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1.
Niger J Clin Pract ; 22(12): 1675-1679, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31793473

RESUMO

Aims: The aim of this in vitro investigation was to evaluate the efficiency of self-adhering flowable resin composite (Vertise Flow, Kerr, Orange, CA, USA) and different surface treatments in the repair microtensile bond strength (µTBS) of aged nanofill resin composites using a universal adhesive. Materials and Methods: Aged substrates (×5000 thermocycling) were prepared using a nanofill (Filtek Ultimate; 3M ESPE) resin composite and randomly assigned to different surface treatments: (1) no treatment (control), (2) acid etching with 37% phosphoric acid, (3) Al2O3sandblasting, and (4) sandblasting with CoJet (3M ESPE). After surface treatment, specimens were further divided into two groups: no universal adhesive application and universal adhesive application. Vertise Flow was added to the substrates at 2-mm layer increments to a height of 5 mm and light cured. Restored specimens were sectioned to obtain 1.0-mm2 beams for µTBS testing. Data were analyzed with two-way analysis of variance and Tukey's honest significant difference tests (P < 0.05). Results: The lowest µTBS values were recorded in the control and acid etching groups with no universal adhesive application (P < 0.05). Universal adhesive application significantly increased the repair µTBS values of all surface treatments (P < 0.05), except CoJet treatment. There were no significant differences between Al2O3sandblasting, CoJet application, and acid etching groups with the universal adhesive application (P > 0.05). Conclusion: Vertise Flow can be used effectively in the repair of old nanofill resin composites. The usage of universal adhesive with prior acid etching to obtain acceptable repair performance would be the practical choice under clinical conditions.


Assuntos
Resinas Compostas/química , Colagem Dentária/métodos , Esmalte Dentário/química , Adesivos Dentinários , Dentina/química , Cimentos de Resina/química , Adesivos , Análise do Estresse Dentário , Humanos , Teste de Materiais/métodos , Propriedades de Superfície , Resistência à Tração
2.
J Interv Cardiol ; 2019: 6945372, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31772543

RESUMO

Objectives: To assess the expansion pattern of coronary stents by using different balloon inflation times and pressures. Background: The selection of coronary stent size and its proper deployment is crucial in coronary artery interventions, having an impact on the success of the procedure and further therapy. Methods: Ten pairs of different stents were deployed under nominal pressure using sequential (5, 5, 10, and 10 seconds of repeated inflations, thus 30 seconds of summarized time) and continuous (30 seconds) deployment pattern. After each given time-point, intraluminal stent measurements were performed by optical coherence tomography (OCT) and intravascular ultrasound (IVUS). Results: Both in-stent diameters and cross-section areas (CSA) of paired stents measured by OCT at all sequential time-points were significantly smaller compared to given manufacturers charts' values (90% to 94% for diameters and 81% to 88% for CSA, p<0.05). Significant increase of in-stent diameter and CSA was observed across the step-by-step deployment pattern. In-stent lumen measurements were significantly larger when sequential deployment pattern was applied compared to continuous deployment. Additional measurements were also done for overlapping segments of stents, showing smaller in-stent measurements of the latter compared to nonoverlapping segments. Validation of OCT and IVUS measurements using a phantom metallic tube showed perfect reproducibility with OCT and overestimation with IVUS (8% for diameters and 16% for CSA). Conclusions: Stent diameter after deployment is time-dependent and not only pressure-dependent. Different stent expansion behavior, depending on the applied deployment pattern (sequential and nonsequential), was observed.


Assuntos
Angioplastia Coronária com Balão , Desenho de Equipamento , Stents , Angioplastia Coronária com Balão/instrumentação , Angioplastia Coronária com Balão/métodos , Angiografia Coronária/métodos , Humanos , Teste de Materiais/métodos , Stents/classificação , Stents/normas , Fatores de Tempo , Tomografia de Coerência Óptica/métodos , Ultrassonografia de Intervenção/métodos
3.
J Interv Cardiol ; 2019: 9282876, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31772552

