scholarly journals Synthesis, Characterization and Testing of Antimicrobial Activity of Composites of Unsaturated Polyester Resins with Wood Flour and Silver Nanoparticles

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1122
Author(s):  
Przemysław Pączkowski ◽  
Andrzej Puszka ◽  
Malgorzata Miazga-Karska ◽  
Grażyna Ginalska ◽  
Barbara Gawdzik
Keyword(s):  
Silver Nanoparticles ◽  
Staphylococcus Epidermidis ◽  
Polyester Resin ◽  
Wood Flour ◽  
Unsaturated Polyester ◽  
Thermomechanical Properties ◽  
Resin Composites ◽  
Polyester Resins ◽  
Before And After

This paper presents the properties of the wood-resin composites. For improving their antibacterial character, silver nanoparticles were incorporated into their structures. The properties of the obtained materials were analyzed in vitro for their anti-biofilm potency in contact with aerobic Gram-positive Staphylococcus aureus and Staphylococcus epidermidis; and aerobic Gram-negative Escherichia coli and Pseudomonas aeruginosa. These pathogens are responsible for various infections, including those associated with healthcare. The effect of silver nanoparticles incorporation on mechanical and thermomechanical properties as well as gloss were investigated for the samples of composites before and after accelerating aging tests. The results show that bacteria can colonize in various wrinkles and cracks on the composites with wood flour but also the surface of the cross-linked unsaturated polyester resin. The addition of nanosilver causes the death of bacteria. It also positively influences mechanical and thermomechanical properties as well as gloss of the resin.

scholarly journals Moisture Resistance, Thermal Stability and Fire Behavior of Unsaturated Polyester Resin Modified with L-histidinium Dihydrogen Phosphate-Phosphoric Acid

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 932
Author(s):  
Kamila Sałasińska ◽  
Maciej Celiński ◽  
Kamila Mizera ◽  
Mateusz Barczewski ◽  
Paweł Kozikowski ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Polyester Resin ◽  
Unsaturated Polyester ◽  
Fire Behavior ◽  
Fire Retardant ◽  
Thermomechanical Properties ◽  
Unsaturated Polyester Resin ◽  
Dihydrogen Phosphate ◽  
Smoke Emission ◽  
Volatile Products

In this paper, the fire behavior of unsaturated polyester resin (UP) modified with L-histidinium dihydrogen phosphate-phosphoric acid (LHP), being a novel intumescent fire retardant (IFR), was investigated. Thermal and thermomechanical properties of the UP with different amounts of LHP (from 10 to 30 wt. %) were determined by thermogravimetric analysis (TG) as well as dynamic mechanical thermal analysis (DMTA). Reaction to small flames was studied by horizontal burning (HB) test, while fire behavior and smoke emission were investigated with the cone calorimeter (CC) and smoke density chamber. Further, the analysis of volatile products was conducted (TGA/FT-IR). It was observed that the addition of LHP resulted in the formation of carbonaceous char inhibiting the thermal decomposition, burning rate and smoke emission. The most promising results were obtained for the UP containing 30 wt. % of LHP, for which the highest reduction in maximum values of heat release rate (200 kW/m2) and total smoke release (3535 m2/m2) compared to unmodified polymer (792 kW/m2 and 6895 m2/m2) were recorded. However, some important disadvantage with respect to water resistance was observed.

Organic Rectorite-modified Unsaturated Polyester Resin Composites

2006 ◽  
Vol 41 (9) ◽  
pp. 1051-1065 ◽  
Author(s):  
Li Yuan ◽  
Xiao-Yan Ma ◽  
Guo-Zheng Liang ◽  
Yun Huang
Keyword(s):  
Polyester Resin ◽  
Unsaturated Polyester ◽  
Unsaturated Polyester Resin ◽  
Resin Composites

scholarly journals Highly variable effect of sonication to dislodge biofilm-embedded Staphylococcus epidermidis directly quantified by epifluorescence microscopy: an in vitro model study

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Erik T. Sandbakken ◽  
Eivind Witsø ◽  
Bjørnar Sporsheim ◽  
Kjartan W. Egeberg ◽  
Olav A. Foss ◽  
...  
Keyword(s):  
Staphylococcus Epidermidis ◽  
Biofilm Formation ◽  
In Vitro Model ◽  
Laser Scanning Microscopy ◽  
Epifluorescence Microscopy ◽  
Variable Effect ◽  
Prosthetic Joint Infections ◽  
Before And After ◽  
Vitro Model

Abstract Background In cases of prosthetic joint infections, culture of sonication fluid can supplement culture of harvested tissue samples for correct microbial diagnosis. However, discrepant results regarding the increased sensitivity of sonication have been reported in several studies. To what degree bacteria embedded in biofilm are dislodged during the sonication process has to our knowledge not been fully elucidated. In the present in vitro study, we have evaluated the effect of sonication as a method to dislodge biofilm by quantitative microscopy. Methods We used a standard biofilm method to cover small steel plates with biofilm forming Staphylococcus epidermidis ATCC 35984 and carried out the sonication procedure according to clinical practice. By comparing area covered with biofilm before and after sonication with epifluorescence microscopy, the effect of sonication on biofilm removal was quantified. Two series of experiments were made, one with 24-h biofilm formation and another with 72-h biofilm formation. Confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) were used to confirm whether bacteria were present after sonication. In addition, quantitative bacteriology of sonication fluid was performed. Results Epifluorescence microscopy enabled visualization of biofilm before and after sonication. CLSM and SEM confirmed coccoid cells on the surface after sonication. Biofilm was dislodged in a highly variable manner. Conclusion There is an unexpected high variation seen in the ability of sonication to dislodge biofilm-embedded S. epidermidis in this in vitro model.

