203 results match your criteria Journal of applied biomaterials & functional materials[Journal]


Plantar pressure distribution in patients with neuropathic diabetic foot.

Authors:
A Merolli L Uccioli

J Appl Biomater Biomech 2005 Jan-Apr;3(1):61-4

Unita' di Ortopedia e Chirurgia della mano, C.I.C., Universita' Cattolica, Roma - Italy.

Purpose: To describe the plantar pressure distribution in a selected group of patients with diabetic foot and to highlight their alterations in gait cycle, which follow the involvement of the foot in systemic diabetic neuropathy.

Methods: Ten patients with diabetic foot due to insulin dependent diabetes mellitus (IDDM) were studied. Gait cycle kinematics were video-recorded, both in frontal (AP view) and in sagittal (LL view) planes. Read More

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October 2012

Pins composed of poly(L-lactic acid)/poly(3- hydroxybutyrate-co-hydroxyvalerate) PLLA/PHBV blends: Degradation in vitro.

J Appl Biomater Biomech 2005 Jan-Apr;3(1):50-60

Centro de Ciencias Médicas e Biologicas, Pontifícia Universidade Catolica, S o Paulo - Brazil.

Bioabsorbable polymers have shown good clinical success in the fixation and stabilization of bone fractures. Understanding and controlling polymer prosthetic degradation and the effect of the degradation products in vivo are crucial for successful implant developments. In this study, pins made from blends of PLLA/PHBV of varying compositions were degraded in phosphate buffer and characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and scanning electron microscopy (SEM). Read More

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October 2012

Endothelial cell adhesion force estimation at the nanoscale.

J Appl Biomater Biomech 2005 Jan-Apr;3(1):42-9

Department of Bioengineering, Politecnico di Milano, Milano - Italy.

Endothelial cell adhesion to a synthetic surface includes a definite set of molecular interactions. Cell adhesion is managed by fibronectin and vitronectin in extracellular matrix (ECM) that binds the receptor site of the trans-membrane protein dimers, the integrins. These proteins contain one of the binding sites (I-like domain receptor) for the Arg-Gly-Asp (RGD) peptides that are the established adhesion receptor sites in the ECM. Read More

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October 2012

Evaluation of bioresorbable implants from bovine bone: In vitro preliminary observations.

J Appl Biomater Biomech 2005 Jan-Apr;3(1):35-41

Human Anatomy Laboratory, Research Center for Biocompatibility, Department of Medical Sciences, University of Eastern Piedmont 'A. Avogadro', Novara - Italy.

Biocompatibility evaluation is a fundamental step in developing new biomaterials. Implants derived from bovine tibial compact bone were analyzed with in vitro tests using fibroblast and osteoblast-like cells. Initially, cell attachment and proliferation were quantified. Read More

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October 2012

Cytotoxic and genotoxic effects of the exposure of human lymphocytes to a calcium phosphate cement in vitro.

J Appl Biomater Biomech 2005 Jan-Apr;3(1):29-34

Departamento de Ciencias de la Salud, Universidad Autonoma Metropolitana, Iztapalapa - Mexico.

The cytotoxic and genotoxic effects of a phosphate bone cement on human peripheral lymphocyte cultures exposed for 48 hr were determined. The mitotic index and the integrity of the DNA molecule were used as biocompatibility markers. It was found that the cement was not cytotoxic, but genotoxic at concentrations of >/=100 microg/ml. Read More

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October 2012

Bone tissue responses to Mg-incorporated oxidized implants and machine-turned implantsin the rabbit femur.

J Appl Biomater Biomech 2005 Jan-Apr;3(1):18-28

Department of Biomaterials/Handicap Research, University of Goeteborg, Goeteborg - Sweden.

Previous studies have demonstrated a significant improvement in the bone response to oxidized titanium implants. Little is known about the effects of specific oxide properties on the bone tissue responses to titanium implants. This study in-vestigated the bone tissue responses to magnesium (Mg)-incorporated oxidized titanium implants and machine-turned titani-um implants in the rabbit femur. Read More

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October 2012

Stem cell factor receptor KIT (CD117) in aseptic hip prosthesis loosening.

J Appl Biomater Biomech 2005 Jan-Apr;3(1):11-7

Institute of Pathology, Johannes Gutenberg University of Mainz - Germany.

