BACKGROUND: Dental Unit Water Line (DUWL) deliver water to different handpieces in a dental unit. The water in DUWL circulates in a closed system, where it is taken from a container. The quality of dental water is of considerable importance since patients and dental staff are regularly exposed to water and aerosols generated from dental equipment. Output water from DUWLs may be a potential source of infection for both dental health care personnel and patients.
OBJECTIVE: To assess the microbial contamination in the DUWL among dental clinics in Chennai.
METHODS: An in vitro study was conducted on 60 water samples from 20 dental clinics in Chennai in December 2019. Water samples were collected from three different sources of the Dental unit according to ADA guidelines. The collected samples were assessed for the presence of Aspergillus, Acinetobacter, Pseudomonas aeruginosa, and Legionella by agar plate method. The data were analysed using SPSS software version 20.
RESULTS: Legionella was the most prevalent microorganism with 70% prevalence in a three-way syringe and 50% in scaler and airotor, followed by Pseudomonas aeruginosa and Acinetobacter with 10% prevalence in scaler and airotor and Aspergillus with a prevalence of 10% in the three-way syringe.
CONCLUSIONS: Most of the dental units were contaminated with Aspergillus, Legionella, Pseudomonas aeruginosa and Acinetobacter which pose a serious threat to the patients as well as the dentists.

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BACKGROUND: Dental unit waterline (DWL) infection control is critical to infection prevention. Identifying challenges and barriers to its implementation is a first step toward understanding how to improve engagement.
METHODS: A survey was distributed to dentists, dental hygienists, and dental assistants via the Qualtrics XM platform (Qualtrics). Responses were analyzed to quantify engagement in practices contrary to Centers for Disease Control and Prevention guidance and identify avenues to improve engagement.
RESULTS: Although oral health care providers recognized DWL infection control was important, there was a lack of clarity about appropriate routine engagement (eg, what lines should be tested), what should be noted in practice infection control records, and steps to be taken in response to a failed test result (ie, ≥ 500 colony-forming units/mL), such as taking a chair out of service.
CONCLUSIONS: Survey results showed there were considerable gaps in knowledge and practice that could lead to patient harm. Oral health care provider training may not prepare personnel adequately to engage in, let alone supervise, DWL infection control. DWL infection control, like other aspects of infection control, requires action informed via an understanding of what needs to be done. Although good intentions are appreciated, better approaches to DWL infection control information dissemination and strategies to engage dental assistants, dental hygienists, and dentists in best practices are needed.
CONCLUSIONS: Evolving standards of care, including infection control, should be reflected in the provision of dental treatment. Improvements in communicating and ensuring engagement in best practices are needed when it comes to DWL infection control.

BACKGROUND: Ensuring the safety of dental unit waterlines (DUWLs) has become a pivotal issue in dental care practices, focusing on the health implications for both patients and healthcare providers. The inherent structure and usage conditions of DUWLs contribute to the risk of biofilm formation and bacterial growth, highlighting the need for effective disinfection solutions.The quest for a disinfection method that is both safe for clinical use and effective against pathogens such as Staphylococcus aureus and Escherichia coli in DUWLs underscores the urgency of this research.
METHODS: Chlorine dioxide disinfectants at concentrations of 5, 20, and 80 mg/L were used to treat biofilms of S. aureus and E. coli cultured in DUWLs. The disinfection effectiveness was assessed through bacterial counts and culturing. Simultaneously, human skin fibroblast cells were treated with the disinfectant to observe changes in cell morphology and cytotoxicity. Additionally, the study included corrosion tests on various metals (carbon steel, brass, stainless steel, aluminum, etc.).
RESULTS: Experimental results showed that chlorine dioxide disinfectants at concentrations of 20 mg/L and 80 mg/L significantly reduced the bacterial count of S. aureus and E. coli, indicating effective disinfection. In terms of cytotoxicity, higher concentrations were more harmful to cellular safety, but even at 80 mg/L, the cytotoxicity of chlorine dioxide remained within controllable limits. Corrosion tests revealed that chlorine dioxide disinfectants had a certain corrosive effect on carbon steel and brass, and the degree of corrosion increased with the concentration of the disinfectant.
CONCLUSIONS: After thorough research, we recommend using chlorine dioxide disinfectant at a concentration of 20 mg/L for significantly reducing bacterial biofilms in dental unit waterlines (DUWLs). This concentration also ensures satisfactory cell safety and metal corrosion resistance.

