Non-coated Groups Research Articles

Silver-coated tibial plateau leveling osteotomy implants do not improve surgical site infection rates over noncoated implants in a randomized trial in 73 canines.

To evaluate the incidence of surgical site infections (SSIs) in dogs undergoing a tibial plateau leveling osteotomy (TPLO) with silver-coated (SC) and noncoated (NC) TPLO plates. 65 dogs (73 surgical procedures). Client-owned dogs undergoing a TPLO procedure between November 2021 and May 2023 were prospectively enrolled. Dogs were randomly assigned either an SC or NC TPLO plate at the time of surgery. Follow-up was performed at 2 weeks and 8 weeks postoperatively by in-person examination, client questionnaire, or telephone interview. Dogs were followed up 100 days postoperatively for any incisional or implant complications. Among 73 stifles that underwent a TPLO, the overall SSI rate was 8.2% (6/73), with an infection rate of 14.3% (5/35) in the NC group and 2.6% (1/38) in the SC group; this difference was not significant (P = .17). Five of these infections were superficial, and only 1 deep SSI was recorded within the 100-day study period (NC group). Although no significant difference was noted between the SC and NC groups, likely due to a small sample size and overall low infection rate, there was a trend showing a higher infection rate in the NC group. No conclusions can be drawn on the impact of silver coating on deep or organ/space incisional infections due to the low incidence reported in this study (n = 1). Further investigation of SC TPLO implants in a larger and more long-term clinical study is warranted.

Evaluation of High-Performance Polyether Ether Ketone Polymer Treated with Piranha Solution and Epigallocatechin-3-Gallate Coating.

Dental implantation has become a standard procedure with high success rates, relying on achieving osseointegration between the implant surface and surrounding bone tissue. Polyether ether ketone (PEEK) is a promising alternative to traditional dental implant materials like titanium, but its osseointegration capabilities are limited due to its hydrophobic nature and reduced surface roughness. The aim of the study is to increase the surface roughness and hydrophilicity of PEEK by treating the surface with piranha solution and then coating the surface with epigallocatechin-3-gallate (EGCG) by electrospraying technique. The study includes four groups intended to investigate the effect of piranha treatment and EGCG coating: a control group of PEEK discs with no treatment (C), PEEK samples treated with piranha solution (P), a group of PEEK samples coated with EGCG (E), and a group of PEEK samples treated with piranha solution and coated with EGCG (PE). Surface roughness, wettability, and microhardness were assessed through statistical analysis. Piranha treatment increased surface roughness, while EGCG coating moderated it, resulting in an intermediate roughness in the PE group. EGCG significantly improved wettability, as indicated by the reduced contact angle. Microhardness increased by about 20% in EGCG-coated groups compared to noncoated groups. Statistical analysis confirmed significant differences between groups in all tests. This study demonstrates the potential of EGCG coating to enhance the surface properties of PEEK as dental implants. The combined piranha and EGCG modification approach shows promise for improved osseointegration, although further vivo research is necessary. Surface modification techniques hold the key to optimizing biomaterial performance, bridging the gap between laboratory findings and clinical implementation in dental implantology.

Control of Browning, Enzyme Activity, and Quality in Stored Fresh-cut Fruit Salads through Chitosan Coating Enriched with Bergamot Juice Powder.

In this study, fresh-cut fruit salads composed of apples, pears, kiwis, and pineapples were stored at +4 °C for 18 days under distinct conditions: non-coated (NC), chitosan-coated (CH), and bergamot juice powder extract-enriched chitosan-coated (CHBE). Storage endpoint decay percentages were as follows: NC group: 100%, CH group: 26.67-53.3%, CHBE group: 13.33-26.67%. CHBE had the highest moisture content (87.05-89.64%), soluble solids (12.40-13.26%), and chroma values (2.35-6.60). CHBE and NC groups had 2.10% and 6.61% weight loss, respectively. The NC group had the highest polyphenol oxidase activity (19.48 U mL-1) and browning index (0.70 A420/g); CH group: 0.85 U mL-1, 0.35 A420/g; CHBE group: 0.57 U mL-1, 0.27 A420/g. CHBE showed a titratable acidity of 1.33% and pH 3.73 post-storage, impeding microbial proliferation with the lowest counts (2.30-3.24 log CFU g-1). The microbial suitability of the NC group diminished after day 6, with an overall preference score of 1.00. Conversely, the CH and CHBE groups scored 3.15 and 4.56, highlighting the coatings' effectiveness. Bergamot juice powder extract further enhanced this, mitigating browning and enhancing quality. Results reveal tailored coatings' potential to extend shelf life, improve quality, and enhance fruit salads' acceptability. This study underscores the importance of edible coatings in addressing preservation challenges, emphasizing their role in enhancing food quality and consumer acceptability. Incorporating edible coatings is pivotal in mitigating deterioration issues and ensuring the overall success of fresh-cut fruit products in the market.

