Analysis of microbial communities of ocular prostheses and anophthalmic sockets using 16S rRNA gene sequencing.

Ocular prostheses are liable to host microbial adhesion, which can favor conjunctival inflammation. Knowing the microbiota of the ocular prosthesis and anophthalmic socket is important for predicting infection-related pathogens. This study evaluated the microbiota of the prostheses and anophthalmic sockets of six individuals by 16S rRNA sequencing. The microbial abundance and diversity were analyzed using the Operational Taxonomic Units at the genus level. Forty-seven phyla, capturing 1,258 named genera, were recorded in the sample set. In both sites, the most frequent genera were Fusobacterium, Staphylococcus, Prevotella, and Streptococcus. The microbial abundance was higher for the anophthalmic socket than for the prosthesis. Alpha diversity showed no significant differences in bacterial richness or diversity between sites. Although the microbial abundance in the anophthalmic socket was higher, both sites had similar microbiota with high diversity and low dominance among the genera.

Influence of antimicrobial photodynamic therapy with different pre-irradiation times on children's dental biofilm: randomized clinical trial.

PURPOSE: Photodynamic therapy (PDT) is effective in reducing pathogenic microorganisms in the oral cavity and in preventing dental diseases. This study evaluated the pre-irradiation time using PDT (diode laser associated with 0.01% methylene blue) to decrease the number of microorganisms in the visible plaque in permanent teeth. METHODS: This randomized clinical trial included 108 homologous lower permanent first molars (36 and 46) with biofilm from 54 children aged six to 12 years. PDT was performed (0.01% methylene blue photosensitizer/therapeutic laser-InGaAIP), according to the following protocols: Group 1, biofilm collection of the distal area of the lingual surface of 36 µm before PDT; group 2, mesial area of the lingual surface of 36 µm 1 min after PDT; group 3, area of the lingual surface of 46 µm before PDT; and group 4, mesial area of the lingual surface of 46 µm 5 min after PDT. RESULTS: After statistical analysis, significant differences were observed between the groups (p = 0.000). In groups 2 and 4, the number of bacteria tended to decrease, with a more evident bacterial reduction in group 4. CONCLUSIONS: Pre-irradiation reduced the number of colony-forming units of mature bacterial biofilms in vivo. A time of 5 min resulted in a greater reduction in the number of colony-forming units. CLINICAL TRIAL REGISTRATION: ReBEC Identifier: RBR-6bqfp3; Date of Register: March 2nd, 2020. Retrospectively Registered.

Complex design of surgical instruments as barrier for cleaning effectiveness, favouring biofilm formation.

BACKGROUND: Inadequately reprocessed reusable surgical instruments (RSIs) may harbour infectious agents which may then be transferred to a suitable site for replication. AIM: To determine the cumulative effect of 20 cycles of contamination, cleaning (manual or manual followed by automated) and steam sterilization on high-complex-design RSIs used for orthopaedic surgery. METHODS: New flexible medullary reamers and depth gauges were contaminated by soaking in tryptone soya broth, containing 5% sheep blood and 109 cfu/mL of Staphylococcus aureus (ATCC 25923), for 5 min. To mimic a worse-case scenario, RSIs were dried 7 h and subjected to either (a) rinsing in distilled water, (b) manual cleaning or (c) manual plus automated cleaning (reference standard), and steam sterilization. The contamination, cleaning, and sterilization cycle was repeated 20 times. Adenosine triphosphate (ATP) was measured after cleaning procedures; microbial load and residual protein were measured following the 10th and 20th reprocessing, in triplicate. Scanning electron microscopy (SEM) was used to confirm soil and biofilm presence on the RSIs after the 20th reprocessing. FINDINGS: Manual and manual plus automated cleaning significantly reduced the amount of ATP and protein residues for all RSIs. Viable bacteria were not detected following sterilization. However, SEM detected soil after automated cleaning, and soil, including biofilms, after manual cleaning. CONCLUSION: Soil and/or biofilms were evident on complex-design RSIs following 20 cycles of contamination and reprocessing, even using the reference standard method of cleaning. Although the depth gauges could be disassembled, biological residues and biofilm accumulated in its lumen. The current design of these RSIs prevents removal of all biological soil and this may have an adverse effect on patient outcome.

Analysis of the Beaufort Gyre Freshwater Content in 2003-2018.

