Cell Adhesion and in Vivo Osseointegration of Sandblasted/Acid Etched/Anodized Dental Implants

The authors describe a new type of titanium (Ti) implant as a Modi-anodized (ANO) Ti implant, the surface of which was treated by sandblasting, acid etching (SLA), and anodized techniques. The aim of the present study was to evaluate the adhesion of MG-63 cells to Modi-ANO surface treated Ti in vitro and to investigate its osseointegration characteristics in vivo. Four different types of Ti implants were examined, that is, machined Ti (control), SLA, anodized, and Modi-ANO Ti. In the cell adhesion study, Modi-ANO Ti showed higher initial MG-63 cell adhesion and induced greater filopodia growth than other groups. In vivo study in a beagle model revealed the bone-to-implant contact (BIC) of Modi-ANO Ti (74.20% ± 10.89%) was much greater than those of machined (33.58% ± 8.63%), SLA (58.47% ± 12.89), or ANO Ti (59.62% ± 18.30%). In conclusion, this study demonstrates that Modi-ANO Ti implants produced by sandblasting, acid etching, and anodizing improve cell adhesion and bone ongrowth as compared with machined, SLA, or ANO Ti implants. These findings suggest that the application of Modi-ANO surface treatment could improve the osseointegration of dental implant.     

Effect of Plasma Treatment on Titanium Surface on the Tissue Surrounding Implant Material

Early osseointegration is important to achieve initial stability after implant placement. We have previously reported that atmospheric-pressure plasma treatment confers superhydrophilicity to titanium. Herein, we examined the effects of titanium implant material, which was conferred superhydrophilicity by atmospheric-pressure plasma treatment, on the surrounding tissue in rat femur. Control and experimental groups included untreated screws and those irradiated with atmospheric-pressure plasma using piezobrush, respectively. The femurs of 8-week-old male Sprague-Dawley rats were used for in vivo experiments. Various data prepared from the Micro-CT analysis showed results showing that more new bone was formed in the test group than in the control group. Similar results were shown in histological analysis. Thus, titanium screw, treated with atmospheric-pressure plasma, could induce high hard tissue differentiation even at the in vivo level. This method may be useful to achieve initial stability after implant placement.     

First Experimental Study of the Influence of Extracellular Vesicles Derived from Multipotent Stromal Cells on Osseointegration of Dental Implants

Herein, the aim was to study the state of the bone tissue adjacent to dental implants after the use of extracellular vesicles derived from multipotent stromal cells (MSC EVs) of bone marrow origin in the experiment. In compliance with the rules of asepsis and antiseptics under general intravenous anesthesia with propofol, the screw dental implants were installed in the proximal condyles of the tibia of outbred rabbits without and with preliminary introduction of 19.2 μg MSC EVs into each bone tissue defect. In 3, 7, and 10 days after the operation, the density of bone tissue adjacent to different parts of the implant using an X-ray unit with densitometer was measured. In addition, the histological examinations of the bone site with the hole from the removed device and the soft tissues from the surface of the proximal tibial condyle in the area of intra-bone implants were made. It was found out that 3 days after implantation with the use of MSC EVs, the bone density was statistically significantly higher by 47.2% than after the same implantation, but without the injection of MSC EVs. It is possible that as a result of the immunomodulatory action of MSC EVs, the activity of inflammation decreases, and, respectively, the degree of vasodilation in bones and leukocyte infiltration of the soft tissues are lower, in comparison with the surgery performed in the control group. The bone fragments formed during implantation are mainly consolidated with each other and with the regenerating bone. Day 10 demonstrated that all animals with the use of MSC EVs had almost complete fusion of the screw device with the bone tissue, whereas after the operation without the application of MSC EVs, the heterogeneous histologic pattern was observed: From almost complete osseointegration of the implant to the absolute absence of contact between the foreign body and the new formed bone. Therefore, the use of MSC EVs during the introduction of dental implants into the proximal condyle of the tibia of rabbits contributes to an increase of the bone tissue density near the device after 3 days and to the achievement of consistently successful osseointegration of implants 10 days after the surgery.     