Effect of Silicon Carbide Coating on Osteoblast Mineralization of Anodized Titanium Surfaces.

The objective of this study was to evaluate the influence of the titanium nanotube diameter and the effect of silicon carbide (SiC) coating on the proliferation and mineralization of pre-osteoblasts on titanium nanostructured surfaces. Anodized titanium sheets with nanotube diameters of 50 and 100 nm were used. The following four groups were tested in the study: (1) non-coated 50 nm nanotubes; (2) SiC-coated 50 nm titanium nanotubes; (3) non-coated 100 nm nanotubes and (4) SiC-coated 100 nm nanotubes. The biocompatibility and cytotoxicity of pre-osteoblasts were evaluated using a CellTiter-BlueCell Viability assay after 1, 2, and 3 days. After 3 days, cells attached to the surface were observed by SEM. Pre-osteoblast mineralization was determined using Alizarin-Red staining solution after 21 days of cultivation. Data were analyzed by a Kruskal-Wallis test at a p-value of 0.05. The results evidenced biocompatibility and non-cytotoxicity of both 50 and 100 nm diameter coated and non-coated surfaces after 1, 2 and 3 days. The statistical analysis indicates a statistically significant higher cell growth at 3 days (p < 0.05). SEM images after 3 days demonstrated flattened-shaped cells without any noticeable difference in the phenotypes between different diameters or surface treatments. After 21 days of induced osteogenic differentiation, the statistical analysis indicates significantly higher osteoblast calcification on coated groups of both diameters when compared with non-coated groups (p < 0.05). Based on these results, we can conclude that the titanium nanotube diameter did not play any role on cell viability or mineralization of pre-osteoblasts on SiC-coated or non-coated titanium nanotube sheets. The SiC coating demonstrated biocompatibility and non-cytotoxicity and contributed to an increase in osteoblast mineralization on titanium nanostructured surfaces when compared to non-coated groups.

Multivariate analysis approach for assessing coated dry-cured ham flavor quality during long-term storage.

This study aimed to investigate the effect of coatings on the quality of ripened dry-cured hams during long-term storage, especially the profile of volatile compounds. The coatings were made up of 33% palm oil, 16.5% water, 39.7% cassava starch, 6.8% corn starch, 1.6% mono- and diglycerides of fatty acids, 0.6% tert-butylhydroquinone (TBHQ), and 1.8% sodium carbonate. The results showed that the moisture content of the coated ham (48.93-49.59%) was higher than that of the noncoated ham (44.37%). The average peroxide value (POV) and b* value were lower in the coated hams than in the noncoated hams (5.52 and 8.99meq/kg, respectively), and the sensory attributes of the coated hams had better overall acceptability scores. The changes in the contents of 39 volatile flavor compounds were evaluated through a multivariate statistical analysis, revealing that 20 identified compounds could be related to the decrease in fat pungent aroma, and most belonged to the long-chain benzene and carboxylic acid family. Meanwhile, 2-nonanone, nonanal, amyl alcohol, and 2-heptanone indicated that they could be used as markers to distinguish between the coated and noncoated groups.

Collagen Coating Effects on Fe-Mn Bioresorbable Alloys.