Objective: This study aimed to investigate specific inflammatory pathomechanisms, i.e. the expression of the stem cell factor receptor KIT (CD117) in tissue specimens from patients with aseptic hip prosthesis loosening (AHPL) with special emphasis on colocalization with the mast cell specific marker tryptase. Read More

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October 2012

The microbial infection of biomaterials: A challenge for clinicians and researchers. A short review.

J Appl Biomater Biomech 2005 Jan-Apr;3(1):1-10

Department of Experimental Surgery, Rizzoli Orthopedic Institutes, Bologna and University of Eastern Piedmont 'A. Avogadro', Novara - Italy.

The increasing use of biomaterials and medical devices has led to the development of new families of diseases related precisely to the use of the biomaterials and medical devices themselves. Microbial contamination of the devices is a serious and widespread problem in surgery because it often causes devastating infections and loss of the implanted devices. The methods of contamination in medical devices are dependent on many peculiar factors including the chemistry of the biomaterial, the physical properties of the surface, the design of the medical device, the implanted anatomical site, the extension of surgical invasion, and the time of application. Read More

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October 2012

Surface modification of hydrogel intraocular lenses to prevent cell proliferation.

J Appl Biomater Biomech 2004 Sep-Dec;2(3):183-90

Laboratoire des Biomatériaux et Polymères de Spécialité, UMR 7052, Université Paris 13, Villetaneuse - France.

Intraocular lenses made from a hydrogel matrix were coated with a bioactive polymer exhibiting sulfonate and carboxylate groups. The anchorage of the macromolecular chains bearing the anionic groups to the hydrogel implant surface was obtained by an intermolecular reaction of the photosensitive groups attached to the ionic polymer, in order to obtain a pseudo-interpenetrated network. Cell proliferation assays performed on coated and uncoated hydrogel lenses showed an inhibiting effect of the bioactive polymer coating by up to 40% at day 6. Read More

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October 2012

Pressure drop vs flow relationship in isolated preterm lamb tracheae.

J Appl Biomater Biomech 2004 Sep-Dec;2(3):177-82

Department of Bioengineering, Politecnico di Milano, Milano - Italy.

Knowledge of immature tracheae mechanical behavior is fundamental in understanding the effects exerted on the upper airways by tidal liquid ventilation (TLV). Particularly, negative pressure can take place along the airways during expiration, which can cause airway collapse and flow limitation; therefore, representing a critical issue in preterm infant patients, whose airways are less stiff than adult ones. In this study, we investigated the expiratory pressure drop vs flow relationship of isolated preterm lamb tracheal samples to determine their hydraulic resistance, collapse pressure and collapse flow rate; a liquid flow through the samples was obtained by applying negative pressure at the outlet (cephalad) extremity of the tra-cheal sample, while keeping the inlet (caudal) extremity at atmospheric pressure. Read More

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October 2012

The adhesion of Flow 2002 fibroblasts to titanium implant materials is influenced by different surface topographies and is related to the immunocytochemical expression of fibronectin.

J Appl Biomater Biomech 2004 Sep-Dec;2(3):169-76

Department of Normal Human Morphology, University of Trieste, Trieste - Italy.

Osteointegrated titanium dental implants are widely used biomaterials that have to integrate within the alveolar bone and interact with periodontal soft tissues. In this study, we investigated the immunocytochemical expression of the extra-cellular matrix (ECM) protein fibronectin (FN) and type I collagen (Coll I) in Flow 2002 fibroblast cultures spread on grade III-titanium samples with five different surface topographies and we correlated the immunocytochemical data to the adhesion capability of these cells to the above-mentioned substrates. Five different surfaces of grade III-titanium implants were at first characterized both by scanning electron microscopy (SEM) and by laser profilometry for surface roughness evaluation. Read More

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October 2012

In vitro biocompatibility of duplex stainless steel with and without 0.2% niobium.

J Appl Biomater Biomech 2004 Sep-Dec;2(3):162-8

Department of Oral and Maxillofacial Surgery and Periodontology, School of Dentistry of Ribeirao Preto, University ofSao Paulo, Sao Paulo - Brazil.

Stainless steel is frequently used as a biomaterial. Chemical composition alterations can be undertaken to improve its mechanical and biological properties. This investigation aimed to compare the biocompatibility of duplex stainless steel, with and without 0. Read More

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October 2012

Mechanical and ultrastructural evaluation of quartz post-endodontic reconstructions.

J Appl Biomater Biomech 2004 Sep-Dec;2(3):156-61

Department of Technology and Health, Italian National Institute of Health, Roma - Italy.

