Effect Of Chemical Disinfection Research Articles

Effect of chemical disinfection on the dimensional stability of polyvinyl ether siloxane impression material: a systemic review and meta-analysis

Background and objectivesPolyvinyl ether siloxane (PVES) possesses ideal characteristics for making precise and accurate dental impressions. PVES dimensional stability owes to its better polymeric properties derived from its parent materials poly ethers and polyvinyl siloxanes. As recommended use of chemical disinfecting agents is getting more popular, there is a growing concern associated with the effect of disinfectants on PVES dimensional stability. This study was aimed to understand the PVES behavior when subjected to chemical disinfectants.Materials and methodologyThe data was collected from research studies retrieved from Google Scholar, Scopus, and PubMed using MeSH terms of keywords “vinyl polyether siloxane AND Disinfection” or (Vinyl polyether siloxane OR polyvinyl siloxane ether OR PVES) AND (disinfectant OR disinfection)” without any restriction to publication date. The PRISMA (Preferred Reporting Items for Systemic Review and Meta-Analysis) directions were observed during the data collection, screening of studies, and meta-analysis. The primary data were retrieved, and batch exported from databases using Harzing’s Publish or Perish software; primary analysis was performed in Microsoft Excel, while statistical analysis for effect size, two-tailed p-values, and heterogeneity among studies was performed using Meta Essentials. The effect size was calculated using Hedge’s g values at the 95% confidence level using the random-effects model. Heterogeneity among studies was measured using the Cochrane Q and I2.Results and conclusionDental impressions made from the PVES elastomeric impression materials showed no significant changes in dimensional stability. Immersion in the chemical disinfectant for 10 min was associated with clinically irrelevant changes in the dimensions of the PVES impressions. Disinfection with sodium hypochlorite was associated with clinically significant changes in dimensions, with a two-tailed p-value of 0.049. Disinfection with 2–2.5% glutaraldehyde solution was not associated with any significant dimensional variability.

Evaluation of the efficacy of a novel disinfecting material on the surface topography of gutta-percha: An in vitro study.

The effect of chemical disinfection on gutta-percha (GP) has to be closely studied whether it affects surface topography and thereby causes leakage and reinfection of canals. The purpose of the study is to assess the surface topography of GP cones after disinfecting with a novel disinfecting material, graphene oxide (GO), and compare the same with other disinfecting materials, including sodium hypochlorite (NaOCl) and silver nanoparticles (AgNps). After determining the power (0.84) of the study, 48 GP cones were taken and categorized into four different groups based on disinfecting agents. Forty-eight GP cones (ISO size 30 6% taper, DIADENT) were taken and are randomly selected and grouped as follows according to the disinfecting agents: Group 1 - control (untreated GP points, n = 12), Group 2 - NaOCl (n = 12), Group 3 - AgNPs (n = 12), and Group 4 - GO (n = 12), respectively. After treating with the above disinfecting materials, the surface topography of samples was evaluated using atomic force microscopy. The data were analyzed statistically using one-way ANOVA and post hoc (Tukey's honestly significant difference) tests. IBM SPSS (version 21.0) software was used. The tests performed were one-way ANOVA and post hoc. Statistically, significance was set at a P ≤ 0.05. The root means square values and surface roughness values were lesser for the GO group and AgNPs when compared with the NaOCl group, which were statistically significant. Within the limitations of the study, this study had shown lesser surface topography deterioration of GP cones when treated with GO and AgNPs, whereas more deterioration was observed with NaOCl.

Efectos de los desinfectantes químicos sobre la dureza superficial de las resinas acrílicas termocuradas. Estudio in vitro

Introduction: Acrylic resins (i.e., heat cured acrylic resins) are the most common materials used to manufacture removable dental prostheses involving maxillofacial prostheses such as obturators. Their mechanical and physical properties must be adequate for their use and durability. It is therefore vital to assess how their properties are affected by different disinfectants. Aims: The purpose of this research was to evaluate the effect of chemical disinfectants on surface hardness of the acrylic resins. Material and Methods: Forty specimens (65 mm in length, 10 mm in width and 2.5 mm thick) were manufactured from heat cured acrylic resins for hardness testing according to ISO 1567:1999. The study consisted of four main sets according to the disinfectants applied (control, 1% hypochlorite, 4 % chlorhexidine, and Efferdent®) and each set contained ten specimens. All specimens were placed in saline solution at 37°C and incubated for 60 days. Acrylic specimens were then tested by using a hardness tester three times and the average reading was recorded. All data were analyzed using SPSS version 16. The results were analyzed at a significant level (p≤0.05). The ANOVA (analysis of variance) test was used to assess whether there were any significant differences among all groups. The comparisons between means were obtained by using a Tukey test. Results: There was a slight decrease in the mean values of surface hardness after immersing in chemical disinfectants. The chlorhexidine-assigned specimens had the lowest value of mean surface hardness. On the other hand, the control group had the highest mean value. However, there were no significant differences regarding surface hardness among all groups (p>0.05). Conclusion: The use of chemical disinfectants slightly decreases the surface hardness of heat-cured acrylic resins.

