Clinical Materials (Clin Mater )

Publisher: Elsevier

Description

Incorporated into Biomaterials

  • Impact factor
    0.00
  • 5-year impact
    0.00
  • Cited half-life
    0.00
  • Immediacy index
    0.00
  • Eigenfactor
    0.00
  • Article influence
    0.00
  • Website
    Clinical Materials website
  • Other titles
    Clinical materials (Online)
  • ISSN
    0267-6605
  • OCLC
    60639532
  • Material type
    Periodical, Internet resource
  • Document type
    Internet Resource, Journal / Magazine / Newspaper

Publisher details

Elsevier

  • Pre-print
    • Author can archive a pre-print version
  • Post-print
    • Author can archive a post-print version
  • Conditions
    • Voluntary deposit by author of pre-print allowed on Institutions open scholarly website and pre-print servers
    • Voluntary deposit by author of authors post-print allowed on institutions open scholarly website including Institutional Repository
    • Deposit due to Funding Body, Institutional and Governmental mandate only allowed where separate agreement between repository and publisher exists
    • Set statement to accompany deposit
    • Published source must be acknowledged
    • Must link to journal home page or articles' DOI
    • Publisher's version/PDF cannot be used
    • Articles in some journals can be made Open Access on payment of additional charge
    • NIH Authors articles will be submitted to PMC after 12 months
    • Authors who are required to deposit in subject repositories may also use Sponsorship Option
    • Pre-print can not be deposited for The Lancet
  • Classification
    ​ green

