Gordon W G Smith1, June McNeil, Gordon Ramage, Andrew J Smith. 1. Institute of Infection and Immunity, College of Medical Veterinary and Life Sciences, Glasgow Dental School, University of Glasgow, Glasgow, UK. andrew.smith@glasgow.ac.uk
Abstract
BACKGROUND: The cleaning stage of instrument decontamination processes is a critical control point, and removal of protein deposits is used as a marker of cleaning efficacy. An important factor is the choice of cleaning solution especially in the absence of any defined standards for detergent effectiveness. METHODS: Following method validation, stainless steel tokens were inoculated with reconstituted citrated blood and added to a 24-multiwell plate and immersed in different cleaning solutions for 5 minutes, agitated at 25 (20°) tilts/min at 22°C and at the manufacturers' recommended temperatures. Desorbed protein was measured using the bicinchoninic acid assay. RESULTS: From a starting concentration with a median of 3,700 μg of blood protein of all solutions tested, alkaline detergent (Haemo-sol) removed the largest proportion of protein (median, 2,070 μg), and surgical handwash removed the least protein (median, 0 μg). Reverse osmosis water demonstrated useful blood-removing properties with a median of 1,421 μg. CONCLUSION: The cleaning system we utilized is a simple, inexpensive method to compare the cleaning efficacies of detergents and may be used as a first stage in benchmarking cleaning efficacy of detergents. Not all solutions used in cleaning dental instruments are efficacious at removal of blood.
BACKGROUND: The cleaning stage of instrument decontamination processes is a critical control point, and removal of protein deposits is used as a marker of cleaning efficacy. An important factor is the choice of cleaning solution especially in the absence of any defined standards for detergent effectiveness. METHODS: Following method validation, stainless steel tokens were inoculated with reconstituted citrated blood and added to a 24-multiwell plate and immersed in different cleaning solutions for 5 minutes, agitated at 25 (20°) tilts/min at 22°C and at the manufacturers' recommended temperatures. Desorbed protein was measured using the bicinchoninic acid assay. RESULTS: From a starting concentration with a median of 3,700 μg of blood protein of all solutions tested, alkaline detergent (Haemo-sol) removed the largest proportion of protein (median, 2,070 μg), and surgical handwash removed the least protein (median, 0 μg). Reverse osmosis water demonstrated useful blood-removing properties with a median of 1,421 μg. CONCLUSION: The cleaning system we utilized is a simple, inexpensive method to compare the cleaning efficacies of detergents and may be used as a first stage in benchmarking cleaning efficacy of detergents. Not all solutions used in cleaning dental instruments are efficacious at removal of blood.