bluuebunny/crossref_metadata_2025_split huggingface dataset:
The long‐term behavior of poly‐L‐lactide screws in a minipig fracture model: Preliminary report
Authors: Hasegawa Yukiharu , Sakano Shinji , Iwase Toshiki , Warashina Hideki 
Published: November 2002

AbstractThe long‐term degradation tissue response to poly‐L‐lactide (PLLA) screw was investigated for a minipig tibia fracture. As a bone‐fracture model, three PLLA screws per animal were used to fix a tibia that had been subjected to a crank‐shaped osteotomy. A total of 12 nine‐month‐old male minipigs were used. In time period from 1 month to 3 years, clinical, radiographic, and pathological studies were conducted. On macroscopic examination, no clear granuloma or fistula formation was noted for 3 years. On microscopic examination, no osteoclasts or giant cells were detected around the screws during the 3 years postoperatively. A substantial degradation of PLLA screw was observed between 2 and 3 years. At 3 years only slight residual breakdown products were found in macrophages. On electric microscopic examination, numerous degraded polymers were seen in a small number of macrophages around the screws. In this model, fixation of tibia fractures using PLLA screws was not associated with any side effects, and was safe and useful for up to 3 years. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 679–685, 2002
Mechanical properties of coagulated albumin and failure mechanisms of liver repaired with the use of an argon‐beam coagulator with albumin
Authors: Moffitt T. P. , Baker D. A. , Kirkpatrick S. J. , Prahl S. A. 
Published: November 2002

AbstractHemostasis in the traumatized liver has been achieved by thermally denaturing topically applied albumin. In this article, the mechanical properties of liver and denatured albumin (solder) were measured, and the failure methods of liver repaired with albumin were identified. The ultimate tensile strength and Young's modulus were measured for healthy liver (N = 20) and thermally damaged liver (N = 20). The ultimate tensile strength and Young's modulus were measured for three concentrations of coagulated albumin (25, 38, and 53%) in a single layer and for two layers of denatured 38% albumin. Failure under tension of argon‐beam coagulator soldered liver on the parenchymal surface (N = 30) with 38% albumin in two layers had a 70% occurrence for tearing at a mean stress of 39 kPa and a 23% occurrence for shearing at a mean stress of 7 kPa. Liver repaired on the interior surface (N = 11) failed in tension by tearing (64%) at a mean stress of 34 kPa and by shearing (36%) at a mean stress of 6 kPa. Argon‐beam coagulator soldering with 38% albumin took 6 s/cm2 for two layers of solder and gave the best balance of usability, strength, and matching of mechanical properties with those of the liver. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 722–728, 2002
Knoop hardness depth profiles and compressive strength of selected dental composites polymerized with halogen and LED light curing technologies
Authors: Uhl Alexander , Mills Robin W. , Vowles Richard W. , Jandt Klaus D. 
Published: November 2002

AbstractAfter the first light‐emitting diode (LED) light curing units (LCUs) became available commercially, a comparison of mechanical properties between materials polymerized with conventional halogen lamps and this new technology was required. This study, therefore, investigated the curing performance of two conventional commercial halogen LCUs (Translux CL, Spectrum800), a custom‐made LED LCU prototype, and one of the first commercially available LED LCUs (LUXoMAX). The Spectrum800 was adjusted to a similar irradiance to the custom‐made LED LCU prototype. Both technologies were compared by measuring compressive strength and Knoop hardness depth profiles for selected dental composites polymerized for 20 or 40 s. Four dental composites (Z100, Spectrum TPH, Solitaire2, and Definite) were used. Two of these composites (Solitaire2 and Definite) contain co‐initiators in addition to the standard photoinitiator camphorquinone. In general, the material hardness obtained with the LUXoMAX was statistically significantly (p < 0.05) lower at the depths of 0.1, 1.0, 1.9, and 3.1 mm, for all composites and curing times, than for the other three LCUs. The LED LCU prototype achieved, with one exception, up to a depth of 1.9 mm a material hardness for the composites Z100, Spectrum TPH and Solitaire2 that was not statistically significant different (p < 0.05) from the hardness obtained with the halogen LCUs. At a greater depth (3.1 mm), however, the LED LCU prototype showed statistically significantly lower hardness values than the halogen units. The compressive strength test showed at a 95% confidence level that similar compressive strengths were achieved with the LCUs LUXoMAX and Spectrum800, and the Translux and LED LCU prototype. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 729–738, 2002
Hydroxyapatite‐based composite for dental implants: An in vivo removal torque experiment
Authors: Kong Young‐Min , Kim Dong‐Hwan , Kim Hyoun‐Ee , Heo Seong‐Joo , Koak Jai‐Young 
Published: November 2002

