RESUMO
Developing cost-effective and high-performance catalyst systems for dry reforming of methane (DRM) is crucial for producing hydrogen (H2) sustainably. Herein, we investigate using iron (Fe) as a promoter and major alumina support in Ni-based catalysts to improve their DRM performance. The addition of iron as a promotor was found to add reducible iron species along with reducible NiO species, enhance the basicity and induce the deposition of oxidizable carbon. By incorporating 1 wt.% Fe into a 5Ni/10ZrAl catalyst, a higher CO2 interaction and formation of reducible "NiO-species having strong interaction with support" was observed, which led to an â¼80% H2 yield in 420 min of Time on Stream (TOS). Further increasing the Fe content to 2wt% led to the formation of additional reducible iron oxide species and a noticeable rise in H2 yield up to 84%. Despite the severe weight loss on Fe-promoted catalysts, high H2 yield was maintained due to the proper balance between the rate of CH4 decomposition and the rate of carbon deposit diffusion. Finally, incorporating 3 wt.% Fe into the 5Ni/10ZrAl catalyst resulted in the highest CO2 interaction, wide presence of reducible NiO-species, minimum graphitic deposit and an 87% H2 yield. Our findings suggest that iron-promoted zirconia-alumina-supported Ni catalysts can be a cheap and excellent catalytic system for H2 production via DRM.
Assuntos
Óxido de Alumínio , Hidrogênio , Ferro , Metano , Níquel , Zircônio , Metano/química , Zircônio/química , Catálise , Ferro/química , Hidrogênio/química , Óxido de Alumínio/química , Níquel/químicaRESUMO
BACKGROUND: Mechanical complications affect the stability of implant restorations and are a key concern for clinicians, especially with the frequent introduction of new implant designs featuring various structures and materials. This study evaluated the effect of different prosthetic index structure types and implant materials on the stress distribution of implant restorations using both in silico and in vitro methods. METHODS: Four finite element analysis (FEA) models of implant restorations were created, incorporating two prosthetic index structures (cross-fit (CF) and torc-fit (TF)) and two implant materials (titanium and titanium-zirconium). A static load was applied to each group. An in vitro study using digital image correlation (DIC) with a research scenario identical to that of the FEA was conducted for validation. The primary strain, sensitivity index, and equivalent von Mises stress were used to evaluate the outcomes. RESULTS: Changing the implant material from titanium to titanium-zirconium did not significantly affect the stress distribution or maximum stress value of other components, except for the implant itself. In the CF group, implants with a lower elastic modulus increased the stress on the screw. The TF group showed better stress distribution on the abutment and a lower stress value on the screw. The TF group demonstrated similar sensitivity for all components. DIC analysis revealed significant differences between TF-TiZr and CF-Ti in terms of the maximum (P < 0.001) and minimum principal strains (P < 0.05) on the implants and the minimum principal strains on the investment materials in both groups (P < 0.001). CONCLUSIONS: Changes in the implant material significantly affected the maximum stress of the implant. The TF group exhibited better structural integrity and reliability.
Assuntos
Implantes Dentários , Materiais Dentários , Análise do Estresse Dentário , Análise de Elementos Finitos , Titânio , Zircônio , Zircônio/química , Humanos , Materiais Dentários/química , Análise do Estresse Dentário/métodos , Estresse Mecânico , Planejamento de Prótese Dentária , Módulo de Elasticidade , Simulação por Computador , Imageamento TridimensionalRESUMO
CD73 is a cell-surface ectoenzyme that hydrolyzes the conversion of extracellular adenosine monophosphate to adenosine, which in turn can promote resistance to immune checkpoint blockade therapy. Immune response may therefore be improved by targeting tumor CD73, and this possibility underlines the need to non-invasively assess tumor CD73 level. In this study, we developed a cysteine site-specific 89Zr-labeled anti-CD73 (89Zr-CD73) IgG immuno-PET technique that can image tumor CD73 expression in living bodies. Anti-CD73 IgG was reduced with tris(2-carboxyethyl)phosphine, underwent sulfohydryl moiety-specific conjugation with deferoxamine-maleimide, and was radiolabeled with 89Zr. CT26 mouse colon cancer cells, CT26/CD73 cells engineered to constitutively overexpress CD73, and 4T1.2 mouse breast cancer cells underwent cell binding assays and western blotting. Balb/c nude mice bearing tumors underwent 89Zr-CD73 IgG PET imaging and biodistribution studies. 89Zr-CD73 IgG showed 20-fold higher binding to overexpressing CT26/CD73 cells compared to low-expressing CT26 cells, and moderate expressing 4T1.2 cells showed uptake that was 38.9 ± 1.51% of CT26/CD73 cells. Uptake was dramatically suppressed by excess unlabeled antibody. CD73 content proportionately increased in CT26 and CT26/CD73 cell mixtures was associated with linear increases in 89Zr-CD73 IgG uptake. 89Zr-CD73 IgG PET/CT displayed clear accumulation in CT26/CD73 tumors with greater uptake compared to CT26 tumors (3.13 ± 1.70%ID/g vs. 1.27 ± 0.31%ID/g at 8 days; P = 0.04). Specificity was further supported by low CT26/CD73 tumor-to-blood ratio of 89Zr-isotype-IgG compared to 89Zr-CD73 IgG (0.48 ± 0.08 vs. 2.68 ± 0.52 at 4 days and 0.53 ± 0.07 vs. 4.81 ± 1.02 at 8 days; both P < 0.001). Immunoblotting and immunohistochemistry confirmed strong CD73 expression in CT26/CD73 tumors and low expression in CT26 tumors. 4T1.2 tumor mice also showed clear 89Zr-CD73 IgG accumulation at 8 days (3.75 ± 0.70%ID/g) with high tumor-to-blood ratio compared to 89Zr-isotype-IgG (4.91 ± 1.74 vs. 1.20 ± 0.28; P < 0.005). 89Zr-CD73 IgG specifically targeted CD73 on high expressing cancer cells in vitro and tumors in vivo. Thus, 89Zr-CD73 IgG immuno-PET may be useful for the non-invasive monitoring of CD73 expression in tumors of living subjects.
