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Volume 50, Number 3, June 2017

Monitoring the decontamination efficacy of the novel Poseidon-S disinfectant system in dental unit water lines 

Mari Fujita, Izumi Mashima, Futoshi Nakazawa


Corresponding author:

Futoshi Nakazawa, Corresponding author. Department of Oral Microbiology, School of Dentistry, Health Sciences University of Hokkaido, 1757 Kanazawa, Ishikari-Tobetsu, Hokkaido 061–0293, Japan. 


Background and purpose: 

Contaminated dental unit waterlines (DUWLs) are a known source of specific health care-acquired infections because of the difficulty in keeping them clean during routine dental practice. Recently, an electrolysis apparatus that uses only the chlorine normally present in municipal water, the Poseidon-S system, was developed as a novel additive-free disinfectant system to control microbial contamination in DUWLs. 



The microbiological quality of water samples collected from DUWLs was assessed before and after installation of the Poseidon-S system in terms of the total viable counts (TVCs) of microorganisms. The microbicidal effects of the electrolyzed water against oral organisms and its cytotoxicity against human oral-derived cell lines were also examined. 



Water samples from the DUWLs initially had average microbial TVCs of 103–106 colony-forming units (CFU)/mL. After installation of the Poseidon-S system, the number of microorganisms in the water samples decreased to less than 1 × 102 CFU/mL. The electrolyzed water also exhibited remarkable microbicidal effects on the microorganisms present in the DUWLs as well as microorganisms commonly isolated from human oral cavities, but showed low cytotoxicity towards human oral-derived cells. 



This study demonstrated that routine use of the Poseidon-S system can effectively maintain low microbial levels in DUWLs. 


Key words:

cytotoxicity, dental unit water lines (DUWLs), disinfection system, electrolyzed water, microbial contamination