Preliminary Data Related to the Effect of Climacostol Produced by the Freshwater Ciliate Climacostomum virens on Human Adenovirus.

The new epidemiological scenario has so far focused on the environmental circulation of human viral pathogens. Owing to the side effects of chemical disinfectants, there is an increasing need for knowledge on the use of virucidal compounds, especially those of a natural origin. Climacostol is a molecule produced by a freshwater ciliate and it exhibits activity against bacterial and fungal pathogens. We thus also speculated that there might be an effect on viral viability, which has never been tested. To evaluate such activity, we chose human adenovirus (HAdV), which is representative of waterborne viruses. We conducted experiments using HAdV serotype 5, whose titer was determined by infecting HeLa cell cultures. HAdV5 was shown to be sensitive to climacostol at a concentration of 0.0002 mg/mL, with an approximate 3 Log10 reduction when the initial titer of HAdV5 was approximately 104 and 103 TCID50/mL. These preliminary results could be an important starting point for further research aimed at improving the characterization of climacostol activity under different experimental conditions and against various viruses, including enveloped ones (i.e., the coronavirus). The production of climacostol by a protist living in fresh water also suggests a possible application in the activated sludge of wastewater treatment plants.

The Effect of Chemical Disinfectants on the Setting Time and Dimensional Change of Alginate Impression Material.

Aims: The aim of this study was to evaluate the effect of mixing different concentrations of chlorhexidine, iodine ,and sodium hypochlorite solutions on the setting time and dimensional change of alginate impression material. Materials and methods: Total number of samples (40) has been prepared in this study. Ten samples for control group made from pouring alginate impressions of metal model .The other groups made by mixing alginate with 0.05% iodine, 0.5% chlorhexidine and 0.5% sodium hypochlorite solutions. Dimensional change was measured with AutoCAD program .The Setting time was also measured for each group. Statistical analysis was performed using ANOVA and Duncan multiple range test. Results: no significant difference in the linear dimensional change among the tested groups ,sodium hypochlorite added to alginate as disinfectant showed the highest dimensional changes among the other groups. There was a significant difference among the tested groups in the setting time. It was found that treating the alginate with sodium hypochlorite and chlorhexidine disinfecting agents accelerated the setting time of the material. Conclusion: The testing disinfecting agents can be used safely regarding dimensional change.

Effect of Chemical Disinfection on Chitosan Coated PMMA and PETG Surfaces-An In Vitro Study.

In oral sciences, chitosan application is of interest due to its antimicrobial and hemostatic activity. Chitosan coating of dentures and other intraoral devices could be beneficial for treatment of denture stomatitis or in the management of postoperative bleeding. Disinfection of dentures and prosthodontic materials is crucial before their use in patients. This study investigated the influence of chemical disinfectants on chitosan-coated surfaces. A total of 100 specimens were made: 50 of PMMA (polymethyl methacrylate), and 50 of PETG (polyethylene terephthalate glycol-modified) material and coated with 2% chitosan acetate solution. In each material, 5 groups (10 specimens each) were established and disinfected with Printosept-ID (L1), MD 520 (L2), Silosept (L3), or Dentavon (L4), or stored in distilled water (L0, control group). After disinfection, all specimens underwent abrasion tests (30,000 cycles in a tooth-brushing simulator). Areas without chitosan coating were measured by digital planimetry both before and after the disinfection/abrasion procedure and a damage-score was calculated. Regarding chitosan coating, the statistical analysis showed a significant influence of the disinfectants tested and significant differences between disinfectants (p < 0.05). Chitosan coating was most stable on PMMA and PETG after disinfection with MD 520 (L2). Otherwise, active oxygen containing disinfectants (L3, L4) led to the greatest alterations in the chitosan coating.

