几种齿科合金生物相容性的比较

用银钯合金、镍铬合金、钴铬合金、2号合金的浸提液体外培养小鼠成纤维细胞(L929),以含10%胎牛血清的RPMI1640培养基作为阴性对照组。用5种浸提液分别培养L929细胞4 h、7 h、24 h、48 h后,用MTT法检测细胞增值率并计算caspase-3活化度。在荧光显微镜下观察48 h后各组细胞的状态。使用凋亡相关因子caspase-3的表达强度辅以时间梯度分析其与齿科合金生物相容性的相关性。结果表明:加样培养48 h后各实验组均有大量凋亡细胞,但是有明显的不同,在镍铬合金组内可见橙色坏死细胞;各组细胞的毒性为0级,其细胞增值率的排序为:钴铬合金组>2号合金组>银钯合金组>镍铬合金组;各实验组的Caspase-3活性有显著的差异(P<0.01),Caspase-3活化度由高到低的排序为:钴铬合金组>2号合金组银钯合金组>镍铬合金组。各时间点Caspase-3活化度也有显著的差异(P<0.01),其由大到小的排序为:4 h、48 h、7 h、24 h;这几种齿科合金生物相容性由高至低的排序为:钴铬合金>2号合金>银钯合金>镍铬合金。镍离子、银离子是影响其生物相容性的主要因素。在时间梯度的辅助下评价4种齿科合金生物相容性,Caspase-3与MTT的结果一致.     

3D打印医用钛合金的抗菌性能和体外生物相容性

应用选择性激光熔融技术(SLM)制备出3D打印医用钛合金Ti-6Al-4V和Ti-6Al-4V-5Cu,用平板共培养法研究测定其抗菌性能,用CCK8细胞增殖测定法、鬼笔环肽细胞骨架染色法和Annexin-V/PI流式细胞术研究了这种合金的抗菌性能和对小鼠胚胎成骨前体细胞(MC3T3-E1)的体外生物相容性影响。结果表明,3D打印Ti-6Al-4V-5Cu合金具有较高的抗菌性能,对金黄色葡萄球菌的抗菌率达到(57.03±1.55)%。在CCK8细胞增殖毒性测定、细胞骨架鬼笔环肽染色实验和Annexin-V/PI双标记法流式分析三种研究中Ti-6Al-4V-5Cu表现的优越,具有更好的体外生物相容性。     

Zirconium Alloys for Orthopaedic and Dental Applications

Zirconium alloys for biomedical applications are receiving increasing attention due to their two unique properties: 1) the formation of an intrinsic bone‐like apatite layer on their surfaces in body environments, and 2) better compatibility with magnetic resonance imaging (MRI) diagnostics due to their low magnetic susceptibility, as well as their overall excellent biocompatibility, mechanical properties, and bio‐corrosion resistance. In particular, since both of the MRI quality and speed depend on magnetic field strength, there is a compelling drive for use of high magnetic field strength (>3 Tesla) MRI systems. This paper provides a comprehensive review of the characteristics of commercially pure (CP) Zr and Zr‐based alloys as orthopaedic and dental implant materials. These include their 1) phase transformations; 2) unique properties including corrosion resistance, biocompatibility, magnetic susceptibility, shape memory effect, and super‐elasticity; 3) mechanical properties; 4) current orthopaedic and dental applications; and 5) the d‐electron theory for Zr alloy design and novel Zr‐alloys. The mechanical properties of Zr‐based bulk metallic glasses (BMGs) and their application as implant materials are also assessed. Future directions for extending the use of Zr‐alloys as orthopaedic and dental implants are discussed.

