Biofilm problems in dental unit water systems and its practical control

Abstract

Dental chair units (DCUs) contain integrated systems that provide the instruments and services for a wide range of dental procedures. DCUs use water to cool and irrigate DCU-supplied instruments and tooth surfaces during dental treatment. Water is supplied to these instruments by a network of interconnected narrow-bore (2-3 mm) plastic tubes called dental unit waterlines (DUWLs). Many studies over the last 40 years demonstrated that DUWL output water is often contaminated with high densities of micro-organisms, predominantly Gram-negative aerobic heterotropic environmental bacteria, including Legionella and Pseudomonas species. Untreated DUWLs host biofilms that permit micro-organisms to multiply and disperse through the water network and which are aerosolized by DCU instrument use, thus exposing patients and staff to these micro-organisms, to fragments of biofilm and bacterial endotoxins. This review concentrates on how practical developments and innovations in specific areas can contribute to effective DUWL biofilm control. These include the use of effective DUWL treatment agents, improvements to DCU supply water quality, DCU design changes, development of automated DUWL treatment procedures that are effective at controlling biofilm in the long-term and require minimal human intervention, are safe for patients and staff, and which do not cause deterioration of DCU components following prolonged use.

First report of an acute purulent maxillary sinusitis caused by Pseudomonas aeruginosa secondary to dental implant placement in an immunocompetent patient

“…Numerous studies have shown that the problem of bacterial contamination of dental unit water lines (DUWLs) is widespread. [6][7][8][9][10] Microbial DUWLs contamination generally arises from municipal water piped into the dental unit, working handpieces of a unit, suck-back of patient saliva into the line, and the biofilm formed inside DUWLs. In particular, biofilms -sessile microbial communities exhibiting greater resistance to surfactants, biocides and antibiotics than their planktonic counterpart 10 -can constantly release bacteria, 11 thus providing a reservoir for continuous high-level contamination of DUWLs.…”

“…[6][7][8][9][10] Microbial DUWLs contamination generally arises from municipal water piped into the dental unit, working handpieces of a unit, suck-back of patient saliva into the line, and the biofilm formed inside DUWLs. In particular, biofilms -sessile microbial communities exhibiting greater resistance to surfactants, biocides and antibiotics than their planktonic counterpart 10 -can constantly release bacteria, 11 thus providing a reservoir for continuous high-level contamination of DUWLs. 6,12,13 P. aeruginosa is the most frequent contaminant of DUWLs, being isolated in up to 50% of samples of dental unit water at concentrations of up to 2 × 10 5 CFU/ml.…”

Contaminação Microbiana das Soluções de Processamento Radiográfico: Risco de Infecção Cruzada

“…A modesta contaminação da fonte externa de água dos consultórios e clínicas evidencia que a problemática da contaminação da água do equipo e do processamento radiográfico é consequência da própria rotina do consultório e não se origina fora dele 5 .…”

“…Dentre esses patógenos destacam-se os gêneros Enterococcus e Pseudomonas, além de microrganismos da família Enterobacteriaceae 2,3 . Por vezes, esses microrganismos se originam da própria cavidade bucal dos pacientes ou do sistema de água do consultório 5 . Esses microrganismos podem se incorporar às soluções utilizadas no processamento radiográfico, formando biofilme nos reservatórios nas câmaras escuras, facilitando a sobrevivência microbiana 3 .…”

Is water in dental units microbiologically safe?

“…Among the most common bacteria found in dental unit waterlines are, among others, Legionella pneumophila, Pseudomonas aeruginosa, Staphylococcus aureus, Ralstonia pickettii, Arthrobacter woluwensis, Microbacterium testaceum, and bacteria of the genus Brevibacterium, Corynebacterium, Enterococcus and Micrococcus. Human -derived bacteria may get into dental unit waterlines most often as a result of secondary contamination, e.g., by aspiration of patient material back into the handpiece or water lines or they can get into dental unit waterlines from water bottles [12][13][14][15][16].…”