OBJECTIVE: Ultrasonic scaling is extensively applied as part of the initial therapy for periodontal diseases, which has been restricted since the outbreak of the COVID-19 pandemic due to droplets and aerosols generated by ultrasonic devices. An extraoral scavenging device (EOS) was designed for diminishing droplets and aerosols in dental clinics. The objective of this study is to evaluate the effect of EOS on eliminating droplets and aerosols during ultrasonic supragingival scaling.
METHODS: This single-blinded, randomised controlled clinical trial enrolled 45 patients with generalised periodontitis (stage I or II, grade A or B) or plaque-induced gingivitis. The patients were randomly allocated and received ultrasonic supragingival scaling under three different intervention measures: only saliva ejector (SE), SE plus EOS and SE plus high-volume evacuation (HVE). The natural sedimentation method was applied to sample droplets and aerosols before or during supragingival scaling. After aerobic culturing, colony-forming units (CFUs) were counted and analysed.
RESULTS: Compared with the level before treatment, more CFUs of samples throughout treatment could be obtained at the operator\'s chest and the patient\'s chest and the table surface when using SE alone (p < 0.05). Compared with the SE group, the SE + EOS group and the SE + HVE group obtained decreasing CFUs at the operator\'s chest and the patient\'s chest (p < 0.05), while no significant difference was determined between these two groups.
CONCLUSIONS: The EOS effectively eliminated splatter contamination from ultrasonic supragingival scaling, which was an alternative precaution for nosocomial contamination in dental clinics.

Water contamination in dental unit waterlines (DUWLs) is a potential source of healthcare-associated infection during dental care. The aim of this study was to evaluate the microbiological quality of DUWLs water from newly installed dental chairs in a French University Hospital. The microbiological quality of water from 24 new DUWLs initially disinfected by ICX Renew-prior to use of the dental units for patient treatment-was assessed for total culturable aerobic bacteria at 22°C and 36°C, Legionella sp., Pseudomonas aeruginosa, and total coliforms. Among the 24 samples analyzed, 21 were compliant with the water quality levels: 19 had no bacteria, and 2 contained only 4 and 1 CFU/mL for total culturable aerobic bacteria at 22°C and 36°C, respectively. Three samples were non-compliant due to contamination by P. aeruginosa (4, 2, and 2 CFU/100 mL). Controlling and preventing the microbiological contamination of DUWLs, especially by pathogenic bacteria, at the time of the installation of the new dental chairs are crucial to prevent healthcare-associated infection in dentistry.
OBJECTIVE: Dental unit waterlines (DUWLs) of new dental chairs may be contaminated before their first clinical use, so an initial shock disinfection is crucial at the time of their installation. The microbiological analyses are crucial to control the water quality of DUWLs before their first clinical use because their disinfection does not guarantee the elimination of all bacteria.

