Efficacy of various decontamination methods and sterilization on contaminated and inoculated diamond-coated burs

The objective of this study was to evaluate the efficacy of various decontamination methods and subsequent sterilization on contaminated and inoculated diamond-coated burs. One hundred forty new diamond-coated burs and 120 extracted human molars were utilized in this study. The burs were divided into 7 groups (n = 20): 1, positive control; 2, negative control; 3, new, unused burs; and 4 to 7, burs subjected to various combinations of cleaning methods (manual cleaning, use of a cleaning stone, and/or ultrasonic cleaning) after contamination. In all of the groups except group 3, the burs were sterilized and used to abrade the enamel and dentin of the sterilized extracted teeth. In groups 1 and 4 to 7, the burs were subsequently inoculated with 1 of the following microorganisms: Enterococcus faecalis (ATCC 19433), Staphylococcus aureus (ATCC 6538), Pseudomonas aeruginosa (ATCC 15442), or Geobacillus stearothermophilus (ATCC 7953). Twenty-four hours after inoculation, the burs in group 2 and groups 4 to 7 were subjected to the cleaning treatments and sterilized with steam. The burs in all 7 groups were then cultured for bacterial contamination. No growth of any bacterial type was observed in any of the groups except the positive control group. The use of a cleaning stone in combination with manual or ultrasonic cleaning resulted in the least amount of remaining tooth debris on the diamond-coated burs. The contaminated and inoculated diamond-coated burs tested in this study were successfully sterilized, and the tested bacteria were eliminated. If using a diamond-coated bur multiple times, practitioners should consider utilizing debridement with a cleaning stone followed by either manual or ultrasonic cleaning and then by a single cycle of steam sterilization.