Publications in this journal

  • [Show abstract] [Hide abstract]
    ABSTRACT: A calcia base investment has high stability even with melted titanium and, therefore, can produce an excellent titanium casting. In this study, titanium powder was distributed to a calcia base investment as an expanding agent, and the firing temperature of the mold was controlled at 800 degrees C. The calcia base investment with 6.1% wt titanium powder expanded 1.7% during 2 h heating at 800 degrees C. The marginal discrepancies between the die and the titanium crown were improved by the addition of the titanium powder to the investment. The mean thickness of the cement layer between the epoxy teeth and the crown using 6.1% wt titanium powder content was from 40-80 microns.
    Clinical Materials 02/1994; 16(3):155-60.
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    ABSTRACT: Successful adhesive dentistry is reliant on the strength and durability of the resin-bond. This is affected by the alloy and its preparation, the properties of the luting resin, and the condition of the tooth. This in-vitro study investigated three months of preparation of the alloy surfaces and three different types of one resin luting cement. Results demonstrated that alumina-blasted nickel-chromium alloy specimens were significantly more resistant to failure under tensile loading than gold alloy samples however prepared. Alumina-blasted, heat-treated gold alloy specimens showed significantly higher tensile failure loads than those of alumina-blasted gold. The performance of the different resins with the alumina-blasted nickel-chromium or the alumina-blasted, heat-treated gold alloy specimens was similar. However, for the alumina-blasted gold alloy specimens, there was a significant difference when comparing resin types.
    Clinical Materials 02/1994; 17(2):105-9.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Highly porous dental implants of a cylindrical shape were fabricated from commercial grade titanium REP-atomized powders by EDC. They were intended to have the maximum porosity for maximum osseointegration, but to maintain the minimum mechanical properties functionally required. Two level full factorial experiments were conducted with respect to the sample weight, capacitance, input energy and electrode configuration. All samples were X-rayed prior to tests to ascertain the presence, extent and distribution of internal macroscopic voids. Torque and compression tests were conducted to evaluate the yield or ultimate strengths (34-90 cm N and 205-502 MPa, respectively). These results indicate that macroscopic void-free, highly porous implants can be fabricated.
    Clinical Materials 02/1994; 17(4):203-9.
  • Clinical Materials 02/1994; 16(4):223-7.
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    ABSTRACT: To evaluate the influence of type I collagen and hydroxyapatite coatings on the ability of Dacron fiber to achieve biologic fixation to bone, tows with the following coatings were evaluated in vivo: avian collagen (A); an avian collagen/hydroxyapatite composite (AH); bovine tendon collagen (B); a bovine tendon collagen/hydroxyapatite composite (BH); and plain (uncoated) Dacron tow (C). The Dacron tows were placed unstressed in the cancellous bone of both lateral femoral condyles of rabbits. Tissue reaction to each kind of Dacron tow was evaluated histopathologically, histomorphometrically and biomechanically. Inflammatory reaction was apparent around the AH and BH Dacron fibers at 2 weeks. There was no such reaction in the A, B, and C specimens, thus implicating the hydroxyapatite particles as the cause. At later time periods specimens A, B, and C all induced new bone formation. Direct contact between the Dacron fibers and trabecular bone was apparent in A and B. The pull-out strength of the B fibers was higher than the controls at a statistically significant level, but there was no significant difference between any of the other specimens and C (controls). There was no significant difference between any coating and controls at 8 or 16 weeks. Dacron fibers coated with bovine tendon collagen exhibited the best biocompatibility to bone and improved the anchoring to bone in the early time intervals by maintaining direct contact between Dacron fibers and trabecular bone.(ABSTRACT TRUNCATED AT 250 WORDS)
    Clinical Materials 02/1994; 15(1):43-50.
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    ABSTRACT: The design of a plasticized, biodegradable polymeric material, suitable for application as a controlled-release system, was attempted. A poly(DL-lactic acid) oligomer was plasticized with 1,2-propylene glycol and glycerol. The latter plasticizer showed poor compatibility whereas 1,2-propylene glycol was compatible with the polymer up to high concentrations. The mixtures prepared displayed considerable depression of processing temperature and enhanced delivery of salicylic acid, in the early stages of release. It seemed, therefore, feasible to produce systems which allow easy and safe processing and can be injected into a body cavity, without the need for surgical retrieval after completion of the release. Furthermore, the differential rate of drug delivery might be of profound interest for cases where elevated drug doses are necessary in the beginning of treatment.
    Clinical Materials 02/1994; 15(2):89-92.
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    ABSTRACT: To study the shape effect upon surrounding tissue of artificial dental root made of synthetic hydroxyapatite, this paper deals with the numerical analysis of the artificial root on functioning jawbone with the aid of the finite element method (FEM). The stress distribution around artificial roots in the shape of a cylinder, a cone, and three types of corrugated cone, including the newly tailored type implanted in the mandibular molar region, was analyzed in the plane strain state. The numerical results showed that the stress distribution was sensitive to the artificial root shape, and that the stress state was distributed in mitigatory way around the roots of the newly tailored form. The pattern of osteogenesis in the animal experiment and the finite element analysis (FEA) pattern showed a close correlation. Osteogenesis was assumed to occur in the weak or moderate stress distribution zone. The principal stress trajectory pattern in the lamina dura around the tailored artificial root was indicated as being either parallel or normal to the root surface. From this study, the biomechanical property of the tooth can be identified as a vehicle of mastication forces which disperse stresses moderately and equally upon surrounding tissues. Also, the periodontal ligament can be identified as a converting system of principal stress trajectories.