Hydrographic data collected from research cruises, bottom-anchored moorings, drifting Ice-Tethered Profilers, and satellite altimetry in the Beaufort Gyre region of the Arctic Ocean document an increase of more than 6,400 km3 of liquid freshwater content from 2003 to 2018: a 40% growth relative to the climatology of the 1970s. This fresh water accumulation is shown to result from persistent anticyclonic atmospheric wind forcing (1997-2018) accompanied by sea ice melt, a wind-forced redirection of Mackenzie River discharge from predominantly eastward to westward flow, and a contribution of low salinity waters of Pacific Ocean origin via Bering Strait. Despite significant uncertainties in the different observations, this study has demonstrated the synergistic value of having multiple diverse datasets to obtain a more comprehensive understanding of Beaufort Gyre freshwater content variability. For example, Beaufort Gyre Observational System (BGOS) surveys clearly show the interannual increase in freshwater content, but without satellite or Ice-Tethered Profiler measurements, it is not possible to resolve the seasonal cycle of freshwater content, which in fact is larger than the year-to-year variability, or the more subtle interannual variations.

Multiscale properties of instantaneous parasympathetic activity in severe congestive heart failure: A survivor vs non-survivor study.

Multifractal analysis of cardiovascular variability series is an effective tool for the characterization of pathological states associated with congestive heart failure (CHF). Consequently, variations of heartbeat scaling properties have been associated with the dynamical balancing of nonlinear sympathetic/vagal activity. Nevertheless, whether vagal dynamics has multifractal properties yet alone is currently unknown. In this study, we answer this question by conducting multifractal analysis through wavelet leader-based multiscale representations of instantaneous series of vagal activity as estimated from inhomogeneous point process models. Experimental tests were performed on data gathered from 57 CHF patients, aiming to investigate the automatic recognition accuracy in predicting survivor and non-survivor patients after a 4 years follow up. Results clearly indicate that, on both CHF groups, the instantaneous vagal activity displays power-law scaling for a large range of scales, from ≃ 0.5s to ≃ 100s. Using standard SVM algorithms, this information also allows for a prediction of mortality at a single-subject level with an accuracy of 72.72%.

In vitro biomechanical comparison of six different fixation methods following 5-mm sagittal split advancement osteotomies.

The sagittal split ramus osteotomy (SSRO) is a surgical technique used widely to treat many congenital and acquired mandibular discrepancies. Stabilization of the osteotomy site and the potential for skeletal relapse after the procedure are still major problems. The aim of this study was to compare the mechanical stability of six methods of rigid fixation in SSRO using a biomechanical test model. Sixty polyurethane replicas of human hemimandibles were divided into six groups. In group I, the osteotomies were fixed with two four-hole titanium miniplates; in group II, with one four-hole miniplate; in group III, with one four-hole miniplate+a bicortical screw; in group IV, with a grid miniplate; in group V, with a four-hole locking miniplate; and in group VI, with a six-hole miniplate. A linear load in the premolar region was applied to the hemimandibles. The resistance forces (N) needed to displace the distal segment by 1, 3, and 5mm were recorded and the data transmitted from the load cell to a computer. One-way analysis of variance with Tukey's post hoc test was performed to compare the means between groups. For the three displacement conditions, there was a strong tendency for the 2.0-mm plate+screw and the grid plate to have higher values.

Point-process high-resolution representations of heartbeat dynamics for multiscale analysis: A CHF survivor prediction study.

Multiscale analysis of human heartbeat dynamics has been proved effective in characterizeing cardiovascular control physiology in health and disease. However, estimation of multiscale properties can be affected by the interpolation procedure used to preprocess the unevenly sampled R-R intervals derived from the ECG. To this extent, in this study we propose the estimation of wavelet coefficients and wavelet leaders on the output of inhomogeneous point process models of heartbeat dynamics. The RR interval series is modeled using probability density functions (pdfs) characterizing and predicting the time until the next heartbeat event occurs, as a linear function of the past history. Multiscale analysis is then applied to the pdfs' instantaneous first order moment. The proposed approach is tested on experimental data gathered from 57 congestive heart failure (CHF) patients by evaluating the recognition accuracy in predicting survivor and non-survivor patients, and by comparing performances from the informative point-process based interpolation and non-informative spline-based interpolation. Results demonstrate that multiscale analysis of point-process high-resolution representations achieves the highest prediction accuracy of 65.45%, proving our method as a promising tool to assess risk prediction in CHF patients.

Characterization of mesenchymal progenitor cells in crown and root pulp from human mesiodentes.