AbstractScrew‐shaped dental implants were fabricated from commercially pure Ti (c.p. Ti) and HA‐based composites. The HA‐based composites were fabricated by mixing HA with Al2O3‐coated ZrO2 powders. The mechanical properties of these composites were enhanced by a factor of 3. These were implanted into the rabbit tibiae and the removal torque to loosen the implants in vivo was measured in order to investigate the osteointegration. After a healing period of 6 weeks, the implants were retrieved with a torque gauge instrument. The HA‐based composite implants showed an almost 2‐times‐higher removal torque when compared to the Ti implants (ANOVA, p < 0.05), indicating excellent biocompatibility to bone. Thus, HA‐based composites had not only better mechanical properties but also similar bioactivity as HA itself. It is believed that a HA‐based composite is suitable for artificial dental implants. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 714–721, 2002
S/e‐PTFE episcleral buckling implants: An experimental and histopathologic study
Authors: Mortemousque B. , Leger F. , Velou S. , Graffan R. , Colin J. , Korobelnik J. F. 
Published: November 2002

AbstractTo investigate tissue changes induced by the implantation of a silicone band coated with expanded polytetrafluoroethylene (S/e‐PTFE) used as scleral buckling, an experimental and histopathological study was performed in rabbits. The right eyes of eight rabbits were implanted for 28–85 days with S/e‐PTFE. No complications were encountered in any of the eyes, so histopathological examinations could be performed. Encapsulations combined with numerous giant cells were found to be surrounding the implants in seven eyes, and deposits from the mineral salts of calcium were found in three eyes, forming granulomas possibly caused by irregularities of the implant surface. The porous structure allowed a peripheral colonization by fibrovascular tissue. Taking into account the histological results, the use of this material does not appear suitable. However, this inflammation was limited and did not merge on surrounding tissues. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 686–691, 2002
Effect of antibiotics on the properties of poly(methylmethacrylate)‐based bone cement
Authors: He Y. , Trotignon J. P. , Loty B. , Tcharkhtchi A. , Verdu J. 
Published: November 2002

AbstractThe goal of this study was to examine the relationship between gentamicin concentration in Palacos R bone cement (in the mass fraction range of 0–9.4%) and various properties of the cement. The results from the thermal, density, and static compression tests show that gentamicin favors the cement polymerization in its final steps, and forms a diphasic structure with the cement [poly(methylmethacrylate)] matrix. The static compression properties in the dry state are only slightly modified by the presence of the antibiotic. Concerning aging in water at 37 °C, two types of behavior can be distinguished: below a critical concentration, approximately 3–4%, the extraction of gentamicin by water is slow and there is only a slight change of static compression properties. In contrast, above this critical concentration, the gentamicin extraction is fast and almost complete after 48 weeks, and there is a considerable loss of static compression properties. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 800–806, 2002
In vivo release of vancomycin from biodegradable beads
Authors: Liu Shih‐Jung , Wen‐Neng Ueng Steve , Lin Song‐Shu , Chan Err‐Cheng 
Published: November 2002