RESUMO

Background: While the evaluation of burr speed was discussed regarding platelet aggregation, the association between platform speed and acute lumen gain of rotational atherectomy remains unknown. Methods: Through the evaluation of the potential of low-speed rotational atherectomy (LSRA) in in-vitro experiments, minimum lumen diameter (MLD) and minimum lumen area (MLA) after conventional high-speed rotational atherectomy (HSRA group) and those after LSRA following HSRA (LSRA+HSRA group) treated by 1.5 mm burrs were measured by optical frequency domain imaging (OFDI) in 30 consecutive human lesions. Results: The in-vitro experiments demonstrated that MLD and MLA after LSRA+HSRA were significantly larger (MLD: LSRA+HSRA=1.50 ±0.05 mm, HSRA= 1.43 ±0.05 mm, p=0.015; MLA: LSRA+HSRA= 1.90 ±0.17 mm2, HSRA= 1.71±0.11 mm2, and p= 0.037), requiring more crossing attempts (LSRA= 134 ±20 times, HSRA= 72 ±11 times, and p< 0.001). In human studies, there was no significance in reference vessel diameter and lesion length before the procedure between two groups. MLDs after LSRA+HSRA were significantly larger than those in HSRA (LSRA+HSRA= 1.22 ±0.16 mm, HSRA= 1.07 ±0.14 mm, and p= 0.0078), while MLAs after LSRA+HSRA tended to be larger (LSRA+HSRA= 1.79 ±0.51 mm2, HSRA= 1.55 ±0.47 mm2, and p= 0.19). There was no significance in the occurrence of in-hospital complication, including slow flow or no reflow, major dissection, and procedural myocardial infarction, between LSRA+HSRA and HSRA. Conclusions: LSRA can achieve larger lumen gain compared, whereas HSRA can pass calcified lesions easily. Combination of LSRA and HSRA is a safe and feasible strategy for severely calcified lesions in clinical practice.


Assuntos
Aterectomia Coronária , Doença da Artéria Coronariana , Vasos Coronários , Teste de Materiais/métodos , Intervenção Coronária Percutânea/métodos , Idoso , Aterectomia Coronária/efeitos adversos , Aterectomia Coronária/instrumentação , Aterectomia Coronária/métodos , Doença da Artéria Coronariana/patologia , Doença da Artéria Coronariana/cirurgia , Vasos Coronários/diagnóstico por imagem , Vasos Coronários/patologia , Vasos Coronários/cirurgia , Desenho de Equipamento , Feminino , Humanos , Japão , Masculino , Pessoa de Meia-Idade , Cirurgia Assistida por Computador/métodos , Resultado do Tratamento , Calcificação Vascular/cirurgia
4.
Niger J Clin Pract ; 22(11): 1475-1482, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31719267

RESUMO

Objective: To compare the shear bond strength of resin cement to zirconia-based monolithic CAD-CAM materials subjected to different surface treatments. Methods: 2 brands of monolithic zirconia blocks (Vita YZ HT, Sirona inCoris TZI), yttrium-stabilized tetragonal zirconia (IPS e.max ZirCAD) and zirconia-reinforced lithium silicate ceramic (Vita Suprinity) were divided into six groups according to the surface treatment received: no treatment (control), HF acid etching, sandblasting, sandblasting + Er:YAG laser irradiation, Er:YAG laser irradiation and CoJet. Composite resin cylinders were bonded to blocks with self-adhesive resin cement (Theracem). Shear bond strength was evaluated after thermocyling. Failure modes were examined using SEM. Data was analyzed statistically by using 2-way ANOVA and post-hoc Tukey's test (P < 0,05). Results: The bond strength was significantly affected by the surface treatment and the type of CAD-CAM blocks (P < 0,001). Surface treatment with CoJet revealed significantly higher bond strength compared to sandblasting in Y-TZP and monolithic zirconia specimens. Conclusions: Monolithic zirconia blocks showed higher bond strength values compared to Y-TZP zirconia block in sandblasting and CoJet groups. HF acid etching is more effective than sandblasting and CoJet for Vita Suprinity.


Assuntos
Cerâmica/química , Resinas Compostas/química , Teste de Materiais/métodos , Cimentos de Resina/química , Resistência ao Cisalhamento , Zircônio , Projeto Auxiliado por Computador , Colagem Dentária , Humanos , Microscopia Eletrônica de Varredura , Propriedades de Superfície , Ítrio
5.
Mater Sci Eng C Mater Biol Appl ; 105: 110020, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31546350

