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  • 1
    Electronic Resource
    Electronic Resource
    Interface mechanics of porous titanium implants (1981)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 15 (1981), S. 73-82 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The interfacial shear properties of bone tissue growth into porous coated Ti-6A1-4V femoral implants have been examined as a function of the pore size of the porous surface. Three particle size range powders (297 μm, 420-500 μm, 595-707 μm) were used to fabricate cylindrical implants which were inserted into the femoral medullary canal of dogs for 6 months. Push-out tests on the removed femurs are reported and reveal: (i) that those implants residing in cortical bone exhibited significantly higher shear properties than the equivalent implants in cancellous bone and (ii) that the interfacial shear strength and stiffness decreased with increasing pore diameter within the range 175-325 μm. The extent of bone ingrowth into the surface of the implants was measured using quantitative optical microscopic techniques. This indicated that the percentage of bone which had grown into the surface was inversely proportional to the square root of the pore size and that further the shear properties of the interface were proportional to the extent of bone in-growth.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820150111
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  • 2
    Electronic Resource
    Electronic Resource
    Fatigue of acrylic bone cement-effect of frequency and environment (1989)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 23 (1989), S. 819-831 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: This study was conducted to investigate some fundamental fatigue testing variables as they apply to the response characteristics of acrylic bone cement. Cyclic loading under load control was conducted at frequencies of 1, 2, 5, 10, and 20 Hz in air at room temperature. At a tensile stress range of 0.3-20.0 MPa the fatigue life increased linearly with logarithmic frequency. The effect of conditioning and testing in saline at both room temperature and 37°C at similar stress levels and a frequency of 10 Hz were also examined. When compared to dry testing at room temperature, testing in saline at 37°C resulted in a reduction in fatigue life while testing in saline at room temperature produced an increase in fatigue life. Of a number of statistical distributions considered, the Weibull was found to be the most appropriate in documenting the findings of this investigation. A companion fractographic investigation of the failure surfaces demonstrated distinct regions of crack growth and fast fracture.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820230802
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  • 3
    Electronic Resource
    Electronic Resource
    Design and fabrication of two types of artificial tendons for evaluation of surgical techniques (1975)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 9 (1975), S. 149-155 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Double-loop tendons of fixed and adjustable lengths, and tendons with inner porous tapes both for anastomosis to tendon stumps have been made from readily available materials. By using stainless steel wire and polymer fibers, breakloads have been obtained that range from 20 to 100 lb and elongations have been reduced to less than 2%. Pore sizes up to 50 × 250 μ2 were achieved by using woven, knitted, and braided polyester tapes. For all tendons, Silastic was used to isolate inner fibers and to effect smooth gliding. Preliminary evaluation of these devices, after being implanted in the feet of chickens for 4 weeks, indicates that anastomotic strength of unions formed by use of loops is about 1000 g compared to more than 2000 for unions formed by tissue ingrowth.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820090418
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  • 4
    Electronic Resource
    Electronic Resource
    Amount and surface structure of albumin adsorbed to solid substrata with different wettabilities in a parallel plate flow cell (1990)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 24 (1990), S. 1599-1614 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: In this article we studied the adsorption of serum albumin to substrata with a broad range of wettabilities from solutions with protein concentrations between 0.03 and 3.00 mg · mL-1 in a parallel-plate flow cell. Wall shear rates were varied between 20 and 2000 s-1. The amount of albumin adsorbed in a stationary state was always highest on PTFE, the most hydrophobic material employed and decreased with increasing wettability of the substrata. Increasing stationary amounts of adsorbed albumin were observed with increasing wall shear rates at the lowest protein concentration. Inverse observations were made at the highest protein concentration. Transmission electron micrographs of replicas from the albumin-coated substrata showed that proteins were mostly adsorbed in islandlike structures on the hydrophobic substrata. The tendency to form islandlike structures was shear rate- and concentration-dependent and disappeared gradually going to more hydrophilic substrata. On glass, the most hydrophilic material employed, a homogeneous, well distributed, fine knotted, reticulated structure was found. In conclusion, this study demonstrates that both the amount of adsorbed albumin as well as the surface structure of the adsorbed proteins are regulated by the substratum wettability. This observation may well account for the fact that substratum properties can be transferred by an adsorbed protein film to the interface with adhering cells or microorganisms.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820241205
