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  • 11
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 43 (1998), S. 270-276 
    ISSN: 0021-9304
    Keywords: magnetron sputtering ; calcium phosphates ; subperiosteal ; oesteogenesis ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The aim of this study was to obtain more information about the initial biological events around RF magnetron sputtered calcium phosphate (Ca-P) coatings. Therefore, uncoated and coated disks were inserted subperiosteal into the tibia of a goat. The coatings were deposited on commercially pure titanium. The thickness of the coating was 0.1 or 2.0 μm. All the as-sputtered coatings were subjected to an additional heat treatment for 2 h at 500°C. After 1 and 3 weeks of implantation the experimental disks were retrieved and prepared for histological and physicochemical analysis. The histological results demonstrated that the periosteum covered the specimens after both implantation periods. In between the periosteum and implant an acellular layer and a collagen matrix was observed. Energy dispersive spectrometry revealed that the acellular layer consisted of C, Ca, and P ions for the 0.1 μm thick Ca-P coatings. The 2 μm thick Ca-P coatings also showed the presence of sulfate ions in this layer. Only organic material was found on the titanium disks. Further, SEM showed that even after 3-week implantation, a substantial thickness of both coatings was still maintained. Thin film X-ray diffraction demonstrated that after both implantation periods, the CaP-0.1 coating was still present. FTIR of the retrieved specimens demonstrated on the coated disks the formation of additional carbonate apatite (CO3-AP) associated with an organic phase (NH2 groups). On basis of these findings we conclude that our experimental approach is very suitable for the investigation of the healing process around Ca-P coatings. Further, we again demonstrated that the initial interfacial response to Ca-P materials differs from titanium. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 43: 270-276, 1998
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 25 (1991), S. 973-989 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The aim of this study was to obtain more information about the bone reaction to titanium and hydroxypatite (HA)-coated titanium implants during the first 3 months after implantation. Therefore, uncoated and coated implants were inserted into the tibia of rabbits for various implantation periods. The histological results demonstrated that although there were no marked differences in bony reaction at the cortical level to the different implant materials, HA-coating appeared to induce more bone formation in the medullary cavity. It was also noted, that 3 months after insertion loss of coating thickness had occurred.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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  • 13
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 25 (1991), S. 1535-1545 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The objective of this study was to evaluate a new type of percutaneous device (PD) designed to be implanted in soft tissues. The new PD consisted out of: (1) a flange-shaped subcutaneous component, made from sintered titanium fiber-web, and (2) a percutaneous component, made from dense sintered hydroxyapatite. The PDs were inserted in the back of 15 rabbits. The surgical procedure was performed in two steps. In the first session the subcutaneous component was placed. In the second session, after 3-4 months the percutaneous component was fixed in the subcutaneous component. The implants were left in situ for 1 and 4 months after the second implantation session. Clinical and histological investigations were performed. It is found, that there was only a limited epidermal downgrowth in the percutaneous area. No inflammatory reaction was observed in the dermal connective tissue. Histological analysis also demonstrated that titanium fiber mesh evokes minor adverse effects of the surrounding tissues. In conclusion, these experiments have shown that stabilization of the PD in the hypodermal area by using a sintered titanium fiber-web structure favors the longevity of PDs implanted in soft tissues.
    Additional Material: 10 Ill.
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  • 14
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 27 (1993), S. 603-610 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The aim of this study was to investigate bone response to and biostability of three different hydroxyapatite (HA)-coatings. Therefore, coated and uncoated titanium implants were inserted into the tibia of rabbits. Implantation times were at 3 and 12 weeks. The histological evaluation included measurement of the amount of bone apposition to the various implant surfaces. The results demonstrated at 3 and 12 weeks no marked differences in bony reaction at the cortical level to the different implant materials. However, compared with the 3-week specimens, at 12 weeks extensive maturation of the woven bone callus had occurred. In addition, all 12-week implants induced bone formation in the medullary cavity. It was also noted that all HA-coatings showed loss of coating thickness. Quantitative determination of bone contact demonstrated that all 12-week implants showed the same high amount of bone apposition. © 1993 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 15
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 28 (1994), S. 1477-1484 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Plasma-sprayed hydroxylapatite coatings on metals such as titanium have been investigated for many years and have shown a good biocompatibility when implanted in bony tissues. Radiofrequency magnetron sputtering was used as an alternative method to deposit thin films of hydroxylapatite on titanium substrates. X-ray diffraction demonstrated that the sputtered layer was crystalline with a preferred (001) crystallographic orientation with the C-axis perpendicular to the substrate surface. Scanning electron microscopy showed that the deposited films had a uniform and dense structure. The calcium phosphate ratio varied between 1.5 and 2.0, as determined by energy-dispersive X-ray analysis. The in vitro dissolution appeared to be determined by the degree of the coating's crystallinity. © 1994 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
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  • 16
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 29 (1995), S. 1061-1069 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The trabecular bone response to noncoated and fluorapatite (FA), hydroxyapatite (HA), and hydroxyapatite heattreated (HAHT) plasma-sprayed coated implants was investigated in a goat animal model. Forty-eight cylindrical implants were inserted into the trabecular bone of the lateral and medial femoral condyles of twelve goats according to a split plot design. After an implantation period of twelve weeks, the bone-implant interface was evaluated histologically. Quantitative histomorphometrical measurements demonstrated a significant difference in bone contact between implants inserted in the lateral and medial condyles. In addition, a significant difference in bone apposition was observed between the coated and the uncoated implants. Finally, all Ca-P coatings showed reduction in coating thickness. Measurements revealed that FA and HAHT showed less reduction in coating thickness than HA coating. Despite the coating reduction, the bone remained in close contact with the implant surface. © 1995 John Wiley & Sons, Inc.
    Additional Material: 12 Ill.
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  • 17
    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.
    Type of Medium: Electronic Resource
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  • 18
    ISSN: 0021-9304
    Keywords: surface topography ; plasma etching ; cellular orientation ; focal adhesion point ; in vitro ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: During this study, microtechnology and plasma etching were used to produce gratings 1.0 (TiD01), 2.0 (TiD02), 5.0 (TiD05), and 10.0 μm wide (TiD10) into commercially pure titanium wafers. After incubation of rat dermal fibroblast (RDFs) on these surfaces for 3 days, the cells were observed with scanning electron (SEM), transmission electron (TEM), and confocal laser scanning microscopy (CLSM). Results showed that the RDFs as a whole and their stress fibers oriented strictly parallel to the surface pattern on the TiD01 and TiD02 surfaces. On the TiD05 and TiD10 surfaces, this orientation was not observed. In addition, TEM and CLSM demonstrated that the focal adhesion points (FAP) were located mainly on the surface pattern ridges. TEM revealed that FAP were wrapped occasionally around the edges of the ridges. Only the RDFs on both the TiD05 and TiD10 surfaces protruded into the grooves and possessed FAP on the walls of the grooves. Attachment to the groove floor was observed only on the TiD10 textures. Comparison of these results with earlier observations on microtextured silicone rubber substrata suggests that material-specific properties do not influence the orientational effect of the surface texture on the observed RDF cellular behavior. The proliferation rate of the RDFs, however, seems to be much higher on titanium than on silicone rubber substrata. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 40, 425-433, 1998.
    Additional Material: 13 Ill.
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  • 19
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 41 (1998), S. 41-48 
    ISSN: 0021-9304
    Keywords: plasma spray ; titanium ; surface roughness ; bone reaction ; implant ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The aim of this study was to investigate the biological and mechanical response of bone to titanium plasma-sprayed implants of different roughnesses. Three types of titanium plasma-spray coating were applied to beam-shaped implants: Ti2, Ti3, and Ti4, with a Ra of 16.5, 21.4, and 37.9 μm, respectively. An Al2O3 grit-blasted implant (Ti-un) with a Ra of 4.7 μ was used as a control. In total, 72 implants were inserted in the tibial cortical bone of nine adult female goats. These implants were evaluated histologically and mechanically 3 months after implantation. At the end of the experiment, of the 72 inserted implants, two implants (one Ti2 and one Ti4) were lost. Histological evaluation of the other retrieved implants revealed a uniform bone reaction for all implants. The unloaded plasma-spray coatings showed no signs of delamination at the implant-coating interface. Occasionally, particles of the Ti4 coating broke free and were found near the implant. Histomorphometry revealed no difference in bone contact for the different implants (P 〉 0.05). Furthermore, the push-out test showed no significant difference (P 〉 0.05). Linear regression showed no interaction between the push-out values and the roughness values (r = 0.5). On the basis of these results, it may be concluded that the used surface roughnesses did not lead to differences in bone response or mechanical attachment strength in goat cortical bone. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 41, 41-48, 1998.
    Additional Material: 9 Ill.
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  • 20
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 42 (1998), S. 266-271 
    ISSN: 0021-9304
    Keywords: calcium phosphate ; ion beam analysis ; coating ; Rutherford backscattering ; elastic recoil detection ; biomaterial ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: RF magnetron sputter deposition was used to deposit thin calcium phosphate (hydroxyapatite) layers on titanium alloy substrate material. We determined the precise amount of calcium, phosphorus, oxygen, and hydrogen in these films by combining two ion-beam analysis techniques: Rutherford backscattering spectrometry (RBS) and elastic recoil detection (ERD). Variables were power level, partial oxygen pressure, or additional water vapor. Also examined was the influence of additional bias power to the substrates during deposition and the effect of annealing on the final composition of the deposited layers. Measurements showed that the Ca/P ratio decreased with increasing oxygen pressure or decreasing sputtering power. In addition, the Ca/P ratio increased when a bias was applied to the substrates. The O/P ratio of the films decreased with additional oxygen pressure but increased when additional water vapor was applied during deposition. All as-deposited films showed a higher hydrogen content than stoichiometric HA. The hydrogen content in the films deposited with water vapor was more than 7 times higher than in the films deposited under pure argon conditions. After annealing, the hydrogen content decreased to about 3.5 at % whereas in stoichiometric HA the hydrogen content amounts to 4.5 at %. After annealing, the oxygen concentration in the film also decreased. We assume that hydrogen disappears out of the film as H2O during annealing. For the targets used in these experiments, sputter deposition at 400 W, with additional water vapor and annealing at 500°C, produced films with a stoichiometry closest to that of hydroxyapatite. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 42, 266-271, 1998.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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