Aesthetics is a very important element in dentistry, but requires the support of good mechanical performance. Quartz fiber used in post-endodontic reconstruction is an aesthetic material, although there is little research concerning its mechanical properties. This study evaluated the retentive property of post-endodontic reconstruction, composed of a quartz fiber post. Read More

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October 2012

Inhibition of Ni release from NiTi and NiTiCu orthodontic archwires by nitrogen diffusion treatment.

J Appl Biomater Biomech 2004 Sep-Dec;2(3):151-5

CREB - Department of Materials Sciences and Metallurgical Engineering, ETSEIB Universidad Politécnica of Catalonia, Barcelona - Spain.

The effects of nickel (Ni) allergy from NiTi alloys were reduced due to the titanium nitrided coating obtained by nitrogen gas diffusion at different temperatures. The samples were immersed in artificial saliva at 37 degrees C for different periods demonstrating that the titanium nitride coating prevents biodegradation. In addition, the lack of low friction coefficient for the NiTi super-elastic archwires makes the optimal use of these materials in orthodontic applications difficult. Read More

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October 2012

In vitro and in vivo follow-up of titanium transmucosal implants with a zirconia collar.

J Appl Biomater Biomech 2004 Sep-Dec;2(3):143-50

Cattedra di Clinica Odontoiatrica, Ateneo Vita e Salute, San Raffaele Hospital, Milano - Italy.

The advantages of transmucosal healing implants with a bioactive zirconia collar as a support for partially fixed prosthodontic restorations are optimal peri-implant marginal tissue sealing, reduction in plaque accumulation and satisfactory aesthetic results. The zirconia used in this study evidenced not only optimal clinical performances, but also good biocompatibility. The results from this study demonstrated that zirconia coating enhances fibroblasts and osteoblast-like cell adhesion, spreading and proliferation, favoring microscopic tissue/cell in-growth and clinical implant fixation improvement. Read More

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October 2012

The role of fretting damage in total hip arthroplasty with modular design hip joints -evaluation of retrieval studies and experimental simulation methods.

Authors:
P Schaaff

J Appl Biomater Biomech 2004 Sep-Dec;2(3):121-35

European Commission, Joint Research Centre, Institute for Health and Consumer Protection, Ispra (VA) - Italy.

Retrieval studies of total hip arthroplasty were reviewed to assess the clinical relevance of fretting damage on the clinical outcome of total hip arthroplasty with modular design artificial hip joints. In this case, fretting denotes the small rel-ative displacement between the two contacting surfaces at the taper joint of a modular hip prosthesis under cyclic loading caused by walking. Fretting causes a local disruption of the passivation surface layer exposing new metal to the aggressive body envi-ronment. Read More

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October 2012
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A comparative evaluation of chondrocyte/scaffold constructs for cartilage tissue engineering.

J Appl Biomater Biomech 2004 Jan-Apr;2(1):55-64

Laboratory of Biological Structure Mechanics, Politecnico di Milano, Milano - Italy.

This study aimed to evaluate three biodegradable scaffolds as cell carriers for in vitro cartilage regeneration using mature human chondrocyte cells. We compared cell distribution, viability and morphology and we evaluated the mechanical properties of the constructs after 2 weeks of in vitro culture. The materials used as scaffolds were fibrin glue, a collagen sponge and a polyurethane foam (DegraPol(R)). Read More

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October 2012

Finite element analysis of a knee joint replacement during a gait cycle.

Authors:
M Soncini L Vandini

J Appl Biomater Biomech 2004 Jan-Apr;2(1):45-54

Department of Bioengineering, Politecnico di Milano, Milano - Italy.

A three-dimensional (3-D) computer model was developed to predict, simultaneously, the knee joint replacement motions and the stresses occurring within the tibial insert under complex loading conditions. Friction contacts, polyethylene elastic- plastic behavior and soft tissue restraints were considered. Finite element analysis of the entire gait cycle was performed applying the displacement and loading conditions reported in the draft ISO 14243-1. Read More

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October 2012

Titanium for osteointegration: Comparison between a novel biomimetic treatment and commercially exploited surfaces.

J Appl Biomater Biomech 2004 Jan-Apr;2(1):35-44

Department of Chemistry, Materials and Chemical Engineering "G.Natta", Politecnico di Milano, Milano - Italy.

