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PubMed2004

Gastroprotective and anti-inflammatory effects of resin from Protium heptaphyllum in mice and rats.

The natural resin collected from the trunk wood of Protium heptaphyllum is used in folk medicine to treat inflammatory conditions and to hasten wound repair. In the search of new potential anti-inflammatory agents with gastroprotective property, the present study evaluated its effects in experimental models of gastric ulcer and inflammation. In mice, the resin (200 and 400 mg/kg) significantly attenuated the gastric damage induced by ethanol or acidified ethanol (HCl/ethanol), in a manner similar to N-acetyl-L-cysteine (NAC), a replenisher of sulfhydryls. Unlike NAC the resin failed to restore the ethanol-induced depletion of non-protein sulfhydryl content, indicating a different mechanism of gastroprotection. However, in 4-h pylorus-ligated rats, the resin significantly reduced the total acidity without much change in gastric secretory volume. In rats, at similar doses the resin did not modify the hind-paw edema induced by carrageenan, but effectively reduced the formation of cotton pellet-induced granuloma, suggesting its inhibitory effect on collagen formation but not on acute edema. Furthermore, the vascular permeability increase induced by acetic acid was significantly reduced in mice that received 400 mg/kg resin. The resin demonstrated no overt toxicity in mice up to an oral dose of 5 g/kg. Phytochemical analysis revealed the presence of alpha- and beta-amyrins as principal triterpenoid constituents of resin, which were previously described to have anti-ulcer property. These findings indicate the potential gastroprotective and anti-inflammatory property of P. heptaphyllum resin and further support its popular use in gastrointestinal disorders.

Acetic Acid↗
PubMed2006

The effect of polishing techniques on the surface roughness and color change of composite resins.

STATEMENT OF PROBLEM: Surface characteristics may affect the color change and surface roughness of composite resins. PURPOSE: This study evaluated the surface roughness and color change of a hybrid, a microhybrid, and a nanohybrid composite resin polished with the use of polishing discs, wheels, and a glaze material. MATERIAL AND METHODS: Fifty discs (10 x 2 mm) were fabricated for each composite resin (nanohybrid, Grandio; microhybrid, Filtek Z250; hybrid, Quadrant Universal LC) for a total of 150 discs, prepared using polyester strips and divided into 5 groups of 10. One of the groups served as control (C) and had no surface treatment (n=10). The specimens of the experimental groups were ground with 1000-grit silicon carbide paper. In 4 experimental groups (n=10), specimen surfaces were polished with polishing discs (D) (Sof-Lex), with polishing wheels (W) (Astropol), with polishing discs preceding the glaze application (DG) (Biscover), or with polishing wheels preceding the glaze application (WG), respectively. Color was assessed using a small area colorimeter. The color differences (DeltaE) values between the specimens of Group C and the experimental groups were calculated, and the data were compared using 2-way analysis of variance (ANOVA) (alpha=.05). Subsequently, the surface roughness (Ra) of the specimens was evaluated using a profilometer, and the data were analyzed by 2-way ANOVA followed by a Tukey multiple comparisons test (alpha=.05). RESULTS: The polishing technique and type of composite resin significantly affected the Ra and DeltaE values of the composite resins (P<.001). While the use of polishing wheels produced the highest Ra values when compared to the other polishing techniques (P<.001), the nanohybrid composite resin showed the lowest Ra values compared to the other composite resins in the control groups (P<.001). All of the nanohybrid and microhybrid composite resin groups were found to be significantly different from each other in terms of color difference (P<.001). CONCLUSION: The highest Ra values were obtained with hybrid composite resins due to the size of the filler particles that were exposed after polishing. Although the smoothest surfaces were obtained with polyester strips, the use of glaze material after polishing discs or polishing wheels resulted in significantly lower Ra and DeltaE values than the use of the latter alone. The glaze appears to fill the structural microdefects and provide a more uniform, regular surface.

Analysis of Variance↗
PubMed2006

Elimination of resin acids by advanced oxidation processes and their impact on subsequent biodegradation.

