Abstract
The purpose of this study was to investigate the effect of a system which automatically adjusts hydrogen peroxide colloidal-Ag dose to reduce colonization and growth of heterotrophic bacteria in dental unit waterlines and wastewaters. Thirty dental units were assigned into three groups with respect to the protocol employed: Group 1 : 10 units were selected for automatic administration. Group 2 : 10 units were selected for manual administration and Group 3: 10 units served as controls. Water samples from DUWLs and waste waters were collected every week for ten weeks. They were inoculated onto various specific agar media and incubated at 28-37°C for 2-7 days. After counting the colonies of microorganisms, the mean numbers were determined as cfu/mL A statistically significant difference in median total viable counts reduction was found for both treatment and control groups’ dental units waterlines for all weeks (p < 0.01). However, there was no significant difference among the waste water samples. The tested system of has been found to be as effective as manual application for improving the dental unit waterlines. Yet, none of these systems has proved enough antibacterial effect for dental unit wastewaters.
Highlights
The issue of presence of large numbers of microorganisms in dental unit water has become a major concern in terms of increased risk of infection for dental patients and staff, and is incompatible with good hygiene and cross-infection control practices [1,2]
The bacteria isolated from Dental Units Waterlines (DUWLs) included both opportunistic ones and the pathogens [3]
There was no significant difference between Group 1 and control group’s waste waters
Summary
The issue of presence of large numbers of microorganisms in dental unit water has become a major concern in terms of increased risk of infection for dental patients and staff, and is incompatible with good hygiene and cross-infection control practices [1,2]. The bacteria isolated from Dental Units Waterlines (DUWLs) included both opportunistic ones and the pathogens [3]. Biofilms are well-organized communities of cooperating microorganisms that can include bacteria, protozoa, diatoms, and fungi [5,6,7,8]. These microbiotas are predominantly harmless, but potentially pathogenic organisms may be present in the biofilm [9]. Some particles evaporate forming droplet nuclei < 5μm in diameter that remain airborne for many hours [10] This DUW contamination poses risks for immune compromised individuals [1]. Water line and hand piece anti-retraction valves can transport the pathogens from asymptomatic patients and cause cross-infection [12]
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