Effect of chemical disinfectants and accelerated aging on maxillofacial silicone elastomers: An In vitro Study.

Maxillofacial prostheses need frequent refabrication due to degradation of color and deterioration of physical properties of the elastomer. This study attempted to evaluate the change in color stability, Shore A hardness, and surface roughness of two maxillofacial silicones, A-2186 and Cosmesil M511, when submitted to chemical disinfection and accelerated aging. This was a comparative in vitro study. The materials included two silicone elastomers - A-2186 and Cosmesil M511 (Factor II Incorporated) - functional intrinsic red pigment and three disinfectants - Fittydent tablet, chlorhexidine gluconate 4%, and neutral soap. The specimens in each group of elastomer were evaluated initially for color, hardness, and surface roughness, which were further divided into subgroups and subjected to disinfection and accelerated aging. The evaluation of color was performed with the help of an ultraviolet reflectance spectrophotometer. Shore A hardness was evaluated using a durometer and surface roughness, with a digital roughness tester followed by scanning electron microscopy analysis. Analysis of variance and Tukey's multiple comparison test were used for statistical analysis. Accelerated aging caused a significant decrease in color, increase in Shore A hardness, and variation in surface roughness in both silicone elastomer groups. Chemical disinfection presented significant changes in color and surface roughness whereas no significant effect on Shore hardness, irrespective of the disinfectant used. The maxillofacial silicone elastomers presented deterioration in color, hardening, and significant variations in surface roughness when subjected to chemical disinfection and accelerated aging, which provides a valid baseline for future research.

Comparison of Antimicrobial Effects of Chemical Disinfectants with Centaury Oil

Comparison of Antimicrobial Effects of Chemical Disinfectants with Centaury Oil

Ultrasound-guided joint and soft tissue interventions

Minor procedures with an injection needle are frequently performed in orthopedic clinics. They may be of a diagnostic, diagnostic and therapeutic or purely therapeutic nature. Ultrasound guidance while inserting the needle allows for a safe medicine administration and evacuation of fluid contents. It improves the efficacy of such procedures by ensuring accurate needle insertion in the target site. Ultrasound-guided procedures reduce the duration of treatment (e.g. medicines reach the target site directly; all fluid collections are removed, even multilocular ones) and minimize pain (by the selection of optimal access sites omitting tendons, vessels and peripheral nerves). This paper presents the principles of performing ultrasound-guided interventions. A detailed description of such a technique is provided and the most commonly injected medicines as well as their adverse reactions and contraindications are discussed. Attention is also paid to image optimization and the role of procedure site selection with the exclusion of other pathologies in the puncture site (such as tumors, foreign bodies and vascular or nerve pathologies). What is more, the author also discusses the principles of needle length and thickness selection as well as the manners of its insertion in relation to the transducer. Moreover, the principles of aseptics that are mandatory during such interventions are also presented and the way to protect transducers from the effects of chemical disinfectants is discussed. Furthermore, the paper contains numerous photographs of performed interventions. It is addressed to clinical practitioners and its aim is to facilitate and improve the efficacy of the procedures which are commonly performed in orthopedics. Ultrasound guidance of joint and soft tissue interventions should become a gold standard in all orthopedic clinics.

Inactivation Kinetics of Various Chemical Disinfectants on Aeromonas hydrophila Planktonic Cells and Biofilms

The present article focuses on the inactivation kinetics of various disinfectants including ethanol, sodium hypochlorite, hydrogen peroxide, peracetic acid, and benzalkonium chloride against Aeromonas hydrophila biofilms and planktonic cells. Efficacy was determined by viable plate count and compared using a modified Weibull model. The removal of the biofilms matrix was determined by the crystal violet assay and was confirmed by field-emission scanning electron microscope. The results revealed that all the experimental data and calculated Weibull α (scale) and β (shape) parameters had a good fit, as the R(2) values were between 0.88 and 0.99. Biofilms are more resistant to disinfectants than planktonic cells. Ethanol (70%) was the most effective in killing cells in the biofilms and significantly reduced (p<0.05) the biofilms matrix. The Weibull parameter b-value correlated (R(2)=0.6835) with the biofilms matrix removal. The present findings deduce that the Weibull model is suitable to determine biofilms matrix reduction as well as the effectiveness of chemical disinfectants on biofilms. The study showed that the Weibull model could successfully be used on food and food contact surfaces to determine the exact contact time for killing biofilms-forming foodborne pathogens.