Bioresorbable iron-manganese alloys (Fe-30%Mn) are considered as one of the next-generation resorbable materials for orthopedic applications. Previous in vitro study showed that Fe30Mn scaffolds with 10% porosity displayed strong mechanical properties and adequate degradation rate without severe cytotoxicity effect. However, the cellular compatibility of these alloys in terms of cell-to-cell and alloy-to-cell interactions is not ideal. Collagen is the most abundant protein in human bone, providing structural support beneficial to bone healing. We hypothesized that coating collagen on Fe30Mn can improve osteointegration or activities promoting cell adhesion, migration, and proliferation, as the alloy degrades. After preparing collagen coating on Fe-30Mn via spin coating, we conducted a corrosion test and a direct cytotoxicity test on four Fe30Mn groups: non-porous and 10% porosity, with and without collagen coating. Furthermore, we evaluated and compared the morphologies of cells over a period of 7 days. Results showed that there was no significant difference between the collagen-coated and non-coated groups in corrosion rates, yet a significant decrease from the porous non-coated group to the porous collagen-coated group in cytotoxicity level was found. Cell morphology on the porous non-coated group displayed round shape, whereas that on the porous collagen-coated group displayed flattened spreading. The study showed that the collagen coating significantly increased the initial cell viability and adhesion for both the porous and non-porous groups without impeding their degradation rates. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:523-535, 2020.

Effect of protective coating on microleakage of conventional glass ionomer cement and resin-modified glass ionomer cement in primary molars: An In vitro study.

The aim of this in vitro study was to evaluate and compare the effect of protective coating G-Coat Plus on microleakage of conventional glass ionomer cement (CGIC) and resin-modified glass ionomer cement (RMGIC) in primary molars. A total of 120 samples were divided into four groups with 30 samples in each group. Group A - teeth restored with CGIC. Group B - teeth restored with CGIC coated with G-Coat Plus. Group C - teeth restored with RMGIC. Group D - teeth restored with RMGIC coated with G-Coat Plus. Microleakage was tested using 2% basic fuschin dye penetration and measured at ×40 original magnification under the stereomicroscope. The results of this in vitro study showed that coating with G-Coat Plus showed a reduction in microleakage in CGIC and complete absence of microleakage in RMGIC when compared to the noncoated groups, which was statistically significant. CGIC without G-Coat Plus showed highest microleakage followed by RMGIC without G-Coat Plus, followed by a relatively less microleakage in CGIC with G-Coat Plus. Significant reduction in microleakage was seen in conventional GIC and RMGIC with G-Coat Plus when compared to conventional GIC and RMGIC without G-Coat Plus.

On the synthesis and characterization of β-tricalcium phosphate scaffolds coated with collagen or poly (D, L-lactic acid) for alveolar bone augmentation.

Objectives:After tooth loss, dimensional alterations on the alveolar bone ridge can occur that can negatively affect the placement of dental implants. The purpose of this study was to evaluate the synthesis, and mechanical properties of β-tricalcium phosphate (β-TCP) scaffolds coated with bioabsorbable polymers, namely, collagen and poly (D, L-lactic acid) (PDLLA).Materials and Methods:β-TCP powder was obtained by reactive milling and then characterized by X-ray diffraction and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). β-TCP scaffolds were obtained by replica method, in which polyurethane foams are immersed in β-TCP suspension and thereafter submitted to a thermal treatment to remove the polyurethane and sinter the ceramic. Type-I collagen or PDLLA were used to coat the β-TCP scaffolds by dip-coating method. Scaffolds were separated in four groups depending on the coating material: noncoated (Group A), double immersion in collagen (Group B), double immersion in PDLLA (Group C), and ten immersions in PDLLA (Group D). Samples were characterized by compressive tests and SEM/EDS. Data were statistically analyzed through two-way ANOVA (p = 0.05).Results:Chemical and microscopic analyses revealed proper morphology and chemical composition of powder particles and scaffolds with or without polymeric coatings. Scaffolds coated with PDLLA showed higher compressive strength (0.11 ± 0.054 MPa) than those of collagen (0.022 ± 0.012 MPa) or noncoated groups (0.024 ± 0.012 MPa).Conclusions:The coating method of β-TCP with PDLLA revealed a potential strategy to increase the mechanical strength of porous ceramic materials while collagen can enhance cell migration.

In vitro abrasion of resin-coated highly viscous glass ionomer cements: a confocal laser scanning microscopy study.