RESUMO

In situ High-Temperature X-ray diffraction (HT-XRD) from 400 to 900 °C was carried out to obtain patterns of bio hydroxyapatite every 20 °C during calcination processes at heating rates of 3, 6, and 9 °C/min to determine changes in its structural parameters as well as in its thermal expansion coefficient (TEC) for a and c lattice parameters. Additionally, High-Resolution Transmission Electron microscopy (HR-TEM) demonstrates that this HAp has an ordered nano like plate crystalline structure. The raw sample exhibits broad X-ray peaks originated by its nano size, and after calcination at about 700 °C, these become narrowed due to crystal growth. The calculation of the TEC as a function of the temperature for this hydroxyapatite shows a nonlinear increment for the a and c lattice parameters. Lattice thermal expansion occurs as water and organic matter are lost as the coalescence of HAp crystals take place; furthermore, as the heating rate increases, so does the lattice volume. Thermal analyses confirm that crystal growth is a process that starts after the bone sample has lost all its organic material and then bio-hydroxyapatite size changes from nano to micro-scale. A simulation using the PDF-4 software confirmed the nanometric size of the hydroxyapatite.


Assuntos
Durapatita/química , Teste de Materiais/métodos , Difração de Raios X , Animais , Osso e Ossos/efeitos dos fármacos , Osso e Ossos/ultraestrutura , Varredura Diferencial de Calorimetria , Bovinos , Durapatita/farmacologia , Temperatura Alta , Minerais/análise
6.
Urology ; 134: 79-83, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31476349

RESUMO

OBJECTIVE: To better understand the impact of laser fiber-tip configuration on lithotripsy performance, we undertook an in vitro study comparing 3 fiber-tip configurations: (1) new (single-use), (2) cleaved (reusable), and (3) coated (cut with scissors). METHODS: Lithotripsy was performed using a Ho:YAG laser utilizing fragmentation (1 J × 10 Hz) and dusting (0.5 J × 20 Hz) settings. BegoStones were fragmented with a laser fiber advancing at a speed of 1 mm/s (220 seconds of activation). Three fiber-tip configurations were tested: new single-use standard (242 µm core) and cleaved (272 µm core), compared to the same fiber-tip coated/cut flush with scissors, respectively. Study outcome was difference in stone mass before and after each experiment. Power output was measured using a power meter. RESULTS: Fragmentation for new or cleaved fibers was greater than the coated/cut flush fiber-tip (P <.05). For 1 J × 10 Hz and 0.5 J × 20 Hz settings, fragmentation was 59% and 75% higher with new fiber-tip compared to the coated/cut flush fiber-tip, respectively. For 1J × 10 Hz and 0.5 J × 20 Hz settings, fragmentation was 51% and 45% higher with cleaved fiber-tip compared to the coated/cut flush fiber-tip, respectively. Power output at the end of laser activation was higher for new and cleaved fiber-tips. CONCLUSION: New and cleaved laser fibers demonstrated superior lithotripsy performance compared to fibers that were coated/cut flush with scissors. Cutting single-use laser fibers risks damaging the fiber-tip which can disperse the energy and reduce lithotripsy efficiency.


Assuntos
Desenho de Equipamento , Lasers de Estado Sólido , Litotripsia a Laser , Cálculos Urinários/terapia , Desenho de Equipamento/efeitos adversos , Desenho de Equipamento/classificação , Análise de Falha de Equipamento/métodos , Humanos , Lasers de Estado Sólido/normas , Lasers de Estado Sólido/uso terapêutico , Litotripsia a Laser/efeitos adversos , Litotripsia a Laser/instrumentação , Litotripsia a Laser/métodos , Teste de Materiais/métodos
7.
Mater Sci Eng C Mater Biol Appl ; 104: 109949, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31499955

RESUMO

The paper presents a comparative study of the impact that TiN, ZrN and DLC nanocoatings on titanium implants have on animal organisms. The experiment lasted 602 days and used 15 laboratory animals (rabbits from the Lagomorph species). Implants, eight of each type, were implanted subcutaneously in the cervical region. The control group consisted of three animals. Over the course of the experiment, at the beginning and subsequently every 7 days, the animals had their blood drawn and analysed for parameters indicating inflammation. Once the experiment ended, a histopathological evaluation of the animals' internal organs was conducted, and the places where the implants came into contact with the tissue were also assessed. The results of the laboratory tests did not indicate any characteristics of inflammation for any of the coatings. The histopathological examination confirmed biocompatibility in all cases. This is of great importance in the case of the DLC coating, which, due to its tribological properties - a low friction coefficient - has a very high potential for application in various areas of medicine.


