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Objetivo. Evaluar la influencia de diferentes marcas de revestimientos dentales en la adaptación marginal e interna de las cofias metálicas. Método. La investigación fue in vitro, analítico, experimental y transversal; para ello, se confeccionaron 48 cofias metálicas, las cuales fueron cementadas en dientes humanos previamente tallados, luego las cofias fueron cortadas mesio-distalmente para evaluar su adaptación. La adaptación fue evaluada usando un estereomicroscopio Leica DM6000M. Para determinar si hay diferencia en la adaptación marginal e interna se empleó el análisis de varianza, la prueba de comparación múltiple y la prueba de Duncan. Adicionalmente, la prueba de Fisher, se utilizó para evaluar la adaptación total. Resultados. La mejor adaptación marginal e interna de las cofias metálicas lo presenta el revestimiento Fórmula 1 (Whipmix), seguido del Castorit súper C (Dentaurum) y Bellasun (Bego). Conclusión. Los revestimientos dentales no mostraron influencia en la adaptación marginal; sin embargo, si mostraron influencia en la adaptación interna.
Objective. To evaluate the influence of different brands of dental investments on the marginal and internal adaptation of metal copings. Method. The research was in vitro, analytical, experimental and transversal. For this, 48 metal copings were made, which were cemented on previously carved human teeth, then the copings were cut mesio-distally to evaluate their adaptation. The adaptation was evaluated using a Leica DM6000M stereomicroscope. To determine if there is a difference between marginal and internal adaptation; the analysis of variance, the multiple comparison test and the Duncan test were used. Furthermore, Fisher's exact test was used to evaluate the total adaptation. Results. The best marginal and internal adaptation of metal copings is presented by the Formula 1 coating (Whipmix), followed by Castorit super C (Dentaurum) and Bellasun (Bego). Conclusion. Dental investments did not show influence on marginal adaptation; however, they did show influence on internal adaptation.
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BACKGROUND:In recent years,metal-organic frameworks have been widely used in the biomedical field because of their unique properties,and metal-organic frameworks can be applied to implant surface modification for improving their biological properties and the surgery's success rate. OBJECTIVE:To introduce metal-organic frameworks commonly used in implant surface modification and the preparation and action mechanism of surgical implants modified by metal-organic frameworks. METHODS:The articles concerning metal-organic frameworks used in implant surface modification published from 2010 to 2023 were searched on PubMed,Web of Science and CNKI.Finally,64 articles were included for review. RESULTS AND CONCLUSION:(1)Metal-organic frameworks have the properties of high porosity,large specific surface area,and diverse spatial structure.As bioactive material,metal-organic frameworks have attracted much attention in tissue engineering and regenerative medicine.(2)The metal-organic frameworks commonly used in the field of implant surface modification include three types.Zeolitic imidazolate frameworks are commonly used as carriers,carrying various drugs and biomolecules.The MIL series are suitable for drug carriers and nanoenzymes.Bio-metal-organic frameworks have many applications because of their diverse structure and are characterized by excellent biosafety.(3)The preparation of implant materials modified by metal-organic frameworks can be mainly divided into two types:one is to incorporate metal-organic frameworks into pretreated implants;the other is to synthesize metal-organic frameworks in situ on pretreated implants.(4)Metal-organic frameworks on the implant surface could release their components,load drugs,catalyze active reactions,or combine with other materials,giving implants antibacterial and anti-inflammatory characteristics and promoting osseointegration.The preparation method of metal-organic framework coatings needs further improvement,and the metabolism and distribution of metal-organic framework coatings should be deeply explored,and its clinical application should be actively promoted.