等离子体引发马来酸酐水溶液聚合

研究了低温等离子体引发马来酸酐单体在水溶液中的聚合,通过红外光谱和紫外 -可见吸收光谱的分析表明有聚马来酸生成;考察了在 13 56MHz放射频率下影响马来酸酐聚合的因素,得到较优的工艺条件:单体初始质量分数为 40% ~45%,放电时间 60s、放电功率 340J、聚合温度 60℃、聚合时间 3h,马来酸酐转化率可达 32%。     

等离子体引发丙烯酰胺的水溶液聚合

运用等离子体技术对丙烯酰胺进行了水溶液中的引发聚合的研究,考察了后聚合时间,放电时间,放电功率,丙烯酰胺浓度等因素对聚合转化率以及吸水率等方面的影响。丙烯酰胺聚合时会发生自交联,生成的聚合物可以作为吸水树脂应用,其吸水率最高达２００左右,要大大高于热聚合时生成的聚合物的吸水率。     

等离子体诱导下丙烯酸在PET表面的接枝聚合

利用等离子体对聚对苯二甲酸乙二酯（PET）薄膜进行表面处理,并诱导引发丙烯酸（AAc）在其表面接枝聚合,制备了具有结合牢固、高亲水性的聚丙烯酸（PAAc-g-PET）复合膜。通过表面衰减全反射-傅里叶红外光谱（ATR-FTIR）结构表征,证明了PAAc成功接枝到PET薄膜上。通过对AAc在PET薄膜表面接枝率的动力学影响因素的系统分析,获得了高接枝率下的PAAc-g-PET复合膜的最佳实现条件。     

Comparison of Selective Laser Melted Titanium and Magnesium Implants Coated with PCL

Degradable implant material for bone remodeling that corresponds to the physiological stability of bone has still not been developed. Promising degradable materials with good mechanical properties are magnesium and magnesium alloys. However, excessive gas production due to corrosion can lower the biocompatibility. In the present study we used the polymer coating polycaprolactone (PCL), intended to lower the corrosion rate of magnesium. Additionally, improvement of implant geometry can increase bone remodeling. Porous structures are known to support vessel ingrowth and thus increase osseointegration. With the selective laser melting (SLM) process, defined open porous structures can be created. Recently, highly reactive magnesium has also been processed by SLM. We performed studies with a flat magnesium layer and with porous magnesium implants coated with polymers. The SLM produced magnesium was compared with the titanium alloy TiAl6V4, as titanium is already established for the SLM-process. For testing the biocompatibility, we used primary murine osteoblasts. Results showed a reduced corrosion rate and good biocompatibility of the SLM produced magnesium with PCL coating.     

Morphology,Composition, and Bioactivity of Strontium-Doped Brushite Coatings Deposited on Titanium Implants via Electrochemical Deposition

Surface modification techniques have been applied to generate titanium implant surfaces that promote osseointegration for use in dental applications. In this study, strontium-doped brushite coatings were deposited on titanium by electrochemical deposition. The phase composition of the coating was investigated by energy dispersive X-ray spectroscopy and X-ray diffraction. The surface morphologies of the coatings were studied through scanning electron microscopy, and the cytocompatibility and bioactivity of the strontium-doped brushite coatings were evaluated using cultured osteoblasts. Osteoblast proliferation was enhanced by the addition of strontium, suggesting a possible mechanism by which strontium incorporation in brushite coatings increased bone formation surrounding the implants. Cell growth was also strongly influenced by the composition of the deposited coatings, with a 10% Sr-doped brushite coating inducing the greatest amount of bone formation among the tested materials.     

Long-term Interactions of Circulating Neutrophils with Titanium Implants,the Role of Platelets in Regulation of Leukocyte Function

Despite the fact that different biomaterials are widely used in many biomedical applications, they can still cause side effects. Therefore, our aim was to assess neutrophil activity during the inflammatory phase of the repair process and long-term interactions between circulating neutrophils and Titanium (Ti) implants. Additionally, neutrophil in vitro response after stimulation by the extract of antimicrobial peptides (AMP extract), pentoxifylline (PTX) and some platelet-rich (L-PRP and PURE PRP) and platelet-poor (PPP) concentrates were tested. The study was conducted on eight sheep after Ti implant insertion into the tibia and revealed that the Ti implant did not cause any side effects during the course of experiment. After addition of L-PRP into neutrophils, culture activity of these cells significantly increased (p < 0.01), whereas treatment with AMP extract, PURE PRP, PPP or PTX caused decrease in neutrophil enzymatic response (on the basis of elastase, myeloperoxidase and alkaline phosphatase release) and free radical generation. These effects were observed in neutrophils isolated during the inflammatory phase as well as 4 and 10 months after implantation. Obtained results will be useful in regulation of inflammatory response during implantation of biomaterial and create possibility to modulate the cells response towards pro- or anti-inflammatory to reduce host tissue damage.     

