Background. Severe contamination of dental unit waterlines was found in healthcare settings. The benefits of decontamination methods are controversial. The aim of this review was to systematically evaluate disinfection methods in contamination control of dental unit waterlines. Methods. The terms ‘dental unit waterline(s) or DUWL(s) or dental unit water line(s)’ were searched through PubMed, Cochrane Library, Embase, Web of Science and Scopusup to 31 May 2021. The DUWLs’ output water was incubated on R2A agar at 20–28 °C for 5–7 days to evaluate heterotrophic mesophilic bacteria. The risk of bias was evaluated by a modified Newcastle-Ottawa quality assessment scale. Results. Eighteen papers from the literature were included. One study indicated that water supply played a crucial role in disinfecting DUWLs. Three studies indicated that flushing decreased bacteria counts but did not meet the American CDC standard (500 c.f.u. ml−1). All chlorine- and peroxide-containing disinfectants except sodium hypochlorite in one of 15 studies as well as three mouthrinses and citrus botanical extract achieved the standard (≤500 c.f.u. ml−1). The included studies were of low (1/18), moderate (6/18) and high (11/18) quality. Conclusion. Independent water reservoirs are recommended for disinfecting DUWLs using distilled water. Flushing DUWLs should be combined with disinfections. Nearly all the chlorine-, chlorhexidine- and peroxide-containing disinfectants, mouthrinses and citrus botanical extract meet the standard for disinfecting DUWLs. Alkaline peroxide would lead to tube blockage in the DUWLs. Regularly changing disinfectants can reduce the risk of occurrence of disinfectant-resistant strains of microbes.

Objectives To evaluate the effectiveness of a prevention strategy against the spread of SARS-CoV-2 infection among dental hospital staff over a 3-month period. Materials and methods The effectiveness of the prevention strategy, which adopted healthcare staff protective measures, including patient triage and correct usage of personal preventive equipment, was evaluated by SARS-CoV-2 detection and serological testing. Patients who visited the Affiliated Stomatology Hospital, Zhejiang University School of Medicine, Hangzhou, China, between January 31 and March 1 (lockdown period) and March 2 and April 27 (reopening period) in 2020 and in the same period in 2019 were included in the study. Patients’ diagnosis, age, gender, and several undergoing aerosol-generating procedures during the study period were collected from the hospital’s database. Corresponding data were compared year-on-year (2020-on-2019). A total of 757 hospital staff underwent SARS-CoV-2 detection and serological testing on April 28–29, 2020. Results During the lockdown and reopening period in 2020, the number of hospital visits was dramatically decreased to about 6% and 58%, respectively, compared with the same period in 2019. However, emergency visits were increased 16- and 6.4-fold. A total of at least 6654 patients (13.58%) underwent aerosol-generating procedures during the study period in the year 2020. All hospital staff were negative according to SARS-CoV-2 detection and serological testing (IgG, IgM) data. Conclusion During the study period in 2020, the total number of hospital visits dramatically reduced but emergency visits significantly increased. The prevention strategy implemented successfully prevented SARS-CoV-2 infection spread among healthcare workers in a dental hospital. Clinical relevance The prevention strategy indicated patient triage and how to adopt preventive measures for controlling SARS-CoV-2 spread among healthcare workers. These data can be used as a reference for other sectors suffering from the COVID-19 pandemic. Supplementary Information The online version contains supplementary material available at 10.1007/s00784-021-03886-9.

The healing of chronic wounds, which bring profound problems, can be effectively promoted by skin tissue engineering using scaffolds with features of extracellular matrix (ECM) for supporting native cell growth. Protein ultrafine fibrous scaffolds, although with similar morphology and chemical composition to ECMs, show poor wet stability which leads to substantial deformation, low mechanical properties, and fast degradation. This research provides a two-step dry state treatment including a cross-linking process by ethylene glycol diglycidyl ether (EGDE) and a blocking process by lysine for the modification of zein ultrafine fibrous scaffold model. This distinctive two-step dry state treatment could effectively avoid fiber deformation before fully cross-linking and more importantly the concern of cytotoxicity. The modified zein/EGDE scaffolds displayed remarkable reduced shrinkage of merely 1.25%, enhanced thermal stability, improved mechanical properties around 3−4 fold, retardant degradation to above 60 days, and promoted cytocompatibility about three fold. This work revealed the possibility to develop strong, wet stable, and cytocompatible ultrafine fibers from various proteins for a wide variety of applications in the fields, such as, tissue engineering scaffolds, biosensors, and drug carriers.

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