The aim of this study was to evaluate the effect of resin coating on the wear depth of highly viscous glass ionomer cements (HVGICs) after 40,000 cycles, corresponding to over 8years of tooth brushing. A resin composite (Gradia Direct Posterior), two HVGICs (EQUIA Fil and Riva Self Cure), a resin coating (EQUIA Coat) and a conventional varnish (Fuji Varnish) were used in the study. The control groups were the resin composite group and the non-coated HVGICs groups. Samples (n=8) were produced in flat plastic moulds at 23±1°C and stored in artificial saliva sodium acetate-acetic acid-glycerine formalin (SAGF medium) for 7days at 37±1°C. The abrasion test was carried out in a toothbrush simulator (Willytec) with a load of 1N using abrasive toothpaste slurry. Vertical loss was measured at different cycles under confocal laser scanning microscopy (CLSM). Data were analysed using one-way ANOVA, Tukey's HSD test, repeated measures ANOVA and Bonferroni tests (p<0.05). The resin composite group showed significantly lower vertical wear loss than the non-coated groups and the varnished groups of HVGICs (p<0.05). HVGICs with resin coating had better wear resistance than the varnished and non-coated groups (p<0.05). Furthermore, regarding the material-based wear, HVGICs with resin coatings abraded less than the resin composite group tested (Gradia Direct Posterior 5.06±0.54μm, EQUIA Fil 4.06±1.68μm, Riva Self Cure 4.73±2.44μm), but statistically, there were no significant differences between them after 40,000 cycles (p>0.05). After 40,000 cycles, when the total wear loss of the materials including both coatings wear was compared, there were no differences between the non-coated and the resin-coated groups. The results of this study indicate that the resin coating protects the glass ionomer materials from excessive wear until 20,000 cycles making both HVGICs to abrade in a similar manner as the resin composite. If we include the wear of the coating to the general material wear loss at 40,000 cycles, the total wear loss is quite similar for all HVGICs, regardless of the protection with varnish or resin coating. Within the limitation of this study, we have foreseen that resin coating will protect and make the HVGIC materials as wear resistant as resin composites in clinical situations for a long time.

Effect of a magnetron-sputtered ZrSiN/ZrO2 film on the bond strength of commercially pure titanium to porcelain

The excessively thick and nonadherent titanium oxide layer formed during the porcelain sintering process can cause bonding problems between titanium and porcelain. The purpose of this study was to evaluate the effect of a magnetron-sputtered ZrSiN/ZrO2 composite film on the bond strength of commercially pure titanium (CP Ti) to porcelain. Sixty-eight cast titanium specimens were prepared according to the ISO 9693 standard and then divided into 2 coated and 2 noncoated groups (n=17). The ZrSiN/ZrO2 composite film was deposited on specimens of the 2 coated groups by magnetron sputtering. A low-fusing porcelain was applied on 1 coated group and 1 noncoated group. A surface profilometer, surface roughness tester, energy-dispersive X-ray analysis (EDS), scanning electron microscopy (SEM), and x-ray diffraction (XRD) were used to examine the characteristics of the film and the interfacial properties, while the bond strength of titanium-porcelain specimens was analyzed with the 3-point bend test. The results were analyzed with an independent samples t test (α=.05). The mean bond strength of ZrSiN/ZrO2-coated CP Ti to porcelain (43.67 ±2.08 MPa) was significantly higher than that of the noncoated group (35.44 ±3.56 MPa). A generally cohesive failure mode was observed in the coated group, but the failure mode in the noncoated group was adhesive. EDS data showed that the ZrSiN/ZrO2 film effectively prevented the intrusion of oxygen into the Ti substrate. The data suggested that the magnetron-sputtered ZrSiN/ZrO2 film could significantly improve the bond strength of CP Ti to porcelain and this may have clinical significance.

In Vivo Evaluation of a New Surfactant Polymer Coating Mimicking the Glycocalyx of Endothelial Cells

The purpose of this study was to demonstrate that a proprietary surfactant polymer (SP) coating does not adversely affect the hemodynamic performance of cardiopulmonary bypass (CPB) or gas exchange in oxygenators. The new coating was applied to a CPB circuit including cannulae, reservoir, oxygenator, and blood pump implanted into 12 pigs, divided into groups with either coated or noncoated pumps. CPB flow was maintained at a fixed level of approximately 2.4 L/min for 6 hours with full heparinization. Hemodynamic data and pump performance were recorded every hour, and blood samples were taken every 2 hours. After sacrifice, the CPB circuit and major organs were macroscopically examined. There was no significant difference in the oxygen transfer rate between the two groups. The coating did not adversely affect oxygenator inlet or outlet pressures. There was no significant difference between the two groups in microthrombi seen in the oxygenators. No thromboemboli were noted in the major organs on gross or histologic examination. In conclusion, this new SP coating did not decrease gas exchange performance, and its biocompatibility evaluations revealed no differences between coated and noncoated groups under aggressive heparin use.