     

X-Ray Spectrometric Analysis of Noble Metal Dental Alloys

The analysis of noble metal dental alloys for the various constituent elements is a difficult and tedious task by chemical or fire assay procedures. X-ray spectroscopy offered the possibility of increased speed, especially if solid metal samples were employed. This technique was investigated particularly with respect to the analysis of dental alloys having the nominal composition in percent, of gold 72, silver 12, copper 10, platinum 2, palladium 2, and zinc 2. Alloys were prepared by melting the component elements in a high frequency furnace and casting the metal into disk form. Compositions of the castings were determined by chemical analysis. Optimum procedures for casting the sample and for X-ray analysis were established, and analytical curves were developed relating concentrations to measured intensities of the X-ray lines Au L_β, Ag K_α, Cu K_α, Pt L_α, Pd K_α, and Zn K_α. The observed typical coefficients of variation for the method were Au 0.34 percent, Ag 0.44 percent, Cu 2.2 percent, Pt 1.6 percent, Pd 1.2 percent, and Zn 0.72 percent. The results indicate that the method is sufficiently accurate and has marked advantages of speed and simplicity compared to chemical analysis.     

Importance of the Casting Process. Comparative Survey of the Commonly Used Ni-Cr Dental Alloys

Mobile or fixed dental prostheses are a common and important part of life. Many noble metal-based alloys have been used in prosthodontics, and they need a correct evaluation of their technical, biological, and clinical properties. The present study proposes a new approach for the manufacturing process. We emphasize the key role of each step for combined process of heating, casting and spin for completing works of Ni-Cr alloys with improved physical-chemical properties, as a protocol for quality of the obtained physiognomic dental restorations. The differences in composition distribution between cast and raw materials were investigated by energy dispersive x-ray spectroscopy (EDX), while the surface morphology was inspected by scanning electron microscopy (SEM). Important aspects related to crystal lattice were revealed through the x-ray diffraction (XRD) method and they are closely related to the centrifugal casting process.     

Biocompatibility of Apatite-Containing Implant Materials

Thermochemical decomposition of hydroxyapatite in phosphoric acid was studied with the aim of producing polymineral gradient-resorptivity composites. The procedure was tested on the BAK-1000 glass–apatite composite. The results indicate an enhancement of resorptivity, without changes in the performance parameters or crystal structure, thereby suggesting a new approach to controlling the bioactivity of apatite-containing bioceramics.     

泡沫碳化硅的生物相容性

依据国家标准 GB/T16886,评价了用"高分子热解结合可控熔渗反应烧结技术一制备的泡沫碳化硅的生物相容性.结果表明:这种泡沫碳化硅没有细胞毒性,没有潜在的皮肤致敏性,遗传毒性试验、皮下和骨植入试验均未见异常反应,具有良好的生物相容性,可应用在外形复杂和长段承重骨缺损的修复.     

儿茶素对镍铬合金电化学腐蚀性能的实验研究

采用电化学工作站的开路电位和电化学阻抗谱法对牙科铸造镍铬合金在不同浓度表没食子儿茶素没食子酸酯(EGC)人工唾液中的腐蚀行为进行了比较,并用扫描电镜观察比较了腐蚀后镍铬合金的表面形貌.结果表明,镍铬合金在不同浓度EGCG人工唾液中的开路电位大小顺序为1.09/L<4.0g/L<0g/L,且在1.09/L、4.0g/LEGCG人工唾液中其开路电位较快地达到了一个稳定值;同时,镍铬合金在不同浓度EGCG人工唾液中的等效电路极化电阻大小顺序为1.09/L<4.0g/L<0g/L.扫描电镜显示镍铬合金在不同浓度EGCG中均有不同程度的腐蚀,表面出现点蚀,分布不均匀,孔径大小不一,其中以1.09/L EGCG人工唾液中的腐蚀最明显,其次是4.0g/L EGCG.由此均说明镍铬合金在1.0g/L EGCG人工唾液中的耐腐蚀性能最差,各试件的耐腐蚀性能排序为1.0g/L EGCG<4.0g/L EGCG<0g/L EGCG.     