OBJECTIVE: Mesiodentes are usually found in the central position of the upper or lower jaw as supernumerary teeth. Here, we obtained 10 mesiodentes and three permanent teeth (PT) and separated the dental pulp (DP) from these into crown and root portions. We then characterized and compared the isolated crown portion-derived cells (crown cells) with root portion-derived cells (root cells) using a range of in vitro assays. MATERIALS AND METHODS: Crown cells and root cells were examined for cell surface marker expression, colony-forming unit-fibroblast (CFU-F), cell proliferation, cell cycle characteristics and markers, and osteogenic and adipogenic differentiation. RESULTS: The proportion of CD105-positive cells (CD105(+) cells) in the crown cells vs the root cells varied among the mesiodentes, but not among the PT. When there were more CD105(+) cells in the root cells than in the crown cells, the root cells showed higher CFU-F, proliferation capacity, and osteogenic differentiation capacity. In contrast, when the crown cells contained more CD105(+) cells than the root cells, the crown cells showed the higher CFU-F, proliferation capacity, and osteogenic differentiation capacity. In addition, the sorted CD105(+) cells showed higher CFU-F and proliferation capacity than the sorted CD105(-) cells. CONCLUSION: These results indicated that proportion of CD105(+) cells is an effective means of characterizing DP-derived cells in mesiodentes.

Antibiofilm activity of irrigating solutions associated with cetrimide. Confocal laser scanning microscopy.

AIM: To evaluate the antibiofilm activity of sodium hypochlorite (NaOCl) and chlorhexidine (CHX) solutions associated with cetrimide (CTR), and QMiX using confocal laser scanning microscopy. METHODOLOGY: Enterococcus faecalis (ATCC- 29212) biofilms were induced on bovine dentine blocks for 14 days. The dentine blocks containing biofilm were immersed for 1 min in the following solutions: 2.5% NaOCl; 2.5% NaOCl + 0.2% CTR; 2% CHX; 2% CHX + 0.2% CTR; 0.2% CTR; QMiX. After contact with the solutions, the dentine blocks were stained with Live/Dead(®) BacLight for analysis of the remaining biofilm using confocal laser scanning microscope. Images were evaluated using the BioImage_L software to determine the total biovolume (µm(3) ), the green biovolume (live cells) (µm(3) ) and the percentage of substrate coverage (%). The data were subjected to nonparametric statistical test using Kruskal-Wallis and Dunn's tests at 5% significance level. RESULTS: After exposure to irrigants, the total biovolume observed for CHX, CHX+CTR, CTR, QMiX was similar to distilled water (P > 0.05). NaOCl and NaOCl+CTR had the lowest total and green biovolume. The CTR and QMiX had intermediate green biovolume, with greater antibacterial activity than CHX and CHX+CTR (P < 0.05). The NaOCl and NaOCl+CTR solutions were associated with microorganism removal and substrate cleaning ability. CONCLUSIONS: NaOCl and NaOCl+CTR solutions were effective on microorganism viability and were able to eliminate biofilm. The addition of cetrimide did not influence antibacterial activity.

Volumetric upper airway assessment in patients with transverse maxillary deficiency after surgically assisted rapid maxillary expansion.

Transverse maxillary deficiency is commonly found in patients with sleep apnea and is also related to abnormal breathing patterns. Maxillary expansion procedures promote widening of the nasal floor and reduce the resistance to airflow, and have a positive influence on nasopharynx function. In order to evaluate volume changes in the upper airway, 15 adult patients with transverse maxillary deficiency underwent surgically assisted rapid maxillary expansion (RME) until a slight overcorrection of the crossbite was obtained. Cone beam computed tomography (CBCT) volumetric images were obtained at three predefined time points. The mean age of the patients was 30.2 (±7.4) years; nine were females and six were males. The area, volume, and the smallest transverse section area of the airway were assessed using Dolphin Imaging 3D software. Statistical comparisons were made of the changes between time periods. No statistically significant differences were found for volume or area. However a significant difference was found between the preoperative and immediate postoperative smallest transverse section area (P<0.05). Maxillary expansion, as an isolated procedure, does not result in a statistically significant improvement in the airway dimensions and results in an inferior relocation of the smallest transverse section area.

Multiscale wavelet p-leader based heart rate variability analysis for survival probability assessment in CHF patients.

A priori discrimination of high mortality risk amongst congestive heart failure patients constitutes an important clinical stake in cardiology and involves challenging analyses of the temporal dynamics of heart rate variability (HRV). The present contribution investigates the potential of a new multifractal formalism, constructed on wavelet p-leader coefficients, to help discrimination between survivor and non survivor patients. The formalism, applied to a high quality database of 108 patients collected in a Japanese hospital, enables to assess the existence of multifractal properties amongst congestive heart failure patients and to reveal significant differences in the multiscale properties of HRV between survivor and non survivor patients, for scales ranging from approximately 60 to 250 beats.

