不同杆圈接触形态对焊接面机械性能影响的研究

目的:探讨不同的杆圈接触形态对杆卡附着体焊接面机械性能的影响。方法:利用特殊工具加工不同杆圈接触形态的试件。测量焊接间隙,使用相同的Nd:YAG激光焊接参数进行焊接;肉眼观察焊缝区外观,测试焊件的抗拉强度,使用扫描电镜观察,比较不同的杆圈接触形态对焊接面机械性能的影响。结果:各实验组均未能实现全层焊透,无明显气孔等焊接缺陷。实验组与对照组伸长率与母材组对比显著降低,但在抗拉强度上不存在显著性差异(P<0.05)。结论:当焊接参数相同时,杆圈接触的形态未对焊接面的机械性能产生显著性影响。     

Effect of various surface treatments on the retention properties of titanium to implant restorative cement

There are conflicting results in the literature and divergent manufacturers' recommendations concerning the retention properties of implant restorative cements, and they can provide inadequate retention of implants, especially short or single implants. The objective of this study was to investigate the effects of sandblasting and different types of laser irradiation on the interfacial bond between titanium and resin cement through shear testing. A total of 60 samples (10?mm in length and 12?mm in diameter) were cut from titanium rods. The samples were divided into four equal groups according to the surface treatment: control, sandblasted, Nd:YAG laser-irradiated, and Er:YAG laser-irradiated. After surface treatment, the implant restorative cements were applied to the titanium samples which were stored in distilled water at 37°C for 24?h. The samples were then subjected to shear bond strength testing using a universal testing machine with a crosshead speed of 1?mm/min. The data were analysed with the Kruskal-Wallis and Mann-Whitney U tests (α?=?0.05). The highest mean bond strength was observed in the control group, followed by the sandblasted group. A statistically significant difference in shear bond strength was found between the sandblasted group and both the laser-irradiated groups (p?相似文献   

The bone-implant interface: a dynamic surface.

This study quantifies and compares bone formation on and around roughened titanium implants with roughened cobalt chromium, polished solid implants, and titanium fibermetal implants. Cylindrical rods were implanted into the medullary canal of the distal femur of rabbits. The bone-implant interface was studied 3, 6, and 12 weeks after surgery using histomorphometric methods. Roughened surface implants demonstrated significantly more bone directly apposed to the surfaces when compared to the polished or fiber/metal implants at 6 and 12 weeks after surgery. New bone formation and remodeling of bone occurred directly on roughened surfaces as late as 12 weeks after implantation, but not on the unroughened implants. These results suggest that roughening of the surfaces of both titanium and cobalt chromium implants can enhance osseointegration and may be useful clinically for the fixation of prosthetic components.     

钛金属材料表面微形态对兔成骨细胞生物学行为的影响

目的 体外观察钛金属材料不同表面微形态对兔成骨细胞生物学行为的影响.方法 采用激光扫描、喷砂、机械加工和抛光技术在钛金属基片上制备四种不同的表面微形态,激光扫描表面(LS)为50μm宽度的平行微沟槽,机械加工表面(MS)为100 μm宽度大环形沟槽,两种表面均为规则纹理,喷砂表面(SS)为完全粗糙表面,抛光表面(PS)为光滑表面;扫描电镜观察表面形态特征并测定表面形态的粗糙度(Ra),分别在不同基片表面接种兔成骨细胞,培养12 d,测定细胞24 h黏附情况、12 d增殖情况、11 d碱性磷酸酶活性,并通过扫描电镜和荧光显微镜观察细胞形态,统计分析各组间的差异.结果 细胞黏附LS=SS>MS=PS,细胞增殖SS>LS>MS=PS,ALP活性LS=SS>MS=PS,在LS和SS表面上的细胞黏附、增殖及ALP活性均高于MS和PS表面(P<0.05).结论 钛金属材料表面微形态对兔成骨细胞的黏附、增殖、分化以及细胞形态产生影响,细胞级别的规则微沟槽表面为成骨细胞提供了一个更适合的生长环境.     