N-羧甲基壳聚糖的制备及其生物相容性评价

以壳聚糖、乙醛酸为原料,制备了不同羧化度的水溶性N-羧甲基壳聚糖(N-CMC),进行了羧化度的测定、FTIR结构表征及生物相容性评价.结果表明,制备的5种N-CMC羧化度(D.C.)在25%～78%,FITR谱图中在1590cm-1处存在羧甲基的特征吸收峰,羧甲基化发生在壳聚糖(CTS)的2位N上.用小鼠成纤维细胞株L929评价材料的细胞毒性,在设置的62.5～5000μg/ml浓度内均具有良好的细胞相容性.动物组织相容性实验表明,相同质量N-CMC的胶体溶液比膜剂更易被组织降解吸收;在肌肉组织中其降解吸收快于皮下组织.溶血性测试表明5种羧化度样品的溶血率均<5%.表明N-CMC是一种优良的生物医用材料.     

Electropolishing of NiTi for Improving Biocompatibility

A modified electrolyte （CH3COOH-HClO4-A-B） for electropolishing （EP） of NiTi was presented for improving the corrosion resistance and biocompatibility of the alloy. Using the proposed parameters, a homogeneous and uniform surface was obtained. Atomic force microscopy （AFM） revealed that the surface roughness （Ra） for EP sample （23.21 nm） was close to mechanical polishing （MP） sample （19.36 nm）. Analysis by X-ray photoelectron spectroscopy （XPS） showed that Ti/Ni ratio increased from 3.1 for MP sample to 27.6 for EP sample. Measurements using potentiodynamic polarization in Hanks＇ solution showed that no pitting occurred for EP sample even though the applied potential increased up to 1500 mV （vs SCE）, while the MP sample was broken down at 650 mV. The present study indicates that electropolishing NiTi with this modified electrolyte contributes to the improved biocompatibility of NiTi.     

胶原蛋白-葡甘聚糖-壳聚糖(CKCS)共混膜的生物相容性研究

通过内皮细胞-膜复合物的培养、组织学观察和MTT法对细胞增殖的测定以及动态凝血实验、溶血实验和复钙实验考察了胶原蛋白-葡甘聚糖-壳聚糖(CKCS)共混膜的细胞相容性和血液相容性,为共混膜在生物医学领域的应用提供理论依据.     

Biocompatibility of diamond-like nanocomposite thin films

Diamond-like nanocomposite (DLN) films consist of network structure of amorphous carbon and quartz like silicon. In the present work, DLN films have been synthesized on pyrex glass and subsequently, their biocompatibility have been investigated through primary and secondary cell adhesion, cytotoxicity, protein adsorption and murine peritoneal macrophage activation experiments. Variable degree of cell and protein response have been found based on variable film synthesis parameters but in overall, required biocompatibility has been established for all types of film-coating.     

Biocompatibility of immobilized aligned carbon nanotubes

In vivo host responses to an electrode-like array of aligned carbon nanotubes (ACNTs) embedded within a biopolymer sheet are reported. This biocompatibility study assesses the suitability of immobilized carbon nanotubes for bionic devices. Inflammatory responses and foreign-body histiocytic reactions are not substantially elevated when compared to negative controls following 12 weeks implantation. A fibrous capsule isolates the implanted ACNTs from the surrounding muscle tissue. Filamentous nanotube fragments are engulfed by macrophages, and globular debris is incorporated into the fibrous capsule with no further reaction. Scattered leukocytes are observed, adherent to the ACNT surface. These data indicate that there is a minimal local foreign-body response to immobilized ACNTs, that detached fragments are phagocytosed into an inert material, and that ACNTs do not attract high levels of surface fouling. Collectively, these results suggest that immobilized nanotube structures should be considered for further investigation as bionic components.     