Assuntos
Carbono/química , Materiais Revestidos Biocompatíveis/química , Diamante/química , Estanho/química , Titânio/química , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Inflamação/tratamento farmacológico , Masculino , Teste de Materiais/métodos , Próteses e Implantes , Coelhos , Propriedades de Superfície
8.
Mater Sci Eng C Mater Biol Appl ; 104: 109947, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31499970

RESUMO

Due to its good biodegradability and mechanical properties, magnesium alloys are considered as the ideal candidate for the cardiovascular stents. However, the rapid degradation in human physiological environment and the poor biocompatibility seriously limit its application for biomaterials. In the present study, a chitosan/heparinized graphene oxide (Chi/HGO) multilayer coating was constructed on the AZ31B magnesium alloy surface using layer-by-layer (LBL) method to improve the corrosion resistance and biocompatibility. The results of attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), Raman spectrum (RAMAN), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) showed that a dense and compact Chi/HGO multilayer coating was fabricated on the magnesium alloy surface. The results of potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), pH value changes and magnesium ion release suggested that the multilayer coating can significantly enhance the corrosion resistance of the magnesium alloy. Moreover, the Chi/HGO multilayer coating could not only significantly reduce the hemolysis rate and platelet adhesion, but also promote the adhesion and proliferation of endothelial cells. Therefore, the Chi/HGO multilayer coating can simultaneously improve the corrosion resistance and biocompatibility of the magnesium alloys.


Assuntos
Quitosana/química , Materiais Revestidos Biocompatíveis/química , Grafite/química , Heparina/química , Magnésio/química , Ligas/química , Adesão Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Corrosão , Células Endoteliais/efeitos dos fármacos , Humanos , Teste de Materiais/métodos , Microscopia Eletrônica de Varredura/métodos , Adesividade Plaquetária/efeitos dos fármacos , Espectrometria por Raios X/métodos , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Propriedades de Superfície/efeitos dos fármacos
9.
Mater Sci Eng C Mater Biol Appl ; 104: 109896, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31499977

RESUMO

Zinc alloys have been explored as potential materials for biodegradable vascular stents due to their tolerable corrosion rates and tunable mechanical properties. However, the performances of Zn alloys were not supported with enough toxicity or biological compatibility evaluation, particularly hemocompatibility for vascular scaffolding application. In this work, the hemocompatibility of three zinc alloys (Zn-0.8Cu, Zn-0.8Mn and Zn-0.8Li) was evaluated with 316 L stainless steel and pure zinc as controls. The hemolysis ratios of 316 L stainless steel, pure Zn, Zn-0.8Cu, Zn-0.8Mn and Zn-0.8Li were 0.38 ±â€¯0.08%, 1.04 ±â€¯0.21%, 0.47 ±â€¯0.21%, 0.57 ±â€¯0.14% and 0.52 ±â€¯0.22%, respectively, for direct contact method. Platelets aggregation on the 316 L stainless steel was observed, while the adhered platelets on the Zn alloys exhibited round shape with few pseudopodia spreading. The number of adhered platelets on the three zinc alloys (Zn-0.8Cu, Zn-0.8Mn and Zn-0.8Li) had no statistically difference compared with 316 L stainless steel, while significant fewer than the pure Zn group. None remarkable platelet activation, hematocyte aggregation, coagulation or complement activation was observed in any Zn alloy group. Furthermore, the Zn alloys prolonged prothrombin time and partial thromboplastin time, demonstrating a potential function of anticoagulation. The results demonstrated that Zn alloys presented in this work are indeed meeting the hemocompatible requirements of implant and showing the promise for perspective application as biodegradable stent.


Assuntos
Ligas/química , Materiais Biocompatíveis/química , Lítio/química , Magnésio/química , Zinco/química , Implantes Absorvíveis , Ligas/administração & dosagem , Materiais Biocompatíveis/administração & dosagem , Coagulação Sanguínea/efeitos dos fármacos , Ativação do Complemento/efeitos dos fármacos , Corrosão , Hemólise/efeitos dos fármacos , Humanos , Lítio/administração & dosagem , Teste de Materiais/métodos , Ativação Plaquetária/efeitos dos fármacos , Aço Inoxidável/química , Stents , Zinco/administração & dosagem
10.
Mater Sci Eng C Mater Biol Appl ; 104: 109946, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31499982