Assuntos
5'-Nucleotidase , Neoplasias do Colo , Cisteína , Tomografia por Emissão de Pósitrons , Zircônio , Animais , 5'-Nucleotidase/metabolismo , Zircônio/química , Neoplasias do Colo/diagnóstico por imagem , Neoplasias do Colo/metabolismo , Neoplasias do Colo/imunologia , Neoplasias do Colo/patologia , Camundongos , Linhagem Celular Tumoral , Tomografia por Emissão de Pósitrons/métodos , Cisteína/metabolismo , Humanos , Radioisótopos , Feminino , Camundongos Endogâmicos BALB C , Distribuição Tecidual , Camundongos Nus , Proteínas Ligadas por GPI/metabolismo , Proteínas Ligadas por GPI/imunologia , Imunoglobulina G/imunologia , Imunoglobulina G/metabolismoRESUMO
In restorative dentistry, the lack of occlusal space may lead to the mutilation of healthy tissue in order to provide sufficient space for the restorative material. Noprep dentistry can be achieved by placing high-bite restorations, followed by Simple Orthodontic Extrusion (SOE) of other teeth to close the created open bite. This rapid, partial orthodontic treatment is well accepted by patients as it can be easily performed using simple buttons, and it takes only a few weeks to reestablish occlusal contacts. The SOE technique is a further development of the Dahl concept. It has the advantages without the disadvantages. Two applications of this technique are presented in this article: the treatment of the severe wear of anterior teeth with no-prep palatal veneers made of Polymer-infiltrated Ceramic Network (PICN, 'hybrid ceramic') material and the realization of no-prep zirconia resin-bonded bridges (RBBs) to replace missing lateral incisors. An original 3D-printed resin guide for correctly positioning RBBs and facilitating the removal of excess composite cement is also presented. This work highlights the considerable advantages of multidisciplinary collaboration in the field of minimally invasive dentistry.
Assuntos
Facetas Dentárias , Humanos , Feminino , Incisivo , Mordida Aberta/terapia , Prótese Adesiva , Zircônio/química , Desgaste dos Dentes/terapiaRESUMO
Chlorpyrifos (CPS) is widely found in food and water sources due to agricultural use, posing health and environmental risks. Therefore, this work introduces a fluorescent sensor design of silver nanoparticle-embedded nano zirconium-based metal-organic frameworks (UiO-66-NH2@AgNPs) for accurate examination of CPS. Briefly, UiO-66-NH2 was synthesized hydrothermally, exhibiting weak luminescence owed to ligand-to-metal charge transfer (LMCT). Here, it limits its direct utility in fluorescence-based detection. To address this limitation, silver nanoparticles (AgNPs) were introduced into UiO-66-NH2, enhancing fluorescence via the metal-enhanced fluorescence (MEF) effect. Briefly, a comprehensive spectral analysis such as XPS, SEM, TEM, PXRD, etc., was performed to validate the synthesis of UiO-66-NH2@AgNPs. Subsequent evaluation revealed that CPS effectively quenched the luminescence intensity of UiO-66-NH2@AgNPs through a static quenching mechanism. The fluorescence intensity exhibited good linearity with CPS concentration in the span of 10 to 1,000 ng/mL, with a recognition limit of 191.5 ng/mL(S/N = 3). The interaction involved Ag-S bond formation and electrostatic interactions, reducing fluorescence intensity. The method was confirmed through successful CPS detection in fruit samples. The UiO-66-NH2@AgNPs nanoprobe offers a simple, sensitive, and accurate platform for CPS sensing, with potential for future use in detecting CPS in fruits and vegetables.
