Objective: To carry out measurements of the Hg levels and personal exposure in Turkish dental clinics, and to evaluate possible adverse effects on the CNS in dental personnel.

Setting: Five dental clinics (1 private, 4 public) in Erzurum, Turkey.

Subjects and methods: 43, Hg vapour-exposed dental staff were examined and 43 hospital employees with no known exposure to Hg acted as the control group. Hg concentrations in plasma and urine were analysed by atomic absorption spectrophotometry. Possible effects on the central nervous system (CNS) were estimated by neuropsychological tests (Weschler Memory Scale-Revised (WMS-R) and Verbal Test of Memory Processes (VTMP)) and two self-administered questionnaires (Symptom Checklist-90-Revised (SCL-90-R) and Beck Depression Inventory (BDI)).

Results: The dental staff group had higher whole blood (B-Hg) and urine (U-Hg) Hg levels than the control group. The mean B-Hg value was 2.18nmol/l and U-Hg was 1.17nmol/nmol creatinine. U-Hg had an inverse relationship with logical memory (in WMS-R test) and total retention score (in VTMP test), and a positive relationship with increased scores of Anxiety and Psychoticism (in SCL-90-R).

Conclusion: These results may represent long-term consequences of low Hg exposure. In dentistry, to decrease toxic effects, proper Hg hygiene should be practiced by all dental health care workers.