Polymerization of halogenated anilines by plasma

This work presents an experimental study about the electric conductivity in polyanilines synthesized by plasma obtained from halogenated anilines in which chlorine or iodine atoms are bonded in meta position to the aniline rings. The objective is to study the enhancement of the electric conductivity of these structures due to the addition of electronegative atoms to the polymeric chains. The results show that the halogenated anilines produce polymers with an electric conductivity up to eight orders of magnitude higher than those of the undoped polyanilines, reaching ～10^?4 S/cm. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4682–4689, 2006     

Enhanced Properties of Dissimilar Rubber Blends Using Microencapsulated Sulfur Through Acetylene Plasma Polymerization

Surface modification of sulfur by vacuum plasma polymerization with acetylene was applied in order to modify its surface properties without losing reactivity for vulcanization. A nm‐thin layer of crosslinked polyacetylene was deposited on the surface of the sulfur powder. Its surface energy was decreased as monitored by wetting in liquids of various polarities. A delay in the onset of weight loss by sublimation in thermal gravimetric analysis was shown by the plasma‐modified sulfur. Scanning electron microscopy showed a core/shell structure of the coated sulfur. In 50:50 blends of styrene‐butadiene rubber and ethylene‐propylene‐diene rubber, the encapsulated sulfur samples resulted in pronounced improvements in the mechanical properties relative to the use of unmodified sulfur.

     

Plasma Polymerization Surface Modification of Carbon Black and its Effect in Elastomers

Surface modification of carbon black by plasma polymerization was aimed to reduce its surface energy in order to compatibilize the filler with various elastomers. A fullerenic carbon black was used for the modification process. Thermogravimetric analysis, wetting behavior with liquids of known surface tension, TEM and TOF‐SIMS were used to characterize the carbon black before and after modification. The state of plasma‐coated carbon black in rubber was studied by means of conductivity measurements. The behavior of the modified filler in rubber was studied using the Payne effect and stress/strain properties. The study shows that plasma‐coated carbon black results in a better dispersion in different rubber systems than the uncoated version.

     

电感耦合等离子发射光谱测定钛白粉中的二氧化钛

用电感耦合等离子体发射光谱(ICP-AES)法测定钛白粉中的二氧化钛,试样用硫酸和硫酸铵加热分解,盐酸溶解盐类。通过与GB1706-2006结果对照,表明,方法的RSD为0.45%。     

Antibacterial Titanium Implants Biofunctionalized by Plasma Electrolytic Oxidation with Silver,Zinc, and Copper: A Systematic Review

Patients receiving orthopedic implants are at risk of implant-associated infections (IAI). A growing number of antibiotic-resistant bacteria threaten to hamper the treatment of IAI. The focus has, therefore, shifted towards the development of implants with intrinsic antibacterial activity to prevent the occurrence of infection. The use of Ag, Cu, and Zn has gained momentum as these elements display strong antibacterial behavior and target a wide spectrum of bacteria. In order to incorporate these elements into the surface of titanium-based bone implants, plasma electrolytic oxidation (PEO) has been widely investigated as a single-step process that can biofunctionalize these (highly porous) implant surfaces. Here, we present a systematic review of the studies published between 2009 until 2020 on the biomaterial properties, antibacterial behavior, and biocompatibility of titanium implants biofunctionalized by PEO using Ag, Cu, and Zn. We observed that 100% of surfaces bearing Ag (Ag-surfaces), 93% of surfaces bearing Cu (Cu-surfaces), 73% of surfaces bearing Zn (Zn-surfaces), and 100% of surfaces combining Ag, Cu, and Zn resulted in a significant (i.e., >50%) reduction of bacterial load, while 13% of Ag-surfaces, 10% of Cu-surfaces, and none of Zn or combined Ag, Cu, and Zn surfaces reported cytotoxicity against osteoblasts, stem cells, and immune cells. A majority of the studies investigated the antibacterial activity against S. aureus. Important areas for future research include the biofunctionalization of additively manufactured porous implants and surfaces combining Ag, Cu, and Zn. Furthermore, the antibacterial activity of such implants should be determined in assays focused on prevention, rather than the treatment of IAIs. These implants should be tested using appropriate in vivo bone infection models capable of assessing whether titanium implants biofunctionalized by PEO with Ag, Cu, and Zn can contribute to protect patients against IAI.     