Assuntos
Clorpirifos , Nanopartículas Metálicas , Estruturas Metalorgânicas , Prata , Zircônio , Clorpirifos/análise , Prata/química , Zircônio/química , Estruturas Metalorgânicas/química , Nanopartículas Metálicas/química , Espectrometria de Fluorescência , Limite de Detecção , Inseticidas/análiseRESUMO
PURPOSE: To investigate the effects of different surface treatments and thicknesses on the color, transparency, and surface roughness of ultra-transparent zirconia. METHODS: A total of 120 Katana ultra-translucent multi-layered zirconia specimens were divided into 12 groups according to the thickness (0.3, 0.5, and 0.7 mm) and surface treatment (control, airborne particle abrasion [APA], lithium disilicate coating, and glaze on). Color difference (ΔE00) and relative translucency parameter (RTP00) were calculated using a digital spectrophotometer. The surface roughness (Ra, Rq, Sa, and Sq) was measured using a non-contact profile scanner. The surface morphologies and microstructures of the samples were observed using a tungsten filament scanning electron microscope. Statistical analyses were performed by one-way and two-way analysis of variance (ANOVA) followed by post hoc multiple comparisons and Pearson's correlation (α = 0.05). RESULTS: The results showed that the surface treatment, ceramic thickness, and their interactions had significant effects on ΔE00 and RTP00 (p < 0.001). The surface treatment significantly altered the micromorphology and increased the surface roughness of the ceramic samples. APA exhibited the lowest transparency, largest color difference, and highest surface roughness. Zirconia with 0.3 mm and 0.7 mm thicknesses showed strong negative correlations between Sa and RTP00. CONCLUSIONS: The three internal surface treatments significantly altered the surface roughness, color difference, and transparency of ultra-transparent zirconia. As the thickness increased, the influence of the inner surface treatment on the color difference and transparency of zirconia decreased. CLINICAL IMPLICATIONS: For new zirconia internal surface treatment technologies, in addition to considering the enhancement effect on the bonding properties, the potential effects on the color and translucency of high-transparency zirconia should also be considered. Appropriately increasing the thickness of zirconia restorations helps minimize the effect of surface treatment on the optical properties.
Assuntos
Cor , Teste de Materiais , Microscopia Eletrônica de Varredura , Espectrofotometria , Propriedades de Superfície , Zircônio , Zircônio/química , Porcelana Dentária/química , Materiais Dentários/química , Colagem Dentária/métodosRESUMO
In this work, we report on an electrochemical method for the signal-on detection of caspase-3 and the evaluation of apoptosis based on the biotinylation reaction and the signal amplification of methylene blue (MB)-loaded metal-organic frameworks (MOFs). Zr-based UiO-66-NH2 MOFs were used as the nanocarriers to load electroactive MB molecules. Recombinant hexahistidine (His6)-tagged streptavidin (rSA) was attached to the MOFs through the coordination interaction between the His6 tag in rSA and the metal ions on the surface of the MOFs. The acetylated peptide substrate Ac-GDEVDGGGPPPPC was immobilized on the gold electrode. In the presence of caspase-3, the peptide was specifically cleaved, leading to the release of the Ac-GDEVD sequence. A N-terminal amine group was generated and then biotinylated in the presence of biotin-NHS. Based on the strong interaction between rSA and biotin, rSA@MOF@MB was captured by the biotinylated peptide-modified electrode, producing a significantly amplified electrochemical signal. Caspase-3 was sensitively determined with a linear range from 0.1 to 25 pg/mL and a limit of detection down to 0.04 pg/mL. Further, the active caspase-3 in apoptosis inducer-treated HeLa cells was further quantified by this method. The proposed signal-on biosensor is compatible with the complex biological samples and shows great potential for apoptosis-related diagnosis and the screening of caspase-targeting drugs.
Assuntos
Técnicas Biossensoriais , Caspase 3 , Estruturas Metalorgânicas , Azul de Metileno , Estruturas Metalorgânicas/química , Azul de Metileno/química , Humanos , Caspase 3/metabolismo , Células HeLa , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Apoptose , Estreptavidina/química , Biotinilação , Eletrodos , Limite de Detecção , Zircônio/química , Ácidos FtálicosRESUMO
OBJECTIVES: This study aimed to evaluate the feasibility of monolithic zirconia laminate veneers (MZLV) compared to lithium disilicate laminate veneers (LDLV). MATERIALS AND METHODS: Sixty resin replicas, each prepared with depths of 0.5 mm, 0.7 mm, and 1 mm, were produced using a 3D printer from acrylic teeth. Laminate veneers of these thicknesses were milled from pre-sintered monolithic zirconia (3rd generation) and lithium disilicate blocks. The intaglio surface of MZLV was treated with air abrasion using 110 µm diameter silica-modified aluminium oxide particles and ceramic primer, while LDLV was etched with etchant gel and treated with the ceramic primer before cementation with resin cement. Vertical marginal discrepancy (VMD) was assessed using a stereomicroscope, and a load-to-failure test was conducted using a universal testing machine. Failure modes were evaluated macroscopically on fractured surfaces. Data were analysed statistically using Two-way ANOVA and Bonferroni correction (α = 0.05). RESULTS: LDLV samples exhibited significantly larger VMD compared to MZLV samples across all thicknesses, especially in cervical, palatal, and mean data. Within the LDLV group, load-to-fracture values for 0.7 mm and 1.0 mm thicknesses were similar, whereas for 0.5 mm thickness, it was significantly lower. In the MZLV group, load-to-fracture values were lower for 0.7 mm and 1.0 mm thicknesses compared to LDLV, but higher for 0.5 mm thickness. CONCLUSIONS: Material choice and restoration thickness significantly influence laminate veneer restorations' success. MZLV generally exhibits superior vertical marginal fit compared to LDLV, with varying load-to-failure values across different thicknesses. Clinical management of debonding in MZLV is simpler compared to restoration fracture in LDLV. CLINICAL RELEVANCE: Considering clinical factors, MZLV may be a preferable option to LDLV for this restoration with the thickness of 0.5 mm.