scholarly journals Microleakage at enamel and dentin margins with a bulk fills flowable resin

2014 ◽  
Vol 08 (01) ◽  
pp. 001-008 ◽  
Author(s):  
Nicola Scotti ◽  
Allegra Comba ◽  
Alberto Gambino ◽  
Davide Salvatore Paolino ◽  
Mario Alovisi ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Resin Composite ◽  
In Vitro Study ◽  
Artificial Ageing ◽  
Resin Composites ◽  
Class V ◽  
Dye Penetration ◽  
Before And After ◽  
Blue Solution

ABSTRACT Objective: The aim of this in vitro study was to evaluate the marginal sealing ability of a bulk fill flowable resin composite on both enamel and dentin substrates. Materials and Methods: 48 non-carious molars were selected and four Class-V cavities were prepared at the CEJ of each sample. Cavities were filled with Venus Diamond (Heraeus Kulzer); Venus Diamond Flow (Heraeus Kulzer) and Surefil SDR (Dentsply). Samples were divided into two groups: First group samples were immersed in a methylene blue solution for 30 min at 25°C. Second group samples were artificially aged and then treated with methylene blue. Samples were sectioned in the center of the restoration and observed with a 40x stereomicroscope, and the percentage of cavity infiltration was calculated. Results: Results were analyzed statistically by ANOVA (P < 0.05). The amount of infiltration was significantly lower for the enamel substrate compared with dentin (P = 0.0001) and in samples immediately immersed in methylene blue compared with those that were artificially aged (P = 0.011). The interaction between the composite material and the marginal substrate significantly affected dye penetration (P = 0.006). Conclusions: Bulk fill flowable resins provided significantly better marginal seal in dentin, both before and after artificial ageing. Nanohybrid resin composites and bulk fill flowable resins showed similar microleakage values at enamel margins. Bulk fills flowable resins provided significantly better marginal seal in dentin, both before and after artificial ageing. Nanohybrid resin composites and bulk fill flowable resins showed similar microleakage values at enamel margins.

scholarly journals The effect of a bleaching agent on the pigment removal and the bond strength of bulk-fill resin composites: an in vitro study

2018 ◽  
Vol 47 (5) ◽  
pp. 298-304
Author(s):  
Caroline de Farias CHARAMBA ◽  
Renally Bezerra Wanderley LIMA ◽  
Sônia Saeger MEIRELES ◽  
Rosângela Marques DUARTE ◽  
Ana Karina Maciel ANDRADE
Keyword(s):  
Bond Strength ◽  
Color Change ◽  
Resin Composite ◽  
Distilled Water ◽  
Filling Material ◽  
Resin Composites ◽  
Bleaching Agent ◽  
Microtensile Testing ◽  
Before And After

Abstract Introduction In order to simplify the technique, reduce the time required for direct adhesive restorations, bulk-fill resin composites have been developed be applied in bulk placement up to 4 mm increments. Objective Evaluating the color change (ΔE) and the microtensile bond strength (μTBS) of bulk fill resin composites (BFRC) to dentin after the immersion in regular beverages and the application of bleaching systems. Method Forty-five human molar teeth were randomly distributed in three groups according to the filling material (n=15): Filtek Bulk Fill, Tetric N Ceram Bulk Fill and Filtek Z100. The restored teeth were immersed in coffee, wine and distilled water (n=5) for 72 hours. The color parameters were measured using a spectrophotometer, having as basis the CIE L*a*b*, before and after tooth staining and application of bleaching processes. Subsequently, the teeth were sectioned to obtain the specimens for the microtensile testing. The ΔE values were analyzed applying the Kruskal-Wallis and the Wilcoxon tests, and the μTBS values were analyzed applying the ANOVA and the Bonferroni tests (p<0.05). Result There were no significant differences in the ∆E values when comparing the BFRCs to the conventional resin composite (CRC) in most of the experimental groups. The ∆E values did not present significant differences before and after the application of bleaching processes for all the tested resin composites. The BFRCs presented higher μTBS values than the CRC after exposure to distilled water, wine and bleaching agent. Conclusion The studied BFRCs presented similar color stability to the CRC. The BFRCs presented higher bond strength to the dentin than the CTC in most of the evaluated conditions. The bleaching agent was not effective in whitening the stained restored teeth.

Research on the Microstructure of Leather/Resin Composites

2013 ◽  
Vol 833 ◽  
pp. 326-329 ◽  
Author(s):  
Hua Yong Zhang ◽  
Xiao Jian Liu
Keyword(s):  
Cross Section ◽  
Polyester Resin ◽  
Raw Materials ◽  
Resin Composite ◽  
Unsaturated Polyester ◽  
Optical Microscope ◽  
Environmental Scanning ◽  
Resin Composites ◽  
Leather Wastes ◽  
Scanning Electron

Reuse of leather wastes has been paid much attention. In this article, the chrome tanned cattle (pig) leather and unsaturated polyester resin or epoxy resin were used as raw materials, leather/resin composite material was prepared. The composite sections were examined by optical microscope and environmental scanning electron microscope. By observing the cross section morphology, the performance of composites can be speculated, the effective direction for further research on leather/resin composites and development can be provided.

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