AbstractThe current delivery system of antibiotics for the treatment of osteomyelitis uses polymethylmethacrylate (PMMA) beads as a local drug‐release agent. The nonbiodegradable nature of the PMMA, however, necessitates a second operation to remove the beads. This article explores the alternative of using biodegradable polymers as antibiotic beads for a long‐term drug release in vivo. To manufacture an antibiotic bead, lactide‐glycolide copolymers were mixed with vancomycin. The mixture was compressed and sintered at 55 °C to form beads 8 mm in diameter. An in vivo animal model was proposed to characterize the elution rate of antibiotic over a 55‐day period. Biodegradable beads released high concentrations of antibiotic (well above the breakpoint sensitivity concentration) in vivo for the period of time needed to treat bone infection; that is, 4–6 weeks. A bacterial inhibition test was also carried out to determine the relative activity of the released antibiotics. The diameter of the sample inhibition zone ranged from 8 to 18 mm, which is equivalent to 9.1 to 100% of relative activity. In addition, the antibiotic concentration of systemic blood was found to be very low. Antibiotic‐impregnated biodegradable beads may have a potential role in the prevention and management of surgical infections. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 807–813, 2002
Predictive modeling of the mechanical properties of particulate hydroxyapatite reinforced polymer composites
Authors: Balać Igor , Uskoković Petar S. , Aleksić Radoslav , Uskoković Dragan 
Published: November 2002

AbstractThe influence of particle geometry and volume fraction on the mechanical properties of a hydroxyapatite (HAp) particulate reinforced polymer (poly‐L‐lactide and collagen) matrix composite was investigated through finite‐element (FE) analysis. For cube‐shaped (near sharp and curved corners and edges) embedded particles, it was found that the maximum stress concentration factor (SCF) in the matrix decreases with an increase of the HAp particle volume fraction (PVF). The maximum stress concentration in the matrix material containing a spherical inclusion has low sensitivity to the PVF. The compressive Young's modulus was found to be slightly dependent on particle shape, but very sensitive to PVF. Calculated stiffness values from FE analysis were compared to the experimental results available in the literature and with predictions from the Halpin–Tsai model. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 793–799, 2002
Osseointegration on metallic implant surfaces: Effects of microgeometry and growth factor treatment
Authors: Frenkel Sally R. , Simon Jordan , Alexander Harold , Dennis Michael , Ricci John L. 
Published: November 2002

AbstractOrthopedic implants often loosen due to the invasion of fibrous tissue. The aim of this study was to devise a novel implant surface that would speed healing adjacent to the surface, and create a stable interface for bone integration, by using a chemoattractant for bone precursor cells, and by controlling tissue migration at implant surfaces via specific surface microgeometry design. Experimental surfaces were tested in a canine implantable chamber that simulates the intramedullary bone response around total joint implants. Titanium and alloy surfaces were prepared with specific microgeometries, designed to optimize tissue attachment and control fibrous encapsulation. TGFβ, a mitogen and chemoattractant (Hunziker EB, Rosenberg LC. J Bone Joint Surg Am 1996;78:721–733) for osteoprogenitor cells, was used to recruit progenitor cells to the implant surface and to enhance their proliferation. Calcium sulfate hemihydrate (CS) was the delivery vehicle for TGFβ; CS resorbs rapidly and appears to be osteoconductive. Animals were sacrificed at 6 and 12 weeks postoperatively. Results indicated that TGFβ can be reliably released in an active form from a calcium sulfate carrier in vivo. The growth factor had a significant effect on bone ingrowth into implant channels at an early time period, although this effect was not seen with higher doses at later periods. Adjustment of dosage should render TGFβ more potent at later time periods. Calcium sulfate treatment without TGFβ resulted in a significant increase in bone ingrowth throughout the 12‐week time period studied. Bone response to the microgrooved surfaces was dramatic, causing greater ingrowth in 9 of the 12 experimental conditions. Microgrooves also enhanced the mechanical strength of CS‐coated specimens. The grooved surface was able to control the direction of ingrowth. This surface treatment may result in a clinically valuable implant design to induce rapid ingrowth and a strong bone‐implant interface, contributing to implant longevity. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 706–713, 2002
Light scattering and in vitro biocompatibility studies of poly (vinyl pyrrolidone) derivatives with amino‐acid‐dependent groups
Authors: Baritaki Stavroula , Tzanakakis George N. , Alifragis John , Zafiropoulos Alexis , Tashmukhamedov Ravshan I. , Tsatsakis Aristidis , Shtilman Mikhail I. , Rizos Apostolos K. , Krambovitis Elias 
Published: November 2002