RESUMO

The reinforcement of PMMA bone cements using carbon based nanomaterials has demonstrated to be a potential solution to their poor mechanical properties. The achievement of an optimal dispersion of the nanoparticles within the polymeric matrix is a crucial but not easy stage in the production of high-quality reinforced materials. In this work, a useful route for the graphene (G) functionalisation, via silanisation with (3-methacryloxypropyl) trimethoxy silane (MPS), has been developed, providing a remarkable enhancement in dispersibility and mechanical properties. With the purpose to define the critical graphene surface oxidation parameters for an optimal silanisation, different routes were thoroughly analysed using infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The results showed that the silanisation significantly improved the G dispersibility: whereas the pristine G dispersion fell down within the first 24 h, the silanised G showed an adequate stability after 5 days. Additionally, this improved dispersibility produced a notable increase in the mechanical properties of the G-reinforced bone cements: in comparison with the pristine G, the compression and bending strength of silanised G increased by 12% and by 13.7% respectively and the fracture toughness by 28%. These results provide very useful information on the relevance that the characteristics of the superficial oxidation of graphene have on the effectiveness of the silanisation process, besides an interesting functionalisation procedure for advanced dispersion and reinforcement of G-PMMA bone cements.


Assuntos
Cimentos para Ossos/química , Grafite/química , Polimetil Metacrilato/química , Silanos/química , Teste de Materiais/métodos , Estresse Mecânico , Propriedades de Superfície/efeitos dos fármacos , Resistência à Tração/efeitos dos fármacos
11.
Mater Sci Eng C Mater Biol Appl ; 104: 109884, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31500005

RESUMO

In this study, we have successfully doped hydroxyapatite (HA) with zinc (Zn2+), sulphate (SO42-) and fluoride (F-) ions to develop a new composition of bioceramic, Ca10-x Znx(PO4)6-y(SO4)y(OH)2-z-yFz(SO4)y, (x = 0, 0.2, 0.6, 1.0, y = 0, 0.5 and z = 0,1.0 mol), using wet precipitation method. The obtained materials were analysed using XRD, FTIR, FESEM, and XPS techniques to investigate the phase purity, particle morphology and elemental composition, respectively. A model anticancer drug (Doxorubicin, DOX) was loaded onto the surface of the Zn/SO4-FHA materials. About 100% loading of DOX with a controlled release profile was obtained. Degradation of materials in Simulated body fluid (SBF) was greatly improved with the incorporation of Zn2+/SO42- ions in comparison to HA/FHA, which makes it highly bioactive materials. In vitro cell viability and adhesion of Human fetal osteoblast (hFOB) cell were investigated. Cell viability has demonstrated that the hFOB cells proliferated at a high rate on Zn/SO4-FHA materials, confirming the in vitro biocompatibility of the materials. Alkaline phosphatase (ALP) activity and intracellular calcium deposition of hFOB cells seeded on 1ZnSO4-FHA disc surface was statistically higher than observed on pure HA and FHA discs, indicating that hFOB cells differentiated into mature osteoblasts on 1Zn/SO4-FHA disc surfaces. Taken together, our results suggest that HA substituted by (Zn2+, 0.2 mol), (SO42-, 0.5 mol) and (F-, 1 mol) (1Zn/SO4-FHA) material was a promising material for hard tissue scaffolds.


Assuntos
Materiais Biocompatíveis/química , Regeneração Óssea/efeitos dos fármacos , Hidroxiapatitas/química , Hidroxiapatitas/farmacologia , Nanopartículas/química , Sulfatos/química , Zinco/química , Materiais Biocompatíveis/farmacologia , Líquidos Corporais/química , Adesão Celular/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Durapatita/química , Fluoretos/química , Humanos , Teste de Materiais/métodos , Osteoblastos/efeitos dos fármacos , Osteogênese/efeitos dos fármacos
12.
Mater Sci Eng C Mater Biol Appl ; 104: 109969, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31500016

