As mercury exposure at higher levels is known to cause similar health effects an association cannot be ruled out

Dr Ewan Macdonald, University of Glasgow

Dr Ewan Macdonald and colleagues found that dentists had higher levels of mercury in their bodies, compared with a sample group of academics.

They also found that dentists were significantly more likely to report kidney disorders and memory disturbances than the academic staff.

Possible link

The authors stopped short of making a direct link. But writing in the journal Occupational and Environmental Medicine, they said: "As mercury exposure at higher levels is known to cause similar health effects an association cannot be ruled out."

Researchers obtained urine, hair and nail samples from 180 dentists in the west of Scotland and 180 academics from the University of Glasgow.

Levels of mercury were four times higher on average among dentists compared with academics.

The levels were found to be strongly associated with the number of hours worked, the number of fillings handled and the number of fillings they had themselves.

While the mercury concentrations were high, just one of the dentists had levels in excess of health and safety recommendations.

Nevertheless, dentists were 10 times more likely to have sought medical treatment for kidney disorders and three times more likely to have experienced fertility problems. There were also more than twice as likely to have suffered from memory disturbances.

Further research

The authors called for more research to be carried out and for dental surgeries to be monitored to ensure staff are not exposed to high mercury concentrations.

They wrote: "Further health surveillance of all members of dental teams, including dental nurses and dental hygienists, should be carried out to determine the nature of this association and the preventive health measures which may be required."

In an accompanying editorial, Dr Dianna Echeverria, from Battelle Center for Public Health Research and Evaluation in Seattle, said more research was needed.

She said the study had failed to compare like with like and would have been better if it had included dentists who were not exposed to mercury in their work.

She said: "A more uniform dental population needs to be evaluated."

A spokesman for the British Dental Association said: "The BDA is interested to see the results of this research, albeit on the basis of a small sample of dentists."

It suggested dentists could limit their exposure to mercury by wearing gloves, ensuring good ventilation in rooms, take steps to minimise the risk of spills and that instruments and equipment are cleaned thoroughly.

The BDA also recommends regular testing of clinical staff.