摘要:

AbstractThe clinical performance of somatoprosthetic materials and some elastic impression materials has been related to their resistance to tearing. In most instances, the test method used has been tearstrengthdeterminations, many of which are notoriously sensitive to variations in specimen geometry. It has been shown that theenergyper unit area of new torn surface is independent of specimen geometry. Two relatively simple equations were found to determine the probable range of energies involved in tearing standardized trouser‐shaped specimens regardless of the elastic properties of the materials tested. The energies so obtained for three highly extensible materials were found to be relatively independent of specimen geometry within the unstretched limits specified by ASTM test No. D 1938–62T. It is, therefore, concluded that a modification of Greensmith's trousers method for determining tear energy can be conveniently applied to extensible materials of dental inter

ISSN:0021-9304    

DOI:10.1002/jbm.820020302

出版商:John Wiley&Sons, Inc.    

年代:1968

数据来源: WILEY

摘要:

AbstractEthylene oxide appears to be an ideal sterilant for many heat‐sensitive items, but there are a number of disadvantages which require caution in its usage. Ethylene oxide has some deleterious effects on certain plastics and rubber. In particular, it acts as a solvent on such acrylic plastics as Lucite and Plexiglas, and it will attack the plasticizers found in many flexible medical‐grade tubing formulations. Perhaps more significant is the fact that this sterilant can produce some serious toxic manifestations when medical plastics are not properly degassed. This paper reviews some of the toxicities already reported in the medical literature and also presents new data on the hemolysis liability of many gassterilized pharmaceutical plastics. Both human blood hemolysis studies and cell culture data on 18 different polymers suggest that plasticized vinyl plastics have the highest toxicogenic potential. Experimental data presented on the solubility and partial pressure of ethylene oxide in a homologous series of phthalic acid esters indicate that the structure and concentration of plasticizers play a major role in the selection of the most effective degassing procedures to be used following ethylene oxide sterilizat

ISSN:0021-9304    

DOI:10.1002/jbm.820020303

出版商:John Wiley&Sons, Inc.    

年代:1968

数据来源: WILEY

摘要:

AbstractThis paper reports on three investigations into the toxic potential of plastics, resins and addivtives, with emphasis on those having medical, dental, or pharmaceutical application. The following points were noted: (1) two different lots of PVC resin contained toxic material which was leachable into a biological system and an extreme eosinophilic response was noted; (2) a large group of chemical agents currently being used or having potential for use in various plastics formulations were investigated for toxic potential. As a group, the stabilizers showed the greatest degree of toxicity and if these are used in conjunction with a plasticizer in a plastic formulation, the toxic potential is greatly increased due to an increased opportunity to migrate from the plastic. It may be concluded from this work that safe plastics for medical, dental, and pharmaceutical applications can technically be manufactured. In order to protect the patient who ultimately comes in contact with the plastic device in one way or another, it behooves the concerned manufacturer to be certain his product is not responsible for injury to the user. This certianty can only be gained by an adequate and diverse evaluation program.

ISSN:0021-9304    

DOI:10.1002/jbm.820020304

出版商:John Wiley&Sons, Inc.    

年代:1968

数据来源: WILEY

摘要:

AbstractThe photometric method of clot detection has been used to measure the effect of surface contact on the later, or polymerization, stage ofin vitroblood coagulation. Preliminary evidence has been obtained for the existence of such an effect and the importance of protein adsorption and mass transfer to the interpretation of clotting rates has been underlined.

ISSN:0021-9304    

DOI:10.1002/jbm.820020305

出版商:John Wiley&Sons, Inc.    

年代:1968

数据来源: WILEY

摘要:

AbstractThein vitroviscoelastic properties of the human aorta were characterized by subjecting excised aortas of different ages to various mechanical testing procedures. A complete characterization of the properties of the human aorta was necessary in order to find a comparable synthetic material for use in a systemic simulator. Several synthetic materials were tested. One silicone rubber system had properties closely approximating those of the human aorta.

ISSN:0021-9304    

DOI:10.1002/jbm.820020306

出版商:John Wiley&Sons, Inc.    

年代:1968

数据来源: WILEY

摘要:

AbstractSymplexes of proteins were taken for comparison with biological structures like the skin of mammals. Particles of these symplexes were set into regular order by diffusing and fixing polyvalent metal ions of protons, yielding anisotropic membranes with some properties of extracellular strucutres. Determination of the symplex optimum allowed a comparison of the properties with different acid partners. Four fifths of the amino groups of the scleroproteins that could be titrated by monomeric acids could be bounded by the polyacids. In a neutral medium, all symplexes behave like coherent polyamphiions with the behavior of long chain molecules. Swelling and dissolving of mammalian skin desintegrates the scleroproteins, partly down to the primary helix. These proteins with polyuronic acids such as alginic acid in form of a symplex did not give individual or specific reactions when implanted into the living organism but were slowly decomposed by unspecific proteases.

ISSN:0021-9304    

DOI:10.1002/jbm.820020307

出版商:John Wiley&Sons, Inc.    

年代:1968

数据来源: WILEY

摘要:

AbstractThe microprobe analyzer has proved to be a valuable tool in investigation of dental and medical materials problems, and the results of a number of studies are described. Interesting aspects of the amalgam–tooth interface have been examined and dental calculus compostion has been determined. Surgical implant studies have included evaluation of appliance alloys and failure analysis of surgical device

ISSN:0021-9304    

DOI:10.1002/jbm.820020308

出版商:John Wiley&Sons, Inc.    

年代:1968

数据来源: WILEY

摘要:

AbstractA dilute HCl wash of Ag3Sn powder results in a dental amalgam exhibiting 20% higher tensile strength. It was found that the fracture propagation paths in treated and untreated specimens were different.The support of the National Institute of Dental Research under Grant No. DE‐30233 and Program Project DE‐02111 is gratefully acknowled

ISSN:0021-9304    

DOI:10.1002/jbm.820020309

出版商:John Wiley&Sons, Inc.    

年代:1968

数据来源: WILEY

ISSN:0021-9304    

DOI:10.1002/jbm.820020310

出版商:John Wiley&Sons, Inc.    

年代:1968

数据来源: WILEY

ISSN:0021-9304    

DOI:10.1002/jbm.820020301

出版商:John Wiley&Sons, Inc.    

年代:1968

数据来源: WILEY