Wood pulping and paper production generate a considerable amount of wastewater, containing many pollutants among them resin and fatty acids. Resin acids contribute substantially to effluent toxicity and were identified to be detrimental to microorganisms of activated sludge and in particular to bacteria in anaerobic wastewater treatment system and other forms of aquatic life. The objective of the present study was to check the applicability of the ozone and advanced oxidation processes (AOPs) to eliminate resin acids from aqueous solutions and to determine the ozone dose required. Furthermore, an investigation of the influence of the oxidation methods on subsequent biological destruction of the byproducts was performed. Aqueous solution of the resin acids: abietic, dehydroabietic and isopimaric acids with different initial composition were subjected to ozonation or AOP processes at different ozone doses. After ozonation or advanced oxidation pretreatment the model solutions were biodegraded in aerated vessels containing activated sludge. During ozonation of the resin acids aqueous solutions the resin acids were almost eliminated, however the reduction of chemical oxygen demand (COD) was rather low. The ozone dose required to obtain reduction of resin acids >90% was in the range of 0.1-0.7mgO(3)/mgCOD, depending on the composition and concentration of model solutions. The toxicity of ozonated resin acids solutions decreased with increasing applied ozone dose up to about 0.3-0.5mgO(3)/mgCOD, thereafter increased. Ozonation and other AOP processes did not increase the rate of biodegradation of resin acids model solutions in aerated activated sludge systems compared to not pretreated solutions.

Acids, Carbocyclic↗
PubMed2002

Sulfoacylated poly(styrene-divinylbenzene) copolymers as resins for cation chromatography. Comparison with sulfonated, dynamically coated and silica gel cation exchangers.

Most important properties of an ion chromatographic resin are influenced by the resin matrix, the type of functional group and the ion-exchange capacity. Highly crosslinked PS-DVB resins of 5 microm diameter have been functionalized by sulfoacylation, by sulfonation and by dynamic coating over a wide range of exchange capacities. These materials allow a study of the influence of different ion-exchange sites and capacities. The influence of the degree of functionalization on resin performance is completely reverse for sulfoacylated and sulfonated resins. The HETP values for all observed analytes (Cu, Pb, Zn, Ni, Co, Cd, Mn, Ca, Mg) in a tartaric acid elution system decrease for sulfoacylated resins with increasing capacity, for sulfonated resins with decreasing capacity. The performance of sulfoacylated exchangers is better than for dynamically coated ones and far better than for sulfonated resins. The performance of silica gel based cation-exchangers such as BioSil CAT is in most cases better than observed for sulfoacylated resins.

Cation Exchange Resins↗
PubMed2003

Tensile bond strength of four resin luting agents bonded to bovine enamel and dentin.

STATEMENT OF PROBLEM: The resistance to fracture of ceramic restorations depends on adequate bonding to tooth structure. The dental substrate and the types of resin luting agents used are believed to produce variability in adhesive properties. PURPOSE: The purpose of this study was to evaluate the tensile bond strength of 4 resin luting agents to bovine enamel and dentin. MATERIAL AND METHODS: Forty bovine incisors were embedded in acrylic resin and ground horizontally with water-cooled silicon carbide paper to expose enamel (20 teeth) and dentin at the enamel/dentin junction (20 teeth). Ten standard cone-shaped specimens with a 3-mm diameter base were prepared for each of the following resin cements: Resin Cement, Rely X ARC, Nexus, and Enforce. Five specimens of each material were bonded to enamel and the other 5 to dentin with these resin luting agents and their respective adhesive systems, according to the manufacturers' directions. After 7 days of storage in distilled water at 37 degrees C, specimens were subjected to tensile forces in a universal testing machine at a crosshead speed of 0.5 mm/min until fracture. Bond strength data were analyzed with analysis of variance for substrate and material. Means were compared with Tukey's test at the 0.05 level of significance. RESULTS: Analysis of variance disclosed that both substrate (P<.001) and material (P<.05) demonstrated statistically significant differences, but their interaction was not significant. The bond strengths (MPa) obtained for Resin Cement (11.5 +/- 3.0), Rely X ARC (11.4 +/- 3.1), Nexus (10.0 +/- 1.4), and Enforce (11.8 +/- 2.8) were statistically the same for enamel. For dentin, bond strengths (MPa) for Rely X ARC (9.6 +/- 1.8), Resin Cement (9.3 +/- 0.9), and Enforce (7.8 +/- 2.9) were significantly higher than for Nexus (3.5 +/- 0.8). Significantly higher bond strengths (MPa) were also observed for enamel (11.2 +/- 2.5) than dentin (7.5 +/- 1.6). CONCLUSION: Within the limitations of this study, tensile bond strengths of resin luting agents to enamel were higher than those to dentin, and the bond strength values of Nexus to dentin were significantly lower (P<.05) than the other cements tested.