RESUMO

Ti-xCu coatings with varied Cu contents were deposited by hybrid HiPIMS/DC magnetron co-sputtering to achieve optimum microstructures and surface chemistries for applications as multi-functional, blood-contacting interfaces. We have demonstrated that control over the chemistry and microstructure of the coatings provides interfaces that simultaneously exhibit antibacterial properties, show endothelial cell (EC) compatibility, and prevent smooth muscle cell (SMC) proliferation. Using XRD and HRTEM analyses, we identified distinct microstructures for coatings with various Cu/(Cu + Ti) atomic concentrations. The corrosion resistance was controlled by the microstructure of the Ti-xCu coatings and decreased with increases in the Cu atomic concentration. XPS and ICP-MS results provided evidence that copper ions are released from the coatings upon immersion in PBS solution. We have demonstrated that the Cu-containing phases are weak points that are attacked and corroded easily, resulting in the release of Cu ions from the coatings. The coatings with Cu/(Ti + Cu) ratios ranging from 3 to 65 at.% inhibited the viability of SMCs significantly. The optimized coating with Ti and Cu/CuTix crystals and Cu/(Ti + Cu) ratio of 16 at.% showed significant improvements in EC compatibility as well as reduced viability of SMCs, holding great promise for the surface modification of cardiovascular devices such as stents and coronary implants. The coatings with amorphous phases and Cu/(Ti + Cu) ratios of 55 and 65 at.% showed excellent antibacterial properties against Staphylococcus aureus bacteria. The coating with 55.0 at.% Cu is an encouraging material for the surface engineering of blood-contacting implant surfaces that have antibacterial properties but are not cytotoxic to SMCs.


Assuntos
Sistema Cardiovascular/efeitos dos fármacos , Cobre/química , Cobre/farmacologia , Propriedades de Superfície/efeitos dos fármacos , Titânio/química , Titânio/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/farmacologia , Corrosão , Células Endoteliais da Veia Umbilical Humana , Humanos , Teste de Materiais/métodos , Miócitos de Músculo Liso/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos
13.
Mater Sci Eng C Mater Biol Appl ; 104: 109895, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31500047

RESUMO

The repair and restoration of bone defects in orthopaedic and dental surgery remains a major challenge despite advances in surgical procedures and post-operative treatments. Bioactive glasses, ceramics, glass-ceramics and composites show considerable potential for such applications as they can promote bone tissue regeneration. This paper presents an overview of the mechanical properties of various bioactive materials, which have the potential for bone regeneration. It also identifies current strategies for improving the mechanical properties of these novel materials, as these are rarely ideal as direct replacements for human bone. For this reason bioactive organic-inorganic composites and hybrids that have tailorable mechanical properties are of particular interest. The inorganic component (bioactive glass, ceramic or glass-ceramic) can provide both strength and bioactivity, while the organic component can add structural reinforcement, toughness and processability. Another topic presented in this paper includes 3D porous scaffolds that act as a template for cell attachment, proliferation and bone growth. Mechanical limitations of existing glass and ceramic scaffolds are discussed, along with the relevant challenges and strategies for further improvement. Advantages and disadvantages of different bioactive materials are critically examined. This paper is focused on optimization of biomaterials properties, in particular mechanical properties and bioactivity.


Assuntos
Materiais Biocompatíveis/química , Cerâmica/química , Vidro/química , Animais , Materiais Biocompatíveis/administração & dosagem , Regeneração Óssea/efeitos dos fármacos , Substitutos Ósseos/química , Osso e Ossos/efeitos dos fármacos , Humanos , Teste de Materiais/métodos , Porosidade
14.
Mater Sci Eng C Mater Biol Appl ; 104: 109960, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31500051

RESUMO

3D printing-based technologies can fabricate scaffolds offer great precision to control internal architecture and print complicated structures based upon the defect site. However, the materials used in the direct printing are restricted depending on the printing technology used and the indirect one can overcome this limitation. In the present study, indirect 3D printing approach was used to develop bone scaffolds from polylactic acid/ polycaprolactone/ hydroxyapatite (PLA/PCL/HA) composites. Casting of the composite suspensions was done into a dissolvable 3D printed negative mold, in order to achieve simultaneous macro- and micro-porous composites, using freeze drying/particle leaching method. To evaluate morphology, functional groups, and elemental analysis of the scaffolds, scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and energy dispersive spectroscopy (EDS) were respectively used. Scaffolds' porosity was measured with the aid of liquid replacement technique. Also, the mechanical strength of scaffolds was examined by compression test and measuring the compressive modulus Considering the microstructure, porosity and pore size as well as mechanical property, the scaffold composed of PLA/PCL 70/30 w/w and 35% HA was more favorable. The PLA/PCL/HA 70/30-35% scaffold presented a porosity of 77%, an average pore size of 160 µm, and Young's modulus of 1.35 MPa. Cell adhesion, viability and mineral deposits formation for PLA/PCL/HA scaffolds at PLA/PCL ratios of 70/30, 50/50 and 30/70 and the fixed amount of HA (35%) were also studied in vitro by the means of MG63 cells. The cytotoxicity assessment showed that the cells could be viable and proliferate on the scaffolds. The results indicated that composite scaffold with the PLA/PCL weight ratio of70/30 accomplished more favorable properties in terms of biocompatibility, viability, and osteoinduction property.