Assuntos
Adaptação Marginal Dentária , Porcelana Dentária , Facetas Dentárias , Zircônio , Porcelana Dentária/química , Zircônio/química , Humanos , Teste de Materiais , Análise do Estresse Dentário , Falha de Restauração Dentária , Propriedades de Superfície , Materiais Dentários/química , Planejamento de Prótese DentáriaRESUMO
OBJECTIVES: The first aim of this study was to determine whether there is a difference in degree of conversion (DC) of touch-cure cements polymerized by self-curing with adhesive or dual-curing under reduced light. The second aim was to compare interfacial adaptation of zirconia restoration cemented using touch-cure cements self-cured or dual-cured by reduced light. METHODS: The DC of touch-cure resin cements with adhesive was measured continuously using Fourier transform infrared spectrometry. Experimental groups differed depending on touch-cure cement. Each group had three subgroups of polymerization method. For subgroup 1, the DC was measured by self-curing. For subgroups 2 and 3, the DCs were measured by dual-curing with reduced light penetrating 3 mm and 1 mm zirconia blocks, respectively. For interfacial adaptation evaluation, Class I cavity was prepared on an extracted third molar, and zirconia restoration was fabricated. The restoration was cemented using the same cement. Groups and subgroups for interfacial adaptation were the same as those of the DC measurement. After thermo-cycling, interfacial adaptation at the tooth-restoration interface was evaluated using swept-source optical coherence tomography imaging. RESULTS: The DC of touch-cure cement differed depending on the measurement time, resin cement, and polymerization method (p < 0.05). Interfacial adaptation was different depending on the resin cement and polymerization method (p < 0.05). CONCLUSION: For touch-cure cement, light-curing with higher irradiance presented a higher DC and superior interfacial adaptation than light-curing with lower irradiance or self-curing. CLINICAL RELEVANCE: Although some adhesives accelerate the self-curing of touch-cure cement, light-curing for touch-cure cement is necessary for zirconia cementation.
Assuntos
Teste de Materiais , Polimerização , Cimentos de Resina , Zircônio , Cimentos de Resina/química , Zircônio/química , Espectroscopia de Infravermelho com Transformada de Fourier , Autocura de Resinas Dentárias , Lâmpadas de Polimerização Dentária , Cura Luminosa de Adesivos Dentários , Propriedades de Superfície , Técnicas In Vitro , Humanos , Dente Serotino , Restauração Dentária Permanente/métodosRESUMO
Because of its superior strength, esthetic properties, and excellent biocompatibility, zirconia is preferred for dental prosthetic such as crowns and bridges. However, zirconia crowns and bridges are susceptible to secondary caries owing to margin leakage. Silver is a well-known antibacterial agent, making it a desirable additive to zirconia crowns and bridges for secondary caries prevention. This study focuses on imparting zirconia composite with antibacterial properties to enhance its protective capacity in dental restorations. We used the sol-gel method to dope Ag into zirconia. Silver-doped zirconia powders were prepared at Zr:Ag molar ratios of 100:0,100:0.1, 100:0.5, 100:1, 100:3, and 100:5 (respective samples denoted as Ag-0, Ag-0.1, Ag-0.5, Ag-1, Ag-3, and Ag-5) and were subjected to firing at various temperatures (400 °C-1000 °C). We performed x-ray diffraction to investigate the crystal phase of these powders and x-ray fluorescence and field emission scanning electron microscopy to analyze their elemental composition and surface morphology, respectively. Moreover, we performed spectrophotometry to determine theL*a*b* color values, conducted dissolution tests, and quantified the Ag content through inductively coupled plasma optical emission spectroscopy. In addition, we studied the antibacterial activity of the samples. Analyses of the samples fired at ⩽600 °C revealed a predominantly white to grayish-white coloration and a tetragonal crystal phase. Firing at ⩾700 °C resulted in gray or dark gray coloration and a monoclinic crystal phase. The Ag content decreased after firing at 900 °C or 1000 °C. Ag-0.5 and above exhibited antibacterial activity against bothEscherichia coliandStaphylococcus aureus. Therefore, the minimum effective silver-doped zirconia sample was found to be Ag-0.5. This study allows the exploration of the antimicrobial potential of silver-doped zirconia materials in dental applications such as prosthdontical lining materials, promoting the development of innovative restorations with protective capacity against secondary caries.