AbstractTwo poly (vinyl pyrrolidone) (PVP) families with amino‐acid residues (glycine, β‐alanine, γ‐aminobutiric acid and ϵ‐aminocaproic acid) on the base of the co‐polymer N‐vinyl pyrrolidone and allyl‐glycidyl ether (VP‐AGE) and on the base of epoxidized PVP (EPVP) were synthesized. Static and dynamic light scattering measurements of these PVP derivatives in water showed that their structure/ behavior were similar to that of PVP. The bioreactivity was also similar to that of PVP. Further investigation of the immunoreactive properties of the derivatives in in vitro proliferation assays with fresh normal human peripheral blood lymphocytes and monocytes led to the determination of a costimulatory profile for each derivative in terms of polyclonal stimulation, specific antigen presentation, and immunoglobulin secretion. This profile allows the selection of an appropriate derivative as a carrier that would suit the immunoreactivity needs of the immobilized ligand. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 830–837, 2002
Immobilization of an oxalate‐degrading enzyme on silicone elastomer
Authors: Malpass Charley A. , Millsap Kevin W. , Sidhu Harmeet , Gower Laurie B. 
Published: November 2002

AbstractUrinary biomaterials are compromised by device‐related urinary tract infections, bacterial biofilm formation, and biomineral encrustation. In the absence of urinary infection, calcium oxalate is the prevalent encrustation mineral formed. Considering this, a novel approach was taken in the study reported here, in that an oxalate‐degrading enzyme, oxalate oxidase (OXO), was immobilized on the surface of silicone elastomer (PDMS), a common urological biomaterial. It was hypothesized that the enzymatic action of OXO could lower urinary oxalate levels near the device surface, thereby preventing calcium oxalate crystal formation. The PDMS surface was functionalized with the use of radio‐frequency plasma discharge (RFPD) in the presence of water vapor, then coated with 3‐aminopropyltriethoxysilane (AMEO). The resulting aminated surface was covalently coupled with OXO via glutaraldehyde bioconjugation. The ability of the OXO‐coated PDMS to prevent calcium oxalate encrustation was evaluated with the use of a modified Robbins device (MRD) encrustation model. RFPD performed on PDMS resulted in an increase in the hydrophilicity of treated surfaces, as measured by contact angle. X‐ray photoelectron spectroscopy studies showed increases in elemental oxygen, after water‐vapor plasma, and in nitrogen after AMEO derivatization. The immobilized enzyme was shown to retain 47.5% of its specific enzymatic activity as compared to free enzyme. In vitro experiments for 6 days, with the use of a MRD, showed 53% less encrustation deposits on discs coated with OXO than control discs. The results from the current study suggest that PDMS‐immobilized oxalate‐degrading enzymes are active against calcium oxalate encrustation. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 822–829, 2002
An evaluation of the cytotoxic effects of orthodontic bonding adhesives upon a primary human oral gingival fibroblast culture and a permanent, human oral cancer‐cell line
Authors: Huang Tsui‐Hsien , Tsai Ching‐Yi , Chen Shiow‐Ling , Kao Chia‐Tze 
Published: November 2002

AbstractThe purpose of this investigation was to determine the cytotoxic effects of three different kinds of orthodontic adhesive on a human primary gingival fibroblast culture (GF) and a human oral cancer‐cell line (OC2). The adhesives comprised a self‐cure bonding resin, a light‐cure bonding resin, and a hybrid glass ionomer. Any differences between the cytotoxic potencies of eluates of the orthodontic materials on GF and OC2 cells were quantified colorimetrically (MTT test). The results are as follows: For the hybrid glass ionomer, the survival rate of GF cells exposed to the liquid component revealed a significant dose‐dependent decrease (p < 0.05). The liquid component and the mixed hybrid glass‐ionomer material reflected a significant dose‐dependent decrease (p < 0.05) in exposed OC2 cell survival. Associated with an increase in the cell exposure concentration of Resin A, Resin B, Paste A, Paste B, Resin A + B, Paste A + B and the set material of the self‐cure resin adhesive, was a significant decrease in survival rate for cultured GF and OC2 cells (p < 0.05). Associated with an increase in the concentration of the primer, paste, and mixed material of the light‐cure resin adhesive to which test cells were exposed, the survival rate reflected a decrease for GF cells (p < 0.05). The survival rate of cells exposed to light‐cure resin paste reflected no difference for OC2 cells. It is concluded that the liquid of the hybrid glass‐ionomer cement, Resin A and Resin B and Resin A + B of the self‐cure resin and the primer of the light‐cure resin are toxic agents to the GF and OC2 cell lines. Primary human gingival fibroblasts were found to be more sensitive than the tested human oral carcinoma cell line from most of the substances. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 814–821, 2002
Machinability of cast commercial titanium alloys
Authors: Watanabe I. , Kiyosue S. , Ohkubo C. , Aoki T. , Okabe T. 
Published: November 2002