The objective of this preliminary in vitro biological study was to assess the effect of the surface physicochemical and topographical properties of a novel bioactive titanium (BSP) obtained by BioSpark treatment. A short-term study was per-formed to evaluate the bone cell response to BSP and compare it to two commercially available materials: no treated (TI) and chemically etched (ETC) titanium. Material characterization was carried out using scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), non-contact laser profilometry (LPM), and Thin Film X-ray Diffraction (TF-XRD). Read More

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October 2012

Wear studies of all UHMWPE couples under various bio-tribological conditions.

J Appl Biomater Biomech 2004 Jan-Apr;2(1):29-34

Department of Mechanical and Biomedical Engineering, National University of Ireland Galway, Galway - Ireland.

Wear tests were undertaken in which ultra high molecular weight polyethylene (UHMWPE) was rubbed against itself. Tests primarily employed a pin-on-plate wear test machine, with distilled water, Ringer solution and dilute bovine serum being used as the lubricants. Loads of 10N and 40N were employed, and some test pins had a rotational motion added. Read More

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October 2012

Influence of heat treatment on structural, mechanical and wear properties of crosslinked UHMWPE.

J Appl Biomater Biomech 2004 Jan-Apr;2(1):20-8

Department of Chemistry, Materials and Chemical Engineering "G.Natta", Politecnico di Milano, Milano - Italy.

New crosslinked ultra high molecular weight polyethylenes (UHMWPEs) have recently been developed, characterized and introduced in clinical applications. UHMWPE cross-linking treatments are very promising for reducing osteolysis induced by wear debris. The irradiation type, gamma or beta, the dosage and the thermal treatment performed during or following the irradiation process are all factors affecting polyethylene wear resistance. Read More

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October 2012

Protein interaction with hydrogel contact lenses.

Authors:
R Sariri

J Appl Biomater Biomech 2004 Jan-Apr;2(1):1-19

Department of Biology, Gilan University, Rasht - Iran.

The first event observed at the interface between a contact lens and tear fluid is protein adsorption. Tears have a rich and complex composition, allowing a wide range of interactions and competitive processes. The majority of studies avail-able on protein adsorption have focused on blood/plasma/serum protein on solid surfaces. Read More

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October 2012

Precipitation of carbonateapatite from a revised simulated body fluid in the presence of glucose.

J Appl Biomater Biomech 2003 Sep-Dec;1(3):200-8

Solid State Chemistry, Faculty of Chemistry, University of Bochum, Bochum - Germany.

Revised simulated body fluid (rSBF) was modified by the addition of glucose in a physiological amount. The influence of this compound on calcium phosphate crystallization from supersaturated solutions equal to 4 x rSBF ionic concentrations was studied under physiological conditions (solution pH=7.35-7. Read More

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October 2012
2 Reads

Skull biomechanics: The energy absorbability of the human skull frontal bone during fracture under quasi-static loading.

J Appl Biomater Biomech 2003 Sep-Dec;1(3):194-9

Division of Biomechanics and Engineering Design, K.U. Leuven, Leuven - Belgium.

Four human skulls were studied in order to determine the energy absorbed corresponding to a fracture due to quasi-static loading on the frontal bone. Using a dedicated experimental set up, the force-deformation characteristics of the specimens were recorded, calculating energy absorption. Mean values of 1975 +/- 703 N, 4. Read More

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October 2012

Injectable calcium phosphate hydraulic cement (CPHC) used for periodontal tissue regeneration: A study of a dog model.

J Appl Biomater Biomech 2003 Sep-Dec;1(3):186-95

INSERM U595, Federation of Odontology Research, Department of Periodontology, Louis Pasteur University, Strasbourg - France.

Injectable calcium phosphate hydraulic cement (CPHC) is a new bone substitute family. This study aimed to evaluate the use of CPHC in surgical periodontitis-simulating defects in a dog model. CPHC was obtained by adding powder mixtures of different calcium phosphates with different solubility. Read More

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October 2012

Bioactive polymers grafted on silicone to prevent Staphylococcus aureus prosthesis adherence: in vitro and in vivo studies.

J Appl Biomater Biomech 2003 Sep-Dec;1(3):178-85

INSERM EMI-U 9933, Hopital Xavier Bichât, Paris - France.

As joint prostheses become infected preventive strategies are needed. Silicone prostheses were coated with a COO - and SO3 - bearing bioactive copolymer, Q5, synthesized by radical polymerization and the adherence of Staphylococcus aureus (S. aureus)to them was evaluated in vitro and in vivo. Read More

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October 2012

Porous titanium obtained by a new powder metallurgy technique: Preliminary results of human osteoblast adhesion on surface polished substrates.

