Microbial Contamination In Dental Unit Waterlines Research Articles

Dental unit waterlines and health risks of pathogenic microbial contamination: An update review

Recently, there has been great concern about the levels of oral diseases associated with inappropriate and unsanitary oral care methods. In this line, the most serious is the water contamination with pathogenic microbes. Owing to the water microbial contamination of dental units, patients' oral health is threatened as a result of systemic disorders. Patients receiving treatment in dental unit waterlines were found to be affected by dangerous bacteria. Since both clients and dental staff are exposed to aerosols and water from dental equipment, the water should be of great quality. Due to the fact that dental unit waterlines (DUWLs) create a suitable environment for microbial development and the formation of biofilms, the water is often contaminated with a high density of several microorganisms (e.g., bacteria, fungi, protozoa, viruses), causing a health problem for dentists, patients and elderly patients, especially those with immunocompromised. This has fueled interest in presenting the current situation to shed light on (i) the microbial contamination of DUWLs and (ii) the connected infectious risks. It is essential that an elevated degree of mouth care be combined with adequate water quality and preventive dental units to maintain oral comfort, prevent deterioration, and promote public health. The growing population of individuals with compromised immune systems and the latest technological advancements concerning biofilms, water quality, etc. necessitate the implementation of improved management practices and the application of decontamination protocols for waterlines.

Microbial Contamination of Dental Unit Waterlines and Potential Risk of Infection: A Narrative Review.

Several studies have revealed that dental unit waterlines (DUWLs) are often contaminated by large numbers of various micro-organisms (bacteria, fungi, protozoa, viruses). Microbial contamination in DUWLs may originate from the mains water piped into the dental unit, the suck-back of patients’ saliva into the line due to the lack of adequate valves, and contamination from bottled water systems. Some of the main determinants of microbial contamination in DUWLs are: a very small lumen size (0.5–2 mm) of the tubing used, high surface-to-volume ratio (6:1), low throughput and the materials of which the tubing is made, water stagnation outside of working hours. The environmental conditions present inside the conduits of the dental unit may facilitate the proliferation of micro-organisms and the consequent formation of biofilm on the interior surface of the pipes of DUWLs. During the use of handpieces, particularly high-speed rotating instruments, a spray is thrown up in the form of aerosols or spatters containing biological material (saliva, blood and dental plaque) and micro-organisms. This means that the health of both dental staff and patients could be at risk of infection. The risk of cross-infections in dental settings can be tackled by implementing combined interventions to prevent the contamination of DUWLs.

Disinfection effect of slightly acidic electrolyzed water on Dental unit water lines

Objective To explore the disinfection effect of slightly acidic electrolyzed water on dental unit water lines (DUWLs). Methods First, a total of 5 dental chair units (DCUs) with self-contained water supply were selected and were placed with freshly slightly acidic electrolyzed water (SAEW) every night. And then, we collected water samples from dental handpieces and water outlet of the gun for three purposes at 8 am and 12 am of the next day to count bacterial colony. This research included four stages involving that the content of effective chlorine of SAEW was about 40 mg/L with 20 days for continuous disinfection, the content of effective chlorine was about 20 mg/L with 10 days for continuous disinfection and 7 days for stopped disinfection, the content of effective chlorine was about 10 mg/L with 15 days for continuous disinfection. Results The average pass rates of water samples were 99.25%, 98.00%, 98.33% with SAEW of three different concentrations for the disinfection of DUWLs. The pass rate of water quality was changed from initial 100% to 0 without disinfection for water lines for 7 days. Conclusions There is microbial contamination in DUWLs. The disinfection effect is remarkable with SAEW for DUWLs, and there is no significant difference among DUWLs of different concentrations. Therefore, SAEW with low concentration of effective chlorine can be applied in clinic for continuous disinfection of DUWLs with self-contained water supply by taking all factors (disinfection effect, safety of dental treatment instruments, degree of comfort of patients and so on) into account. Key words: Disinfection; Slightly acidic electrolyzed water; Dental chair unit; Dental water lines

Monitoring the decontamination efficacy of the novel Poseidon-S disinfectant system in dental unit water lines.

Contaminated dental unit waterlines (DUWLs) are a known source of specific health care-acquired infections because of the difficulty in keeping them clean during routine dental practice. Recently, an electrolysis apparatus that uses only the chlorine normally present in municipal water, the Poseidon-S system, was developed as a novel additive-free disinfectant system to control microbial contamination in DUWLs. The microbiological quality of water samples collected from DUWLs was assessed before and after installation of the Poseidon-S system in terms of the total viable counts (TVCs) of microorganisms. The microbicidal effects of the electrolyzed water against oral organisms and its cytotoxicity against human oral-derived cell lines were also examined. Water samples from the DUWLs initially had average microbial TVCs of 103-106 colony-forming units (CFU)/mL. After installation of the Poseidon-S system, the number of microorganisms in the water samples decreased to less than 1×102CFU/mL. The electrolyzed water also exhibited remarkable microbicidal effects on the microorganisms present in the DUWLs as well as microorganisms commonly isolated from human oral cavities, but showed low cytotoxicity towards human oral-derived cells. This study demonstrated that routine use of the Poseidon-S system can effectively maintain low microbial levels in DUWLs.

Update on infectious risks associated with dental unit waterlines

Modern dental chair units consist of a network of interconnected narrow-bore plastic tubes called dental unit waterlines (DUWLs). The water delivered by these DUWLs acts as both a coolant for a range of instruments and an irrigant during dental treatments. The quality of water is of considerable importance because both patients and dental team are regularly exposed to water and aerosols generated by dental equipment. Studies have demonstrated that DUWLs provide a favourable environment for microbial proliferation and biofilm formation, and that water is consequently often contaminated with high densities of various microorganisms (bacteria, fungi, protozoa, viruses). The presence of high levels of microbial contamination may be a health problem for dentists and patients, especially those who are immunocompromised. The current status of knowledge on microbial contamination of DUWLs is presented, with an emphasis on the infectious risk associated with DUWLs and on the various approaches for disinfecting and protecting DUWLs.

Impact of cleaning regimes on dental water unit contamination

Microorganisms that have been identified in dental unit waterlines (DUWLs) are of concern because they can cause infections, especially in immunocompromised patients. This study aimed to assess the incidence of microbial contamination in DUWLs before and after intervention to reduce contamination, and to investigate the presence of coliforms, Escherichia coli and Pseudomonas aeruginosa. Water samples were collected aseptically from the waterlines. The high-speed hand-piece and dental chair units were served by one distillation apparatus, which was fed by the potable tap water of four dental clinics. Different interventions were used: chlorination, flushing before clinics and between patients, draining at the end of the day, and freshly distilled water on a daily basis. There was a significant difference between the level of contamination in the high-speed hand-piece (1.5-2.7 log CFU/ml) and dental chair unit water (2.0-3.5 log CFU/ml). Coliforms (0.9%) E. coli (0.9%) and Pseudomonas (1.8%) were detected during 2008. This study indicates the need to monitor water quality regularly and prevent stagnation in DUWLs to reduce the number of viable bacteria to <100 CFU/ml. We recommend flushing the DUWL for 2 min before the first patient and for 10-20 s between patients, flushing the dental unit at the end of the day and draining it overnight to reduce the development of biofilms, and chlorination of the DUWLs.