Respirability, microstructure and filler content of composite dusts.

Dusts were generated from five composites, with two different shades each. Between 54 and 70 mass percent of the dust (60 to 92% of the particles) collected was respirable. The average particle size collected was 3.97 microns by mass (0.9 microns by number of particles). Between 14 and 22% of the dust generated was respirable. Filler content of the respirable dust particles was within 3 mass percent of the amount of filler in each cured composite. Powder x-ray diffraction revealed that respirable dust particles collected from composites reported to contain crystalline silica fillers contain the same crystalline silica. The results indicate that improperly protected dental personnel who are regularly exposed to composite dusts generated during high-speed finishing of composites containing quartz filler may be at risk for developing silicosis. Dental personnel should wear masks specifically designed to filter respirable silica when finishing composite restorations with high-speed instrumentation.