Assuntos
Antibacterianos , Teste de Materiais , Prata , Difração de Raios X , Zircônio , Zircônio/química , Prata/química , Prata/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , Testes de Sensibilidade Microbiana , Materiais Dentários/química , Materiais Dentários/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Microscopia Eletrônica de Varredura , Pós , Propriedades de Superfície , Escherichia coli/efeitos dos fármacos , HumanosRESUMO
Rehabilitation of pulpotomized primary molars with an appropriate restoration is essential for recovering function and safeguarding the durability of the treatment. This study aimed to assess and compare the surface roughness of stainless steel (ST) crowns, zirconia (ZR) crowns, fiberglass (FG) crowns, and lithium disilicate (LD) endo-crowns as a restoration for pulpotomized primary molars also, evaluating the surface roughness of their antagonists. Sixty pulpotomized primary mandibular first molars were used for qualitative surface roughness evaluation and divided into four groups (n = 15/group) according to the crown type (group-ST, group-ZR, group-FG, group-LD). While the other sixty sound, unprepared primary maxillary first molars were used for evaluation of their surface roughness against the tested crowns. Specimens' preparation and cementation were carried out according to each crown type and manufacturer's instructions. The surface roughness was done using a two-body wear test. The data were statistically analyzed. All tested crowns showed an increased change in surface roughness, except group-ZR, which had the least change in surface roughness after mechanical wear with no statistically significant difference(P = 0.681). All crown types significantly increased the surface roughness of their antagonists after mechanical wear, except group-ST which showed insignificant affection (p ≥ 0.05). Zirconia crowns and lithium disilicate endo-crowns had the least change in surface roughness compared to other groups while SSCs showed the least tooth loss in the antagonist enamel.
Assuntos
Coroas , Porcelana Dentária , Dente Molar , Propriedades de Superfície , Dente Decíduo , Zircônio , Porcelana Dentária/química , Humanos , Zircônio/química , Aço Inoxidável/química , Teste de MateriaisRESUMO
Thyroid nodules (TNs) have emerged as the most prevalent endocrine disorder in China. Fine-needle aspiration (FNA) remains the standard diagnostic method for assessing TN malignancy, although a majority of FNA results indicate benign conditions. Balancing diagnostic accuracy while mitigating overdiagnosis in patients with benign nodules poses a significant clinical challenge. Precise, noninvasive, and high-throughput screening methods for high-risk TN diagnosis are highly desired but remain less explored. Developing such approaches can improve the accuracy of noninvasive methods like ultrasound imaging and reduce overdiagnosis of benign nodule patients caused by invasive procedures. Herein, we investigate the application of gold-doped zirconium-based metal-organic framework (ZrMOF/Au) nanostructures for metabolic profiling of thyroid diseases. This approach enables the efficient extraction of urine metabolite fingerprints with high throughput, low background noise, and reproducibility. Utilizing partial least-squares discriminant analysis and four machine learning models, including neural network (NN), random forest (RF), logistic regression (LR), and support vector machine (SVM), we achieved an enhanced diagnostic accuracy (98.6%) for discriminating thyroid cancer (TC) from low-risk TNs by using a diagnostic panel. Through the analysis of metabolic differences, potential pathway changes between benign nodule and malignancy are identified. This work explores the potential of rapid thyroid disease screening using the ZrMOF/Au-assisted LDI-MS platform, providing a potential method for noninvasive screening of thyroid malignant tumors. Integrating this approach with imaging technologies such as ultrasound can enhance the reliability of noninvasive diagnostic methods for malignant tumor screening, helping to prevent unnecessary invasive procedures and reducing the risk of overdiagnosis and overtreatment in patients with benign nodules.
Assuntos
Nódulo da Glândula Tireoide , Zircônio , Nódulo da Glândula Tireoide/diagnóstico por imagem , Nódulo da Glândula Tireoide/diagnóstico , Nódulo da Glândula Tireoide/patologia , Humanos , Zircônio/química , Ouro/química , Metabolômica , FemininoRESUMO
Purpose: This study aimed to confirm the synergy effect of these two materials by evaluating osteoblast and antibacterial activity by applying a double-layered hydroxyapatite(HA) zirconium oxide(ZrO2) coating to titanium. Methods: The specimens used in this study were divided into four groups: a control group (polished titanium; group T) and three experimental groups: Group TH (RF magnetron sputtered HA deposited titanium), Group Z (ZrO2 ALD deposited titanium), and Group ZH (RF magnetron sputtered HA and ZrO2 ALD deposited titanium). The adhesion of Streptococcus mutans (S.mutans) to the surface was assessed using a crystal violet assay. The adhesion, proliferation, and differentiation of MC3T3-E1 cells, a mouse osteoblastic cell line, were assessed through a WST-8 assay and ALP assay. Results: Group Z showed a decrease in the adhesion of S. mutans (p < 0.05) and an improvement in osteoblastic viability (p < 0.0083). Group TH and ZH showed a decrease in adhesion of S. mutans (p < 0.05) and an increase in osteoblastic cell proliferation and cell differentiation (p < 0.0083). Group ZH exhibited the highest antibacterial and osteoblastic differentiation. Conclusion: In conclusion double-layered HA and ZrO2 deposited on titanium were shown to be more effective in inhibiting the adhesion of S. mutans, which induced biofilm formation, and increasing osteoblastic differentiation involved in osseointegration by the synergistic effect of the two materials.
