Pleural plaques in dentists from occupational asbestos exposure: a report of three cases.

BACKGROUND

White asbestos (chrysotile) has been used in dentistry since 1930 when it was introduced as a lining material for casting rings.

METHODS

All three patients presented with pleural plaques on chest X-rays as well as on CT-scans. They were working as dentists for 35-45 years. Under the instructions of the first dentist we represented precisely the whole process of manipulating a kind of paper that contained asbestos. In order to measure asbestos fibers concentration we used the membrane filter method and phase contrast optical microscopy. Dry asbestos sheets were scanned with x-ray diffraction and electron microscope.

RESULTS

Analysis of the filter demonstrated 0.008 fibers/cm(3) during the sampling period. X-ray diffraction analysis revealed that the material consisted of chrysotile exclusively. Electron microscope pictures confirmed the presence of chrysotile.

CONCLUSION

Everyday occupational exposure for many years even to low asbestos levels, under poor ventilation conditions in a closed space, could cause pleural lesions.