J Appl Biomater Biomech 2003 Sep-Dec;1(3):172-7

Department of Special Surgical Sciences, UCO Odontology and Stomatology, University of Trieste, Trieste - Italy.

This study concerns a novel powder metallurgy method for producing porous titanium (pTi) exhibiting high mechanical properties. The preparation procedure consisted of the following stages: first, the preparation of Ti and titanium hydride (TiH2) powder mixtures and their consolidation with a cold isostatic press, followed by a sintering of the green bodies performed with hot isostatic press (HIP) equipment. Thermal decomposition in controlled environment of the TiH2 phase results in the foam structure. Read More

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October 2012

N+ ion implantation of Ti6Al4V alloy and UHMWPE for total joint replacement application.

J Appl Biomater Biomech 2003 Sep-Dec;1(3):164-71

Center for Biomedical Engineering, University of Durham, Durham - UK.

Multidirectional pin-on-plate tribological wear tests were performed to evaluate and compare the tribological behavior of N+ ion-implanted and unmodified Ti6Al4V/ultra high molecular weight polyethylene (UHMWPE) sliding couples, for total joint replacement (TJR) applications. Knoop microhardness indentations were measured and an increase in surface hardness of more than twofold and up to four times, respectively, was observed for the Ti6Al4V alloy and UHMWPE after N+ ion implantation, at a load of 1 gf. Increase in hardness was attributed to the formation of TiN precipitates and cross-linking in the alloy and polymer, respectively. Read More

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October 2012

In vitro and in vivo tests for the biological evaluation of candidate orthopedic materials: Benefits and limits.

Authors:
M Fini R Giardino

J Appl Biomater Biomech 2003 Sep-Dec;1(3):155-63

Experimental Surgery Department, Research Institute Codivilla-Putti, Rizzoli Orthopedic Institute, Bologna - Italy.

The development of reliable experimental models for the clinical use of biomaterials and in predicting implant success or failure is becoming increasingly important in attaining adequate health and safety conditions. This paper summarizes the main benefits and limits of in vitro and in vivo biological tests taking into account general pathophysiological considerations regarding the skeletal tissue. Current findings demonstrate the need to adopt both in vitro and in vivo methodologies and to improve test quality with particular attention to the ethical issues associated with in vivo experiments. Read More

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October 2012

Effects of total hip arthroplasty cemented femoral stem surface finish, collar and cement thickness on load transfer to the femur.

J Appl Biomater Biomech 2003 Jan-Apr;1(1):76-83

Biomechanics Laboratory, Los Angeles Orthopaedic Hospital and Department of Orthopaedics, University of California, Los Angeles - USA.

Stress shielding and load transfer to the femur following total hip arthroplasty have been studied extensively. A number of models have addressed the effects of surface finish of double-tapered, non-collared cemented stems on load transfer to the femur. However, a great number of cemented femoral stem designs in wide use today are not double tapered, and many, such as the Charnley, have collars. Read More

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October 2012

Hydrothane(R) interactions with biological components: a comparison with Chronoflex(R).

J Appl Biomater Biomech 2003 Jan-Apr;1(1):67-75

School of Pharmacy and Biomolecular Sciences, Brighton University, UK.

The interaction of a glycol-containing polyurethane, Hydrothane(R), was assessed with respect to protein adsorption and cell and bacterial adhesion. The results obtained were compared with those from a second polyurethane, Chronoflex(R). Dynamic contact angle (DCA) and protein adsorption studies indicated that the overall hydrophilic nature of Hydrothane in physiological environment was affected by the possible presence of hydrophobic domains still exposed at the surface after wetting. Read More

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October 2012

Cytocompatibility of polyurethane foams as biointegrable matrices for the preparation of scaffolds for bone reconstruction.

J Appl Biomater Biomech 2003 Jan-Apr;1(1):58-66

Bioengineering Department, Politecnico di Milano, Milano - Italy.

This work reports preliminary results on the development of biointegrable scaffolds, composed of biostable 3D polymer matrices and bioabsorbable inorganic salts, to be used for cell anchorage in bone regeneration. Three crosslinked polyurethane foams (PUFs), prepared by one-step bulk polymerisation from a polyether-polyol mixture, polymeric MDI and water as expanding agent, were tested for their ability to promote adhesion and growth of bone-derived cells. The open porosity of these foams ranged from 16 to 31% with an average pore size of 470 /600 microm, compressive strength (at 10% ε ) of 0. Read More

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October 2012

Partially resorbable acrylic bone cements based on self-curing acrylic/phosphate glass formulations.

