摘要:

AbstractUsing rats as a model, porous discs of RPG carbon and polypropylene and polyethylene were localized subperiosteally and supraperiosteally in the skull. Bone and blood vessels grew into the discs, which had adequate pore size, when placed in direct contact with bone. No bone was generated from the periosteum. Both plastic materials were estimated to be better than carbon for use in osseous reconstructive work. More long term material‐tissue stability and reaction studies should be performe

ISSN:0021-9304    

DOI:10.1002/jbm.820090403

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractA written protocol for the investigation of candidate surgical implant materials is quite important. Biomaterials science sections of clinical protocols have been developed for porous alumina ceramic and nonporous vitreous carbon biomaterials.Published data on the properties of the biomaterials were evaluated as related to bone replacement and augmentation. Where necessary, limited laboratory studies were conducted. If decisions could not be reached with respect to a given application, animal studies were initiated. The surgeons worked with biomaterials in the laboratory and the biomaterials scientist attended the experimental surgery procedures.Biomaterials Science Laboratory nondestructive investigations including stereomicroscopic and x‐ray inspections were conducted on the vitreous carbon dental implant systems. The investigations elucidated a number of unexpected features for both implant biomaterials and the overall interaction between the different disciplines resulted in a more complete protocol for the study of these biomaterials at our Medical and Dental Cente

ISSN:0021-9304    

DOI:10.1002/jbm.820090404

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractSixteen ceramic specimens were implanted in the femur of mature rhesus monkeys. The specimens consisted of four groups of a basic calcium aluminate composition with additions of 5, 10, 15 and 20 wt% phosphorous pentoxide (P2O5). The increasing amounts of P2O5caused variations in the resorption rate, microstructure and surface characteristics of the implant. The influence of these variables on bone and tissue growth within and about the implant was investigated.After sacrifice the ceramic‐bone specimens were studied by a tetracycline‐based histological analysis, scanning electron microscopy and energy dispersive analysis.The results indicate an increase in mesenchymal cell proliferation, fibrous and bone tissue formation at the ceramic tissue interface and within the implant with increasing concentrations of P2O5.The results obtained from the study did not furnish sufficient evidence to differentiate between the direct chemical influence the increasing P2O5had on osseous tissue formation or the indirect influence that may have resulted from its effect on the ceramic microstructure and morphol

ISSN:0021-9304    

DOI:10.1002/jbm.820090405

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractBy means of the newly developed Replamineform process, the unique pore microstructures found in the skeletal calcium carbonate of certain reef corals can be replicated or reproduced with high precision in a wide variety of materials suitable for hard tissue implant and prosthetic applications. The advantages of fabricating porous biomaterials with this method include closely controlled size of both the pore diameters and the diameters of the pore interconnections, and virtually complete interconnection of the uniformly spaced pores. These properties are of great importance in implant devices, because tissue ingrowth, the stimulation of new bone formation, the suppression of undersirable scar tissue, the inhibition of adverse body responses, and firm biological fixation of the implanted material all depend upon the nature of the pore‐microstructure configuration. Replamineform preparation of Al2O3, TiO2, hydroxyapatite, silver, Co‐Cr‐Mo alloys, and polymers is described in detail, and the characterization procedures used to determine the physical and structural properties of their materials are discussed. A few of the routinely measured characteristics include (1) quantitative computerized SEM image analysis for determining the volume, size and shape distributions of the macro and microporosity and the grain size measurement of the solid: (2) nondestructive x‐radiography of specimens to reveal any internal defects; (3) mechanical strength measurements of randomly selected specimens. Experimental results up to now clearly demonstrate the superiority of microstructures imparted to metals, ceramics, and polymers with the Replamineform

ISSN:0021-9304    

DOI:10.1002/jbm.820090406

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractThe Replamineform process, a new technique for the fabrication of porous hard tissue implant materials which replicates the skeletal configuration of certain marine invertebrates, was used to manufacture 1 cm long by 0.5 cm diam cylinders. The inherent advantages of porous configurations obtained through this process are controlled, uniform pore size controlled pore‐microstructure ratio, and complete interconnection of pores. The specific materials studied were chrome‐cobalt‐molybedenum alloy, αAlO3, hydroxyapatite prepared by hydrothermal conversion, and the basic (aragonite) CaCO3skeleton of the coral genus Porities. The implants were placed in the cancellous bone of the distal femora and proximal tibiae of adult, mongrel dogs and analyzed at 8 weeks for tissue response and ingrowth. Uniformly, new bone was found to grow into the pores of these materials and become normally mineralized. These findings were determined by microradiography, scanning electron microscopy, electron microprobe analysis, and histology. No evidences of infection, rejection, or encapsulation were seen. In the case of those CaCO3implants left in place for 1 year, there was almost complete resorption of the cylinders, with both bony trabeculae and unmineralized collagen (presumably osteoid) found at the sites of ins