Biocompatibility Pathways in Tissue-Engineering Templates

Tissue engineering, which involves the creation of new tissue by the deliberate and controlled stimulation of selected target cells through a systematic combination of molecular and mechanical signals, usually involves the assistance of biomaterials-based structures to deliver these signals and to give shape to the resulting tissue mass. The specifications for these structures, which used to be described as scaffolds but are now more correctly termed templates, have rarely been defined, mainly because this is difficult to do. Primarily, however, these specifications must relate to the need to develop the right microenvironment for the cells to create new tissue and to the need for the interactions between the cells and the template material to be consistent with the demands of the new viable tissues. These features are encompassed by the phenomena that are collectively called biocompatibility. However, the theories and putative mechanisms of conventional biocompatibility (mostly conceived through experiences with implantable medical devices) are inadequate to describe phenomena in tissue-engineering processes. The present author has recently redefined biocompatibility in terms of specific materials- and biology-based pathways; this opinion paper places tissue-engineering biocompatibility mechanisms in the context of these pathways.     

Wear Performance of Dental Materials: A Comparison of Substructure Ceramics,Veneering Ceramics,and Non‐Precious Alloys

The aim of this in vitro study was to compare the two‐body wear resistance of different dental ceramics and non‐precious alloys. Two‐body wear tests were performed in a chewing simulator with steatite antagonists. A pin‐on‐block design with a vertical load of 50 N for 1.2 × 10⁵ cycles (f = 1.6 Hz; lateral movement: 1 mm, mouth opening: 2 mm) was used for the wear test. Surface roughness R_a (SP6, Perthen‐Feinprüf, G) and wear depth were determined using a 3D‐Profilometer (Laserscan 3D, Willytec, G). Scanning electron microscopy (Quanta FEG 400, FEI, NL) was applied for evaluating wear performance of both, materials and antagonists. Statistics: one‐way ANOVA (α = 0.05). The in vitro wear test showed that the wear performance of dental materials is strongly influenced by the type of material (ceramic, zirconia, or alloy). Zirconia and alloy provided low wear in contrast to glass‐ceramic systems. In contradiction to common expectations, hard zirconia and alloy systems showed even lower antagonistic wear than glass‐ceramics.     

不同材料包裹的肝素缓释微囊生物相容性评价

制备了三种包覆材料不同的肝素微胶囊，研究了它们的缓释速度。然后把三种肝素微量与聚乳酸制成复合材料，研究其生物相容性，结果表明，胶囊中壳聚糖的加入使微量的释放速度变慢。三种微囊与PLA的复合材料经皮肤刺激试验、皮内刺激试验、热原试验、全身急性毒性试验和细胞培养试验，结果表明，所制备的复合材料在生物学评价试验中均星阴性反应，材料无明显毒性，材料中不存在潜在致敏性物质，所合热原含量符合生物体的要求。肝素缓释微胶囊／PLA复合材料符合三维多孔材料的要求，又具有优良的生物相容性。     

琼脂糖的疏水化改性及生物相容性

采用乙酸酐对琼脂糖进行疏水性改性,合成了具有生物活性的琼脂糖醋酸酯.通过红外光谱(FT-IR)、13C核磁共振(13C-NMR)、原子力显微镜和接触角仪对琼脂糖醋酸酯进行了表征.结果表明,琼脂糖C6上引入了乙酰基,随取代度增大,琼脂糖醋酸酯膜表面粗糙度增大,疏水性增强.纺成丝后在水中不溶胀,形态保持完好,吸湿率最小可达...     

碳/碳复合材料的生物相容性及生物应用

碳／碳复合材料继承了碳大有的生物相容性，又具有优良的力学性能，在生物医用材料领域有很大的应用前景。本文总结了医用碳碳／复合材料的研究现状，评述了碳／碳复合材料的生物相容性特点，并详细讨论了碳／碳复合材料生物医用所涉及到的模量、界面及表面改性等问题，对碳／碳复合材料的医用前景进行了展望。     

铝合金时效成形及时效成形铝合金

介绍了铝合金时效成形的方法、基本原理、工艺特点及应用情况,概括了国外研究铝合金时效成形工艺及相关可时效成形铝合金的现状,重点阐述了时效成形对铝合金微观组织结构的影响.