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Quantitative analysis of irregular anatomical structures is crucial in oral medicine, but clinicians often typically measure only several representative indicators within the structure as references. Deep learning semantic segmentation offers the potential for entire quantitative analysis. However, challenges persist, including segmentation difficulties due to unclear boundaries and acquiring measurement landmarks for clinical needs in entire quantitative analysis. Taking the palatal alveolar bone as an example, we proposed an artificial intelligence measurement tool for the entire quantitative analysis of irregular dental structures. To expand the applicability, we have included lightweight networks with fewer parameters and lower computational demands. Our approach finally used the lightweight model LU-Net, addressing segmentation challenges caused by unclear boundaries through a compensation module. Additional enamel segmentation was conducted to establish a measurement coordinate system. Ultimately, we presented the entire quantitative information within the structure in a manner that meets clinical needs. The tool achieved excellent segmentation results, manifested by high Dice coefficients (0.934 and 0.949), intersection over union (0.888 and 0.907), and area under the curve (0.943 and 0.949) for palatal alveolar bone and enamel in the test set. In subsequent measurements, the tool visualizes the quantitative information within the target structure by scatter plots. When comparing the measurements against representative indicators, the tool\'s measurement results show no statistically significant difference from the ground truth, with small mean absolute error, root mean squared error, and errors interval. Bland-Altman plots and intraclass correlation coefficients indicate the satisfactory agreement compared with manual measurements. We proposed a novel intelligent approach to address the entire quantitative analysis of irregular image structures in the clinical setting. This contributes to enabling clinicians to swiftly and comprehensively grasp structural features, facilitating the design of more personalized treatment plans for different patients, enhancing clinical efficiency and treatment success rates in turn.

UNASSIGNED: : The aim of this study was to measure the amount of material extruded in the periapical area using three irrigation needles (Max-I-Probe, NaviTip Fx and IrriFlex flexible needle).
UNASSIGNED: : Mandibular premolars were selected for this study and glass vials were used to gather the extruded debris and they were preweighed. The samples were divided into two groups: Group A (1 mm penetration of needle from working length), which was subdivided into three subgroups: Subgroup A1: Irrigation was made by Max-I-Probe. Subgroup A2: Irrigation was made by NaviTip Fx. Subgroup A3: Irrigation was made by IrriFlex flexible needle. Group B (3 mm penetration of needle), which was subdivided into three subgroups: Subgroup B1: Irrigation was made by Max-I-Probe. Subgroup B2: Irrigation was made by NaviTip Fx. Subgroup B3: Irrigation was made by IrriFlex flexible needle. XP-endo Shaper was used for chemomechanical preparation. After removal from vials, the teeth were incubated and then removed from the incubator and weighed again three times. The average of the readings was taken. Analysis of variance (ANOVA) and least significance difference tests were applied to analyse data.
UNASSIGNED: : All of the needles caused debris extrusion. There was a significant difference between groups (P ≤ 0.001) according to the depth of penetration. The lowest value for debris was observed in subgroup B3 while subgroup A2 had shown the highest mean.
UNASSIGNED: Results revealed that the design and depth of needles significantly affected the debris extrusion. Using more flexible needles and shorter penetration depth for irrigation so that we don\'t need to push the needles so far apically.

This retrospective study examined the dental unit waterline (DUWL) testing practices of Saskatchewan dental clinics over a period of 11 years, with an emphasis on their responses after identification of high microbial levels.
Dental clinics (n = 137) aseptically collected samples of output water from their air/water syringes, handpieces, and ultrasonic scaler lines using Sigma-Aldrich® waterline test kits and delivered them to a quality assurance laboratory. Tests were incubated for seven days at room temperature, and those with heterotrophic plate counts > 500 CFU/mL were reported as failures. Statistical analyses were performed on a database containing 4,093 test results.
Participating clinics submitted an average of 11 DUWL tests per year. Overall, 21% of tests failed, and a moderate positive association (rs=.52, p < 0.001) was found between clinics\' DUWL testing frequency and failure rate. Only 7% of failed DUWL tests were followed up by collection of a subsequent test within two weeks, of which 47% still exceeded the 500 CFU/mL threshold.
Our findings demonstrate an association between DUWL testing frequency and detection of unacceptable microbial levels, along with infrequent retesting and often-inadequate intervention after a failed test. This suggests the need for further efforts at the regulatory and educational levels to maintain adequate water quality during dental treatment.
Procedural water can become contaminated in DUWLs and endanger patients. Regular DUWL monitoring and evidence-based interventions to treat contaminated systems are necessary to safeguard patient health.