Effectiveness of four sterilizing procedures on prophylaxis cups

Though manufactured as a single use, disposable item, prophylaxis (prophy) cups are often cleaned, sterilized or disinfected, and re-used. The purpose of this study was to determine whether 1) sterilization of prophy cups is achieved during routine procedures 2) debris is completely removed after cleaning. Three types of prophy cups (250 of each type) were evaluated. Prophy cups were contaminated with a pumice slurry containing B. stearothermophilus spore. After contamination, cups were distributed equally between ultrasonic or manual cleaning, then further distributed to one of four sterilization procedures: ETO, chemiclave, autoclave, and glutaraldehyde (GLU) immersion (6 3/4 hours). Five cups served as control and were not subjected to sterilization. Additionally, 15 prophy cups were contaminated and immersed in GLU for 10 minutes. Results indicate sterilization may be achieved by all sterilization methods tested. However, recommended disinfection immersion time of 10 minutes for GLU was not effective in achieving adequate disinfection of prophy cups. Photomicrographs indicate debris remains trapped in prophy cups after manual or ultrasonic cleaning. Prophy cup sterilization may be achieved through standard routine sterilization procedures, but remaining debris is likely due to porosity of rubber and configuration of the cups. Time management, cost effectiveness, and sound clinical judgment suggest single use.