Influence of biomaterial surface texture on bone ingrowth in the rabbit femur

The purpose of this study was to examine both the histologic and the mechanical characteristics of bone apposition to an experimental surface, arc-deposited titanium, in a rabbit model and to compare them with those of four previously studied surfaces: one layer of cobalt-chromium beads, three layers of cobalt-chromium beads, plasma-sprayed cobalt-chromium, and uncoated titanium alloy. Bilateral cylindrical implants were press-fit into the lateral femoral condyles of 70 adult New Zealand White rabbits, which were allowed unrestricted activity and then killed at 6 or 12 weeks. The distal femora were harvested, radiographed, and prepared for either mechanical or histologic evaluation. All of the implants with coated surfaces had significantly greater shear strength than the implants of grit-blasted titanium alloy after both 6 and 12 weeks. After 6 weeks, maximum bone apposition occurred in the beaded surfaces. After 12 weeks, the shear strengths and bone apposition of implants of arc-deposited titanium and of one and three layers of cobalt-chromium beads were significantly greater than those of implants of plasma-sprayed cobalt-chromium and grit-blasted titanium alloy. The histologic studies correlated with the mechanical results. After 12 weeks, the bone apposition and mechanical stability of arc-deposited titanium were similar to those of a single layer of beads. There appeared to be no advantage to multiple layers of beads, and the plasma-sprayed cobalt-chromium and gritblasted titanium surfaces showed lower shear strength and bone apposition than the other groups.     

国产纯钛种植体-骨界面的离子扩散研究

目的：研究纯钛在体内的离子扩散及其产生的影响。方法：采用SEM－EDA,EDAX,TOF－SIMS等对国产纯钛种植体界面Ti^ 、Ca^2 、P^-等离子的扩散与分布进行研究。结果：距界面3μm骨组织内Ti^ 含量很高,随着距离变远,Ti^ 含量呈梯度降低,在100μm时含量已极微。骨组织内的Ca^2 、P^-、Na^ 、K^ 等同时向纯钛氧化膜内扩散。Ti^ 的扩散并未造成接触组织的炎症、毒性及致敏反应。结论：与钛接触的骨组织及纯钛氧化膜内的一些元素发生了分布上的变化,说明钛参与了组织内的生化反应过程,钛－骨之间为物理化学性结合。     

表面粗糙度对烤瓷上釉效果的影响

目的 观察上釉前陶瓷不同的表面粗糙度对其上釉后最终表面光洁度的影响.方法 将5组（n=12）烤瓷试件在注水条件下用碳化硅砂纸分别逐级打磨至220^#、320^#、600^#、800^#和1200^#,常规上釉.上釉前、后分别测量表面粗糙度Ra,扫描电子显微镜定性分析表面形貌.结果 1200^#砂纸打磨后上釉获得的表面最光滑（Ra=0.19μm）,220^#砂纸打磨后上釉的试件表面最粗糙（Ra=0.55μm）,各组陶瓷上釉前后的表面粗糙度差异具有统计学意义（P〈0.05）;扫描电子显微镜分析结果 与粗糙度仪测试结果 一致.结论 上釉前应对烤瓷表面进行细磨、抛光,以便在上釉后获得尽量光滑的表面.     

粘结面润湿度对牙本质粘结界面纳米渗漏的影响

目的：观察、比较不同粘结面润湿度对4种全酸蚀粘结剂（OptiBond Solo（OB）、Single Bond（SB）、One-Step（OS）、Prime＆Bond NT（PB））牙本质粘结界面纳米渗漏的影响。方法：选取36颗无龋坏人磨牙，用600目碳化硅砂纸在流水冲洗下预备出统一的牙本质粘结面玷污层。分别用4种全酸蚀粘结剂在不同粘结面润湿度条件下进行粘结处理。每颗牙齿垂直于粘结面切割出4个4mm&#215;0．9mm&#215;4mm粘结试件，避光贮存于氨化硝酸银溶液中24h，在TEM下观察、比较牙本质粘结界面纳米渗漏．结果：不同的粘结面润湿度条件下，4种全酸蚀粘结剂牙本质粘结界面中均可以观察到不同程度的纳米渗漏。结论：粘结面润湿度对含不同有机溶剂粘结剂的牙本质粘结界面纳米渗漏的影响程度不同。     

Effect of cortisone on cells at the bone-marrow interface

Summary A study of the association between the rate of proliferation of marrow fibroblast-like stromal cells (in vitro) and the rate of endosteal bone mineralization (EsMR) (in vivo) was undertaken in an osteopenic rat model. We report than 200 g male rats treated with cortisone acetate (5 mg/day for 7 days) exhibit decreases in marrow fibroblast colony-forming units (FCFU) and tetracycline-based measurements of EsMR at the level of the femoral midshaft. In cortisone-treated rats recovering for 1–3 weeks, the FCFU census and EsMR normalized during the first posttreatment week, remained at control levels after 2–3 weeks, and exhibited a relapse in the third week which signified only partial recovery. These changes were unrelated to patterns of body weight gain. The data indicate that the FCFU census can serve to index endosteal osteoblast vigor.     