Assuntos
Materiais Biocompatíveis/química , Osso e Ossos/efeitos dos fármacos , Durapatita/química , Poliésteres/química , Tecidos Suporte/química , Adesão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Módulo de Elasticidade/efeitos dos fármacos , Humanos , Teste de Materiais/métodos , Porosidade , Impressão Tridimensional , Engenharia Tecidual/métodos
15.
Sensors (Basel) ; 19(17)2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31480227

RESUMO

Wear is a common cause for aseptic loosening in artificial joints. The purpose of this study was to develop an automated diagnostical method for identification of the number and size distribution of wear debris. For this purpose, metal debris samples were extracted from a hip simulator and then analyzed by the electrospray method combined with a differential mobility analyzer, allowing particle detection ranging from several nanometers up to 1 µm. Wear particles were identified with a characteristic peak at 15 nm. The electrospray setup was successfully used and validated for the first time to characterize wear debris from simulated total joint replacement. The advantages of this diagnostic method are its time- and financial efficiency and its suitability for testing of different materials.


Assuntos
Artroplastia de Substituição , Teste de Materiais/métodos , Próteses Articulares Metal-Metal , Aerossóis , Animais , Artroplastia de Quadril , Bovinos , Reprodutibilidade dos Testes , Soro
16.
Nat Protoc ; 14(9): 2599-2626, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31384056

RESUMO

A requirement for biochemical labeling strategies is a pronounced biocompatibility of the underlying reaction methodology. This protocol enables a systematic evaluation of the biocompatibility of (new) reaction methodologies that are potentially attractive for biochemical applications. The cellular environment for in vitro and in vivo applications is mimicked by the one-by-one addition of diverse bio-additives to the reaction. The influence of the bio-additives on the product yield, termed bio-robustness, is quantified by gas chromatography (GC) or NMR techniques, whereas qualitative analysis of the level of biomolecule preservation by ultra-HPLC-mass spectrometry (UHPLC-MS) or gel electrophoresis enables monitoring of the effects of the reaction conditions on the biomolecule stability, e.g., bio-additive modification or degradation. The 22 chosen bio-additives and the required controls can be completely evaluated within 5-7 working days, depending on reaction time, instrument and the general equipment availability of the lab. We illustrate this protocol by assessing the reaction biocompatibility of a copper-catalyzed N-arylation of sulfonamides. The hereby obtained results are compared to those for a reaction that is characterized by high reaction biocompatibility: the energy-transfer-enabled disulfide-ene reaction.


Assuntos
Materiais Biocompatíveis/análise , Teste de Materiais/métodos , Cromatografia Líquida de Alta Pressão , Eletroforese em Gel de Poliacrilamida , Cromatografia Gasosa-Espectrometria de Massas , Células HeLa , Humanos , Espectrometria de Massas
17.
Chemosphere ; 237: 124398, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31376692

RESUMO

The goal of this study was to identify the scaling from the chemical cleaning of a polyvinylidene fluoride (PVDF) membrane, fouled by treating a solution containing inorganic foulants (Al, Fe, and Mn) in the presence of kaolin and humic acid as a natural organic matter at Ca+2 strength of 0.5 mMole. Chemical cleaning of the membrane was conducted using solutions prepared in deionized water and permeate water (PW), and the accumulation of insoluble salts on the membrane during cleaning were evaluated. Energy dispersive spectroscopy analysis was used to verify the presence inorganic foulants, and field emission scanning electron microscopy confirmed the changes in membrane symmetry from the accumulation of the foulants. A Fourier-transformed infrared spectroscopy analysis indicated the presence of new functional groups, i.e., C-Cl and C-O with bond vibrations at 542 cm -1 and 1,026 cm-1, respectively, on the membrane surface. The adsorbed mass of HA in the presence of inorganic foulants decreased from 3.54 ±â€¯0.045 mg to 2.24 ±â€¯0.095 mg and 1.71 ±â€¯0.075 mg, and the flux recoveries decreased from 93.2% to 85.69% and 81.92%, for the pristine to chemically DI and PW cleaned membrane, respectively. However, the membrane characterization results confirmed that Al was the major contributor to the accumulation of inorganic salts on the membrane during chemical cleaning and its role was more severe in the presence of Mn. The fitting results of Hermia's fouling models and a specific fouling analysis confirmed the contribution of complete blocking model with increase in irreversible fouling was observed after chemical cleaning.