Effect of local anesthesia on trigeminal somatosensory-evoked magnetic fields.

For objective neurophysiological evaluation of the function of the trigeminal system, magnetoencephalography- based TSEF (trigeminal somatosensory-evoked field) assessment would be valuable in providing spatial and temporal profiles of cortical responses. However, this necessitates knowledge of how TSEF varies with trigeminal nerve dysfunctions. We introduced a conduction block of the trigeminal nerve using local anesthesia (lidocaine) to temporally mimic nerve dysfunctions, and monitored TSEF changes. Following an electrical stimulation of the lower lip, a magnetic response with peak latency of approximately 20 ms was identified in all participants. Dipole for the peak was estimated on the post-central gyrus in the participant's own magnetic resonance image. After normalization to Montreal Neurological Institute (MNI) space and inter-participant data integration, the summary equivalent current dipole localization among participants remained in the post-central gyrus, suggesting validity of the use of MNI space. Partial anesthesia of the lower lip led to a loss of the waveform characteristics of TSEF for electrical stimulation to the trigeminal nerve. We verified that the 20-ms latency cortical response of TSEF components localized at the primary sensory cortex can serve as a robust neurofunctional marker of experimental trigeminal nerve dysfunction.

Validation of a commercial ELISA for the analysis of the insecticide dinotefuran in a variety of analytically challenging vegetables.

The main objective of this paper was to assess the suitability of an enzyme-linked immunosorbent assay (ELISA) as a rapid and simple screening method for the detection of neonicotinoid insecticide dinotefuran residues in various vegetable samples including carrot, cabbage, green pepper, leek, Japanese mustard spinach (komatsuna), and spinach. Simple dilution of crude sample extracts was effective to circumvent or reduce matrix interference derived from samples. Consequently, ELISA was useful to determine dinotefuran accurately and directly, only requiring methanol extraction and dilution with water. The theoretically estimated limit of detection of dinotefuran for tested samples ranged from 0.06 to 0.12 mg kg(-1). The ELISA gave recovery values close to 100% for all samples except komatsuna, which contained lower concentration levels, and the results of the ELISA agreed well with those obtained with conventional HPLC (r > 0.99). Results show that the ELISA evaluated in this study is suitable for the rapid and simple screening method of dinotefuran residue in agricultural samples even without sample pre-treatment.

PP022 The haemostatic suture (technique of B-Lynch) may be an alternative to control uterine hemorrhage associated with hypertensive disorders.

INTRODUCTION: Postpartum haemorrhage is an important cause of maternal morbidity and mortality, uterine atony being responsible for most of the cases. Hypertensive disorders are supposed to increase the possibility of such complications, mainly when complicated by "abruptio placentae". The classical treatments for postpartum haemorrhage have been based on medications like oxytocin and misoprostol, but more recently a haemostatic uterine suture developed by Christopher B-Lynch has been indicated. Here, we describe our experience of performing such technique and investigate its results in patients complicated by hypertensive disorders. OBJECTIVES: Reporting a series of cases of postpartum haemorrhage treated with the B-Lynch suture. METHODS: This is a descriptive study including 39 patients treated with the B-Lynch suture after postpartum haemorrhage related to uterine atony. The period evaluated was between January 2005 and February 2012. Intravascular oxytocin was routinely used in all cases, with doses changing from 20 to 60 IU. The suture material used was chromed catgut 1.0mm. RESULTS: The mode of delivery was cesarean-section in all cases. Five patients (12.8%) had hypertensive disorder as additional complication and one of these patients had abruptio placentae followed by development of Couvelaire uterus. Overall, the B-Lynch technique helped to control haemorrhage in all cases evaluated. CONCLUSION: We believe that the B-Lynch technique appears as an important procedure to be indicated in cases of postpartum haemorrhage. Therefore, we recommend that this technique should be tried to control such complications before deciding for other more aggressive procedures like hysterectomy. It seems that this treatment may be used in patients complicated by hypertensive disorders.

Outcomes after ischemic stroke for hospitals with and without Joint Commission-certified primary stroke centers.