Adhesiveness↗
PubMed1995

Properties of highly cross-linked autopolymerizing reline acrylic resins.

Transverse bend strength tests and water sorption and solubility tests were done to compare the properties of highly cross-linked autopolymerizing reline resin with those of conventional non-cross-linked autopolymerizing reline resins. The relationship between composition and properties of autopolymerizing reline resins was also investigated. Highly cross-linked reline resins and the one that contained mainly poly(methyl methacrylate) and methyl methacrylate had a higher transverse bend strength and modulus of elasticity than the other reline resins (p < 0.01). The highly cross-linked reline resins also had significantly lower water sorption than the other reline resins (p < 0.01). Reline resins, except for one, had significantly higher solubility than heat-polymerizing denture base acrylic resins (p < 0.01).

Acrylic Resins↗
PubMed2003

The effect of filler and silane content on conversion of resin-based composite.

OBJECTIVE: This study examines the influence of filler loading and silane content on the conversion of photoactivated, resin-based composites as determined using Fourier transform infrared spectroscopy (FTIR). METHOD: Zirconia/silica filler was processed with a silane coupling agent (gamma-methacryloxypropyltrimethoxysilane) to achieve a range of silane-to-filler compositions. Treated fillers were compounded with a photoactivated BisGMA/TEGDMA resin to yield a series of pastes all containing 72 wt% total solids. Diffuse reflectance FTIR was used to characterize methacrylate unsaturation of the silane on the filler particles while paste conversion was determined using transmission FTIR. A resin matrix conversion was determined by adjusting the paste conversion for silane unsaturation. Two additional series of pastes were compounded to achieve variable filler-to-resin ratios using non-treated filler and filler processed with 8 wt% silane. Paste conversion was determined using transmission FTIR. RESULTS: Pastes compounded from fillers containing variable percent silane demonstrated linearly decreasing conversion (R(2)=0.986) with increasing silane content and ranged from 52.7 to 62.8%. Adjusting paste conversion for silane unsaturation yielded similar resin matrix conversion for all cured pastes (65.1+/-0.8%). Pastes compounded with increasing filler-to-resin ratios had progressively decreasing conversion. Correcting for silane unsaturation suggests this effect was independent of whether the filler was silane-treated or not. SIGNIFICANCE: Composite resin matrix conversion as determined via FTIR can be underestimated by the presence of unreacted methacrylate from silane on the filler. A corrected resin matrix conversion can be estimated by adjusting for silane unsaturation. Additionally, increasing filler-to-resin ratio progressively decreases conversion independent of the presence of silane on the filler.

Composite Resins↗
PubMed1999

Effect of MMA-PMMA resin polymerization initiators on the bond strengths of adhesive primers for noble metal.

