ISSN:0021-9304    

DOI:10.1002/jbm.820130602

出版商:John Wiley&Sons, Inc.    

年代:1979

数据来源: WILEY

摘要:

AbstractGreep values of amalgam have been thought to be typical and nearly equal to their order of magnitude, depending on composition and particle shape. Recently it has been shown that trituration time may cause changes in creep magnitudes. The type of mixer and its frequency have contributed additional variabilities. These variations could not be related consistently to changes in creep values. Increases in condensation pressure did contribute to more predictable and constant values found with different mixing times.

ISSN:0021-9304    

DOI:10.1002/jbm.820130603

出版商:John Wiley&Sons, Inc.    

年代:1979

数据来源: WILEY

摘要:

AbstractArtificial tooth roots with porous surface coatings were fabricated by sintering spherical powder of titanium alloy to solid cylindrical cores. The tooth roots were implanted subgingivally in healed mandibular premolar extraction sites of fifteen Rhesus monkeys. Supracrestal abutments were screwed into pretapped holes in the superior aspect of the primary subgingival stage four to eight weeks after implantation of the root. Clinical evaluations were performed monthly. Ten animals were sacrificed for histological evaluation of the functioning free standing implants. Of twenty‐nine implants placed, three were lost and four were rated failures on the basis of histological evaluation. Postmortem evaluations revealed bone growth into the porous surface coating of the primary stage of all the implants. The most characteristic features which could be used to describe differences in the implant histology were the buccal and lingual crestal bone heights measured in relation to the root porosity. Twelve of sixteen implants had crestal bone heights within one millimeter of the superior aspect of the root. Four other implants displayed excessive bone recession, revealing as much as one half of the root porosity supracrestally. The four implant failures could be related to unfavorable features of recipient bone sites. The results demonstrate that the bone growth into the porous surface coatings of artificial tooth roots is an efficacious method of dental implant fixatio

ISSN:0021-9304    

DOI:10.1002/jbm.820130604

出版商:John Wiley&Sons, Inc.    

年代:1979

数据来源: WILEY

摘要:

AbstractTo examine the quantitative change in the γ2 phase, specimens of three conventional, four dispersed‐phase and two ternary amalgams were prepared. A higher energy amalgamator caused more γ2 phase to be formed in conventional amalgam and less in the dispersed‐phase material. With storage at 37°C this γ2 phase decreased quantitatively in dispersed‐phase amalgams over one week but not in conventional amalgams. The selective etch system of γ2 did not disclose this phase in the ternar

ISSN:0021-9304    

DOI:10.1002/jbm.820130605

出版商:John Wiley&Sons, Inc.    

年代:1979

数据来源: WILEY

摘要:

AbstractThe kinetics of attachment of NIL B and SV‐NIL cells to glass, siliconized glass, and surfaces coated with random copolypeptides have been studied. It was found that in the absence of serum proteins, neither the rate nor the extent of attachment of cells is affected by the nature of the surface. In the presence of bovine serum albumin, the total uptake and rate of attachment of both NIL B and SV‐NIL cells to the neutral, hydrophobic, and negatively charged copolymers is decreased compared with attachment to the same surfaces in the absence of protein. In contrast, the attachment of NIL B and SV‐NIL cells to the positively charged (lysyl) copolymers was not decreased in the presence of protein. It was shown that the effect of protein resulted from its adsorption to the surface rather than to the cells. It was also concluded that both the NIL B and SV‐NIL cells consist of a single cell population with respect to adhesiveness, and that both cell lines reach a kinetic equilibrium with the surfaces. This work represents one of the first studies to vary copolypeptide compositions systematically from negatively to neutral to positively charged surface and to examine these substrates without any mediating effects from various serum proteins. The results of this study support the concept that while cells bind to an adsorbed layer of protein rather than directly to the surface, the underlying surface can modify the attachment process by its effect on the protein a

ISSN:0021-9304    

DOI:10.1002/jbm.820130606

出版商:John Wiley&Sons, Inc.    

年代:1979

数据来源: WILEY

摘要:

AbstractA dimensional change occurs during the setting of a dental amalgam. A measurement circuit, which makes it possible to register these changes, is introduced. To this purpose strain gages were used. The registration instrument is tested by comparing different dental amalgam products.