BACKGROUND: The Joint Commission (JC) began certifying primary stroke centers (PSCs) in the United States in 2003. We assessed whether 30-day risk-standardized mortality (RSMR) and readmission (RSRR) rates differed between hospitals with and without JC-certified PSCs in 2006. METHODS: The study cohort included all fee-for-service Medicare beneficiaries ≥65 years old discharged with a primary diagnosis of ischemic stroke (International Classification of Diseases, ninth revision, Clinical Modification 433, 434, 436) in 2006. Hierarchical linear regression models calculated hospital-level RSMRs and RSRRs, adjusting for patient demographics, comorbid conditions, and hospital referral region. Hospitals were categorized as being higher than, no different from, or lower than the national average. RESULTS: There were 310,381 ischemic stroke discharges from 315 JC-certified PSC and 4,231 noncertified hospitals. Mean overall 30-day RSMR and RSRR were 10.9% ± 1.7% and 12.5% ± 1.4%, respectively. The RSMRs of hospitals with JC-certified PSCs were lower than in noncertified hospitals (10.7% ± 1.7% vs 11.0% ± 1.7%), but the RSRRs were comparable (12.5% ± 1.3% vs 12.4% ± 1.7%). Almost half of JC-certified PSC hospitals had RSMRs lower than the national average compared with 19% of noncertified hospitals, but 13% of JC-certified PSC hospitals had lower RSRRs vs 15% of noncertified hospitals. CONCLUSIONS: Hospitals with JC-certified PSCs had lower RSMRs compared with noncertified hospitals in 2006; however, differences were small. Readmission rates were similar between the 2 groups. PSC certification generally identified better-performing hospitals for mortality outcomes, but some hospitals with certified PSCs may have high RSMRs and RSRRs whereas some hospitals without PSCs have low rates. Unmeasured factors may contribute to this heterogeneity.

Associations of maternal employment and three-generation families with pre-school children's overweight and obesity in Japan.

BACKGROUNDS: Maternal employment has been shown to be associated with childhood overweight and obesity (Ow/Ob), but the presence of family members who care for children in place of the mothers might influence children's Ow/Ob and lifestyles. The influence of maternal employment on children's Ow/Ob should be examined together with the presence of caregivers such as grandparents. OBJECTIVES: The effects of maternal employment and the presence of grandparents on lifestyles and Ow/Ob in Japanese pre-school children were investigated. DESIGN/SUBJECTS: Cross-sectional study on 2114 children aged 3-6 years who attended all childcare facilities in a city and primary caregivers was conducted. MEASUREMENTS: Children's weight and height, family environments (family members, maternal employment, single parent, number of siblings and parental Ow/Ob) and lifestyles (dietary, physical activity and sleeping habits) were surveyed using a self-administered questionnaire. Ow/Ob was defined by the International Obesity Task Force cut-offs. RESULTS: The eligible participants were 1765 children. The prevalence of Ow/Ob was 8.4% in boys and 9.9% in girls. Maternal employment was associated positively with irregular mealtimes, unfixed snacking times, bedtime after 10 p.m. and nighttime sleep duration of less than 10 h, whereas three-generation families were associated negatively with irregular mealtimes after adjustment for children's characteristics and family environments. Irregular mealtimes (OR (95% CI); 2.03 (1.36, 3.06)) and nighttime sleep duration of less than 10 h (1.96 (1.28, 3.01)) were associated with increased risks of being Ow/Ob. Both maternal employment and three-generation families were significantly associated with children's Ow/Ob. However, three-generation families maintained a significant association (1.59 (1.08, 2.35)) after adjustment for maternal employment. CONCLUSIONS: These study results suggest that the grandparents who care for pre-school children in place of mothers are more likely to contribute to childhood Ow/Ob than maternal employment. The family-focused lifestyle strategies to prevent childhood Ow/Ob must include grandparents who care for children.

Fouling potentials of polysaccharides in membrane bioreactors (MBRs) assessed by lectin affinity chromatography.

In this study, the fouling potentials of polysaccharides contained in mixed liquor suspension in a membrane bioreactor (MBR) treating municipal wastewater were investigated using lectin affinity chromatography. This investigation was carried out with different membranes to assess the effects of membrane materials on fouling potentials of polysaccharides. In lectin affinity chromatography, some polysaccharides with high affinity to the lectin in the column can be retained in the column. The fouling potentials of the retained polysaccharides were evaluated by dead-end filtration test. Degree of reduction in fouling potential differed considerably when different lectins were used in affinity chromatography indicating that fouling potentials of polysaccharide differed depending on types of polysaccharide. Trends in the reduction of fouling potential were different depending on membrane materials. Characteristics of the organic matter associated with polysaccharides removed by lectins were investigated by means of excitation-emission matrices (EEM). The results of EEM analysis indicate that the characteristics of the organic matter eluted from different lectins were different as long as elution reagents for the lectin were different. Characteristics of the organic matter eluted from the lectins which have the same elution reagent were similar in terms of shapes of EEM fluorescence spectra. However, the trends in reduction of fouling potentials could not be explained by the characteristics of organic matter assessed by EEM analysis. On the basis of the results obtained in this study, it can be concluded that characteristics of membrane and structures or properties of sugar chain would play an important role in determining fouling potentials.