The in‐vitro antibacterial effects of organic salts, chemical disinfectants and antibiotics against pathogens of black disease in fairy shrimp of Thailand

The antibacterial effects of organic salts, chemical disinfectants and antibiotics were evaluated on cultures of Aeromonas hydrophila C03, Aeromonas sobria C26, A. sobria C29, Aeromonas caviae C24 and Acinetobacter sp. SH-94B, the pathogens that cause black disease found in fairy shrimps (Streptocephalus sirindhornae Sanoamuang et al. (2000) and Branchinella thailandensis Sanoamuang, Saengphan & Murugan) of Thailand. The minimal inhibitory concentrations (MICs) of organic salts (sodium chloride and potassium chloride) and antibiotics (oxytetracycline dihydrate, streptomycin sulphate, kanamycin monosulphate, chloramphenicol and ampicillin) were determined using the agar-dilution method. The effect of chemical disinfectants (sodium hypochlorite and chlorine dioxide) was evaluated by exposing bacteria to different concentrations of these chemicals for different periods of time. Interestingly, all strains were intrinsically resistant to 0.25-3% sodium chloride and potassium chloride. The effect of sodium hypochlorite was greater than that of chlorine dioxide, and 5-20 μg mL(-1) of sodium hypochlorite was sufficient to inhibit the growth of these bacteria, but the exposure time varied, depending on the bacterial species. Of the antibiotics tested, chloramphenicol and oxytetracycline dihydrate completely inhibited the selected strains. Chloramphenicol showed the highest antibacterial effect against all pathogenic species--the MIC and minimal bactericidal concentration (MBC) ranged from 0.8 to 3.1 μg mL(-1) from 3.1 to 6.25 μg mL(-1), respectively. To achieve control of black disease during cultivation of fairy shrimp, data derived from this study can be used as a basis for further toxicity tests in vivo.

Influence of chemical disinfection on mechanical and structural properties of type III and IV dental stones

We report on the effect of chemical disinfection in aqueous 1% virkon, 0·525% hypochlorite and slurry solutions on the mechanical and structural properties of type III and IV dental stones. For both dental stones, compressive strength and diametral tensile strength decrease with the application of all types of disinfectants. Virkon disinfectant decreases the mechanical strength with the lowest magnitude. The X-ray diffraction patterns of samples show the existence of dihydrate and hemihydrates microcrystals along with traces of CaSO4.xH2O (x = 0·02–0·48) in as prepared samples, but do reveal that hemihydrate phase is removed after spraying disinfectants. Fractography of the dental stones clearly indicates that the separation between the microcrystals is widened by the disinfection process as a consequence of the possible dissolution of last precipitated gypsum phases. The mechanical properties of the dental stones are effectively decreased after disinfection to different levels.

Effect of disinfection on irreversible hydrocolloid and alternative impression materials and the resultant gypsum casts

Many new products have been introduced and marketed as alternatives to traditional irreversible hydrocolloid materials. These alternative materials have the same structural formula as addition reaction silicone, also known as vinyl polysiloxane (VPS), impression materials. Currently, there is limited in vitro and in vivo research on these products, including on the effects of chemical disinfectants on the materials. The purpose of this study was to compare the effects of a spray disinfecting technique on a traditional irreversible hydrocolloid and 3 new alternative impression materials in vitro. The tests were performed in accordance with the American National Standards Institute/American Dental Association (ANSI/ADA) Specification Nos. 18 and 19. Under standardized conditions, 100 impressions were made of a ruled test block with an irreversible hydrocolloid and 3 alternative impression materials. Nondisinfected irreversible hydrocolloid was used as the control. The impressions were examined for surface detail reproduction before and after disinfection with a chloramine-T product. Type III and Type V dental stone casts were evaluated for linear dimensional change and gypsum compatibility. Comparisons of linear dimensional change were analyzed with 2-way ANOVA of mean ranks with the Scheffé post hoc comparisons (α=.05). Data for surface detail reproduction were analyzed with the Wilcoxon Signed-Rank procedure and gypsum compatibility with the Kruskal-Wallis Rank procedure (α=.05). The alternative impression materials demonstrated significantly better outcomes with all 3 parameters tested. Disinfection with chloroamine-T did not have any effect on the 3 alternative impression materials. The irreversible hydrocolloid groups produced the most variability in the measurements of linear dimensional change. All of the tested materials were within the ADA's acceptable limit of 1.0% for linear dimensional change, except for the disinfected irreversible hydrocolloid impression material. The alternative impression materials performed best for the parameters tested. Spray disinfection had no effect on the alternative impression materials.

