said on Tuesday.

A study of 180 dentists by researchers at the Glasgow Royal Infirmary in Scotland found the dentists had up to four times the normal level of mercury in their urine and nails and had more kidney disorders and memory lapses than the general public.

“We found several differences in the health and cognitive functioning between our dentists and the control group,” Dr. Ewan Macdonald said in a report in the Journal of Occupational and Environmental Medicine.

“These differences could not be directly attributed to their exposure to mercury, but as mercury exposure at higher levels is known to cause similar health effects an association cannot be ruled out,” he added.

Mercury has been used in dentistry for about 150 years but some dentists and researchers believe the fillings can give off harmful vapors that can be dangerous for dentists and patients.

Critics of the fillings claim the mercury can poison the body and lead to health problems affecting the kidneys and other organs and neurological diseases such as Alzheimer’s.

But dental associations say it is safe when mixed with other metals and there are no scientific studies to prove a link between the filling and health problems.

The researchers in Glasgow compared mercury levels in urine, hair and nail samples and the results of psychomotor skills, response times, word recall and health problems of the 180 dentists and an equal number of volunteers.

The dentists had higher levels of the metal in their bodies, reported more health problems and did worse on the tests than the volunteers.