Effect of sealer coating on mechanical and physical properties of permanent soft lining materials

To evaluate the long-term effects of sealer coating on tensile bond strength and surface roughness of soft liners. Failure of the bond between resilient liners and denture base significantly compromise the dentures' longevity. In addition, surface roughness contributes to bacterial adherence on prosthetic materials, increasing the risk of oral infections. Specimens were manufactured from four reliners [Mucopren Soft (MS), Dentuflex (DF); Soft Comfort Denso (SC) and Ufi Gel SC (USC)], distributed into 10 groups (n = 10), according to material and coating treatment. Tensile bond strength was performed after one year of ageing, while surface roughness was evaluated at 0, 1, 3, 6 and 12 ageing months. Bond strength data were submitted to two-way anova and Tukey-HSD tests, while roughness data were submitted to mixed model analysis for repeated measurements (p ≤ 0.05). MS and DF without sealer coating presented the highest tensile bond strength. After coating, DF and SC presented increased tensile bond strength. No surface roughness difference was observed in the non-coated groups over time, acrylic-based reliners presented higher roughness. Among coated groups, only SC presented increased surface roughness. Acrylic-based materials presented reduced roughness at three months. Surface coating was effective for acrylic reliners in maintaining their initial properties. However, sealer coating should be re-applied every 3 months.

Osteoblastic early attachment onto the surface of bioadhesive peptide modified pure titanium

To investigate the long-term integrity and the biological function of interface between the bioadhesive peptide modified implant surface and peri-implant tissue. A short bioadhesive peptide containing Glycine-Tyrosine-Arginine-Glycine-Asparticacid-Serine (GYRGDS) sequence was immobilized onto the titanium implant surface by means of sol-gel coating technique and self-assembled monolayers (SAM). The chemical composition and organic functional groups on the titanium surfaces were characterized using XPS (X-ray photoelectron spectroscopy) and FTIR (Fourier transform infrared spectrometer). The adhesive strength and stability of osteoblasts on various implant surfaces were compared under flow condition. The results showed that alkali/hot water aging treatment could apparently improve the content of -OH functional groups of titanium surface. The chemical reactive Ti-O-Ti bonding at the surface of titanium played a vital role in inducing the formation of organosilane SAM. GYRGDS peptide can be covalently grafted onto the surface of titanium by SAM technique. The resistance of freshly adherent osteoblasts to detachment by flow was shear time dependent. When the four groups were compared under the same flow stress condition (2.05 Pa) at three specific time spans (30 min, 1 h, 2 h), the cells retention rates in GYRGDS-grafted groups were 93.0%, 54.4%, 34.4% respectively and were much higher than those in non-coated groups. It was suggested that GYRGDS might have positive effects on maintaining stability and adherence of cells onto the substrates under flow condition.

Microtensile Bond Strengths of Composite Cores to Pulpal Floor Dentin with Resin Coating

The purpose of this study was to evaluate the effect of resin coating on the microtensile bond strength (MTBS) of indirect composite cores to pulpal floor dentin. Thirty extracted human molars with root canal fillings were used. After post space preparation, dentin surface was coated with either Clearfil SE Bond (SE) or SE with Clearfil Flow FX (SE+FX) for the resin-coated groups, while dentin was treated with ED Primer II (ED) for the non-coated group. Indirect composite cores were cemented with either Panavia F2.0 (PA) or Clearfil DC Core Automix (DC). After 24-hour storage, MTBSs were measured at a crosshead speed of 1 mm/min. Two-way ANOVA indicated that the MTBSs of resin-coated groups were significantly higher than those of the non-coated groups. In particular, the SE+FX/DC group exhibited the highest MTBS. It was thus concluded that resin coating enhanced the dentin bond strength of indirect composite cores to pulpal floor dentin.