Effect of Chemical Disinfection on Dimensional Stability of Polyether Elastomeric Impression Material

Polyether is one of a commonly used material for making impressions in prosthetic dentistry because of its properties like, excellent dimensional stability and low polymerisation shrinkage. Impressions should be properly disinfected before sending to laboratory, but disinfection by immersion may cause dimensional changes because of hydrophilic nature of polyether. So this study was designed to evaluate the effect of disinfection on dimensional stability of polyether impression.

Effect of Chemical Disinfection and Accelerated Aging on Color Stability of Maxillofacial Silicone with Opacifiers

The purpose of this study was to evaluate the color stability of MDX4-4210 maxillofacial elastomer with opacifier addition submitted to chemical disinfection and accelerated aging. Ninety specimens were obtained from Silastic MDX4-4210 silicone. The specimens were divided into three groups (n = 30): Group I: colorless, Group II: barium sulfate opacifier, Group III: titanium dioxide opacifier. Specimens of each group (n = 10) were disinfected with effervescent tablets, neutral soap, or 4% chlorhexidine gluconate. Disinfection was conducted three times a week for 2 months. Afterward, the specimens were submitted to different periods of accelerated aging. Color evaluation was carried out after 60 days (disinfection period) and after 252, 504, and 1008 hours of accelerated aging, using a reflection spectrophotometer. Color alterations were calculated by the CIE L*a*b* system. Data were analyzed by three-way ANOVA and Tukey test (α= 0.05). Group II exhibited the lowest color change, whereas Group III the highest (p < 0.05), regardless of the chemical disinfection and accelerated aging periods. Opacifier addition, chemical disinfection, and accelerated aging procedures affected the color stability of the maxillofacial silicone.

P11.01 Resistance of Acanthamoeba spp. cysts to disinfection treatments

P11.01 Resistance of Acanthamoeba spp. cysts to disinfection treatments

Effect of Chemical Disinfectants and Repair Materials on the Transverse Strength of Repaired Heat‐Polymerized Acrylic Resin

The purpose of this study was to evaluate both the effects of immersion in different chemical disinfectant solutions and the type of repair material on the transverse strength of repaired heat-polymerized acrylic resin. A total of 110 rectangular specimens (65 x 10 x 3 mm) of heat-polymerized acrylic resin (Triplex) were fabricated. After polymerization, the specimens were polished, then stored in distilled water at 37 degrees C for 1 week. The specimens were divided into 11 groups (n = 10) coded A to K. Specimens of Group A remained intact (control). The specimens of Groups C to F and Groups H to K were immersed in the following chemical disinfectant solutions (1%, 2.5%, and 5.25% sodium hypochlorite and 2% glutaraldehyde, respectively) for 10 minutes. The specimens of all groups except those of Group A were sectioned in the middle to create 10 mm gaps and repaired with the same resin (Groups B to F) and autopolymerizing acrylic resin (Groups G to K). The specimens of Groups C to F and Groups H to K were again immersed in the disinfectant solutions in the same sequence. The transverse strength (N/mm(2)) was tested for failure in a universal testing machine, at a crosshead speed of 5 mm/min. Two-way analysis of variance (ANOVA) was performed to evaluate the effects of both the disinfectant solutions and repair materials on the transverse strength of repaired specimens. All data were statistically analyzed using one-way analysis of variance followed by Tukey's test at 95% confidence level. The repaired specimens treated with/without disinfectant solutions showed similar (p > 0.05) transverse strength values. No differences (p > 0.05) were detected among the repaired specimens either with heat-polymerized or autopolymerizing acrylic resins. The intact specimens showed transverse strength values (86.9 +/- 11.8) significantly higher (p < 0.05) than the values of the repaired specimens. Among the repaired specimens, transverse strength was not affected after immersion in the disinfectants for the immersion period tested (10 min). The repair material, either heat-polymerized or autopolymerizing acrylic resin, had no effect on the transverse strength of the repaired acrylic resin specimens.