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BACKGROUND:Polylactic acid has good biocompatibility and biodegradability,and has become a new orthopedic fixation material.However,the lack of cell recognition signal of this material is not conducive to cell adhesion and osteogenic differentiation,which limits its application in biomaterials. OBJECTIVE:3D-printed polylactic acid-nano-hydroxyapatite(nHA)/chitosan(CS)scaffold to evaluate its drug sustained-release and biological properties. METHODS:The porous polylactic acid scaffold(recorded as PLA scaffold)with interporous pores was printed by fused deposition modeling technique,and the scaffold was soaked in dopamine solution to prepare polylactic acid-dopamine scaffold(recorded as PLA-DA scaffold).Nano-hydroxyapatite was immersed in chitosan solution,and then the PLA-DA scaffold was immersed in it to prepare polylactic acid-nano-hydroxyapatite/chitosan scaffold(recorded as PLA-nHA/CS scaffold).The micro-morphology,porosity,water contact angle,and compressive strength of the three scaffolds were characterized.PLA-nHA/CS scaffold loaded with doxycycline(recorded as PLA-nHA/CS-DOX scaffold)was prepared by freeze-drying method,and its drug release was characterized.PLA,PLA-DA,PLA-nHA/CS,and PLA-nHA/CS-DOX scaffolds were co-cultured with MC3T3-E1 cells,separately,to detect cell proliferation and osteogenic differentiation.Staphylococcus aureus suspensions of different concentrations were co-cultured with four groups of scaffolds.The antibacterial performance of scaffolds was detected by inhibition zone test. RESULTS AND CONCLUSION:(1)Under scanning electron microscopy,the surfaces of PLA and PLA-DA scaffolders were dense and smooth,and nHA particles were observed on PLA-nHA/CS scaffolders.The porosity of PLA,PLA-DA and PLA-nHA/CS scaffolds decreased gradually,and the compressive strength increased gradually.The elastic modulus of PLA-nHA/CS scaffolds met the requirements of cancelous bone.The water contact angle of PLA-DA and PLA-nHA/CS brackets was smaller than that of PLA scaffolds.The PLA-nHA/CS scaffold sustainably released drugs in vitro for 8 days.(2)CCK-8 assay showed that the proliferation of MC3T3-E1 cells was not significantly affected by the four groups of scaffolds.The activity of alkaline phosphatase in PLA-DA group,PLA-nHA/CS group,and PLA-nHA/CS-DOX group was higher than that in PLA group.Alizarin red staining showed that compared with PLA group,the cells in PLA-nHA/CS group and PLA-nHA/CS-DOX group showed higher mineralized water level.(3)Inhibition zone test exhibited that PLA and PLA-DA scaffolds had no antibacterial properties.PLA-nHA/CS scaffolds had certain antibacterial properties.PLA-nHA/CS-DOX scaffolds had super antibacterial properties.(4)The results showed that the PLA-nHA/CS-DOX scaffold had good drug release performance,cell compatibility,osteogenic properties,and antibacterial properties.
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BACKGROUND:Calcium phosphate(CaP)coatings are widely used to improve the integration of titanium implants into bone but these coatings are associated with risks of infection.It is thus desirable to confer antibacterial properties to CaP coatings. OBJECTIVE:To prepare CaP-MgO composite coatings by impregnating magnesium oxide(MgO)sol into CaP coatings and assess the in vitro antibacterial activities and cytocompatibility. METHODS:An electrolyte was determined by titration and used for CaP coating electrodeposition on titanium(referred to as Ti-CaP).MgO was impregnated into the coating by immersing in an MgO sol with different mass fractions(15%,30%,50%)and subsequently calcined to form MgO-CaP composite coatings,which were recorded as Ti-CaP-15Mg,Ti-CaP-30Mg and Ti-CaP-50Mg,respectively.Microstructure,tensile properties,critical load,and Mg2+ release of coatings in vitro were characterized.Antibacterial activity was assayed using spread plate method by culturing S.aureus on the pure titanium sheet surface and Ti-CaP,Ti-Cap-15mg,Ti-Cap-30mg and Ti-Cap-50mg surfaces for 24 and 48 hours.Mouse osteoblast suspension was inoculated on pure titanium sheets and Ti-CaP,Ti-CaP-15Mg,Ti-CaP-30Mg and Ti-CaP-50Mg coated titanium sheets,respectively.Cell proliferation was detected by CCK-8 assay,and cell survival rate was calculated.The morphology of composite coating soaked in DMEM was also observed. RESULTS AND CONCLUSION:(1)Homogeneous,microporous CaP coatings consisting of octacaclium phosphate crystal flakes were prepared on titanium by electrodeposition.After sol impregnation-calcination,MgO aggregates were filled into the inter-flake voids.The extent of MgO filling and Mg concentration in the coating increased with the number of sol impregnation procedures.When immersed in phosphate buffered saline,all composite coatings actively released Mg2+ within 1 day;subsequently,the Mg2+ release slowed down on day 3.A small amount of Mg2+ release was still detected on day 7.The yield strength,tensile strength and fracture growth rate of Ti-CaP-30Mg coated titanium were not significantly different from those of pure titanium(P>0.05).There was no significant difference in the critical load of Ti-CaP,Ti-CaP-15Mg,Ti-CaP-30Mg and Ti-CaP-50Mg groups(P>0.05).(2)Except that pure titanium sheet and Ti-CaP had no antibacterial properties,the other samples had good antibacterial properties,and the antibacterial rate increased with the increase of MgO content in the coating.(3)After 1 and 3 days of co-culture,the cell survival rate of Ti-CaP-15Mg,Ti-CaP-30Mg and Ti-CaP-50Mg groups was lower than that of pure titanium group and Ti-CaP group(P<0.05).After 5 and 7 days of culture,there was no significant difference in cell survival rate among five groups(P>0.05).The content of MgO in the coating decreased gradually with the time of immersion in the medium.(4)The MgO sol impregnation added antibacterial properties to the CaP coatings while retained their biocompatibility.