OBJECTIVES: This study was conducted to investigate the effect of MMA-PMMA resin polymerization initiators on the bond strengths of two adhesive metal primers by evaluating the shear bond strengths of resins of silver-palladium-copper-gold (Ag-Pd-Cu-Au) alloy. METHODS: Three types of MMA-PMMA resins for which the polymerization initiators were TBB, BPO-amine and CQ-amine, and two adhesive primers, Metal PrimerII and V-Primer, were used. A brass ring placed over the nonprimed or primed casting alloy disk surface was filled with each resin. The half specimens were stored in water at 37 degrees C for 24 h. In addition, another half specimens were then immersed alternately in water baths at 4 degrees C and 60 degrees C for 1 min each for 20,000 thermal cycles before shear mode testing at a crosshead speed of 0.5 mm/min. RESULTS: There were no significant differences (p > 0.05) in bond strength between the three types of resins with or without thermal cycling when Metal PrimerII was used. However, when Ag-Pd-Cu-Au alloy was primed with V-Primer, the bond strength of CQ-amine resin was significantly weaker than that of TBB resin. Metal PrimerII was more effective for enhancing the bond strength and the bond strength was not affected by thermal cycling, in contrast to V-Primer. SIGNIFICANCE: The effectiveness of Metal PrimerII to enhance the bond strength is not influenced by polymerization mode of MMA-PMMA resin, in contrast to V-Primer when the resin is bonded to Ag-Pd-Cu-Au alloy.

Adhesives↗
PubMed2001

Raman spectroscopy of coloured resins used in antiquity: dragon's blood and related substances.

Dragon's blood is a deep red resin which has been used for centuries by many cultures and much prized for it's rarity, depth of colour and alchemical associations. The original source of dragon's blood resin is believed to be Dracaena cinnabari from Socotra in Africa, but since mediaeval times there have been several alternatives from different geographical locations from the Canary Islands to the East Indies. Here, the Raman spectra of dragon's blood resins from Dracaena draco Liliacae trees growing in several different locations bordering the Mediterranean and Middle East are compared with the resins from alternative botanical sources such as Daemonorops draco, Dracaena cinnabari and Eucalyptus terminalis, which all generically come under the description of dragon's blood. Key vibrational spectroscopic marker bands are identified in the Raman spectra of the resins, which are suggested for adoption as a protocol for the identification of the botanical and possible geographical sources of modern dragon's blood resins. The Raman spectra of materials, which are falsely attributed to dragon's blood resin are also shown for comparison and identification purposes. Changes in the Raman spectra of genuine dragon's blood resin specimens arising from simple processing treatment during the preparation of the resins for sale are also identified, which suggests a possible attribution characteristic for unknown samples.

Africa, Eastern↗
PubMed2004

Adsorption of flavonoids on resins: cyanidin 3-glucoside.

Adsorption of cyanidin-3-glucoside in aqueous batch solutions was studied at pH 3.5 and 20 degrees C using 13 commercial resins with different hydrophobicity, surface areas (SA, 330-1200 m2/g), and pore radii (PR, 20-260 A). The solute affinity toward different resins was described in terms of Langmuir and Freundlich parameters; experimental data were well-fitted to the two isotherms, which were both utilized to compare resins adsorption capacity. The styrene-divinylbenzene EXA-118 resin (SA, 1200 m2/g; PR, 90 A) showed the maximum effectiveness among the tested resins; a good efficacy for removing cyanidin 3-glucoside was shown also by EXA-90 (SA, 630 m2/g; PR, 105 A). Some experiments on a styrene-divinylbenzene resin and an acrylic one demonstrated that adsorption was not influenced by pH variations of the solution within the range of 1.0-4.5. For the 10 resins having PR < or = 105 A, correlation analysis evidenced the linear increasing dependence of Freundlich constant KF on physical characteristics of surface area and pore radius. The adsorption of cyanidin 3-glucoside at 20 degrees C was compared with that of hesperidin performed in batch runs on the same resins. Moreover, the best resin (EXA-118) was tested with a sample of pigmented orange juice to assess its performance in terms of selectivity, adsorption, and desorption capabilities on a real matrix.

Adsorption↗
PubMedDate not supplied

Surface roughness of denture base acrylic resins after processing and after polishing.

