The aims of this study were to determine the microbiological and particle size characteristics of particulate bone collected with a piezosurgery device and bone trap, and to reduce bacterial contamination after treatment of debris with rifamycin SV. Samples were taken from 10 patients who underwent surgical extraction of their third lower molars. The ostectomy was performed with a piezosurgery device, and the debris was collected with a surgical aspiration set equipped with a bone trap. Two aliquots were taken from each sample, one of which was treated with rifamycin SV. The second aliquot, used as a control, was treated with a physiological solution. In the samples immersed in antibiotic solution, there was a statistically significant (P<0.005) reduction in bacterial contamination. The stringent protocol followed in this study has proved valid for collection of material, and treatment with rifamycin SV was found to reduce bacterial contamination in collected material.