Assuntos
Aderência Bacteriana , Diferenciação Celular , Proliferação de Células , Materiais Revestidos Biocompatíveis , Durapatita , Osteoblastos , Streptococcus mutans , Propriedades de Superfície , Titânio , Zircônio , Zircônio/química , Zircônio/farmacologia , Titânio/química , Titânio/farmacologia , Streptococcus mutans/efeitos dos fármacos , Animais , Camundongos , Durapatita/química , Durapatita/farmacologia , Osteoblastos/efeitos dos fármacos , Osteoblastos/citologia , Proliferação de Células/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Aderência Bacteriana/efeitos dos fármacos , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/farmacologia , Linhagem Celular , Antibacterianos/farmacologia , Antibacterianos/química , Adesão Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacosRESUMO
The human head can sometimes experience impact loads that result in skull fractures or other injuries, leading to the need for a craniectomy. Cranioplasty is a procedure that involves replacing the removed portion with either autologous bone or alloplastic material. While titanium has traditionally been the preferred material for cranial implants due to its excellent properties and biocompatibility, its limitations have prompted the search for alternative materials. This research aimed to explore alternative materials to titanium for cranial implants in order to address the limitations of titanium implants and improve the performance of the cranioplasty process. A 3D model of a defective skull was reconstructed with a cranial implant, and the implant was simulated using various stiff and soft materials (such as alumina, zirconia, hydroxyapatite, zirconia-reinforced PMMA, and PMMA) as alternatives to titanium under 2000N impact forces. Alumina and zirconia implants were found to reduce stresses and strains on the skull and brain compared to titanium implants. However, PMMA implants showed potential for causing skull damage under current loading conditions. Additionally, PMMA and hydroxyapatite implants were prone to fracture. Despite these findings, none of the implants exceeded the limits for tensile and compressive stresses and strains on the brain. Zirconia-reinforced PMMA implants were also shown to reduce stresses and strains on the skull and brain compared to PMMA implants. Alumina and zirconia show promise as alternatives to titanium for the production of cranial implants. The use of alternative implant materials to titanium has the potential to enhance the success of cranial reconstruction by overcoming the limitations associated with titanium implants.
Assuntos
Materiais Biocompatíveis , Análise de Elementos Finitos , Teste de Materiais , Procedimentos de Cirurgia Plástica , Crânio , Estresse Mecânico , Titânio , Zircônio , Humanos , Crânio/cirurgia , Titânio/química , Materiais Biocompatíveis/química , Zircônio/química , Procedimentos de Cirurgia Plástica/métodos , Próteses e Implantes , Durapatita/química , Polimetil Metacrilato/química , Óxido de Alumínio/química , Resistência à Tração , Fraturas Cranianas/cirurgia , Força CompressivaRESUMO
It's imperative to create a more ideal biological scaffold for bone defect repair. Calcium phosphate bone cements (CPC) could be used as a scaffold. Some ingredients and osteogenic factors could be added to improve its poor mechanical properties and biological activity. As a macromolecule extracted from traditional Chinese medicine, Hedysarum polysaccharides (HPS) would significantly promote the osteogenic activity of bone biomaterials. Zirconium oxide and starch were added to the solid phase and citric acid was added to the liquid phase to optimize CPC. HPS was loaded onto the scaffold as an osteogenic factor, and the prepared CPS + HPS was characterized. Further, the cytocompatibility of CPS + HPS was assessed according to activity, differentiation, and calcification in neonatal rat calvarial osteoblasts, and the biosafety of CPS + HPS was evaluated according to acute toxicity, pyrogen, sensitization, and hemolysis. The success of CPS + HPS in repairing bone defects was evaluated by using a rabbit femur implantation experiment. After optimization, CPS-20-CA-5 containing 10% starch and 5% citric acid displayed the highest mechanical strength of 28.96 ± 0.03 MPa. HPS-50 was demonstrated to exert the best osteogenic effect. The combination of CPS + HPS achieved HPS-loaded CPC. Material characterization, cytocompatibility, biosafety, and femoral implantation experiments indicated that CPS + HPS possessed better pressure resistance and improved osteogenic ability in bone defect repair.CPS + HPS demonstrated effective pressure resistance and superior osteogenic ability, which may be of great significance for bone defects and bone tissue engineering to promote bone regeneration and repair.