Effects of Thin Hydroxyapatite Coating on Initial Response of Osteoblast-Like Cells

To combine the bioinert titanium with the biological active coating of hydroxyapatite [HA, Ca10(PO4)6(OH)2] a new pulsed laser deposition(PLD) method was applied. The initial osteoblast-like MC3T3-E1 cell response to this thin HA coated(&lt;1μm) surface was compared with non-coated surfaces. Cell responses on four different pure titanium surfaces, such as smooth titanium, HA coated smooth titanium, rough titanium and HA coated rough titanium, were compared. Cell morphology and attachment were examined by scanning electron microscopy after 6, 24 and 72 hrs of culture, cell proliferation by MTS assay after 3, 7 and 14 days. The differentiation of the cells was analyzed by real time PCR up to 21 days. The cells were well spread and attached on all surfaces and showed more irregular shapes on the HA coated specimens. They proliferated continuously on all specimens up to 14 days. Smooth surface specimens showed better cell proliferation than rough ones after 7 days, and the HA coated specimens demonstrated slightly greater MTS activity than the non-coated groups after 14 days. The surface topography affected cell proliferation initially however; there was no significant difference afterwards. Thin HA coating influenced the expression of some genes related with cell differentiation.

Periapatite May Not Improve Micromotion of Knee Prostheses in Rheumatoid Arthritis

Prosthesis migration in bone inevitably occurs in cemented and uncemented total knee arthroplasty tibial components. Cemented designs as the gold standard give immediate fixation whereas cementless designs need a period of bone ingrowth onto the surface irregularities of the implants. The addition of bioactive coatings may enhance this process of ingrowth. A controlled randomized prospective RSA study was carried out on 26 Duracon implants in a rheumatoid arthritis patient group to evaluate the effect of a periapatite coating on the fixation of the tibial tray. The coated and the noncoated groups were matched for sex, age, body mass index, and HSS Knee Score. Stage of preoperative joint destruction and preoperative and postoperative mechanical leg axis showed no differences. We saw no differences in migration between the two groups, but a trend for lesser translations along and rotations about all three axes in the periapatite group. The periapatite-coated components showed a lower variance in subsidence than did the uncoated components. Both groups also showed a high variance in anterior tilting of the components. The cementless PA-coated Duracon prosthesis used in patients with RA may provide improved fixation of tibial components although we could not demonstrate improvement in this small controlled series. Therapeutic Level II. See the Guidelines for Authors for a complete description of levels of evidence.

Shear bond strength of veneering composite resin to titanium nitride coating alloy deposited by radiofrequency sputtering

The success of dental restorations utilizing composite resin over cast alloy has been variable and affected by micro-leakage. The purpose of this study was to investigate the shear bond strength between a composite resin and cast dental alloy coated with a layer of titanium nitride (TiN). Cast disk specimens made of Au-Pd-Ag alloy were randomly divided into four groups. The first group was left uncoated as a control while one group was coated with a metal conditioner, and the other two were coated with TiN at either 200 or 500 W with a radiofrequency magnetron sputtering system. Each group was then bonded to one of two types of light-activated composite resin material. Shear bond strengths were tested and compared for each specimen. The bond strength of each group was analyzed by 2-way ANOVA and by post hoc multiple comparison tests (Fisher's PLSD). As the interaction among groups was not significant (p=0.27) by 2-way ANOVA, TiN coated groups were found to have improved shear bond strength compared with non-coated groups without metal conditioner for both resin composite materials by multiple comparison tests. Furthermore, TiN coating is significantly stronger than non-coated groups with metal conditioner for one of the two resin composite materials examined (p<0.01). The results suggested that metal surface modification by coated TiN represents a technique that may significantly improve the bond between the Au-Pd-Ag alloy and veneering resin composite.

Surface tension effects of heparin coating on arterial line filters.

An investigation was conducted to determine the effects that heparin-coated screen arterial line filters have on the surface tension of cardiopulmonary bypass (CPB) priming solution. Five brands of non-heparin coated arterial line filters (Bard H625, Bentley AF1040, Intersept 40mum, Pall EC3840 and Pall SP3840) and four brands of heparin-coated filters (Bard H640, Bentley AF1040C and AF1040D and Intersept 40mum) were tested in a closed-loop circuit containing two litres of Plasma-Lyte A and pumped at a rate of five litres per minute. Samples were collected at 0.5, 20, 60 and 120 minutes to determine the surface tension of the recirculated solution. The non-heparin coated arterial line filters showed no significant changes in surface tension, either between the individual groups or over time. The benzalkonium-heparin coated filters (Bard H640, Bentley AF1040C and Intersept 40mum) all showed significant decreases in surface tension when compared to zero circulation time or to the noncoated groups. The largest drop in surface tension occurred within the first five minutes of recirculation. The circuit with a Bentley AF 1040D (a new nonbenzalkonium process) coated filter showed no significant change in surface tension.