J Appl Biomater Biomech 2003 Jan-Apr;1(1):48-57

ICTP, Institute of Polymer Science and Technology, CSIC, Madrid - Spain.

Partially resorbable self-curing cements based on poly(methyl methacrylate)/phosphate glasses were prepared by mixing methyl methacrylate monomer with poly(methyl methacrylate) powder in different proportions (20-60 wt-%) of phosphate glass (BV11) in the system 44.5-P2 O5 , 44.5-CaO, 11-Na2 O (mol-%). Read More

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October 2012

Alumina and zirconia ceramics in joint replacements.

J Appl Biomater Biomech 2003 Jan-Apr;1(1):19-32

Department of Orthopaedics, Università Cattolica di Roma, Rome - Italy.

Ceramic biomaterials have gained widespread use in arthroprostheses joints. Ceramic oxides including alumina as á -corundum Al2 O3 and zirconia, as yttria-stabilised zirconia polycrystals, were used in large number of patients, especially in the manufacture of ball heads for hip replacements. The experience and the feedbacks gathered in more than 30-year clinical use of alumina, and 15-year use of zirconia are reviewed. Read More

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October 2012

Modification of polyethylene terephthalate (Dacron) via denier reduction: effects on material tensile strength, weight, and protein binding capabilities.

J Appl Biomater 1995 ;6(4):289-99

Deaconess Hospital/Harvard Medical School, Boston, MA 02215, USA.

Thrombosis remains a significant and potentially catastrophic complication of polyethylene terephthalate (Dacron) prosthetic vascular graft implantation. Numerous attempts have been made to create a novel surface that reduces the adverse effects of blood interaction with the material. The purpose of this study was to create reactive groups on Dacron without significantly altering the chemical and physical properties of the biomaterial. Read More

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http://dx.doi.org/10.1002/jab.770060410DOI Listing

Influence of fluoride on titanium in an acidic environment measured by polarization resistance technique.

Authors:
G Boere

J Appl Biomater 1995 ;6(4):283-8

Academic Centre for Dentistry Amsterdam (ACTA), Department of Dental Materials Science, The Netherlands.

The effect of sodium fluoride on the polarization resistance of titanium was investigated. Titanium plates were exposed to sodium chloride solutions with increasing fluoride concentrations. This was done at pH 7 and 4 at 37 degrees C. Read More

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http://dx.doi.org/10.1002/jab.770060409DOI Listing
March 1996
2 Reads

Finite element analysis of crestal bone loss around porous-coated dental implants.

J Appl Biomater 1995 ;6(4):267-82

Centre for Biomaterials, University of Toronto, Canada.

Crestal bone loss is observed around various designs of dental implants. A possible cause of this bone loss is related to the stresses acting on periimplant bone. To investigate the relationship between stress state and bone loss, two-dimensional finite element models corresponding to bucco-lingual and mesio-distal sections of canine mandibles with one of two designs of porous-coated dental implants were analyzed. Read More

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http://dx.doi.org/10.1002/jab.770060408DOI Listing
March 1996
1 Read

Immobilization of heparin oligosaccharides onto radiofrequency plasma modified pyrolytic carbon-coated graphite.

J Appl Biomater 1995 ;6(4):259-66

Department of Macromolecular Science, Case Western Reserve University, Cleveland, Ohio 44106-7207, USA.

Heparin oligosaccharides with different anticoagulant activities were prepared and immobilized onto pyrolytic carbon coated graphite (PC) heart valve materials commonly used in mechanical heart valve prostheses. Prior to immobilization, PC surfaces were modified by radiofrequency plasma polymerized N-vinyl-2-pyrrolidone (PPNVP) thin films (approximately 100 nm) and derivatized to provide surface hydroxyl groups. Cleaved, low affinity heparin (C-heparin) with factor Xa inhibition activity of 107 to 130 IU/mg, was prepared by partial deaminative cleavage of commercial crude heparin, and high-affinity heparin (HA-heparin) with factor Xa inhibition activity of 550 to 1000 IU/mg was prepared by fractionation of C-heparin using agarose-ATIII affinity chromatography. Read More

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http://dx.doi.org/10.1002/jab.770060407DOI Listing

Effects of sublethal metal ion concentrations on osteogenic cells derived from bone marrow stromal cells.