PURPOSE: Circumstances exist in which the need to adjust denture base acrylic resins is necessary. This process obviously alters the surface of the polished denture base. The purpose of this study was to compare the effects of three chairside polishing kits and conventional polishing on four denture acrylic resins. MATERIALS AND METHODS: Twenty-four 30 x 30 x 2 mm acrylic resin specimens were fabricated with each of four acrylic resins: autopolymerizing, heat processed, injection molded, and microwaveable. One side was polished conventionally with pumice and polishing compound. The other side was polished with one of three chairside polishing kits: Axis, Brasseler, and Shofu. Each side was evaluated by a Dektak 8 Programmable Stylus Profiler to determine the surface roughness (Ra). RESULTS: One-way analysis of variance (ANOVA) revealed that: (1) There was no significant difference in the time it took to polish the specimens with the chairside polishing kits (F=2.118, p=0.14). (2) There was a significant difference in surface roughness between the acrylic resins before any polishing, with the injection-molded and heat-processed being less rough than the autopolymerizing (F=4.588, p=0.005). (3) There was a significant difference in surface roughness between the acrylic resins when conventionally polished, with the injection-molded and microwavable being less rough than the autopolymerizing (F=4.503, p=0.005). Factorial ANOVA revealed that: (1) There was no significant difference in the surface roughness among the chairside polishing kits (F=1.209, p=0.30). (2) There was a significant difference between the acrylic resins, with the heat-processed, injection-molded, and microwaveable being significantly less rough than the autopolymerizing (F=6.610, p=0.0001). (3) There was no significant interaction between the acrylic resins and the chairside polishing kit in the amount of surface roughness (F=1.728, p=0.12). An independent t-test revealed that conventional polishing was significantly smoother than polishing with the chairside polishing kits (t=3.847, p=0.0001). CONCLUSIONS: It was concluded that time was not a factor in using any of the chairside polishing kits. It is recommended that conventional polishing be used after adjustments to the cameo surface of denture acrylic resin.

Acrylic Resins↗
PubMed2006

In vitro biofilm formation on the surface of resin-based dentine adhesives.

Prevention of root caries on exposed root surfaces in the aging population is a significant challenge. Bonding resins can be applied to exposed root surfaces as sealants; however, minimal data exists regarding biofilm formation on the surface of these resins. We hypothesized that an antibacterial dentine-bonding resin containing methacryloxydodecyl-pyridiniumbromide (MDPB) may reduce biofilm formation. Biofilms were produced in pooled stimulated natural whole saliva, supplemented with 1% sucrose, on the surface of 5 dentine-bonding resins (Clearfil SE, OptiBond Solo, Protect Bond, Protect Bond Primer, and Xeno III) using untreated root surfaces as controls. Biofilms were stained using the Live:Dead Baclight bacterial viability stain, viewed with confocal microscopy, and analyzed using ImageJ image-analysis software. Resin surfaces encouraged attachment of live bacteria compared with root surfaces. All resins showed similar bacterial colonization in sections adjacent to the resin surface, but in the central and outer portions of biofilms, Xeno III and Protect Bond Primer showed a viable bacterial load similar to that of the root surface. Fluoride-releasing resins (OptiBond Solo/Protect Bond) did not show reduced biofilm formation. Thus, antibacterial agents within the resins have a minimal effect on biofilm formation, particularly when directly adjacent to the root surface.

Anti-Bacterial Agents↗
PubMed2005

Changes in translucency of resin composites after storage in salivary esterase.

BACKGROUND: Dental resin composites are degraded by salivary enzymes, but the enzymatic influence on the translucency of resin composites has not been determined. PURPOSE: The purpose of this study was to evaluate the changes in translucency of resin composites after storage in the salivary enzyme esterase (ETE, porcine liver esterase, 400 mU/mL) compared with those in phosphate-buffered saline (PBS). MATERIALS AND METHODS: The colors of specimens of three brands of resin composites of various shades were measured after polymerization and polishing (baseline), and after immersion in PBS or ETE for 9 weeks; measurements were determined over white and black backgrounds according to the CIELAB color scale (established by Commission Internationale de l'Eclairage). The final specimen thickness was 1.75 mm. Translucency parameter (TP) was obtained by calculating the color difference between the specimen over a white background and that over a black background. Two-factor, repeated-measures analysis of variance was used to compare differences. RESULTS: TP values varied among and within different shade designations and also among different brands of resin composites. TP values were significantly changed after immersion in PBS and ETE and were influenced by the brand of resin composites, but they were not influenced differently by the immersion solutions of PBS and ETE (p = .05). CLINICAL SIGNIFICANCE: Translucency of dental resin composites is an important esthetic consideration. Based on the results of this study, the influence of salivary esterase on the changes in translucency of dental resin composites is not significantly different from that of phosphate-buffered saline. Therefore, it can be concluded that the enzymatic effects of saliva do not adversely alter the translucency of dental resin composites.