Assuntos
Incrustação Biológica , Membranas Artificiais , Purificação da Água/métodos , Adsorção , Substâncias Húmicas/efeitos adversos , Teste de Materiais/métodos , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier , Ultrafiltração/métodos , Poluentes da Água/isolamento & purificação
18.
J Wound Care ; 28(5): 268-277, 2019 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-31378130

RESUMO

OBJECTIVE: A new test method is described which provides a convenient technique for assessing the combined effects of gravity and compression on the fluid handling characteristics of surgical dressing which can have important implications for their use in the treatment of venous ulcers. Simple ways of improving use of the fluid handling capacity of products currently used clinically are suggested, and the possibility of developing a dressing specifically designed to resist gravitational effects is discussed.


Assuntos
Bandagens Compressivas , Gravitação , Teste de Materiais/instrumentação , Teste de Materiais/métodos , Úlcera Varicosa/terapia , Cicatrização/fisiologia , Humanos
19.
PLoS One ; 14(8): e0220281, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31374079

RESUMO

Measurements of Young's moduli are mostly evaluated using strong assumptions, such as sample homogeneity and isotropy. At the same time, descriptions of measurement parameters often lack detailed specifications. Many of these assumptions are, for soft hydrogels especially, not completely valid and the complexity of hydrogel microindentation demands more sophisticated experimental procedures in order to describe their elastic properties more accurately. We created an algorithm that automates indentation data analysis as a basis for the evaluation of large data sets with consideration of the influence of indentation depth on the measured Young's modulus. The algorithm automatically determines the Young's modulus in indentation regions where it becomes independent of the indentation depth and furthermore minimizes the error from fitting an elastic model to the data. This approach is independent of the chosen elastic fitting model and indentation device. With this, we are able to evaluate large amounts of indentation curves recorded on many different sample positions and can therefore apply statistical methods to overcome deviations due to sample inhomogeneities. To prove the applicability of our algorithm, we carried out a systematic analysis of how the indentation speed, indenter size and sample thickness affect the determination of Young's modulus from atomic force microscope (AFM) indentation curves on polyacrylamide (PAAm) samples. We chose the Hertz model as the elastic fitting model for this proof of principle of our algorithm and found that all of these parameters influence the measured Young's moduli to a certain extent. Hence, it is essential to clearly state the experimental parameters used in microindentation experiments to ensure reproducibility and comparability of data.


Assuntos
Módulo de Elasticidade , Hidrogéis , Teste de Materiais/métodos , Automação , Modelos Teóricos
20.
Microsc Res Tech ; 82(11): 1953-1961, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31411354

RESUMO

The objective of this study was to evaluate and correlate light transmittance (T), initial degree of conversion (IDC), and degree of conversion after 24 hr (DC24) for 22 composite resins (CR) for enamel and dentin use. The transmittance (n = 10) was measured with a spectrometer at a wavelength of 468.14 nm. The degree of conversion (DC; n = 5) was measured with Fourier Transform Near-Infrared Spectroscopy before polymerization, immediately after photoactivation, and 24 hr after photoactivation. Both sets of values are provided as percentages. ANOVA and Games-Howell (α = 5%) tests showed that Filtek Supreme Ultra gave the highest T values of all enamel CRs, while Esthet-X HD presented the lowest. Meanwhile, Venus diamond gave the highest values of all dentin CRs, while Esthet-X HD gave the lowest. For IDC and DC24, ANOVA showed differences between individual CRs and the two CR types (p < .0001). Despite the limitations of this study, it can be concluded that there was no correlation between T and either IDC or DC24 (p > .05); however, IDC and DC24 were strongly correlated (p < .05) by Pearson's correlation. That being said, as a higher DC reflects better mechanical properties, certain conclusions can be drawn about overall performance. The best IDC values were observed for the Opallis enamel resin and the Opallis and Premise dentin resins. Meanwhile, the best DC24 values were observed for the Opallis, Charisma, and Premise enamel resins and the Opallis and Premise dentin resins. Degree of conversion and light transmittance showed differences between composite resin types (enamel and dentin) and brands. It is important to know at the moment of composite choice taking into account mechanical and optical properties.


Assuntos
Resinas Compostas/química , Teste de Materiais/métodos , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície
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