Wear of teeth due to occupational exposure to airborne olivine dust

Objectives. To clarify whether high tooth wear of employees in a mining industry that extracts the mineral olivine could be associated with airborne dust exposure in their working environment. Method. The cumulative exposure to airborne mineral dust for the workers in the company was calculated on the basis of their period of employment multiplied by the airborne olivine-dust concentrations, which have been monitored continuously during the past 20 years for all divisions of the company. After invitation 85% of the employees (n = 191) were examined clinically and their dentitions were photographed and duplicated in plaster casts. Four clinicians, working independently, examined the sets of casts/photographs for tooth wear and ranked these from most to least. Two groups of employees were compared with regard to tooth wear, i.e. the 30% with the highest (case) and the lowest (control) estimated dust exposure levels. Tooth wear in the case and control groups was compared using a non-parametric test based on rankings (Mann-Whitney test). Results. Tooth wear differed significantly between the workers in the low and the high mineral dust exposure groups (p < 0.001). The differences were also apparent within three age subsets, although statistical significance was reached only in the 34-44 years subset (p = 0.002). Considerable individual variation was noted within the three exposure groups. Conclusion. Workers with high exposure to airborne olivine dust may contract considerable tooth wear.