Adhesion improvement of polyester/aluminium interface by plasma polymerization pretreatments

Plasma polymerizations (PP) of acrylic acid (AA) and methacrylic acid (MAA) on polyester were used to improve the adhesion of the polyester/aluminium interface. It was found that this adhesion measured by the peel test method is 5-10 times higher than in the case of untreated polyester. Comparisons of the X-ray photoelectron spectroscopy (XPS) results obtained from the treated polyester, the untreated polyester and the reference spectra of poly(acrylic acid) cast from H₂O suggest that the observed adhesion improvement can be explained in terms of the formation of new functionalities at the polyester surface.     

Spheroidization of Titanium Carbide Powders by Induction Thermal Plasma Processing

Highly spherical particles of titanium carbide (TiC) have been produced by in-flight heat processing of irregularly shaped TiC powders in an aerosol reactor under argon-hydrogen and argon-helium induction thermal plasma. The spherical powders obtained by the plasma treatment consist of unagglomerated and uniform particles with mean diameters between 25 and 28.5 μm, which is smaller than the original TiC particle mean diameters (29.5 μm) because of partial evaporation of the particles during the plasma treatment. The spheroidization ratio of the treated TiC powders increases with the increase of hydrogen flow rate in plasma gases and the reduction of powder feeding carrier gas flow rate. Under certain processing conditions, the TiC powders have been completely spheroidized. The morphology and structure of individual spherical particles were examined and their formation mechanism was discussed based on calculation of heat transfer kinetics of the particles in the thermal plasma.     

反相乳液聚合法合成超高分子质量聚丙烯酰胺

采用反相乳液聚合法合成聚丙烯酰胺,通过正交实验确定最佳合成反应条件如下:反应温度为30℃、油水体积比为1∶1、引发剂加量为单体总质量的0.15％、反应时间为4h.进一步通过单因素实验对油水体积比和引发剂加量进行优化,在单体含量为15％、油水体积比为1.2∶1、引发剂加量为0.13％时,制得平均相对分子质量达1.79×1...     

种子微悬浮聚合法制备微胶囊相变材料

以苯乙烯(St)和二乙烯基苯(DVB)为壁材聚合单体,偶氮二异丁腈(AIBN)为引发剂,羟丙基纤维素(HPC)和碳酸钙(Ca CO3)为复合分散剂,用种子微悬浮聚合法制备交联聚苯乙烯(PS)包覆硬脂酸丁酯微胶囊。用扫描电子显微镜(SEM)、差示扫描热量仪(DSC)、粒度分析仪和热重分析仪(TG)表征了微胶囊的形貌和性能,考察了聚合方法、交联剂和分散剂对微胶囊形貌结构和性能的影响。结果表明,种子微悬浮聚合法制备的微胶囊呈粒径分布均匀、规整的球形结构,与常规悬浮聚合法制备的微胶囊相比,相变潜热提高了41.6%,包覆率提高15.1%;随着DVB用量的增加,壁材的交联度增大,微胶囊密封性和热稳定性提高;采用复合分散剂且m(HPC)∶m(CaCO_3)=2.2∶1时,微胶囊相变潜热提高了26.8%。     

Adhesion Properties of Rubbers Modified by Surface Active Substances

The introduction of anionic surface active substances into butadiene-styrene rubbers doubles or trebles the work of delamination (A) for fabric-rubber bonds. The increase of A is due to a rise in mechanical loss through a higher rate of relaxation of a polymer adsorbed by a filler (τ_H). A linear dependence between A and logτ_H is found.     

PET-季戊四醇共聚酯的固相聚合及其结晶性能

采用固相聚合的方法合成了一系列PET-季戊四醇共聚酯,测试了共聚酯的特性黏度随固相缩聚时间的变化,并且用差示扫描量热法研究了该体系的非等温结晶过程,采用偏光显微镜观察了其结晶形态。结果表明:季戊四醇的含量越高,PET-共聚酯的特性黏度出现先下降后上升趋势、形成支化结构的时间越早。在固相聚合反应初期,共聚酯的结晶温度上升,半结晶时间减少;但随着固相聚合时间的延长,共聚酯的结晶温度下降,形成的晶粒变小;而且,共聚酯具有二次结晶现象。