    Clinical Materials 02/1994; 16(3):127-35.
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    ABSTRACT: The purpose of this experimental investigation was to study the incorporation of porous glassy carbon in bone. Cylinders of porous glassy carbon were implanted in drill holes in diaphyses and metaphyses of rabbits tibia for 1, 3, 6, 12 and 24 weeks. Bone ingrowth into the glassy carbon implants was examined by radiographic, histologic, fluorocrome and microradiographic methods. The material caused no pathological reaction. Tissue ingrowth into pores was seen by all examination methods. The amount of bone in the pores increases with time. The ingrowth was most distinctive in those areas where the implant was in close contact with cortical bone or trabeculae of the cancellous bone. Porous glassy carbon can be used as bone substitute, although the small size of implant available is at the present a limitation for its clinical use.
    Clinical Materials 02/1994; 17(2):93-8.
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    ABSTRACT: Five different nanoparticles, potentially useful in magnetic resonance imaging (MRI) after venous administration, were studied for their hemocompatibility. The in vitro methodology evaluated these materials by several parameters: cytotoxicity towards cells cultured in vitro, aggregation ability of platelets, hemolysis inducibility, intrinsic and extrinsic coagulation pathway activation, and complement activation. With the proposed clinical dose, regardless of the cell type used (murine cell line or human endothelial cells) no toxicity was observed. The presence of the particles in blood did not produce any considerable damage: either hemolysis or platelet aggregation or blood coagulation were recorded. However, a slight decrease in aggregation ability of platelets was noticed as well as an increase in partial thromboplastin time. Because of the quick removal of the particles from the bloodstream, these phenomena must be short-lived, thus avoiding significant adverse clinical effects.
    Clinical Materials 02/1994; 15(4):293-301.
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    ABSTRACT: The purpose of this study was to determine the potential of coralline calcium phosphate ceramics to support osteoblast growth for a proposed bone-ceramic composite for skeletal tissue repair. The goal was the development of a matrix with both osteogenic and osteoconductive properties, as compared to ceramic alone, which is solely osteoconductive. MC3T3-E1 osteoblast-like cells were seeded onto sintered and non-sintered porous coralline hydroxyapatite (HA), and onto non-porous hydroxyapatite discs. These in-vitro studies demonstrated that coralline HA supported the growth of osteoblast-like cells. Porous discs supported higher numbers of cells than non-porous discs. Sintering encouraged cell growth, with higher numbers of cells adhered to sintered porous HA discs by day seven. The results suggest that HA can provide a support for osteoblast cells as part of a matrix which may prove to be osteogenic in vivo and may, accordingly, enhance the bone repair process.
    Clinical Materials 02/1994; 17(2):85-91.
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    ABSTRACT: The principal cause of the clinical failure of bioprosthetic heart valves fabricated from glutaraldehyde-pretreated bovine pericardial valves is calcification. The present investigation describes the mineralization of glutaraldehyde-treated bovine pericardium (GBP), in an extra-circulatory environment and the possible methods of prevention via metal ions. Calcification was examined on GBP incubated in metastable solutions of calcium phosphate and the role of certain anesthetic drugs, ferric ions and magnesium ions in the media was evaluated. It seems that the addition of ethyl alcohol, pentothal and xylocaine in the calcium phosphate solutions, variably inhibited the GBP calcification. The metals like Fe3+ ions and Mg2+ ions and their combinations also substantially reduced the GBP mineralization. It is assumed that ferric ions may slow down or retard the calcification process by delaying the proper formation of hydroxyapatite while magnesium ions disrupt the growth of these crystals by replacing Ca2+. Hence, it is conceivable that a combination therapy--via local delivery of low levels of ferric ions and magnesium ions--may prevent the GBP-associated calcification. Further, a very low daily intake of alcohol appears to be beneficial to reduce the profile of calcium deposition at tissue interfaces.
    Clinical Materials 02/1994; 17(4):165-72.
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    ABSTRACT: Changes either within the bone cement or at the cement-bone interface are known to contribute to loosening and hence failure of many cemented joint replacements. This study examines the in vitro changes in the fracture properties of bone cement as a result of storage, at both 21 and 37 degrees C, in air, water, Ringer's solution and lipid over a period of 2 years. Specimens stored in the fluid media were found to behave in a more ductile manner than those stored in air. Samples stored at 37 degrees C behaved in a more brittle manner than those stored at 21 degrees C. Although the work of fracture values measured for the samples stored in the water-based media increased during the first 18 months, this was followed by a decrease in the subsequent 6 months.
    Clinical Materials 02/1994; 16(4):211-6.
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    ABSTRACT: The anterior cruciate ligament of goats was substituted by a high-tensile polyethylene fiber prosthesis. The animals were sacrificed after 6-12 months. Histologically, the implants were separated from a newly formed bony shell by a thick fibrous interface membrane, which was anchored to the bone by Sharpey-like fibers. Within the joint cavity, the implants were enclosed in thick fibrous sheaths, which were continuous with the intra-osseous interface membranes. While the inner granulomatous layer of the interface membrane extended in between the polyethylene fibrils for a short distance, the bulk of the prosthesis was poorly organized. A thick central fibrous band accompanied the intra-osseous and intra-articular portions of the implants throughout their entire lengths. Oblique fibrous tracks linked the interface membranes with the central fibrous bands. The intra-osseous tunnels were considerably expanded when compared to the initially drilled tunnels.