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BACKGROUND:Bioactive glass is a multifunctional synthetic composite material that releases active ions slowly and exhibits certain biological activities after affinity with tissues.Their versatility stems from the versatility of their preparation processes and components,allowing them to be applied in different clinical scenarios. OBJECTIVE:To review the main application forms,application fields of bioactive glass,as well as the influence of doping different elements on its function. METHODS:A literature search was conducted across WanFang Medical Database,CNKI Database,PubMed Database,and Web of Science Database,using the search terms"bioactive glass,slow-release ions,bone tissue engineering,composite scaffold,tissue regeneration and repair,biomedical engineering"in Chinese and English.The timeframe was limited from 2000 to 2023.Finally,88 articles were included for review. RESULTS AND CONCLUSION:(1)In terms of application forms,bioactive glass can be fabricated as coatings,particles,bone cements,and scaffolds according to needs.Coatings have the potential to enhance the biological activity of implants,yet they are susceptible to instability as a result of degradation.Particles offer a viable solution for the repair of irregular bone defects;however,particles produced through traditional methods often possess limited functionality.Bone cement provides the benefits of minimal invasiveness and injectability,yet its application is restricted to smaller bone defects.Scaffolds exhibit excellent mechanical properties and are commonly used for larger-sized bone defects,yet they have limited toughness.(2)In terms of applications,bioactive glass can be used in a variety of tissue regeneration and repair and disease treatment fields,including dentistry,orthopedics,soft tissue engineering,and cancer.(3)In terms of element doping,the addition of specific elements to bioactive glass not only improves its mechanical properties but also endows it with special biological functions such as bioactivity,degradability,and antibacterial properties.(4)Biologically active glass is a versatile material that can be used in different forms and functions by adjusting the preparation process and element doping to meet various clinical needs in bone tissue engineering and is widely used in the field of biomedical engineering.
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ObjectiveTo construct a quantitative prediction model of three indicators（moisture absorption rate， film thickness and coating weight gain） during the coating process of Vitamin C Yinqiao tablets（VCYT） by near-infrared spectroscopy（NIRS）， and to realize the endpoint judgment. MethodReal-time NIRS data of 4 batches of VCYT during the coating process were collected by diffuse reflection method. The coating method employed was the rolling coating method， and the samples were obtained at the spray stage from the coater's sampling port every 10 minutes， and 57 batches of samples（about 1 800 tablets） were collected at various coating times， the tablets were embedded in molten paraffin， cut longitudinally， and observed by stereomicroscope. The film thickness， with a target value of 38 μm， was then measured using Motic Images Advanced 3.2 software. Furthermore， the mositure absorption rate of samples， aiming for a target value of 3%， was determined in accordance with guiding principles for drug hygroscopicity testing in the 2020 edition of Chinese Pharmacopoeia， and 3 samples were randomly selected from each batch（10 tablets per batch）， and the coating weight gain was calculated（target value of 4%）. Partial least squares regression（PLSR） was used to construct a quantitative model of the 3 coating indicators， and the predicted values of the coating indicators were smoothed using the moving average method and used to determine the coating endpoints. ResultThe prediction determination coefficients（Rp2） for moisture absorption rate， film thickness and coating weight gain were 0.933 4， 0.932 6 and 0.965 9， the root mean square errors of prediction（RMSEP） were 0.163 5%， 1.870 9 μm and 0.240 3%， the relative percent deviations（RPD） were 3.711 0， 2.760 7 and 5.415 8， respectively. The results of the external validation set demonstrated that the real-time predicted values obtained by the models exhibited the same trend as the measured values， and the coating endpoint could be accurately predicted（with a prediction error of less than 7.32 min and a relative error of less than 5.63%）. ConclusionThe established NIRS model exhibits excellent predictive performance and can be used for quality control of VCYT during the coating process.
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Introducción: La fijación de las restauraciones indirectas es uno de los pasos más importantes, para conseguir una adecuada retención y sellado de la interfase entre el material restaurador y el diente. Objetivo: Evaluar la resistencia de unión al cizallamiento de diferentes agentes de fijación a dos aleaciones metálicas utilizadas en odontología. Métodos: Estudio experimental in vitro. Cien especímenes de aleaciones de metales base, 50 de níquel-cromo y 50 de níquel-cromo-titanio fueron preparados y divididos de manera aleatoria en 5 grupos. Esta división se realizó acorde con el agente de fijación utilizado: sistema autograbante de dos pasos (Clearfil SE Bond; CSB), sistema adhesivo universal (Single Bond Universal; SBU), cemento resinoso autoadhesivo (Maxcem Elite; ME), ionómero de vidrio (IV) y fosfato de zinc (ZnPO). Posteriormente a la aplicación de cada agente de fijación, los especímenes tratados fueron almacenados en agua destilada por 24 h a 37 ºC y sometidos a un ensayo de resistencia de unión al cizallamiento. Resultados: La resistencia de unión al cizallamiento fue influenciada significativamente por el tipo de agente de fijación (p = 0,002) y el tipo de aleación utilizada (p < 0,001). La resistencia de unión al cizallamiento fue mayor, al utilizar el sistema Clearfil SE Bond, seguida de Single Bond Universal; las diferencias entre Maxcem Elite y el Fosfato de zinc no fueron significativas. Finalmente, el IV no mostró adhesión a ninguna de las aleaciones metálicas utilizadas. Conclusiones: El uso de Clearfil SE Bond aumentó la resistencia de unión de los cementos resinosos a las aleaciones metálicas(AU)
Introduction: The bonding of indirect restorations is one of the most important steps, in order to achieve adequate retention and sealing of the interface between the restorative material and the tooth. Objective: To evaluate the shear bond strength of different bonding agents to two metal alloys used in dentistry. Methods: In vitro experimental study. One hundred specimens of base metal alloys, 50 nickel-chromium and 50 nickel-chromium-titanium were prepared and randomly divided into 5 groups. This division was made according to the bonding agent used: two-step self-etching system (Clearfil SE Bond; CSB), universal adhesive system (Single Bond Universal; SBU), self-adhesive resin cement (Maxcem Elite; ME), glass ionomer (IV) and zinc phosphate (ZnPO). After the application of each bonding agent, the treated specimens were stored in distilled water for 24 hr at 37 ºC and subjected to a shear bond strength test. Results: Shear bond strength was significantly influenced by the type of bonding agent (p = 0.002) and the type of alloy used (p < 0.001). Shear bond strength was highest when using the Clearfil SE Bond system, followed by Single Bond Universal; the differences between Maxcem Elite and Zinc Phosphate were not significant. Finally, IV did not show adhesion to any of the metal alloys used. Conclusions: The use of Clearfil SE Bond increased the bond strength of resinous cements to metallic alloys(AU)
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Humans , Dental Bonding/methods , Dental CementumABSTRACT
The properties of dry-coated paracetamol particles(fast-dissolving model drug)with carnauba wax particles as the coating agent(dissolution retardant)were investigated.Raman mapping technique was used to non-destructively examine the thickness and homogeneity of coated particles.The results showed that the wax existed in two forms on the surface of the paracetamol particles,forming a porous coating layer:i)whole wax particles on the surface of paracetamol and glued together with other wax surface particles,and ii)deformed wax particles spread on the surface.Regardless of the final particle size fraction(between 100 and 800 μm),the coating thickness had high variability,with average thickness of 5.9±4.2 μm.The ability of carnauba wax to decrease the dissolution rate of paracetamol was confirmed by dissolution of powder and tablet formulations.The dissolution was slower for larger coated particles.Tableting further reduced the dissolution rate,clearly indicating the impact of subsequent formulation processes on the final quality of the product.
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Objective:To investigate the antibacterial and osteogenic properties of biomimetic mineralized iodine-loaded coating with micro-nano topography on the surface of bone implants.Methods:After the fiber network structure of sodium hydrogen titanate was constructed by alkali thermal reaction on the surface of Ti6Al4V (noted as AT), it was biomimetically mineralized in the modified simulated body fluid to form a micro-nano topology with high specific surface area (noted as AT-CaP), and finally loaded with PVPI to construct a novel antibacterial osseointegration coating (noted as AT-CaP-PVPI). The study was conducted in AT, AT-CaP, and AT-CaP-PVPI groups, in each of which 3 parallel experiments were performed. The morphology and colony counting of Staphylococcus aureus on the coating surface were observed to detect the in vitro antibacterial performance of the coating. Fifteen male SD rats were randomly divided into 3 groups ( n=5): AT, AT-CaP, and AT-CaP-PVPI. After intramedullary injection of Staphylococcus aureus into the lower end of the femur in the SD rats, titanium rods coated with AT, AT-CaP, and AT-CaP-PVPI were inserted into the marrow cavity. The osteogenesis, volume ratio of new bone mass and number of trabeculae on the surface of the femoral implants were compared between the 3 groups 4 weeks after operation. Results:In AT and AT-CaP groups, a large number of bacteria grew in their inherent elliptical or spherical shape on the implant surface and a large number of colonies were seen on the plate; in AT-CaP-PVPI group, the bacteria on the coating surface exhibited membrane deformation and depression, some of them were completely broken and dissolved, and a large number died. There was almost no new bone formation around the implants in AT group; new bone scattered around the implants with discontinuous distribution in AT-CaP group; a great amount of new bone was seen around the implants with even distribution but no signs of infection in AT-CaP-PVPI group. The volume ratio of new bone mass and the number of trabeculae on the implant surface in AT-CaP-PVPI group were 0.453±0.206 and 6.055±0.536, respectively, significantly higher than those in AT group (0.046±0.028 and 1.667±1.249) and AT-CaP group (0.188±0.052 and 3.804±0.889) ( P<0.05). Conclusion:Biomimetic mineralized iodine-loaded coating with micro-nano topography on the surface of bone implants shows good antibacterial and osteogenic properties.
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OBJECTIVE@#To design and construct a graphene oxide (GO)/silver nitrate (Ag3PO4)/chitosan (CS) composite coating for rapidly killing bacteria and preventing postoperative infection in implant surgery.@*METHODS@#GO/Ag3PO4 composites were prepared by ion exchange method, and CS and GO/Ag3PO4 composites were deposited on medical titanium (Ti) sheets successively. The morphology, physical image, photothermal and photocatalytic ability, antibacterial ability, and adhesion to the matrix of the materials were characterized.@*RESULTS@#The GO/Ag3PO4 composites were successfully prepared by ion exchange method and the heterogeneous structure of GO/Ag3PO4 was proved by morphology phase test. The heterogeneous structure formed by Ag3PO4 and GO reduced the band gap from 1.79 eV to 1.39 eV which could be excited by 808 nm near-infrared light. The photothermal and photocatalytic experiments proved that the GO/Ag3PO4/CS coating had excellent photothermal and photodynamic properties. In vitro antibacterial experiments showed that the antibacterial rate of the GO/Ag3PO4/CS composite coating against Staphylococcus aureus reached 99.81% after 20 minutes irradiation with 808 nm near-infrared light. At the same time, the composite coating had excellent light stability, which could provide stable and sustained antibacterial effect.@*CONCLUSION@#GO/Ag3PO4/CS coating can be excited by 808 nm near infrared light to produce reactive oxygen species, which has excellent antibacterial activity under light.
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Chitosan , Silver Nitrate , Titanium , Anti-Bacterial Agents/pharmacology , Coloring AgentsABSTRACT
OBJECTIVE@#To review antibacterial/osteogenesis dual-functional surface modification strategy of titanium-based implants, so as to provide reference for subsequent research.@*METHODS@#The related research literature on antibacterial/osteogenesis dual-functional surface modification strategy of titanium-based implants in recent years was reviewed, and the research progress was summarized based on different kinds of antibacterial substances and osteogenic active substances.@*RESULTS@#At present, the antibacterial/osteogenesis dual-functional surface modification strategy of titanium-based implants includes: ① Combined coating strategy of antibiotics and osteogenic active substances. It is characterized in that antibiotics can be directly released around titanium-based implants, which can improve the bioavailability of drugs and reduce systemic toxicity. ② Combined coating strategy of antimicrobial peptides and osteogenic active substances. The antibacterial peptides have a wide antibacterial spectrum, and bacteria are not easy to produce drug resistance to them. ③ Combined coating strategy of inorganic antibacterial agent and osteogenic active substances. Metal ions or metal nanoparticles antibacterial agents have broad-spectrum antibacterial properties and various antibacterial mechanisms, but their high-dose application usually has cytotoxicity, so they are often combined with substances that osteogenic activity to reduce or eliminate cytotoxicity. In addition, inorganic coatings such as silicon nitride, calcium silicate, and graphene also have good antibacterial and osteogenic properties. ④ Combined coating strategy of metal organic frameworks/osteogenic active substances. The high specific surface area and porosity of metal organic frameworks can effectively package and transport antibacterial substances and bioactive molecules. ⑤ Combined coating strategy of organic substances/osteogenic active substancecs. Quaternary ammonium compounds, polyethylene glycol, N-haloamine, and other organic compounds have good antibacterial properties, and are often combined with hydroxyapatite and other substances that osteogenic activity.@*CONCLUSION@#The factors that affect the antibacterial and osteogenesis properties of titanium-based implants mainly include the structure and types of antibacterial substances, the structure and types of osteogenesis substances, and the coating process. At present, there is a lack of clinical verification of various strategies for antibacterial/osteogenesis dual-functional surface modification of titanium-based implants. The optimal combination, ratio, dose-effect mechanism, and corresponding coating preparation process of antibacterial substances and bone-active substances are needed to be constantly studied and improved.
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Anti-Bacterial Agents/pharmacology , Coated Materials, Biocompatible/chemistry , Metal-Organic Frameworks/pharmacology , Osteogenesis , Surface Properties , Titanium/pharmacology , Prostheses and ImplantsABSTRACT
OBJECTIVE@#To study microstructure, friction and wear behaviors of silicon-lithium spray coating on the surface of zirconia ceramics and to preliminarily evaluate its esthetic so as to provide support and guidance for the clinical application.@*METHODS@#Zirconia ceramic specimens were randomly divided into three groups: coating group (two subgroups), polishing group (two subgroups), and glazing group (four subgroups), with 10 samples in each subgroup. The two subgroups of coating group were the zirconia ceramics with the untreated and preliminary polishing surfaces sprayed with silicon-lithium coating, respectively. The two subgroups of polishing group were preliminary polishing and fine polishing of zirconia ceramics, respectively. The four subgroups of glazing group were preliminarily polished zirconia ceramics glazed with Biomic and Stain/Glaze products, respectively; and untreated zirconia ceramics glazed with Biomic and Stain/Glaze products, respectively. The above 8 subgroups of zirconia ceramic specimens were used as friction pairs with 80 steatite ceramics for 50 000 chewing cycles under 50 N vertical load and artificial saliva lubrication using chewing simulation. Scanning electron microscope was used to observe the microstructure of the surface and section of the coating group, and the thickness of the coating and glazing were measured. The linear roughness of the coating and polishing groups was mea-sured using a laser confocal scanning microscope. Vickers hardness was measured using a microhardness tester and the esthetic of zirconia ceramic full crown sprayed with silicon-lithium coating was preliminarily evaluated. White light interferometer was used to measure the width, the maximum depth and the volume of the wear scars of each group, and the wear depth of steatite ceramics and wear rate of zirconia ceramic specimens were calculated. Kruskal-Wallis nonparametric test and Dunn's multiple comparisons test were used to analyze the wear depth of each group (α=0.05).@*RESULTS@#The microstructures of the silica-lithium spray coatings on the untreated and preliminarily polished zirconia ceramic surfaces showed the protruding defects, and the line roughness of coating group was larger than that of the polishing group. The median thickness of the silica-lithium spray coating on the preliminarily polished zirconia ceramic was 13.0 μm (interquartile range, IQR: 11.6, 17.9), while that of the silica-lithium spray coating on the untreated zirconia ceramic was 4.4 μm (IQR: 4.1, 4.7). The Vickers hardness and wear rate of the coating group were between the polishing group and the glazing group. The wear depths of the wear scars of steatite ceramics were the glazing group, coating group, and polishing group in descending order, and there was statistically significant difference between glazing and polishing groups (P < 0.05). With the increase of polishing procedure, the wear depth of steatite ceramics decreased in each subgroups. The orders of maximum depth and volume of wear scars of zirconia ceramic were the glazing group, coating group, and polishing group in descending order, and there was statistically significant difference in the maximum depth of wear scars between glazing and polishing groups (P < 0.05).@*CONCLUSION@#The silica-lithium spray coating on the zirconia ceramic, can be used as a new method for zirconia ceramic surface treatment, because it can increase the esthetic of zirconia ceramics compared with polishing and reduce the wear of steatite ceramics compared with glazing.
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Humans , Silicon , Materials Testing , Friction , Lithium , Cicatrix , Surface Properties , Silicon Dioxide , Zirconium/chemistry , Ceramics , Dental PorcelainABSTRACT
Extended circulation of anticancer nanodrugs in blood stream is essential for their clinical applications. However, administered nanoparticles are rapidly sequestered and cleared by cells of the mononuclear phagocyte system (MPS). In this study, we developed a biomimetic nanosystem that is able to efficiently escape MPS and target tumor tissues. The fabricated nanoparticles (TM-CQ/NPs) were coated with fibroblast cell membrane expressing tumor necrosis factor (TNF)-related apoptosis inducing ligand (TRAIL). Coating with this functionalized membrane reduced the endocytosis of nanoparticles by macrophages, but increased the nanoparticle uptake in tumor cells. Importantly, this membrane coating specifically induced tumor cell apoptosis via the interaction of TRAIL and its cognate death receptors. Meanwhile, the encapsulated chloroquine (CQ) further suppressed the uptake of nanoparticles by macrophages, and synergized with TRAIL to induce tumor cell apoptosis. The vigorous antitumor efficacy in two mice tumor models confirmed our nanosystem was an effective approach to address the MPS challenge for cancer therapy. Together, our TM-CQ/NPs nanosystem provides a feasible approach to precisely target tumor tissues and improve anticancer efficacy.
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Cell membrane camouflaged nanoparticles have been widely used in the field of drug leads discovery attribute to their unique biointerface targeting function. However, random orientation of cell membrane coating does not guarantee effective and appropriate binding of drugs to specific sites, especially when applied to intracellular regions of transmembrane proteins. Bioorthogonal reactions have been rapidly developed as a specific and reliable method for cell membrane functionalization without disturbing living biosystem. Herein, inside-out cell membrane camouflaged magnetic nanoparticles (IOCMMNPs) were accurately constructed via bioorthogonal reactions to screen small molecule inhibitors targeting intracellular tyrosine kinase domain of vascular endothelial growth factor recptor-2. Azide functionalized cell membrane acted as a platform for specific covalently coupling with alkynyl functionalized magnetic Fe3O4 nanoparticles to prepare IOCMMNPs. The inside-out orientation of cell membrane was successfully verified by immunogold staining and sialic acid quantification assay. Ultimately, two compounds, senkyunolide A and ligustilidel, were successfully captured, and their potential antiproliferative activities were further testified by pharmacological experiments. It is anticipated that the proposed inside-out cell membrane coating strategy endows tremendous versatility for engineering cell membrane camouflaged nanoparticles and promotes the development of drug leads discovery platforms.
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ObjectiveTo evaluate the caries prevention effect of different fluoride application frequencies in 3-year-old children with active caries. MethodsA total of 337 3-year-old children with dental caries from 12 kindergartens in Changning District of Shanghai were divided into three groups： group 1 received fluoride application once every three months， group 2 received fluoride application once every six months， and the control group received no fluoride application. At baseline， parents completed a questionnaire survey， and oral examinations were conducted at baseline， 7 months， and 16 months after the fluoride intervention to assess the incidence of new dental caries， new dmft， and new dmfs of children. Multivariate logistic regression analysis was used to analyze the relationship between fluoride application and new dental caries， with new dental caries as the dependent variable and local fluoride application， child's gender， age in months， parents' highest education level， frequency of sugary intake （desserts， candies， sweet beverages）， age of toothbrushing initiation， frequency of daily toothbrushing， use of fluoride toothpaste， parental assistance in child’s toothbrushing， and daily use of dental floss as the independent variables. ResultsThere were no significant differences in baseline general conditions and oral health behaviors among group 1 （121 cases）， group 2 （123 cases） and the control group （93 cases） （all P>0.05）. After 16 months' intervention， three children were lost to follow-up due to transferring schools. The new caries rates of group 1 （120 cases）， group 2 （121 cases） and the control group （93 cases） were 5.83%， 24.79% and 52.69%， respectively. The incidence of new caries was significantly lower in group 1 compared to group 2 and the control group （P<0.001）， and it was also significantly lower in group 2 compared to the control group （P<0.001）. The newly-increased caries of group 1， group 2 and the non-fluoride control group were all 0.12 0.52， 0.36 0.68 and 1.16 1.39， respectively. The mean increment of new caries was lower in group 1 compared to group 2 （P=0.040） and the non-fluoride control group （P<0.001）， and it was lower in group 2 compared to the non-fluoride control group （P<0.001）. After adjusting for factors such as gender， parents' education level and child's oral health behaviors by multivariate logistic regression， the results showed that fluoride application once every three months could significantly reduce the risk of dental caries （OR=0.04， P<0.001）. ConclusionLocal use of fluoride has a certain effect on the prevention and treatment of dental caries in children with active caries. Fluoride application once every three months effectively reduces the incidence of new caries and slows down the progression of caries lesions. It is suggested that local application of fluoride should be implemented once every three months for children with active caries.
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Objective@# To investigate the effect of cobalt (Co) and calcium-phosphate (Ca/P) doped coating on titanium surfaces and their angiogenic effect.@*Methods @# Microarc oxidation (MAO) was used to prepare Co-Ca/P-doped and Co-doped coatings. Titanium (Ti) sheet without MAO treatment was used as control. Scanning electron microscopy (SEM) was used to observe the surface micromorphology of the coatings. Energy dispersive spectrometry (EDS) was also applied to detect the doped chemicals and their contents. Standard soaking solutions of these coatings were prepared using an endothelial cell medium (ECM) solution for subsequent angiogenesis experiments. Human umbilical vein endothelial cells (HUVECs) were cultured on Matrigel with ECM soaking solutions for 4 h and 8 h. The microvessels were observed under a microscope, and the number of microtubules and their interconnecting nodes were analyzed with Image J software. @*Results@# Co doped and Co-Ca/P-doped coatings were successfully prepared by MAO, which was demonstrated by both SEM observation and EDS analysis. SEM observation showed that irregular crystals of the above chemicals were present on both Co and Co-Ca/P-doped coatings, commonly with a diameter <2 μm. However, more crystals were observed on the Co-Ca/P coatings than on the Co coating, and the distribution of the crystals was more homogenous on the Co-Ca/P coatings. However, only polishing scratches were observed on the Ti sample surface. EDS analysis indicated that in contrast to only Co in the Co coating, Co, Ca and P were doped within the Co-Ca/P coating, and none of the three elements were observed on the Ti plate surface. The number of vascular rings and nodes formed by HUVECs in the extract of the Co-Ca/P group was significantly higher than that of the Co group (P<0.05), and the angiogenic effect of these two components was significantly better than that of the Ti group (P<0.05). @*Conclusion@#The Co-Ca/P coating exhibits good angiogenic properties in vitro and is valuable for the development of new titanium implants with high surface bioactivity.
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Blood compatibility is the main restriction of blood-contacting medical devices in clinical application, especially long-term blood-contacting medical devices will stimulate the immune defense mechanism of the host, resulting in thrombosis. Heparin anticoagulant coating links heparin molecules to the surface of medical device product materials, improves the compatibility between the material surface interface and the body, and reduces the host immune defense reactions. This study reviews the structure and biological properties of heparin, the market application status of heparin-coated medical products, the insufficiency and improvement of heparin coating, which can provide a reference for the application research of blood contact medical devices.