Assuntos
Cimentos Ósseos , Regeneração Óssea , Fosfatos de Cálcio , Osteogênese , Polissacarídeos , Alicerces Teciduais , Animais , Fosfatos de Cálcio/química , Cimentos Ósseos/química , Cimentos Ósseos/farmacologia , Coelhos , Polissacarídeos/química , Ratos , Alicerces Teciduais/química , Osteogênese/efeitos dos fármacos , Regeneração Óssea/efeitos dos fármacos , Osteoblastos/efeitos dos fármacos , Teste de Materiais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Ratos Sprague-Dawley , Masculino , Zircônio/química , Engenharia Tecidual/métodos , Fêmur/patologiaRESUMO
The Lesser Xing'an-Zhangguangcai Range of northeast China is located in the eastern segment of the Central Asian Orogenic Belt (CAOB), which records intense magmatism during the Mesozoic. The petrogenesis and geodynamic setting of the Early Jurassic intrusive rocks in this region are unclear. In this paper, we present new zircon U-Pb age and whole-rock geochemical data for these intrusive rocks to investigate their origins and tectonic setting. Zircon U-Pb dating suggests these intrusive rocks were emplaced during the Early Jurassic (197-187 Ma). The granites are enriched in silica and alkali, and depleted in MgO and CaO. They are metaluminous to weakly peraluminous, and have high A/CNK values and low zircon saturation temperatures (TZr ~ 779°C), suggesting they are highly fractionated I-type granites derived by partial melting of lower crustal materials. The granites exhibit negative Nb, Ta, P, Eu, and Ti anomalies due to fractional crystallization. The diorites and gabbros have low SiO2 contents and high Mg# values, and are enriched in light rare earth and large-ion lithophile (Ba, K, and Sr) elements, and depleted in heavy rare earth and high field strength (Nb, Ta, and Ti) elements. The geochemical characteristics show that the mafic magmas were derived by partial melting of mantle that had been metasomatized by subduction-related fluids. Based on the geochemical characteristics of coeval intrusive rocks and the regional geological setting, we suggest the Early Jurassic intrusive rocks in the Lesser Xing'an-Zhangguangcai Range were formed along an active continental margin, possibly as a result of bidirectional subduction of the Mudanjiang Oceanic plate between the Jiamusi and Songnen-Zhangguangcai Range massifs.
Assuntos
Sedimentos Geológicos , China , Sedimentos Geológicos/análise , Sedimentos Geológicos/química , Geologia , Fenômenos Geológicos , Zircônio/química , Dióxido de Silício/química , Dióxido de Silício/análise , SilicatosRESUMO
OBJECTIVES: The objective of this in vitro study was to evaluate the effects of different preparation designs on the mean colour change (ΔE*), marginal adaptation, fracture resistance, and fracture types of maxillary and mandibular premolar endocrowns (ECs). METHODOLOGY: A total of 40 extracted maxillary and mandibular premolars were treated endodontically, and each type was subdivided according to the remaining axial height (remaining walls on all surfaces; 2-4 mm) and 2 mm inside the pulp chamber. Specimens were immersed in coffee for 14 days, ΔE* was determined, marginal adaptation was observed, fracture forces test was conducted, and the samples were examined visually at 10× magnification to evaluate failure type and identify fracture origin. The data were entered and analyzed using Statistical Package for Social Sciences, and significance between and within groups was evaluated through ANOVA. The p-value ≤ 0.05 was considered statistically significant. RESULTS: The ΔE* values of the maxillary premolar with 2 mm axial height were the highest (6.8 ± 0.89 units), whereas the lowest value was observed in the mandibular premolar with 4 mm axial height (2.9 ± 0.53 units). Significant differences (p < 0.05) in teeth and design were observed. The marginal adaptation of the mandibular premolar with 4 mm axial height was the highest (30.20 ± 1.53 µm), whereas the lowest marginal adaptation was observed in the maxillary premolar with 2 mm axial height (14.38 ± 0.99 µm), and the difference was statistically significant (p < 0.05). The maximum fracture force was observed in maxillary premolars with 2 mm axial height (2248.15 ± 134.74 N), and no statistically significant difference (p = 0.07) was observed between maxillary and mandibular premolars at 4 mm axial height. CONCLUSION: The recorded ΔE* values of the ECs were within clinically acceptable values or slightly higher, and the marginal adaption values were within acceptable and recommended clinical values in µm. EC preparation with 2 mm axial height in both arches recorded the highest fracture forces. Type III (split fracture) failure was recorded as the highest in the maxillary and mandibular premolar ECs with different axial wall heights.
Assuntos
Dente Pré-Molar , Cor , Adaptação Marginal Dentária , Falha de Restauração Dentária , Zircônio , Humanos , Zircônio/química , Coroas , Técnicas In Vitro , Análise do Estresse Dentário , Maxila , Mandíbula , Fraturas dos Dentes , Planejamento de Prótese DentáriaRESUMO
BACKGROUND: Effects of the aging process on the flexural strength of Y-TZP and different Y-PSZ ceramics of different thicknesses were investigated. METHODS: 300 disc-shaped samples (12 mm diameter, 0.8 and 1.5 mm thicknesses) were made from 5 different zirconia materials 3Y-TZP LA, 4Y-PSZ, 5Y-PSZ, 3 + 5Y-PSZ and 4 + 5Y-PSZ. Experimental groups were artificially aged in an autoclave at 134 °C, 2 bar pressure for 1 and 5 h; control groups were not subjected to any treatment. Microstructural analysis was conducted using Scanning Electron Microscopy, and X-Ray Diffraction analysis determined the crystalline phase content. The impact of aging on flexural strength was investigated with the use of the biaxial flexural strength test. Data were analyzed using three-way ANOVA tests with a significance level of p < 0.05, applying Bonferroni correction for multiple comparisons. RESULTS: Statistically significant differences in flexural strength were observed among the materials and the material thicknesses (p < 0.05), while there were no significant differences among the aging times (p > 0.05). The highest mean flexural strength values were recorded in the case of the 3 Y-TZP-1.5 mm-5 h group (744.1 ± 61.2 MPa), which was attributed to phase-transformation toughening. The lowest values were observed in the case of the 5 Y-PSZ-1.5 mm-5 h (338.3 ± 34.8 MPa) group. CONCLUSIONS: Both material type and thickness significantly affect the flexural strength of zirconia ceramics, whereas aging time does not; thus, material selection and thickness are crucial considerations for clinicians.
