Abstract

Aim A study of 180 dentists in the West of Scotland was conducted to determine their exposure to mercury during the course of their work and the effects on their health and cognitive function.

Design Data were obtained from questionnaires distributed to dentists and by visiting their surgeries to take measurements of environmental mercury.

Methods Dentists were asked to complete a questionnaire including items on handling of amalgam, symptoms experienced, diet and possible influences on psychomotor function such as levels of stress and alcohol intake. They also completed the 12-item General Health Questionnaire. Dentists were asked to complete a dental chart of their own mouths and to give samples of urine, hair and nails for mercury analysis. The dentists were visited at their surgeries where environmental measurements were made in eight areas of the surgery and they undertook a computerised package of psychomotor tests. One hundred and eighty control subjects underwent a similar procedure, completing a questionnaire, having their amalgam surfaces counted, giving urine, hair and nail samples and undergoing the psychomotor test procedure.

Results Dentists were found to have, on average, urinary mercury levels over 4 times that of control subjects although all but one dentist had urinary mercury below the Health and Safety Executive health guidance value of 20 mol mmol^-1 creatinine. Urine was found to be a better biological marker for mercury exposure than hair or nails.

Dentists were significantly more likely than control subjects to have suffered from disorders of the kidney but these symptoms were not significantly associated with their level of mercury exposure as measured in urine. One hundred and twenty two (67.8%) of the 180 surgeries visited had environmental mercury measurements in one or more areas above the Occupational Exposure Standard (OES) set by the Health and Safety Executive. In the majority of these surgeries the high levels of mercury were found at the skirting and around the base of the dental chair. In 45 surgeries (25%) the personal dosimetry measurement (ie in the breathing zone of dental staff) was above the OES.

Conclusion On the basis of these findings, it is recommended that greater emphasis should be made relating to safe handling of amalgam in the training and continuing professional development of dentists, that further studies are carried out on levels of mercury exposure of dental team members during the course of their working day, and that periodic health surveillance, including urinary mercury monitoring, of dental personnel should be conducted to identify possible effects of practising dentistry.

1. Senior Health Services Researcher, NHS Quality Improvement Scotland, Delta House, 50 West Nile Street, Glasgow G1 2NP
2. Professor of Primary Dental Care, Primary Dental Care Research Group, University of Birmingham School of Dentistry, St Chad's Queensway, Birmingham B4 6NN
3. Senior Lecturer in Statistics, Public Health and Health Policy Section, Division of Community Based Sciences, University of Glasgow, 1 Lilybank Gardens, Glasgow G12 8RZ
4. Head of Health Working Lives Group, Public Health and Health Policy Section, Division of Community Based Sciences, University of Glasgow, 1 Lilybank Gardens, Glasgow G12 8RZ
5. Occupational Hygienist, Glasgow Occupational Health, Cuthbertson Building, Glasgow Royal Infirmary, Wishart Street, Glasgow G31 2ER
6. Policy Officer, Business Growth Unit, 5 Cadogan Street, Glasgow G2 6AT
7. Professor of Oral Surgery (retired), Rhu Lodge, Rhu, Helensburgh G84 8NF
8. Lecturer in Community Oral Health, Glasgow Dental Hospital & School, 378 Sauchiehall Street, Glasgow G2 3JZ
9. GDP, 8 North Road, Bellshill, Lanarkshire ML4 1EM
10. Professor of Social Psychology, Health and Human Sciences, Room 4SB.5.23, University of Essex, Wivenhoe Park, Colchester C04 3SQ

Correspondence to: F J T Burke² Primary Dental Care Research Group, University of Birmingham School of Dentistry, St.Chad's Queensway, Birmingham B4 6NN
e-mail: f.j.t.burke@bham.ac.uk