Bone particles disturb new bone formation on the interface of the titanium implant after reaming of the marrow cavity

Histomorphometric studies were conducted in rats to determine whether bone particles would disturb new bone formation on the interface of titanium implants inserted after reaming of the marrow cavity. In eighty 10-week-old female Wistar rats, smooth-surfaced titanium alloy implants were inserted bilaterally into the marrow cavity after reaming in the distal femur. There were three experimental groups: in the irrigated femora, sterile saline was flushed through the medullary canal; in the particle femora, autologous bone particles were inserted into the intramedullary cavity; and in the reamed femora, the implant was inserted without procedures after reaming. The rats were sacrificed at one, two, four or eight weeks postoperatively, and Villanueva bone staining was applied for histomorphometric studies. The bone volume of new bone on the interface of the implant in the irrigated femora was greater than that in the particle or the reamed femora throughout the study period. The results suggest that clearance of bone particles by irrigation after reaming of the marrow cavity significantly facilitates new bone formation on the interface of implants by one week. The findings also suggest the potential clinical application of total canal irrigation prior to insertion of cementless femoral components as well as cemented prosthesis.     

Effect of chronic kidney disease on the healing of titanium implants

Chronic kidney disease (CKD) has become a worldwide public health problem. However, its effect on osseointegration of dental implants is largely unknown. The aim of this study is to investigate whether CKD impairs the quality of the osseointegration of titanium implants. Uremia was induced by 5/6 nephrectomy in mice, and serum levels of BUN, FGF23, PTH and ALP were significantly increased. For in vitro tests, bone marrow mesenchymal stem cells (BMMSCs) were obtained and cultured on titanium discs. There was no significant difference in term of expression of osteogenic marker genes including Osx, Col-1, Ocn, and Opn, as quantified by qPCR. Moreover, Alizarin Red S staining showed comparable mineralized nodules formation. Histomorphometrical analysis of experimental implants inserted in the femurs of CKD mice revealed a trend of decreased BIC ratio at 2-week healing. The strength of bone-implant integration, as measured by a push-in method, was significantly lower for the CKD group at 2 weeks, although a comparable level was reached at 4 weeks. These results demonstrated that CKD only negatively affects the osseointegration of titanium implants at the early stage.     

Berberine inhibits Staphylococcus Epidermidis adhesion and biofilm formation on the surface of titanium alloy

Biofilm formed by Staphylococcus epidermidis (S. epidermidis) is a common cause of periprosthetic infection. Recently, we have discovered that berberine is bacteriostatic for S. epidermidis. The purpose of the present study was to examine the effect of berberine on S. epidermidis adhesion and biofilm formation on the surface of titanium alloy, which is a popular material for orthopedic joint prostheses. Three strains of S. epidermidis (ATCC 35984, ATCC 12228, and SE 243) were used for in vitro experiment. Direct colony counting showed that berberine significantly inhibited S. epidermidis adhesion on the titanium alloy disk in 2 h at the concentration of 45 µg/mL. When examined with crystal violet staining, confocal laser scanning microscopy, and scanning electron microscopy, we found that higher concentrations (>30 µg/mL) of berberine effectively prevented the formation of S. epidermidis biofilm on the surface of the titanium disk in 24 h. These findings suggest that berberine is a potential agent for the treatment of periprosthetic infection. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:1487–1492, 2009     

