Non-fibrous dust load and smoking in dental technicians: a study using bronchoalveolar lavage

A study was conducted with transmission electron microscopy to find whether bronchoalveolar lavage could be used to identify subjects with occupational exposure to mineral particles. Non-fibrous mineral particles in bronchoalveolar lavage (BAL) fluid from 46 dental technicians and 41 white collar controls with lung diseases but free from occupational exposure to dusts were analysed. The total particle concentration in BAL fluid was significantly higher in dental technicians than in controls (12.18 x 10(5) particles/ml of BAL fluid, v 2.03 x 10(5) particles/ml, p < 0.001). Dental technicians had significantly more crystalline silica, aluminium, and alloys containing nickel and chromium. There was a non-significant twofold increase of total particle concentration in the lungs of dental technicians who were smokers compared with non-smokers. The results strongly support the use of BAL fluid analysis to assess dust accumulation in workers in heavily exposed occupations such as dental technicians. This is a valid method to evaluate occupational exposure to non-fibrous mineral particles, and may be useful to determine the occupational aetiology of some respiratory diseases.