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  • 5
    Electronic Resource
    Electronic Resource
    Biological evaluation of the effect of magnetron sputtered Ca/P coatings on osteoblast-like cells in vitro (1995)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 29 (1995), S. 967-975 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A rat bone marrow cell culture was used to evaluate the osteogenic potential of amorphous and crystalline thin calcium phosphate (Ca/P) coatings. The coatings were deposited on titanium discs using a radiofrequency magnetron sputter procedure. Amorphous and crystalline plasma spray Ca/P coated and noncoated titanium discs served as reference material. The cellular behavior was analyzed with quantitative (attachment and proliferation rates) and qualitative (scanning electron microscopy) techniques. No significant differences were found in cell attachment and proliferation rates between the various materials. Scanning electron microscopy showed extracellular matrix formation after 18 days of culture on amorphous plasma-sprayed and the two types of magnetron sputtered coatings. Furthermore, no severe degradation of the magnetron sputtered coatings was observed. They even appeared to induce apatite formation. On basis of the results, we conclude that magnetron sputtering appears to be a promising method to manufacture bioactive ceramic coatings. © 1995 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820290808
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  • 6
    Electronic Resource
    Electronic Resource
    Selection and interaction of biomaterials used in the construction of cardiac bioprostheses (1998)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 39 (1998), S. 568-574 
    Details
    ISSN: 0021-9304
    Keywords: biomaterial ; bioprostheses ; suture ; pericardium ; heart valves ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The mechanical behavior of calf pericardium employed in the manufacture of cardiac bioprostheses was assessed according to the region from which it was selected. For this purpose, selected samples of the tissue were sewn with different types of commercially available sutures and subjected to tensile testing, the results of which were compared with the findings in selected, but not sutured, tissue used as a control. The results confirm a loss of resistance - that is, a reduction of the capacity of sutured samples of the biomaterial to withstand breakage stress compared with control samples. Taking into account the marked resistance to breakage of the suture thread, this phenomenon can only be explained as a consequence of the deleterious mechanical interaction between the suture and chemically treated pericardium. This interaction is illustrated by the shearing force which is responsible for the loss of resistance in the tested samples. These trials demonstrate that the results can be improved and the deleterious interaction diminished, although not eliminated, when the pericardium is selected from a given region. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 39, 568-574, 1998.
    Additional Material: 5 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    An evaluation of bone growth into porous high density polyethylene (1976)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 10 (1976), S. 311-323 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The purpose of this investigation was to study bone growth into porous polyethylene rods as a function of time and pore structure. Previous studies have indicated the biocompatibility of solid polyethylene materials which are currently being used clinically. Porous polyethylene rods were implanted in the femurs of mongrel dogs which were sacrificed four, eight, and 16 weeks postoperatively. The implants were then sectioned and examined histologically and microradiographically. Quantitative techniques were employed to determine the amount of bone ingrowth as a function of time and pore size. The pore structures of the materials were evaluated using optical microscopy and mercury intrusion porosimetry.The results of this investigation have demonstrated that porous polyethylene is capable of accepting bone growth into pores as small as 40 μm. The optimum rate of bone ingrowth was observed in pore sizes of approximately 100 to 135 μm, with no increase in the rate of bone ingrowth observed in samples possessing larger pore sizes. No adverse tissue response was found at implant times up to 16 weeks in pore sizes of 100 μm or larger.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820100212
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  • 8
    Electronic Resource
    Electronic Resource