Effect of bone porosity on the mechanical integrity of the bone-cement interface

BACKGROUND: Osteopenia is one factor that may influence the decision about the type of implant fixation to use in total hip arthroplasty. However, clinical studies generally do not associate the outcome of an arthroplasty with the degree of osteopenia. The mechanical integrity of the cement fixation of an implant may be affected by the relative degree of osteopenia, which could account for some of the variable long-term results after total hip arthroplasty performed with cement. The purpose of this study was to determine the effects of bone porosity, trabecular orientation, cement pressure, and cement penetration depth on fracture toughness at the bone-cement interface. METHODS: Trabecular bone from the proximal part of bovine femora was used with a single brand of commercial acrylic bone cement to form compact-tension interface specimens representing a range of bone porosities, orientations, and cement pressures within a clinically achievable range. All specimens were loaded to failure with use of a servohydraulic testing machine, and fracture toughness at the interface was calculated. After testing, images of a representative sample of specimens were made with use of computed tomography to measure the penetration depth of the cement into the bone. RESULTS: Significant correlations were found between fracture toughness and bone porosity, trabecular orientation, and cement pressure, with bone porosity having the strongest effect (p < 0.000015). Examination of the computed tomographic images also showed a significant correlation between fracture toughness and maximum cement penetration depth (p < 0.033), as well as significant partial correlations between maximum and mean penetration depth and bone porosity (p < 0.0037 and p < 0.0028). CONCLUSION: The fracture resistance of the bone-cement interface is greatly improved when the ability of the cement to flow into the intertrabecular spaces is enhanced.     

含氟牙膏对纯钛表面形态、光泽和色彩的影响

目的:研究含氟牙膏对纯钛表面形态、光泽和色彩的影响。方法:制备规格为11mm×11mm×2mm的纯钛试件板片10片,随机分为两组,每组5片。第1组用含氟牙膏刷洗,第2组用无氟牙膏刷洗。每组处理前后分别测量钛试件的表面粗糙度、反射率和色彩(CIEL*a*b*)值,扫描电镜观察其表面形态。结果:含氟牙膏刷洗组钛试件的反射率下降值、明度下降值和色差均大于无氟牙膏刷洗组(P<0.01),同时含氟牙膏刷洗组钛试件的表面形态改变明显大于无氟牙膏刷洗组。结论:同无氟牙膏相比,含氟牙膏对纯钛的表面形态、光泽和色彩有较大的影响。     

酸蚀时问对牙本质粘结界面纳米渗漏的影响

目的:观察、比较不同酸蚀时间对4种全酸蚀粘结剂(OptiBond Solo(0B)、Single Bond(SB)、One-Step(OS)、Prime&Bond NT(PB))牙本质粘结界面纳米渗漏的影响.方法:选取64颗无龋坏人磨牙,用600目碳化硅砂纸在流水冲洗下预备出统一的牙本质粘结面玷污层,分别选用4种粘结剂在不同粘结面酸蚀时间条件下进行粘结处理;每颗牙齿垂直于粘结面切割出4个4mm×0.9mm×4mm粘结试件,分别在TEM下观察、比较其粘结界面纳米渗漏.结果:4种粘结剂的牙本质粘结界面纳米渗漏均随酸蚀时间的延长而增加.结论:延长酸蚀时间,在牙本质粘结界面中遗留有更多的未封闭结构,加速牙本质粘结界面老化.     

Optimizing the bone cement-implant interface by hydrolysis-resistant conditioning of the metal surface]

PURPOSE: The hydrolytic degradation of the implant-cement interface has to be seen as the main reason for aseptic loosening of cemented total hip replacements. Therefore, a new method of conditioning the metallic surface was developed in order to achieve a hydrolytic-resistant bound stability between the implant and bone cement. Preliminary experimental data on test bodies are presented here. METHOD: The metallic surface of 6 pairs of cylindrical test bodies each (CoCr-alloy, circular testing surface with O 6 mm) were conditioned by the method of silicoating/silanisation to gain a covalent coupling with the applied bone cement. In order to examine the initial stability and the hydrolytic resistance of the metal-cement compound, these pairs of surface-conditioned test bodies (SCT) as well as a reference series of surface-unconditioned test bodies (SUT) were immersed for 0, 30, 90, 150 days (d) in moisture environment (physiological saline solution, 37 degrees C) after coupling with bone cement. The adhesive strength of the test bodies-(bone cement-compounds) were determined by tensile tests on an universal testing machine (Typ Z030, Zwick, Ulm) with gimbal suspension. RESULTS: At time 0 d (that was without immersion of the test bodies) the mean maximum tensile bond strength of the SCT-cement-compounds was 39.5 MPa (SD +/- 4.7 MPa) and that of the SUT-cement-compounds 37.1 MPa (SD +/- 7.3 MPa) (p = 0.575). After immersion the tensile bond strength of the SUT-cement-compounds significantly decreased to an average of 13.5 MPa (SD +/- 2.7 MPa) (30 d), 10 MPa (SD +/- 1.7 MPa) (90 d) and 12.3 MPa (SD +/- 1.4 MPa) (150 d) (p < 0.01). In contrast, the SCT-cement-compounds showed a nearly unchanged high mechanical stability with tensile bond strength values of 37.0 MPa (SD +/- 4.9 MPa) after 30 d, 36.1 MPa (SD +/- 5.0 MPa) after 90 d und 30.2 MPa (SD +/- 4.7 MPa) after 150 d (p > 0.01). CONCLUSIONS: With reservation as to further in vitro and in vivo investigations the increased hydrolytic stability of the metal-cement-bound of surface-conditioned CoCr-alloy test bodies promises an improvement of the long-term stability of cement total joint replacements.     

Effect of roughness of zirconia and titanium on fibroblast adhesion

Abstract:  The aim of this study was to investigate the adhesion (4 and 24 h) and the morphology of fibroblast Balb/c 3T3 seeded onto polystyrene, partially stabilized (ZrO₂Y₂O₃), stabilized zirconia ceramic (3YTZP), and pure titanium (Ti, grade 2). Initial cell adhesion (4 h) was greater (P < 0.05, analysis of variance and Tukey's Multiple Comparisons Test) onto ZrO₂Y₂O₃ and polystyrene than in Ti and 3YTZ. After 24 h, the number of adhered cells was similar between the biomaterials tested, but smaller than onto polystyrene (P < 0.05). Cells were more spread onto glass surface after 4 h, but after 24 h, the morphology and density of the cells were similar in all groups (SEM). Profilometry showed distinct Ra values for each material: glass coverslips and ZrO₂Y₂O₃ (0.09 µm), Ti (0.88 µm), and 3YTZP (30.93 µm). It was concluded that ZrO₂Y₂O₃ promoted the best initial adhesion, thus indicating that surfaces with Ra values smaller than 0.1 µm could be more favorable to initial adhesion.     

Laser-assisted three-dimensional surface modifications of titanium implants: preliminary data

Background: Modern implant systems used in the cervical region do not allow for the ingrowth of peri-implant mucosa. The aim of the present study was to use a laser to modify titanium implants used in that region in order to promote mucosa ingrowth, thereby creating a biological barrier against bacterial infection. Methods: A KrF-excimer laser (=248 nm) was used (=30 ns, f_max=50 Hz, E_max=1.2 J). Craters were generated, under normal atmospheric conditions or in vacuum, in the polished regions of 18 Frialit 2 implants. Surface analysis was performed using a scanning electron microscope, an energy dispersive X-ray technique, and profile analysis. Results: By adjusting the parameters used, it was possible to create canals with widths of up to 100 m and depths of 450 m. Canal morphology was influenced by the laser energy and the surrounding atmospheric conditions. Irradiation with 3,000 pulses (650 mJ per pulse) resulted in rough surfaces under normal atmospheric conditions, whereas these parameters resulted in smooth surfaces in vacuum. The surface chemistry was also influenced by the laser parameters used. Conclusion: Laser-assisted modification of titanium surfaces permits fabrication of 3-D surface modifications. The surface chemistry can also be influenced, depending upon the parameters chosen. Further studies are necessary to evaluate whether ingrowth of mucosa into the canals can be realized.     

壳聚糖表面改性钛合金材料的研究进展

钛合金材料生物性能良好,是骨科常用的内植入材料,但其骨整合性及抗菌性能较差,需进行表面改性以弥补其不足之处。壳聚糖具有良好的生物相容性及成膜性,且可作为载体将目标药物引入钛合金表面,可有效改善钛合金材料的生物学性能,增加其使用范围。本文对近几年壳聚糖表面改性钛合金材料的相关研究进行归纳总结,从壳聚糖涂层改性的方式、钛合金材料成骨性及抗菌性的改善3个方面展开论述,以期为钛合金材料涂层改性在临床中的应用提供指导依据。