Assuntos
Cerâmica , Resistência à Flexão , Teste de Materiais , Microscopia Eletrônica de Varredura , Difração de Raios X , Ítrio , Zircônio , Zircônio/química , Cerâmica/química , Ítrio/química , Fatores de Tempo , Propriedades de Superfície , Análise do Estresse Dentário , Materiais Dentários/químicaRESUMO
BACKGROUND: Marginal misfit and surface roughness of customized implant abutments is critical for restorative success. However, little is known about the comparison of misfit and surface roughness of CAD-CAM Zirconium oxide (ZrO), selective laser melting (SLM) Cobalt Chrome (CoCr) and preformed abutments. The aim of the study is to investigate the relation of misfit and micro-roughness of selective laser melting (SLM), preformed and CAD-CAM implant abutments. METHODS: Thirty internal connection, endosseous dental implants (Ø 4.0 mm x 10 mm, Dentium) were mounted in Polymethyl methacrylate vertically. Ten preformed Titanium alloy (Ti) abutments with 1 mm soft tissue height and Ø 4.5 mm were included as controls. Ten each of Y-TZP and SLM-CoCr, abutment/crowns were fabricated using CAD-CAM milling (CAD-CAM-ZrO) and SLM techniques. Surface micro-roughness (Ra) of the fabricated implant abutment/crown was evaluated with a 3D optical non-contact microscope. All implant restorations were torqued to implants (30 Ncm) using a Tohnichi BTGE digital torque gauge and were analyzed with Bruker micro-CT (Skyscan 1173) to detect micro-gaps at pre-selected points at implant abutment interface. The Ra and misfit data were compared using ANOVA, Tukey-Kramer, Kruskal-Wallis test and Pearson correlation (p < 0.05). RESULTS: Mean Ra among SLM CoCr abutments [0.88 (0.09) µm] were lower than CAD-CAM-ZrO and higher than preformed Ti abutments. Horizontal misfit among SLM-CoCr [45.43 (9.41) µm] and preformed Ti [36.87 (13.23) µm] abutments was not statistically different (p > 0.05). Misfit was significantly higher in Y-TZP samples compared to SLM-CoCr (p = 0.031) and preformed Ti abutments (p = 0.01). Preformed Ti abutments showed significantly lower misfit compared to SLM-CoCr abutments (p = 0.01). A positive linear correlation was observed between the surface roughness (Ra) and vertical misfit (r = 0.61, p < 0.05). CONCLUSION: SLM CoCr abutments showed rough surface compared to preformed Ti abutments, while horizontal misfit was comparable among SLM-CoCr and preformed abutments. Misfit was significantly greater in Y-TZP abutments, compared to SLM and preformed abutments. SLM abutment fabrication technique needs further improvement to provide better fit and surface topography.
Assuntos
Ligas de Cromo , Desenho Assistido por Computador , Coroas , Dente Suporte , Projeto do Implante Dentário-Pivô , Lasers , Propriedades de Superfície , Titânio , Zircônio , Zircônio/química , Titânio/química , Ligas de Cromo/química , Humanos , Planejamento de Prótese Dentária , Adaptação Marginal DentáriaRESUMO
The widespread use of synthetic dyes has serious implications for both the environment and human health. Therefore, there is an urgent need for the development of novel, high-efficiency adsorbents for these dyes. In this study, a Zirconium-based metal-organic framework (MOF) with controllable morphology was in-situ grown on bacterial nanocellulose (BC) via a solvothermal method. The resulting BC@MOF composite nanofibers have a high specific surface area of 651 m2/g and can be assembled into a self-supported porous membrane (BMMCa) through vacuum filtration with the assistance of calcium ions. The addition of Ca(II) significantly enhanced the mechanical properties of the membrane through dispersion effect and electrostatic interactions, as well as enhancing its adsorption performance through the salting-out effect. The BMMCa membrane, with its hierarchical porous structure and high flux, exhibits high selectivity for Congo red (CR) with an ultra-high adsorption capacity of 3518.6 mg/g. Furthermore, the self-supporting membrane achieved rapid and convenient removal of CR through circulating filtration adsorption. The adsorption mechanism and selectivity were verified through the molecular dynamics simulation calculations by Materials Studio (MS) software. This membrane-based adsorbent, with its ultra-high adsorption capacity, good selectivity, and recycling ability, has great potential for practical wastewater treatment applications.