    Use of tricalcium phosphate or electrical stimulation to enhance the bone-porous implant interface (1986)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 20 (1986), S. 65-77 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Implant stabilization by biologic ingrowth into a porous surface offers a durable method of prosthetic fixation. These systems, however, lack the immediate stability offered by the use of acrylic bone cement. The interface strength of porous coated Co—Cr—Mo in a canine model does not approach that of acrylic bone cement until two weeks postoperatively. It is expected that this would be a minimum time period in clinical applications. Both chemical and electrical means have been advocated as methods to affect tissue ingrowth. A study using a canine model was undertaken to determine tissue ingrowth rates utilizing examples of these two methods: (1) impregnation of the porous structures with tricalcium phosphate powder (TCP); or (2) the application of an electrical stimulator to the implant with the implant itself serving as the cathode. Ten implants were coated with TCP, two each at weekly intervals from 1 to 5 weeks. Plain porous rods were likewise implanted, serving as the controls. While histology did reveal a slightly more dense bony structure, the interface bond strength was not affected by TCP. Electrical stimulation of the implant was similarly investigated with an additional time period of 10 weeks. Compared to the controls, the electrically stimulated implants reveal no statistically demonstratable difference in interface strength. Histologic specimens indicate larger areas of calcification than are observed in the controls.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820200107
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  • 9
    Electronic Resource
    Electronic Resource
    Interfacial phenomena: An in vitro study of the effect of calcium phosphate (Ca-P) ceramic on bone formation (1998)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 40 (1998), S. 464-474 
    Details
    ISSN: 0021-9304
    Keywords: calcium phosphate coatings ; magnetron sputtering ; osteoblast ; in vitro ; bone ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: In previous studies we developed a RF magnetron sputter technique for the production of thin Ca-P coatings. With this technique coatings can be produced that vary in Ca/P ratio as well as in structural appearance. The aim of this investigation was to obtain more understanding of the biological behavior of these coatings by way of in vitro experiments. The effect of noncoated titanium (Ti) and three different Ca-P-sputtered surfaces on the proliferation and differentiation (morphology and matrix production) of osteoblast-like cells was studied. Proliferation was determined using counting procedures; morphology was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Fluorescent markers and energy-dispersive X-ray microanalysis (EDX) were used to obtain quantitative and compositional information about the resultant calcified extracellular matrix (ECM). Results demonstrated that proliferation of the osteoblast-like cells was significantly (p 〈 0.05) higher on noncoated than on Ca-P-coated samples. On the other hand, more mineralized ECM was formed on the coated surfaces. In addition, TEM confirmed that the cells on the coated substrates were surrounded by ECM with collagen fibers embedded in crystallized, needle-shaped structures. On the basis of these findings, we concluded that: (1) the investigated Ca-P sputter coatings possess the capacity to activate the differentiation and expression of osteogenic cells, and (2) bone formation proceeds faster on Ca-P surfaces than on Ti substrates. Further, this bone-inductive effect appeared to be dependent on the Ca-P ratio of the deposited coatings. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 40, 464-474, 1998.
    Additional Material: 14 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Evaluation of plasma-spray and magnetron-sputter Ca-P-coated implants: An in vivo experiment using rabbits (1996)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 31 (1996), S. 329-337 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The bone response to different plasma-spray and magnetron-sputter calcium phosphate (Ca-P)-coated implants was evaluated in a rabbit animal model. Four types of Ca-P coatings have been investigated: a plasma-spray Ca-P coating (HA-PS), a heat-treated plasma-spray Ca-P coating (HA-PS/ht), an amorphous magnetron-sputter coating (Ca-P-a), and a crystalline magnetron-sputter coating (Ca-P-c). Seventy-two specially designed cylindrical implants were inserted in the lateral and medial femoral condyles of 18 New Zealand White rabbits. The four differently coated implants were positioned in one animal according to a split-plot design. After implantation periods of 3, 6, and 9 weeks, the bone-implant interface was evaluated histologically. Besides descriptive light microscopical evaluation, quantitative histomorphometrical measurements were done to determine bone contact and the amount of bone surrounding the implant-bone interface.Light microscopical examination revealed that all types of coatings followed the same process of bone healing. Measurements of bone contact at 6 and 9 weeks did not reveal significant differences between the various coatings. For the amount of bone, in a circular region at a certain distance from the implant, the Ca-P-c-coated implants showed a significantly greater amount of bone after 6 weeks of implantation than did the other three Ca-P coatings. At 9 weeks this difference could no longer be measured.On the basis of these findings we concluded that magnetron-sputtered Ca-P coatings show the same process of bone healing as the plasma-sprayed Ca-P coatings when inserted into the trabecular femoral bone of rabbits. © 1996 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
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