ISSN:0021-9304    

DOI:10.1002/jbm.820090407

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractA series of squirrel monkeys received segmental femoral replacements in a study of the strength of the interface developed between the implant and bone. Implants were either made completely of bioglass‐ceramic, or 316L stainless steel with a flame‐prayed coating of bioglass. Fracture torque, energy at fracture, and shear stress at failure were compared to values obtained from a control group of pairs of tibias. Femurs containing bulk bioglassceramic implants showed about a 25% difference in strength compared to the opposite bone, while femurs containing flame‐sprayed implants exhibited extremely low structural strength. While the strength of the metal‐glass bond was very low (<500 kgf/cm2), the bonebioglass bond was found to be at least as strong as the bioglass‐ceramic, and at least 3/4 as strong as the

ISSN:0021-9304    

DOI:10.1002/jbm.820090408

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractAging studies were done on calcia stabilized zirconia rods of 72% theoretical density to determine the effect of actual and simulated biological environments on their strength. They were aged without stress in vitro in Ringer's solution for 1, 2 and 4 weeks or in vivo in rabbits for 12 weeks. Rods aged in vitro showed mean losses in bending strength of 16, 17 and 19% respectively after 1, 2 and 4 weeks of immersion, while those aged in vivo showed a mean loss of 25%. It was concluded that the material tested would be unsatisfactory as an orthopedic replacement because of the rapid decrease in strength which occurred when exposed to actual or simulated biological media.

ISSN:0021-9304    

DOI:10.1002/jbm.820090409

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractA new grade of graphite—isotropic, fine‐grained, and of superior strength—has been produced at the Oak Ridge National Laboratory. The possibility of using this material in orthopedic implants is under study at the University of Illinois. As part of this program, plugs 1/8 in. in diam were inserted in holes drilled in the proximal femur of 2 groups of 8‐week old male rabbits. The groups were sacrificed at the end of 1 and 2 years. A single i.m. injection of achromycin was given 2 days prior to sacrifice. Thin sections of the plugs and surrounding tissue were examined by microradiography and optical microscopy (white light, polarizing, and fluorescent). All bone was normal. Minimal evidence of irritation or fibrous encapsulation a

ISSN:0021-9304    

DOI:10.1002/jbm.820090410

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractDisk‐shaped implants of spinel, alumina, mullite, zircon, a cast Co‐Cr‐Mo alloy, and ultra‐high molecular weight polyethylene (UHMWPE), were implanted in the paraspinalis muscle of 12 adult, male, white New Zealand rabbits. Prior to implantation the implants were characterized with respect to size and shape, weight and surface roughness. After periods of 1 month, 2 months, and 4 months, the rabbits were sacrificed and the tissue specimens were retrieved with the implants still intact. Histological examination of the tissues surrounding the implants along with changes in the size and shape, weight, and surface roughness of the implants were used a criteria for evaluating these materials for implant purposes.No surface degradation of any of the materials was detected using scanning electron microscopy. Fibrous tissue seemed to adhere to the UHMWPE implants more than any other material used in this study. Large amounts of fibrous tissue were also found to adhere to the cast Co‐Cr‐Mo alloy implants.The histological results indicated that within the limits of this investigation, the biocompatibility of the ceramic materials used in this study compared favorably with the clinically used Co‐Cr‐Mo alloy implants and the

ISSN:0021-9304    

DOI:10.1002/jbm.820090411

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractRoom temperature compression creep and recovery tests have been performed using samples of pure poly(methyl methacrylate) (PMMA), three commercially available poly(methyl methacrylate) cements, and several experimental cements. From these tests the influence of density, mixing procedure, particle size, methyl methacrylate‐styrene copolymer, barium sulfate, aquenous storage environments, residual monomer, molecular weight of the continuous phase, benzoyl peroxide, and N,N‐dimethyl‐paratoluidine, upon the creep behavior of PMMA cements has been determined. The important result is that lowering the porosity or residual monomer content, increasing the powder size, or adding an MMA‐styrene copolymer tends to increase the creep resistance of PMMA

ISSN:0021-9304    

DOI:10.1002/jbm.820090412

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY