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OBJECTIVE: To investigate the status and related factors of sterilizers in dental health-care settings in Yunnan Province, with the aim of providing a theoretical basis for the health administrative department to formulate regional quality control programs and systems, proposing reasonable suggestions for optimizing the allocation of sterilizer resources in Yunnan\'s dental health-care settings, thereby improving resource utilization efficiency.
METHODS: This cross-sectional survey was conducted in 2600 dental health-care settings in Yunnan Province in March 2020. Uni-variable linear regression, multi-variable linear regression, curve fitting and threshold effect analysis were used to understand the relationship between dental units and sterilizers.
RESULTS: A total of 2600 dental health-care settings were included. The disinfection and sterilization work were mainly completed by the dental department in 1510(58.1%) institutions. 44(1.7%) institutions were not allocated sterilization equipment, and 1632 (62.8%) had only one sterilizer. The median allocation of sterilizers was 1.0. Uni-variable linear regression showed significant differences in covariates such as dental unit, dental handpiece, disinfection equipment, dentist, and dental assistant, which were more sensitive (p < 0.001) and statistically significant. The adjusted model was more stable in the multi-variable linear regression, and the differences in covariates between different settings were statistically significant. Curve fitting revealed an S-shaped curvilinear relationship between the number of dental units and sterilizers in oral healthcare settings.
CONCLUSIONS: The disinfection and sterilization work was mainly completed by the dental department in dental health-care settings in Yunnan Province. Sterilizer allocation increases with the number of dental units, but some institutions have insufficient allocation of sterilizer and manpower resources, resulting in certain risks of infection control. Thus, it is necessary to strengthen supervision, inspection and regional quality control work in infection control of dentistry.

The contamination of dental unit waterlines (DUWLs) is a major health concern since it can pose cross-infection risks among dental professionals and their patients. Silver is one of the widely used metals in medical fields due to its superior antimicrobial properties. Silver-based agents have been commercially available for the decontamination of dental unit water currently. This systematic review aims to examine the evidence supporting efficacy and safety of application of silver to decontaminate DUWLs. We performed a search of the peer-review literature of studies in six electronic databases using corresponding search terms. Eligibility was restricted to English-language studies exploring the application of silver to decontaminate dental unit water, e.g., silver-based disinfectants and silver-coated dental waterlines tubing. The search identified 148 articles, and 9 articles that met the criteria were synthesized with qualitative narrative analyses. We observed good evidence of antimicrobial efficacy of silver with hydrogen peroxide on diverse microorganism present in DUWLs. Furthermore, there is insufficient evidence on the application of silver nanoparticles (AgNPs) as an efficient material to control the biofilms in DUWLs. Post-treatment data of either the bactericidal and bacteriostatic effects of silver or AgNPs, especially the actual clinical efficacy of long-term application, are scarce. More high-quality research is needed to resolve the gap on the optimal dosage and treatment options required to control bacterial and biofilm in DUWLs with silver-containing materials.

Dental unit water systems are prone to biofilm formation. During use of the dental unit, clumps of biofilm slough off and can subsequently be aerosolized and inhaled by both patient and staff, potentially causing infections. The aim of this study was to determine the microbial load and microbiome of dental unit water, in the Netherlands, and the factors influencing these parameters. In total, 226 dental units were sampled and heterotrophic plate counts (HPC) were determined on the traditional effluent sample. Of all dental units, 61% exceeded the recommended microbiological guidelines of 100 colony forming units per milliliter. In addition, the microbiome, with additional q-PCR analysis for specific species, was determined on an effluent sample taken immediately after an overnight stagnancy period, in which the biofilm is in its relaxed state. These relaxed biofilm samples showed that each dental unit had a unique microbiome. Legionella spp., amoeba and fungi were found in 71%, 43% and 98% of all units, respectively. The presence of amoeba was positively associated with nine bacterial biomarkers and correlated positively with bacterial and fungal DNA and Legionella spp. concentrations, but not with HPC. Only when adhering to disinfection protocols, statistically significant effects on the microbial load and microbiome were seen. The relaxed biofilm sample, in combination with molecular techniques gives better insight in the presence of opportunistic pathogens when compared to the heterotrophic plate counts. Infection control measures should focus on biofilm analysis and control in order to guarantee patient safety.