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Humans , Heparin/chemistry , Anticoagulants/chemistry , Thrombosis , Coated Materials, Biocompatible/chemistry , Surface PropertiesABSTRACT
@#【Objective】 To study the composition and function of tongue coating (TC) and gastrointestinal tract (GIT) microbiota in participants with yellow-greasy tongue coating (YGTC), and to explore the representative metabolite markers and pathways in this group. 【Methods】 Subjects with YGTC or thin-white tongue coating (TWTC) were recruited from December 1, 2021 to October 30, 2022, and the TC and fecal samples were collected. Samples were subjected to both whole-genome shotgun (WGS), and 16S rRNA gene sequencing. The α-diversity analysis, principal component analysis (PCA), and Spearman correlation analysis were performed for two groups. Ultra-performance liquid chromatography combined with tandem mass spectrometry (UPLC–MS/MS) analysis was used to analyze metabolomics and enrichment of metabolic pathways. 【Results】 The results revealed 20 YGTC participates and 19 TWTC participates. At the genus level, the dominant bacterial species of TC flora and intestinal flora in the two groups were roughly the same, but the relative kurtosis difference was marked, and the abundance of potentially pathogenic bacteria in TC and fecal samples of YGTC subjects was higher. There were 9 down-regulated microorganisms in the TC samples, 26 down-regulated microorganisms, and 6 up-regulated microorganisms in YGTC subjects. The α-diversity analysis indicated that the Chao and abundance-based coverage estimator (ACE) indices of TC bacteria in the YGTC subjects showed a decreasing trend, but the difference was not statistically significant (P > 0.05). The α-diversity of fecal samples and the Chao and ACE indices decreased significantly (P < 0.05). PCA showed that the microflora structure of TC and fecal samples were significantly different between the two groups. Spearman correlation analysis showed that there was no correlation between TC and fecal microorganisms at phyla and genus levels in the same subjects (P > 0.05). The metabolomics results demonstrated that fumarate reductase, V/A ATPase, and phosphatidylethanolamine were increased, and glycerate-3p, UDP-glucose, and quinone oxidoreductase metabolites were decreased in YGTC TC samples. Inosine monophosphate (IMP), uridine monophosphate (UMP), and gamma-aminobutyric acid(GABA) were increased in YGTC fecal samples, while the contents of ribo-5P, histidine, biotin,and cobalamin were decreased. Metabolic pathway analysis indicated that the abundance of the TC and fecal samples of the YGTC subjects was relatively low in various metabolic pathways, including amino acid metabolism, carbohydrate metabolism, nitrogen metabolism, and energy metabolism. 【Conclusion】 Structural and functional changes in TC and GIT microbiota or metabolite markers could be potential biological bases of YGTC formation.
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Objective To investigate the effect of different coating methods on production quality of complex and flexible silicone vascular replicas. Methods Based on models of anterior communicating artery aneurysms, several patient-specific models were made by using spray-coating method and brush-spin-coating method respectively, and two methods for making the same vascular structure were quantitatively compared in terms of thickness growth, circumferential uniformity and light transmittance. Results Brush-spin-coating method was better than spray-coating method in the thickness control and coating uniformity for fabrication of vessels with large curvature, variable diameter and straight tube, and the model had preferably light transmittance and surface smoothness. The relative deviation of thickness by brush-spin-coating method was decreased by 8. 9% , 10. 8% and 16. 9% respectively compared with spray-coating method. Conclusions At present stage, the brush-spin coating method has the advantage of thickness uniformity and light transmittance over the spray-coating method in making silicone phantoms, and it has promising application prospects in fluid mechanics field of in vitro experiment on large vessels.
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Objective To improve the performance of artificial joint at biological fixed interface by frettingmechanical stimulation. Methods Taking the bonding sample of active rat bone tissues and inactive titanium bead coating as the research object, by using the self-developed fretting mechanical stimulation test device, the effects of mechanical stimulation with different tangential fretting amplitudes on growth promotion and micro-injury of bone tissues at fixed interface were explored, and the mechanism of growth promotion and micro-injury of bonetissues on the surface of titanium bead coating under fretting stimulation was revealed. Results The mechanical stimulation group with 40 μm fretting amplitude showed the maximum interface bonding force between bone tissues and titanium bead coating. The tangential fraction force-displacement curves changed from elliptic shape to linear shape, and the bonding interface was in adhesion area, which was difficult to become loose. The bone tissues had the most complete structure, and the number of tissue cells adhering and growing on the surface of titanium bead coating was the largest, as well as the distribution range was the widest. With the increase of fretting amplitude, the promoting effect of fretting stimulation on bone growth weakened, the bonding strength between bone tissues and titanium bead coating interface gradually decreased, the internal cavity area increased, the number and proliferation activity of tissue cells decreased to varying degrees as well. Conclusions Fretting stimulation with different amplitudes can promote the growth of bone tissue and cause micro-injury at the same time, and the optimal fretting amplitude is 40 μm.