摘要:

AbstractCyclic polarization curves obtained for a cobalt‐base casting alloy (similar to Vitallium Surgical Alloy) and for 316L stainless steel show that the cobalt‐base alloy exhibits a high (noble) protection potential whereas the stainless steel exhibits a low (active) protection potential. It is suggested that the resistance to crevice corrosion of Vitallium Surgical Alloy results from its high value of protection potential whereas the susceptibility of 316L stainless to severe crevice corrosion results from its low value of protection potent

ISSN:0021-9304    

DOI:10.1002/jbm.820090302

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractA streaming potential experiment was conducted onin vitrobone to determine the effects polyvalent salts have on bone zeta potential. Polyvalent metal salts would be introduced into local physiological electrolytes by corrosion of a metal implant or dissolution of a ceramic implant. It was hypothesized that a change in zeta potential of mineralized tissue, resulting from the introduction of polyvalent salts, could be a cause of tissue instability at the implant interface. Zeta potentials measured in bone were on the order of a few millivolts. Strongly hydrolytic metal cations such as Al+3and Fe+3did not have sufficient activity in buffered neutral electrolytes to alter bone zeta potential. Results suggest that less hydrolytic cations of high valence, and large polarizable anions may affect bone zeta potential.

ISSN:0021-9304    

DOI:10.1002/jbm.820090303

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractThe level of residual ethylene oxide after sterilization was evaluated as a function of aeration time for three medical grade tubings. Toxicity resulting from residual ethylene oxide was determined in anin vitrotissue culture system utilizing L‐cells. The absorption and desorption of ethylene oxide from poly(vinylchloride) and polyether–polyurethane tubing were similar. In contrast, silicone tubing absorbed 85% less ethylene oxide. The time required for desorption of residual ethylene oxide was 2 hr for silicone tubing and 7 to 8 hr for poly(vinylchloride) and polyether–polyurethane tubing. Tubing samples containing 1,500 ppm or more residual ethylene oxide elicited toxic tissue culture reactions whereas samples containing 900 ppm or less showed no toxic tissue culture res

ISSN:0021-9304    

DOI:10.1002/jbm.820090304

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractModified collagen membrane when compared to autograft, homograft, heterograft and silicone polymer memberane, demonstrated a superior adherence on split and full‐thickness surfaces, but proved to be an inferior covering for granulating surfaces. Water vapor transport was found to be adequate and adaptable to modification. It was found to be permeable to most commonly used topical antibiotics, and no significant antigenicity could be demonstrated. In a controlled animal burn study, modified collagen membrane proved superior to homograft and heterograft in regard to mortality, time to grafting, bacteriology and autograft take. These studies provide a background for further laboratory and clinical studies now in progres

ISSN:0021-9304    

DOI:10.1002/jbm.820090305

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractA cobalt based alloy, MP35N, with excellent mechanical properties has been recently introduced as a material for surgical orthopedic implants.A study was made of local and systemic host response to this material in two different mammal species. The implantation time ranged from one to 12 months.The result of this study indicated: MP35N produces a degree of local tissue response comparable to that of 316L stainless steel. No sytemic side effects were observed during the implantation times included in this study.

ISSN:0021-9304    

DOI:10.1002/jbm.820090306

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractThe wettability characteristics of the contact lens material, PHEMA, with respect to water have been determined by using the sessile drop, and the captive air bubble techniques of contact angle goniometry. It is concluded that on PHEMA gels water does not spread spontaneously. Large hysteresis has been observed in the advancing and receding contact angles. This suggests that this hydrogel surface is capable of changing its free energy through reorientation of the polymer side chains and chain segments depending on the nature of the adjacent phase. The water content of the gels does not appear to have an effect on water wettability in the hydration range investigated. The minor wettability differences among the various gels studied were most likely due to differences in surface structure and segmental mobility due to inherent variations in the method of preparation. Small but consistent differences were found between the contact angles measured by the captive bubble method and those obtained by the sessile drop method, the former values being higher. These differences may not be method‐related artifacts and cannot be explained at the present tim

ISSN:0021-9304    

DOI:10.1002/jbm.820090307

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractA segmented polyether urethane was used as the blood contacting surface in a series of 10 heart assist devices implanted in calves for periods up to 35 weeks. At termination, each was examined to correlate blood compatibility and device performance with surface properties, chemical purity, physical stability and affinity for lipid absorption.

ISSN:0021-9304    

DOI:10.1002/jbm.820090308

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractWear testing should be an important part of the investigations into the physical and mechanical properties of some dental materials. It has, however, largely been ignored because of conflicting and unreproducible results. It was decided, therefore, to review the work done by other researchers and to examine the human masticatory cycle, and then present new parameters to design and construct a new dental abrasion testing machine. This new machine is described in detail and its capabilities briefly illustrated.

ISSN:0021-9304    

DOI:10.1002/jbm.820090309

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractImplantable, sustained release drug delivery devices offer benefits not obtained through oral ingestion or injection. These include delivery at a constant therapeutic rate, thus avoiding adverse intermittent and massive dose effects, as well as reliance upon patients taking their prescribed dosages. The drawbacks to their widespread acceptance have been their inability to maintain a zero‐order release rate over an extended period of time and poor biocompatibility. Devices capable of satisfying these requirements have been developed and tested extensively forin vitrorelease of the narcotic antagonist cyclazocine. By using implant models prepared from Hydron, a hydrophilic polymer known to exhibit excellent tissue compatibility, we have found that the release rate could be precisely regulated by proper geometry, copolymer composition, concentration of ionogenic groups and cross‐link density. Devices in such varied forms as capusles, barrier‐film coated tablets and bulk polymerized rods have been testedin vitrofor periods approaching 1

ISSN:0021-9304    

DOI:10.1002/jbm.820090310

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

ISSN:0021-9304    

DOI:10.1002/jbm.820090311

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY