Quantitative Analysis of Selected Microorganisms Present at Various Sites in a Prosthetics Clinic and Dental Laboratory during Complete Denture Fabrication

Background : Contamination with oral commensals and pathogenic microorganisms, and cross contamination between clinic and laboratory can occur. The amount of contamination has not been determined. Methods : Samples from different clinical and laboratory stages before and after disinfection (17 sites, 10 samples per stage) were collected. Laboratory surfaces and equipment were swabbed for 10 days (11 sites). Swabs were cultured for total mixed flora, Streptococci, Lactobacilli, Staphylococcus aureus , aerobic Gram-negative bacteria (AGNB) and Candida . Knowledge of infection control among staff and students was assessed. Results : Clinic: In total, 30–40% of the samples overall were contaminated with mixed flora and Streptococci of >100 cfu/swab; >100 cfu of AGNB and Candida were present on 6% and 1% of samples; 2% contained <100 cfu of S. aureus . Laboratory: In total, 17–48% of the samples overall were contaminated with mixed flora and Streptococci of >100 cfu/swab; >100 cfu of AGNB were present on 11% of samples; none contained >100 cfu of Candida . Disinfection significantly reduced the level of all organisms. Knowledge of infection control was sufficient, but compliance was poor. Conclusion : Although the count of mixed flora was high, potential pathogens such as S. aureus and Candida were low. In immunocompromised patients, this can become a problem.