UNASSIGNED: The aim of this study was to evaluate the hydrogen peroxide and cetylpyridinium chloride as bacterial decontaminants of dental unit water lines at a private Peruvian dental school.
UNASSIGNED: Water samples were obtained from 66 dental units of a University Dental Clinic before decontamination treatment and at days 3 and 7 thereafter. The biofilm treatments were applied equitably among the two treatment groups (n = 22) and one negative control (distilled water). The samples obtained on each collection day were taken to the biochemical laboratory in thermal boxes and then diluted, seeded, and incubated at 37°C for 24h to count colony forming units per milliliter (CFU/mL).
UNASSIGNED: The samples to which hydrogen peroxide were applied had a mean of 1.53 × 105 CFU/mL before application, 0.04 × 105 CFU/mL at day 3, and 0.03 × 105 CFU/mL at day 7, whereas the samples undergoing cetylpyridinium chloride treatment had a mean of 1.74 × 105 CFU/mL before application, 615.38 CFU/mL on day 3, and 307.69 CFU/mL on day 7. Distilled water treatment showed a mean of 1.72 × 105 ± 0.39 × 105 CFU/mL at baseline, 1.51 × 105 ± 1.40 × 105 CFU/mL at day 3, and a mean of 1.74 × 105 ± 0.47 × 105 CFU/mL at day 7. Statistically significant differences were found among the three treatment groups at days 3 (P ≤ 0.001) and 7 (P ≤ 0.001) but not at baseline (P = 0.306).
UNASSIGNED: The antibacterial effect of cetylpyridinium chloride was significantly greater than that of hydrogen peroxide and distilled water, and can, therefore, be used for bacterial control in the water lines of dental units.

Dental unit waterlines (DUWLs) can be considered one of the possible routes of H. pylori transmission, although its presence in DUWLs has not yet been investigated thoroughly. The present study aimed to discover the prevalence of H. pylori and oral streptococci (S. oralis and S. mutans) in DUWLs to evaluate the risk of exposure to human pathogens in dental practices. We collected the output water from 60 dental chair units (DCUs) in 26 private dentistry settings in Turin, searching for H. pylori and oral streptococci (OS) DNA, with a polymerase chain reaction (PCR) technique. At the same time, dentists completed a questionnaire about their DCUs, their main activities, the presence of anti-retraction devices, their attitudes about disinfection, etc. No dental chair unit tested was contaminated with H. pylori or S. mutans; only one dental chair was contaminated with S. oralis (1.7%). Considering the results, we can state that: (i) the lack of H. pylori DNA in water samples analyzed, suggests that municipal water is presumably treated with a sufficient chlorine level to inactivate DNA over time; (ii) the aspiration of oral fluids is limited by anti-retraction valves fitted distally to hand pieces; (iii) propidium monoazide qPCR (PMA-qPCR) could be a good technique to investigate and monitor potential environmental sources of infections such as DUWLs.

Purpose: Dental unit\'s environment and relevant instruments are a major source of infectious diseases caused by a variety of microorganisms. The application of various disinfectants is one of the most effective methods for reducing or eliminating microbial contamination. The objective of this study was to evaluate the antibacterial effects of deconex and sodium hypochlorite against bacterial taxa isolated from dental unit\'s environment of Ahvaz Jundishapur University of Medical Sciences, southwest of Iran. Methods: In order to evaluate the quality of disinfection, sampling was performed from different parts of 100 clinical units. For bacterial recovery and isolation, samples were enriched and cultured onto different microbiological culture media. Species identification was carried out using phenotypic and molecular methods (16S rDNA sequence analysis). In vitro activity of sodium hypochlorite and deconex were determined by the broth micro-dilution method. Results: According to conventional techniques, Bacillus spp (48%) was the most frequently encountered isolates, followed by staphylococcus spp (26%). By using both techniques, Bacillus subtilis was the most frequently encountered species (n=23, 21%), followed by Bacillus licheniformis (n=8, 7.4%), Streptococcus pneumonia (n=8, 7.4%), Staphylococcus epidermidis (n=8, 7.4%), Staphylococcus saprophyticus (n=8, 7.4%) and Staphylococcus warneri. The highest levels of contamination were observed in oral medications. The deconex had lower minimum inhibitory concentration (MIC) concentration in comparasion to sodium hypochlorite, which showed that deconex was a much more potent disinfectant. Conclusion: In conclusion, the results of the present in vitro study showed that deconex had promising results for decontamination of the tested microorganism, and it is recommended for disinfecting of dental units and environment. In this study, the high percentage of dental unit\'s contamination showed the need to improve disinfection procedures, sterilization systems, and the use of an appropriate concentration of deconex and sodium hypochlorite for dental units decontamination .

In 2012, an elderly immunocompromised man died from legionellosis at a hospital in Uppsala, Sweden. The patient had visited a dental ward at the hospital during the incubation period. Legionella spp. at a concentration of 2000 colony-forming units/L were isolated from the cupfiller outlet providing water for oral rinsing. Isolates from the patient and the dental unit were Legionella pneumophila serogroup 1, subgroup Knoxville and ST9. Pulsed-field gel electrophoresis and whole-genome sequencing strongly suggested that the isolates were of common origin. This report presents one of few documented cases of legionellosis acquired through a dental unit.