Aluminum oxide air abrasion particles: A bacteriologic and SEM study

Objective: The objective is to determine if aerobic and anaerobic sampling yields Viable biologic contaminants in the aluminum oxide air abrasion powd er as delivered by the manufacturer and to determine mean particle size for comparison with the published size from manufacturers and the range of siz es in the powders. Method and materials: Samples from 15 unopened aluminum oxide powder containers from 9 different manufacturers were plated on aerob ic and anaerobic culture media. The cultures were incubated at 35 degreesC and observed at 24-hour intervals. Samples of each of the 15 groups were su bjected to scanning electron microscope (SEM) examination. Photomicrographs were obtained and a range and mean particle size determined. Results: Aero bic and anaerobic cultures demonstrated no growth in any of the samples. Me an particle size determined by SEM for 25- to 27.5-mum particles ranged fro m 27.3 mum to 32.0 mum with standard deviations from 1.06 mum to 7.70 mum. Mean particle size for 50 mum particles ranged from 51.6 mum to 59.7 mum wi th standard deviations of 5.48 mum to 14.80 mum. Conclusion: Aluminum oxide powders as delivered by manufacturers appeared to be free from viable micr oorganisms. The powder mean particle sizes approximate the labeled sizes cl osely enough such that they should perform properly in air abrasion tooth p reparation.