title: Effect of different disinfection protocols on microbial and biofilm contamination of dental unit waterlines in community dental practices.
abstract: Output water from dental unit waterlines (DUWLs) may be a potential source of infection for both dental healthcare staff and patients. This study compared the efficacy of different disinfection methods with regard to the water quality and the presence of biofilm in DUWLs. Five dental units operating in a public dental health care setting were selected. The control dental unit had no disinfection system; two were disinfected intermittently with peracetic acid/hydrogen peroxide 0.26% and two underwent continuous disinfection with hydrogen peroxide/silver ions (0.02%) and stabilized chlorine dioxide (0.22%), respectively. After three months of applying the disinfection protocols, continuous disinfection systems were more effective than intermittent systems in reducing the microbial contamination of the water, allowing compliance with the CDC guidelines and the European Council regulatory thresholds for drinking water. P. aeruginosa, Legionella spp, sulphite-reducing Clostridium spores, S. aureus and β-haemolytic streptococci were also absent from units treated with continuous disinfection. The biofilm covering the DUWLs was more extensive, thicker and more friable in the intermittent disinfection dental units than in those with continuous disinfection. Overall, the findings showed that the products used for continuous disinfection of dental unit waterlines showed statistically better results than the intermittent treatment products under the study conditions.
authors.affiliation: Unit of Hygiene, Public Health and Medical Statistics, Department of Biomedical and Neuromotor Sciences, University of Bologna, via S. Giacomo 12, Bologna 40126, Italy. laura.dallolio@unibo.it.
authors.forename: Laura
authors.initials: L
authors.lastname: Dallolio
authors.affiliation: Unit of Hygiene and Quality of Residencial Services, Bologna Local Health Authority, Bellaria Hospital, via Altura 3, Bologna 40139, Italy. amalia.scuderi@ausl.bologna.it.
authors.forename: Amalia
authors.initials: A
authors.lastname: Scuderi
authors.affiliation: Unit of Hygiene and Quality of Residencial Services, Bologna Local Health Authority, Bellaria Hospital, via Altura 3, Bologna 40139, Italy. mariasofia.rini@ausl.bologna.it.
authors.forename: Maria S
authors.initials: MS
authors.lastname: Rini
authors.affiliation: Department of Specialized, Experimental, and Diagnostic Medicine, University of Bologna, via Massarenti 9, Bologna 40138, Italy. sabrina.valente2@unibo.it.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Valente
authors.affiliation: Unit of Hygiene and Quality of Residencial Services, Bologna Local Health Authority, Bellaria Hospital, via Altura 3, Bologna 40139, Italy. patrizia.farruggia@ausl.bologna.it.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Farruggia
authors.affiliation: Bologna Provincial Division, Agency for Environmental Protection and Health Prevention in Emilia-Romagna, via Triachini 17, Bologna 40138, Italy. mbucci@arpa.emr.it.
authors.forename: Maria A Bucci
authors.initials: MA
authors.lastname: Sabattini
authors.affiliation: Department of Specialized, Experimental, and Diagnostic Medicine, University of Bologna, via Massarenti 9, Bologna 40138, Italy. gianandr.pasquinelli@unibo.it.
authors.forename: Gianandrea
authors.initials: G
authors.lastname: Pasquinelli
authors.affiliation: Unit of Hygiene and Quality of Residencial Services, Bologna Local Health Authority, Bellaria Hospital, via Altura 3, Bologna 40139, Italy. anna.acacci@ausl.bologna.it.
authors.forename: Anna
authors.initials: A
authors.lastname: Acacci
authors.affiliation: Unit of Hygiene and Quality of Residencial Services, Bologna Local Health Authority, Bellaria Hospital, via Altura 3, Bologna 40139, Italy. greta.roncarati@ausl.bologna.it.
authors.forename: Greta
authors.initials: G
authors.lastname: Roncarati
authors.affiliation: Unit of Hygiene, Public Health and Medical Statistics, Department of Biomedical and Neuromotor Sciences, University of Bologna, via S. Giacomo 12, Bologna 40126, Italy. erica.leoni@unibo.it.
authors.forename: Erica
authors.initials: E
authors.lastname: Leoni
mesh_terms: D018441:Biofilms; D003149:Community Dentistry; D003748:Dental Equipment / Q000382:microbiology*; D004203:Disinfection / Q000379:methods*; D060766:Drinking Water / Q000592:standards; D014871:Water Microbiology
chemical_list: D060766:Drinking Water