J Appl Biomater 1995 ;6(4):249-58

Center for Biomedical Engineering, University of Kentucky, Lexington 40506-0070, USA.

Ions released from implant surfaces are suspected of playing some role in osteolysis surrounding metal prostheses. To understand how ions may affect osteogenesis, previous work exposed osteogenic cells to metal ions to study acute cytotoxic responses. The purpose of this study was to assess the long-term effects of sublethal ion concentrations on osteogenic cell proliferation and function. Read More

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http://dx.doi.org/10.1002/jab.770060406DOI Listing
March 1996
28 Reads

Mechanical and histological fixation of hydroxylapatite-coated pyrolytic carbon and titanium alloy implants: a report of short-term results.

J Appl Biomater 1995 ;6(4):243-8

Department of Surgery, Ohio College of Podiatric Medicine, Cleveland 44106, USA.

Historically, pyrolytic carbon has been a material for cardiovascular applications, but it has several properties suited for orthopedic uses as well. Pyrolytic carbon has an elastic modulus similar to bone and is highly fatigue resistant, but has not been used in orthopedics because of poor fixation to bone. Plasma sprayed hydroxylapatite (HA) has significantly improved the bonding of bone to titanium alloy implants. Read More

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http://dx.doi.org/10.1002/jab.770060405DOI Listing
March 1996
2 Reads

The response of cancellous and cortical canine bone to hydroxylapatite-coated and uncoated titanium rods.

J Appl Biomater 1995 ;6(4):237-42

Department of Companion Animal and Special Species Medicine, North Carolina State University, Raleigh, USA.

Because of the recent trend in total hip arthroplasty to achieve direct contact of the endoprosthesis with cortical bone, comparison of bone apposition from cortical bone and cancellous bone was performed. The response of cortical and cancellous bone to hydroxylapatite was also compared. Implants in cortical bone demonstrated a higher interface shear strength and more bone apposition than those in cancellous bone over all time periods tested. Read More

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http://dx.doi.org/10.1002/jab.770060404DOI Listing

Histological and mechanical comparison of hydroxyapatite-coated cobalt-chrome and titanium implants in the rabbit femur.

J Appl Biomater 1995 ;6(4):231-5

Department of Orthopaedic Surgery, Medical University of South Carolina, Charleston, USA.

The purpose of this study was to compare hydroxyapatite (HA)-coated titanium (Ti) and HA-coated cobalt-chrome (CoCr) implants in the distal femur of the rabbit by evaluating bone apposition and interfacial shear strength. Bilateral cylindrical implants with a plasma sprayed 50-microns thick HA coating were press-fit into the metaphyseal cancellous bone of the lateral femoral condyles in a transverse fashion, and the animals were sacrificed at 2, 4, and 8 weeks postimplantation. Mechanical strength of the interface between HA and bone was measured using the pushout method. Read More

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http://dx.doi.org/10.1002/jab.770060403DOI Listing

Migration of polyethylene wear debris in hip arthroplasties: a canine model.

J Appl Biomater 1995 ;6(4):225-30

Department of Orthopaedic Surgery, Toronto East General and Orthopaedic Hospital, Ontario, Canada.

The distal migration of polyethylene wear debris appears to be a major cause of loosening and osteolysis of cementless total hip arthroplasties. The use of modern cementing techniques, circumferential porous or hydroxyapatite (HA) coating has been advocated as a means of preventing access of the particles to the bone-implant interface. The purpose of this study was to compare the ability of different methods of implant fixation to prevent wear debris migration. Read More

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http://dx.doi.org/10.1002/jab.770060402DOI Listing

A quantitative technique for reporting surface degradation patterns of UHMWPE components of retrieved total knee replacements.

J Appl Biomater 1995 ;6(1):9-18

Clinical Mechanics Group, Queen's University, Kingston, Ontario, Canada.

A quantitative method of reporting surface degradation of the ultra-high molecular weight polyethylene (UHMWPE) tibial component from retrieved total knee replacements (TKR) was developed. Specific features include a qualitative assessment expressing the patterns in which the damage was detected as well as a quantitative summary of the observed degradation mechanisms. In addition, a method of measuring lower limb alignment changes with time is described and related to the observed damage patterns. Read More

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http://dx.doi.org/10.1002/jab.770060103DOI Listing

Innovations in acrylic bone cement and application equipment.

J Appl Biomater 1995 ;6(1):75-83

Wolff & Kaaber A/S, Farum, Denmark.