Protected endovascular revascularization of subacute and chronic total occlusion of the internal carotid artery.

BACKGROUND AND PURPOSE: The natural course of symptomatic carotid artery occlusion with hemodynamic impairment is poor. Surgical revascularization may improve the outcome; however, its efficacy has not been established yet. The goal of this study was to characterize the technical and clinical outcomes following endovascular recanalization of the ICA under cerebral circulatory protection. MATERIALS AND METHODS: Endovascular recanalization was attempted in 8 patients with symptomatic ICA occlusions. The duration of the occlusion ranged from 7 days to 7 months (mean, 2.5 months), and the mean length of the occlusion was 95 mm. Cerebral hemodynamics ipsilateral to the side of the occlusion were severely impaired in all patients. The endovascular procedure was performed under total cerebral circulatory protection, beginning with proximal protection with a subsequent switch to distal protection after successful guidewire passage. RESULTS: The occlusion was recanalized successfully in 7 of 8 patients (88%), resulting in improvement of ipsilateral cerebral hemodynamics without symptomatic stroke. Small asymptomatic ischemic lesions were detected in 6 of 8 patients (75%) on DWI, and 1 patient developed a mild groin hematoma. Ischemic episodes did not recur during the mean follow-up period of 19 months. However, 1 patient experienced asymptomatic reocclusion, which was re-treated successfully without complications, while another patient developed mild retinal hemorrhage at 3 months after the procedure due to the combination of antiplatelet and anticoagulant therapy. CONCLUSIONS: Endovascular revascularization of an ICA occlusion is feasible and well-tolerated in patients with subacute or chronic total occlusion of the ICA.

Clinical evaluation after a notification policy of linezolid use: a case series of 22 patients.

Linezolid exhibits a broad spectrum of activity against Gram-positive cocci, including Methicillin-resistant Staphylococcus aureus (mRSA) and vancomycin-resistant enterococci (VRe). However, recent studies have already reported the emergence of linezolid-resistant mRSA or VRe. the purpose of this study is to evaluate not only the efficacy of linezolid for the treatment of nosocomial mRSA infections but also the effect of a notification policy of linezolid use. the charts of inpatients who had been treated with linezolid were reviewed for clinical outcome. After introduction of the notification policy of linezolid use, the clinical success rate was 73.3%, and the rate of appropriate linezolid use was 80%, whereas the success rate was 14.2% and the appropriate use rate was 14.3% before the policy. in conclusion, appropriate use controlled by a notification policy of antibiotics use is essential for prevention of the emergence and spread of linezolid-resistant bacteria, and for proper demonstration of its antibacterial ability.

Dental unit water: bacterial decontamination of old and new dental units by flushing water.

OBJECTIVE: To evaluate by means of Petrifilmtrade mark system (3M, St Paul, MN, USA) the level of bacterial contamination in water from old and new dental units (air-water syringes and high-speed turbines) before and after flushing water through waterlines. The old dental units had been used for 13 years and the new dental units for 1 year. A fast method named Petrifilmtrade mark AC (3M) was employed to evaluate the level of water contamination with total aerobic bacteria and Petrifilmtrade mark EC for Escherichia coli and coliforms. METHODS: Dental unit water were collected before and after flushing of 4 (air-water syringes) and 2 min (high-speed turbines) from 24 old and new dental units. Thereafter, samples were diluted, inoculated onto Petrifilmtrade mark plates and incubated. RESULTS: The filtered tap water that filled up dental unit reservoirs showed a low level of bacterial contamination (4 and 15 CFU ml(-1)). However, all water samples from old and new dental units were highly contaminated. The flushing of dental unit waterlines reduced the bacterial count in all dental unit water, but the reduction was better in water from new dental units than from old dental units. E. coli and coliforms were not detected in any water samples analysed. CONCLUSION: Flushing water is a simple measure that should do part of dental routine, because it was able to reduce the level of total aerobic bacteria in water from old and new dental units.