AbstractThis study investigated the machinability of cast orthopedic titanium (metastable β) alloys for possible application to dentistry and compared the results with those of cast CP Ti, Ti‐6Al‐4V, and Ti‐6Al‐7Nb, which are currently used in dentistry. Machinability was determined as the amount of metal removed with the use of an electric handpiece and a SiC abrasive wheel turning at four different rotational wheel speeds. The ratios of the amount of metal removed and the wheel volume loss (machining ratio) were also evaluated. Based on these two criteria, the two α + β alloys tested generally exhibited better results for most of the wheel speeds compared to all the other metals tested. The machinability of the three β alloys employed was similar or worse, depending on the speed of the wheel, compared to CP Ti. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 760–764, 2002
Do multifilament alloplastic meshes increase the infection rate? Analysis of the polymeric surface, the bacteria adherence, and the in vivo consequences in a rat model
Authors: Klinge U. , Junge K. , Spellerberg B. , Piroth C. , Klosterhalfen B. , Schumpelick V. 
Published: November 2002

AbstractWithin the last decade hernia surgery has changed from suture repair to mesh repair. Biomaterials, and multifilaments in particular, are thought to increase the risk of infection. Therefore, the aim of this study was to study the influence of the presence of either a monofilament or a multifilament mesh material on the bacterial infection risk. The filament surface of a monofilament and a multifilament mesh were calculated on the basis of a theoretical model. The adherence of Staphylococcus aureus was measured in vitro by fluorescence analysis. Additionally, the two mesh materials (8‐mm platelets) were implanted subcutaneously in Sprague–Dawley rats with daily surveillance for clinical signs of infection. After 7 days the meshes were explanted for histological and microbiological analysis. Calculations of the mesh surface area revealed a higher level for the multifilament mesh. The extent of adherent bacteria corresponded to the estimated filament surface in vitro. In vivo, the implantation of meshes in the presence of 5 × 106
S. aureus did not show an increased infection rate in rats with either monofilament or multifilament material, compared to the control groups (mesh implantation without S. aureus contamination). However, after 7 days bacteria were still detectable in the majority of the implantation sites, and a clinically inapparent intensification of local inflammation and fibrosis was induced. The increased surface area of a multifilament meshes promotes the persistence of bacteria in the implant bed, though this alone is not sufficient to create a clinically apparent infection. This might explain the development of mesh‐related infections after a delay of several months or even years. In vivo, the adherence of bacteria to the implant material depends on the surface area, which favors the use of monofilament materials. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 765–771, 2002
Tissue reaction and biodegradation of implanted cross‐linked high amylose starch in rats
Authors: Désévaux Cyril , Dubreuil Pascal , Lenaerts Vincent , Girard Christiane 
Published: November 2002

AbstractThe biocompatibility and degradation characteristics of cross‐linked high amylose starch (Contramid®) were investigated in rats over 4 months. Contramid® pellets (3‐mm diameter and thickness) obtained by direct compression, were implanted subcutaneously and intramuscularly. On sequential time points, macroscopic observations of implantation sites were performed and tissue samples were removed, fixed, and histologically evaluated. No macroscopic inflammatory reaction was observed with Contramid®. Upon histologic examination, inflammatory reaction produced by Contramid® was moderate and restricted to implantation sites. The sequence of inflammatory events with Contramid® was similar regardless of implantation site. Degradation of Contramid® pellets was characterized by fragmentation with formation of fibrovascular septa and phagocytosis by macrophages. Finally Contramid® was mostly absorbed by the end of the 4‐month period and substituted by adipocytes. It has been demonstrated that Contramid® is a biocompatible and absorbable material. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 772–779, 2002