Analysis of Variance↗
PubMed1969

Microbiological study of water-softener resins.

Microbial identification using effluents backflushed from exhausted urban and rural tank resins and cleaned resins containing the sulfonated copolymer of styrene and divinylbenzene (SDB) were completed, along with microbial assessment of the concentrated stock salt brine. Forty-four different bacterial and fungal genera were identified. Extensive biochemical and animal virulence tests completed on one of the six bacterial salt brine isolates indicated a pathogenic staphylococcal strain. The retention of Staphylococcus aureus, a Flavobacterium sp, and Escherichia coli B bacteriophage was demonstrated both by using the nonexhausted sodium-regenerated resin and by using the same resin exchanged with different mono-, di-, and trivalent cations. Effluent counts completed after bacterial seepage through the resins indicated the Pb(++) exchanged resin removed 55% of the bacteria; Na(+), Fe(++), and Al(+++) removed 31 to 36% and Ca(++) and Cu(++) removed about 10 to 15%. Seventy per cent or more of the bacteriophage was removed by Fe(++), Cu(++), and Al(+++), whereas the Ca(++) and Na(++) cations removed 25 to 31%. Over a 77-day period, nonsterile tap water was passed through bacterial seeded and uninoculated SDB (Na) resin columns. Effluent and resin elution counts demonstrated the growth and survival of 2 different bacteria per column. Increased bacterial retention, survival, and multiplication occurred concomitantly with accumulation of organic and inorganic materials and the Ca(++) and Mg(++) cations from the tap water. Furthermore, microbial elution from resin particles taken from column depths of 1, 8, and 16 cm indicated a bacterial diminution with increasing depths.

Aluminum↗
PubMed1997

Variability in cytotoxicity and fluoride release of resin-modified glass-ionomer cements.

New-generation glass-ionomer cements contain resin to improve their restorative properties. These resin-modified glass-ionomer cements vary considerably in their chemistry, which could result in corresponding variability in their physical and biological properties. This study investigated the cytotoxicity and the fluoride release of two resin-modified glass ionomers, a conventional glass-ionomer cement, and a resin composite. Samples were prepared and extracted in distilled water for 1, 4, and 7 days; eluates were filtered and tested by means of 3T3 mouse fibroblasts. Cytotoxicity (MTT assay) values were low for all materials and extraction times, indicating minimal cytotoxicity of all materials (less than 30% inhibition). Cytotoxicity of one resin-modified glass ionomer was significantly higher than for the other materials (p < 0.001). One resin-modified glass ionomer and the conventional glass-ionomer cement released significantly more fluoride at each time interval (p < 0.001) than the other resin-modified glass-ionomer cement and the resin composite. Fluoride release and cytotoxicity were correlated (r2 = 0.60; p < 0.001), although the fluoride release does not account for the cytotoxicity observed. Cytotoxicity and fluoride release suggest that one hybrid behaved more like a conventional glass ionomer, and the other like a resin composite. These differences may have implications for material selection in specific clinical situations.

3T3 Cells↗
PubMed1999

Regional measurement of resin-dentin bonding as an array.