Effect of chemical disinfectants on the transverse strength of heat-polymerized acrylic resins submitted to mechanical and chemical polishing

Immersion in chemical solutions used for cleansing and disinfecting prostheses can decrease the strength of denture base resins, making them more prone to fracture during use. The purpose of this study was to assess the effect of immersion in different chemical disinfectants for varying time periods on the transverse strength of 3 mechanically or chemically polished heat-polymerized acrylic resins. A total of 630 rectangular specimens (65 x 10 x 3 mm), 210 per resin (Classico, Lucitone 550, and QC-20), were fabricated. One side of each specimen was not polished and the other was either mechanically (n=300) or chemically (n=300) polished, and immersed for 10, 20, 30, 45, or 60 minutes in either 1%, 2.5%, or 5.25% sodium hypochlorite or 2% glutaraldehyde. Mechanically polished (n=15) and chemically polished (n=15) control specimens were immersed only in distilled water. The transverse strength (N/mm 2 ) was tested for failure in a universal testing machine, at a crosshead speed of 5 mm/min. Data were statistically analyzed using 2-way ANOVA and Student t test. Multiple comparisons were performed using Tukey and Scheffe tests (alpha=.05). There was significant difference (P < .01) between types of polishing, with chemical polishing resulting in lower transverse strength. ANOVA identified significant differences (P < .01) in strength between mechanically polished Lucitone 550 and QC-20, and among all 3 chemically polished resins. No significant differences were observed between resins submitted to both types of polishing or between different immersion periods (10 to 60 minutes), disinfectants, or interaction. Lucitone 550 resin presented the greatest transverse strength values with both types of polishing. Among the mechanically and chemically polished specimens, transverse strength was not affected after immersion in the disinfectants for the immersion periods tested (10 to 60 minutes). Chemically polished control and experimental (immersed in all solutions) QC-20 specimens showed significant differences in transverse strength values.

Effects of chemical disinfectants on the transverse strength of denture base acrylic resins.

The disinfection of dental prostheses by immersion in a chemical solution should be capable of rapid inactivation of pathogenic microorganisms, without causing any adverse effect on the denture base resins. This study evaluated the effect of disinfection immersion on the transverse strength of two heat-cured resins. The denture base resins (Lucitone 550 and QC 20) were polymerized according to the manufacturers' instructions. After polymerization, the specimens were polished, and then stored in water at 37 degrees C for 50 +/- 2 h prior immersion in one of the following solutions for 10 min: 4% chlorhexidine, 1% sodium hypochlorite and 3.78% sodium perborate. The specimens were submitted to disinfection twice, simulating when dentures come from the patient and before being returned to the patient. Ten specimens were made for each group. The transverse strength was evaluated by a 3-point bend test. The flexural strength of the two denture base acrylic resins evaluated remained unaffected after immersion in the three solutions evaluated. In general, the QC 20 resin specimens exhibited lower transverse strength than the Lucitone 550 resin specimens, regardless of immersion solutions.

The Heater–Cooler Unit—A Conceivable Source of Infection

Even drinking water is contaminated with pathogenic microorganisms. This does not necessarily pose a risk for healthy individuals, but it may result in serious consequences in people with impaired immune systems. This is particularly valid if drinking water is used for medical purposes. The heater–cooler unit (HCU) connected to heat exchangers or blankets by tubing, the connection is closed water circuit that contains microorganisms and algae. While connecting the tubing to the heat exchanger, spilling of water cannot be avoided. Microbiological examinations showed that germs and particles pollute the units. Exposure to the patient and the OR equipment has the potential to increase the risk of infection should the HCU water come in contact with the patient. As a result of the high incidence of particle and algae in the HCU, malfunction occurs. Sampling shows &gt;1000/mL CFU (colony forming units) at 36°C and 55/mL CFU at 20°C on average. The specific findings include Pseudomonas and Legionella. Disinfecting HCU is very difficult. Often HCUs do not provide any technology to reduce bacterial or other contamination. The instructions for use of oxygenators often exclude the use of disinfectants. Maintenance instructions for the HCU advocate the use of disinfectants that carry the risk of oxygenator damage and of heat exchanger leakage. The effect of chemical disinfectants and heat exchanger membranes have not been examined, they may impair heat exchanger permeability and function. As an alternative to chemical and thermal disinfection, we used the alternative method of filtration. Using a membrane filter element, we noticed a decreasing number of CFUs from 55 to sterile conditions at 20°C and from &gt;1000 CFUs to 100 CFUs at 36°C (Figure 1). In addition, we noticed a removal of other particles and algae. In conclusion, we have demonstrated a technique that is simple to implement and effectively reduces the microbiological load of the water in the heater– cooler unit.