Introduction: Combined exposure to chromium, nickel and cobalt occurs in many occupations as dental laboratory technicians, electroplating workers and welders. Dental laboratory technicians whom are the main concern in our study are exposed to chromium, nickel and cobalt metal alloys during casting, finishing and polishing of dental prosthesis (e.g. bridges, crowns, partial and complete dentures) and also to small amount of molybdenum, silica beryllium, boron and carbon. The objective of this work was to evaluate the magnitude of exposure to these metals among dental laboratory technicians and their genotoxic effects.Subjects and methods: The study included 30 dental technicians (24 male & 6
females) and 20 comparable control subjects (15 male and 5 females) selected from outpatient clinic and nursing staff in Kasr ElAini hospital. Both groups were subjected to a prepared questionnaire including present, occupational, past and family history , measurement of serum chromium, nickel and cobalt levels, assessment of the chromosomal aberrations in the peripheral blood lymphocytes and measurements of the air levels of the chromium, nickel and cobalt at the work place.