During the development of the microtensile bond-testing method, large variations in bond strengths were noted among serial sections. The reason for these variations is unknown. The purpose of this work was to determine the consistency of resin-dentin bond strengths across the occlusal surface of coronal dentin by dividing composite resin buildups into an array of 1x1 mm beams, the top half consisting of composite resin, and the bottom half consisting of dentin. Extracted human third molars had the occlusal enamel removed as a single section by means of a diamond saw. Resin composite buildups were made after the dentin was bonded with either One-Step or MacBond. After being stored in 37 degrees C water for 1 day, the teeth were vertically sectioned at 1-mm increments into slabs of bonded teeth. Each slab was further subdivided by vertical sections into 1x1x8 mm beams. Each beam was assigned an x-y coordinate and tested for tensile bond strength. Two different clinicians (A and B) performed the same procedures using One-Step in a parallel study. Using One-Step, clinician A obtained a large number of zero bonds in superficial dentin but fewer in deep dentin. This resulted in a very large standard deviation in bond strengths (mean +/- SD of 22+/-20 MPa in superficial dentin and 27+/-14 MPa in deep dentin). Clinician B obtained much higher (p<0.001) and more uniform bond strengths with One-Step (56+/-13 MPa in superficial dentin and 57+/-12 MPa in deep dentin). With MacBond, there were no zero bonds and hence less variation, with a mean of 41+/-13 MPa in superficial dentin and 27+/-12 MPa (x +/- SD) in deep dentin. When pairs of Z100 resin composite cylinders were bonded together with One-Step and then sectioned into an array, there was little variation in regional bond strength (37 +/-1 MPa). Dividing bonded resin composite buildups into an array of 20 to 30 1x1x8 mm beams allows for the evaluation of uniformity of resin-dentin bonds. The method used in this study detected local regional differences in resin-dentin bond strengths. The largest differences were shown to be related to technique rather than to material. The results indicate that resin-dentin bonds may not be as homogenous as was previously thought.

Adhesiveness↗
PubMed2004

Assessment of resin perfusion in hepatic failure in vitro and in vivo.

AIM: To observe the adsorbent effect of resin on endotoxin, cytokine, bilirubin in plasma of patients with hepatic failure and to determine the resin perfusion as an artificial liver support system in the treatment of hepatic failure. METHODS: One thousand milliliters of discarded plasma was collected from each of 6 severe hepatitis patients treated with plasma exchange. The plasma was passed through a resin perfusion equipment for 1-2 h via extracorporeal circulation, and then absorbent indicators of transaminase, bilirubin, blood ammonia, endotoxin and cytokines were examined. In the meantime, study of in vivo resin plasma perfusion was performed on 7 severe hepatitis patients to compare the changes of endotoxin and cytokines in blood before and after perfusion. RESULTS: The levels of total bilirubin, endotoxin, interleukin 1beta and TNF-alpha in plasma were significantly decreased after in vitro resin plasma perfusion. The levels of interleukin 1beta, TNF-alpha and endotoxin in blood were also evidently declined after in vivo resin plasma perfusion. Nevertheless, no obvious changes in IL-6, creatinine (Cr) and urea nitrogen (UN), blood ammonia and electrolytes were found both in vitro and in vivo. CONCLUSION: Bilirubin, endotoxin and cytokines in plasma of patients with hepatic failure can be effectively adsorbed by resin in vitro. Most cytokines and endotoxin in plasma can also be effectively removed by resin in vivo. It demonstrates that resin perfusion may have good treatment efficacy on hepatic failure and can be expected to slow down the progression of hepatic failure.

Adult↗
PubMed1995

Relationship between particle size of barium glass filler and water sorption of light-cured composite resin.

The reaction of barium glass filler with water was determined by investigation of the effects of the particle size of barium glass filler on the water sorption rate and the mechanical properties of composite resin. Barium glass and quartz were milled to obtain powders with different average particle sizes. These powders were silanized and used as inorganic filler in composite resin. Photoactivated base monomer was loaded at 65% (w/w) with these fillers to prepare the composite resin paste. The water sorption of barium glass filled resin was always more than that of quartz filled resin. The amount of sorbed water obtained by barium glass filled resin increased as the particle size decreased. The particle size of the quartz filler did not affect the water sorption. The flexural strength of barium filled resin decreased after water immersion more than that of the quartz filled resin as the particle size decreased. These results suggest that the water durability of barium glass is low and the surface of barium glass filler is damaged by water. Water would be retained in the interface between the barium glass filler and the matrix resin.

Absorption↗