A new bone cement was developed with the purpose of reducing the adverse biological effects during cementation of implants. This bone cement is characterized by lower exotherm, low release of monomer, low residual content of monomer, and retained physical properties. The essential innovation was substitution of half of the methylmethacrylate (MMA) in the monomer with long chain, high molecular weight, less volatile, and less soluble methacrylates (n-decylmethacrylate, isobornyl-methacrylate), as well as alteration of the accelerator system to a mix of dihydroxypropyl-p-toluidine and N,N-dimethyl-p-toluidine. Read More

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http://dx.doi.org/10.1002/jab.770060111DOI Listing

In vitro cytotoxicity testing of neodymium-iron-boron magnets.

J Appl Biomater 1995 ;6(1):69-74

Department of Orthodontics and Children's Dentistry, London, England.

Neodymium-iron-boron magnets are being increasingly used in orthodontic and orthopedic appliances. The purpose of this study was to investigate the in vitro cytotoxicity of these new "super" magnets. A modified agar overlay technique was performed using both L929 mouse fibroblasts and adult human oral mucosal fibroblasts. Read More

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http://dx.doi.org/10.1002/jab.770060110DOI Listing
May 1995
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Fibroblast seeding and culture in biodegradable porous substrates.

J Appl Biomater 1995 ;6(1):65-8

Department of Orthopaedic Surgery, Hôpital Sainte-Justine, Montréal, Canada.

A natural poly(hydroxybutyrate-co-9% hydroxyvalerate) copolyester was processed into a three-dimensional porous foam structure by salt leaching/solvent casting with previously sieved sodium chloride salts. Laboratory-built P(HB-9% HV) foams and commercial collagen sponges were cut into small rectangular specimens, sterilized, and prewetted using ethanol, rinsed with Dulbecco's minimum essential medium + 10% serum culture media, and seeded with fibroblasts isolated from canine anterior cruciate ligaments. The fibroblast cultures into such porous substrates were performed from 0 to 35 days by incubation (5% CO2) at 37 degrees C. Read More

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http://dx.doi.org/10.1002/jab.770060109DOI Listing

Bond strength of metal-ceramic systems in three-point flexure bond test.

J Appl Biomater 1995 ;6(1):55-64

Institut für Theoretische Mechanik, Universität Karlsruhe, Germany.

This study deals with a three-point flexure test for the metal-ceramic bond involving geometrically simple specimens (alloy strips partly coated with ceramic) that can be fabricated with reasonable expenditure and sufficient reproducibility. The calculation of the stress distribution in such specimens with the aid of the finite-element method (FEM) is presented. The aim of this numerical analysis is: to investigate the stress distribution in a ceramometallic specimen with dimensions that, in a large number of experiments, have proven to lead to debonding at one end of the ceramic veneer instead of a crack in the middle of the veneer; and to assign a bond strength to the measured critical bending force that takes into account the influence of the Young's modulus of the alloy as well as a possible deviation of the thickness of the metal substrate from the standard value. Read More

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http://dx.doi.org/10.1002/jab.770060108DOI Listing

Effects of hydroxyapatite and alumina sheaths on postoperative peritendinous adhesions in chickens.

J Appl Biomater 1995 ;6(1):43-53

Department of Orthopedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205.

Two experimental methods for restoring flexor tendon sheath integrity and preventing adhesions around traumatized flexor tendons utilizing artificial tendon sheaths made of either hydroxyapatite (HAp) or alumina were studied in a flexor tendon-trauma model and compared to a standard tendon sheath repair and a control. Eighty toes were divided equally into a control group, a sheath repair group, an HAp group, and an alumina group. Profundus tendons in zone II were divided and repaired after sublimis excision in all groups. Read More

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http://dx.doi.org/10.1002/jab.770060107DOI Listing
May 1995
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Biological response to ligament wear particles.

J Appl Biomater 1995 ;6(1):35-41

Abteilung für Unfallchirurgische Forschung und Biomechanik, Universität Ulm, Germany.

In ligament replacement cases where the artificial ligament has worn and partially or totally ruptured, the released wear particles have been associated with a chronic synovitis that inhibits integration of the ligament and contributes to the ultimate failure of the device. In this study, the biological response to ligament wear particles from nine different artificial ligaments was quantitatively evaluated in vivo. Wear particles, the majority of which were < 7 microns, were generated in vitro. Read More

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http://dx.doi.org/10.1002/jab.770060106DOI Listing