    Clinical Materials 02/1994; 15(1):61-7.
  • [Show abstract] [Hide abstract]
    ABSTRACT: The pathogenesis and rates of infection associated with the use of a wide variety of implantable devices are described. The multi-factorial nature of post-operative periprosthetic infection is outlined and the role of sterilisation of devices is explained. The resistance of bacterial spores is highlighted as a problem and a full description is given of the processes of sterilisation by heat, steam, ethylene oxide, low temperature steam and formaldehyde, ionising radiation and liquid glutaraldehyde. Sterility assurance and validation are discussed in the context of biological indicators and physical/chemical indicators. Adverse effects upon the material composition of devices and problems of process control are listed. Finally, possible optimisations of the ethylene oxide process and their potential significance to the field of sterilisation of implants is explored.
    Clinical Materials 02/1994; 15(3):191-215.
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    ABSTRACT: Alternative materials for autologous nerve grafts in peripheral nerve surgery have long been investigated. This report describes the use of acellular (freeze-thawed) autologous skeletal muscle grafts (ASMG) to bridge a 2 cm gap in the sciatic nerve of rats. Neurophysiologic and morphometric studies performed 6 weeks after surgical procedure showed for the nine treated Sprague-Dawley rats (Group A) a good axon regeneration rate, although this was lower than that for the control group (Group B), a lower Nerve Conduction Velocity (NCV) and a thinner myelin sheath than in group B (n = 9 Sprague-Dawley rats). In the latter case, complete resection of 2 cm of the sciatic nerve was followed by an immediate coaptation of the proximal and distal ends.
    Clinical Materials 02/1994; 16(3):137-43.
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    ABSTRACT: The use of penetrometry for the assessment of materials employed for soft earmoulds is investigated. Selected test conditions are used for the characterisation of 10 materials of five types (cold-cured methacrylate, heat-cured methacrylate, heat-cured silicone, polyvinyl chloride co-polymer and polyethylene copolymer) used in clinical practice. The results are compared with the outcome of subjective assessments surveyed for four representative materials. The effect of ageing is assessed for a heat-cured silicone (Molloplast B) and a heat-cured methacrylate (Coe Super-Soft).
    Clinical Materials 02/1994; 16(3):161-6.
  • [Show abstract] [Hide abstract]
    ABSTRACT: The elaboration of metallic and polymeric particles from the wear of joint replacement components is widely implicated in the pathogensis of aseptic loosening of these implants. Diamond-like carbon (DLC) coatings show great potential as wear-retardant coatings and may offer a possible solution to this problem. We have studied the effects of DLC coatings on cells derived from the tissues that surround a total joint replacement (macrophages, fibroblasts and osteoblast-like cells). There was no evidence that DLC coatings, deposited on a variety of different substrates, caused cytotoxicity in vitro. Cells grown on the coated substrates exhibited normal cellular growth and morphology. DLC coatings are biocompatible in vitro and should now be tested in animal models to determine their behaviour in vivo.
    Clinical Materials 02/1994; 17(1):1-10.
  • [Show abstract] [Hide abstract]
    ABSTRACT: A procedure for the histological visualization of the interface between implants coated with hydroxyl-apatite (HA) and bone, and the reaction of bones to the implants, has been developed. Thick sections of bones with HA-coated stainless-steel implants, were investigated with the implant still in situ with routine and (confocal) fluorescence microscopy. The prosthesis-HA-bone interface, bone cells, necrotic and vascularised bone, bone-ingrowth and bone remodelling could be visualised. After removal of the implant from the sections alternative sections were further processed for routine light microscopy, microradiography and detailed fluorescence studies. It appeared that the HA coating was still intact and the integrity of the HA-bone bond was very well preserved. The HA coating layer had the same appearance as after the first inspection with surface microscopy. However, more details were visible. Prosthesis-related and time-related changes in the appearance of the HA layer were detected. The advantage of the procedure is that observations can be made of bone reactions with the prosthesis still in situ, without previous embedding in plastics, and laborous sectioning and/or grinding procedures. Thereafter, sections can be processed for different histological techniques, e.g. immunocytochemistry, routine histology, microradiography, fluorescence microscopy, apparently without imparing the HA coating layer.
    Clinical Materials 02/1994; 15(2):93-9.
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    ABSTRACT: BOP (biocompatible osteoconductive polymer) is a material proposed for osteosyntheses and for filling of bone defects in orthopaedics, neurosurgery and stomatology. It is a composite made of a copolymer of N-vinylpyrrolidone and methylmethacrylate, of polyamide-6 fibers and of calcium gluconate. The histological investigation includes the study of 30 intact rabbit femurs instrumented with a BOP rod, as well as the study of organs of the reticuloendothelial system. The currently available results show the absence of toxicity on hematopoietic tissue. Zones of osteoblastic activity surround the rods, coupled with an osteoclastic reaction which may result in the partial fragmentation of the polyamide fibers and its incorporation in the newly formed bone. We also observed the encapsulation of the material. The biomechanical approach investigated the mechanical properties of the material in bending and in shear. The radiological aspects of the investigation consisted of computerized axial tomography of the implanted femurs to measure density at the bone-implant interface.
    Clinical Materials 02/1994; 16(4):217-21.

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