ISSN:0021-9304    

DOI:10.1002/jbm.820130607

出版商:John Wiley&Sons, Inc.    

年代:1979

数据来源: WILEY

摘要:

AbstractThe adsorption of blood proteins onto various surfaces in contact withflowingblood plasma or serum has been investigated using Fourier Transform infrared spectroscopy (FT‐IR) coupled with attenuated total reflection (ATR). Comparison of adsorption from a static versus a flowing blood plasma system indicated that a greater amount of protein was adsorbed when the static system was employed, but desorption was observed with the static system and not in the flowing system. When plasma and serum were compared in terms of amount and type of protein adsorbed, little difference was noted in either kinetics of adsorption or stability of the adsorbed layers. Variations in the ratios of infrared adsorption bands (from either plasma or serum) indicate that changes occur during the adsorption process in the protein layers. A comparison of poly(vinyl chloride) to germanium as the protein adsorbing surface in the static system showed differences in terms of the composition of the adsorbed layer

ISSN:0021-9304    

DOI:10.1002/jbm.820130608

出版商:John Wiley&Sons, Inc.    

年代:1979

数据来源: WILEY

摘要:

AbstractA resonance frequency technique was applied to determine the elastic modulus of hydroxyapatite. A Free—Free Vibration Transducer was designed to determine elastic modulus in a longitudinal direction. A Fixed—Free Vibration Transducer was also designed to study elastic modulus of materials where specimens longer than 3 cm in length were not available. Six lots of hydroxyapatite were prepared utilizing the same process. The elastic modulus of hydroxyapatite varied between 3.94 × 1010(dyn/cm2) and 6.30 × 1010(dyn/cm2) in a longitudinal direction. For the same six lots, it varied between 1.95 × 1010(dyn/cm2) and 3.20 × 1010(dyn/cm2) in a cross direction. The elastic modulus values of cortical bone from dog tibias, fibulas, and femurs were also det

ISSN:0021-9304    

DOI:10.1002/jbm.820130609

出版商:John Wiley&Sons, Inc.    

年代:1979

数据来源: WILEY

摘要:

AbstractGlucose oxidase, catalase, and bovine serum albumin were co‐immobilized with glutaraldehyde around a platinum screen or around a single platinum—iridium wire. The potential difference between this dual enzyme electrode and a Ag/AgCl reference electrode was proportional to the logarithm of the glucose concentration over the range from 10 to about 150 mg glucose per 100 ml in buffered solution at pH 7.4 and 37°C. The enzyme electrode responded in serum only if coated with a semipermeable film, such as cellulose acetate, to exclude serum macromolecules. The potentiometric results were similar to those obtained with the two enzymes co‐immobilized in polyacrylamide gel around a platinum screen or with only one of the enzymes, glucose oxidase, covalently coupled to a platinum screen. The results so far suggest that these potentiometric enzyme electrodes may have sufficient specificity for glucose for development of a continuousin vivoglucose

ISSN:0021-9304    

DOI:10.1002/jbm.820130610

出版商:John Wiley&Sons, Inc.    

年代:1979

数据来源: WILEY

摘要:

AbstractDacron velour and knit prostheses were compared with respect to long‐term patency when used as canine aortic implants. These grafts were rated, according to the average numerical value of six equally weighted criteria, in decreasing order of performance: velour I, velour II, circular knit III, velour IV, circular knit V, warp‐knit VI, warp‐knit VII and VIII, warp‐knit IX and warp‐knit X. In general, compacting and crimping methods using halogenated hydrocarbons produced the least successful grafts. Grafts of identical brand but compacted and crimped by different methods exhibited different patencies. No true healing of any of the grafts was observed. Layered deposits of inner fibrous capsule were formed at rates and thicknesses c a acteristic for each type of graft employed. A functioning Dacron femoral‐popliteal bypass removed from a human after 9 months exhibited inner and outer fibrous capsules similar to those from cani

ISSN:0021-9304    

DOI:10.1002/jbm.820130611

出版商:John Wiley&Sons, Inc.    

年代:1979

数据来源: WILEY