bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface Characteristics of RF Magnetron Sputtered Calcium Phosphate Coatings at Different Heat Treatments
Authors: Yonggang Yan , Wolke Joop G.C. , Li Yu Bao , Jansen John A.
Published: March 2009

RF magnetron sputtering was used to produce calcium phosphate coatings on
titanium substrates. The as-sputtered amorphous calcium phosphate (CaP) coatings were subjected to a rapid heating with infrared irradiation and subsequent heating in an autoclave. XRD analyses showed that infrared radiation of the amorphous coatings changed respectively into a crystalline apatite- and a β-pyrophosphate structure. Heating in the autoclave showed for the amorphous CaP coating at 80°C for 2 days and 8 hours at 140°C no change in structure and the formation of a crystalline apatite structure respectively. The amorphous
pyrophosphate(Pyro) coating altered during the autoclave treatment for 2days at 80°C into a monetite phase, while at 140°C an apatite structure was formed. SEM analyses demonstrated that after the different heat-treatments several coating morphologies were obtained. Infrared radiation had no effect on the coating morphology. The autoclave-treated coatings showed the formation of a calcium phosphate precipitate. CaP and Pyro coatings induced a morphologically different precipitate. On the CaP coating, spherocrystallites crystals were formed and the Pyro coatings showed the formation of needle like crystals. EDS analyses
indicated for the autoclave heat treated Pyro coating an increase of the Ca/P ratio from 0.8 to 1.7.
Electrochemically Deposited Calcium Phosphate Coating on Titanium Alloy Substrates
Authors: LeGeros John P. , Lin Shu Jie , Mijares Dindo Q. , Dimaano Fred , LeGeros Racquel Z.
Published: March 2009

Plasma-sprayed HA coating combines the strength of the metal and the bioactivity of the HA. However, this method has several disadvantages. Alternatives to the plasma-spray method such as electrochemical deposition (ECD) and biomimetic or precipitation methods are being explored. The purpose of this study was to develop an ECD method for coating Ti alloy substrate with different calcium phosphates (octacalcium phosphate, calcium deficient apatite, carbonatesubstituted apatite, fluoride-substituted apatite). Pairs of Ti6Al4V plates that have been mechanically polished, ultrasonically cleaned, acid etched, rinsed and dried were used as anodes and cathodes. ECD was carried out using programmed pulse time electric fields. Results showed that uniform coating with only the desired calcium phosphate can be obtained using metastable calcium
phosphate solutions at different pH and temperature conditions and different electrolyte concentrations. Coating thickness varied with the duration of coating deposition. Crystal size varied with other ECD conditions (e.g., pulse time, current density). This method can be used to obtain uniform coating of the desired calcium phosphate composition at low temperatures (25 to 80oC) on substrates of any type of geometry.
Preparation of Bioactive Titanium Alloy Implant and Its Histological Examination
Authors: Xiong Tian Ying , Zhao Ying , Wu J. , Jin Hua-Zi , Wang Li Bin
Published: March 2009

A layer of thick oxide film was formed on Ti6Al4V substrate by anodization.
Subsequently alkali and heat treatment induced to form bonelike apatite layer on its surface in SBF for 7 days. The performances of the implants in vivo were observed by naked eyes and H.E. staining technique. The bone tissues around the surface and interface of the specimen in treated Ti6Al4V group were formed more quickly than those in Ti6Al4V and 316L alloy groups. H.E staining results of treated Ti6Al4V group showed the development of newly formed bone tissues on the implant-bone interface area.
Bone Marrow Autograft Associated to Macroporous Biphasic Calcium Phosphate for Bone Substitution in an Animal Model of Sequels of Radiotherapy
Authors: Malard Oliver , Bouler Jean Michel , Guicheux Jerome , Gauthier Olivier , Lerouxel E. , Daculsi Guy
Published: March 2009

Bone invasion is common in case of Squamous Cell Carcinomas (SCC) of the upper aero-digestive tract. Radiotherapy is required in addition to large surgical tumor removal. This treatment usually generates irreversible injuries on the reparation properties of the tissues, especially on bone. The quality of life of patients undergoing major surgery and radiotherapy in maxillary and mandible areas is reduced, but could be improved by bone reconstruction. The aim of this study was
to evaluate the bone reconstruction possibilities by Macroporous Biphasic Calcium-Phosphate (MBCPÔ). The MBCP substitute was evaluated as granules and associated to autologous bone marrow (BM) graft in irradiated areas, in an inbreeding rodent model. Radiation sequels were created on inferior members of half of the rats. 3 weeks later, 3-mm osseous defects were created on each animal. The inbreeding model allows BM to be grafted without graft-versus-host reaction. Defects
were filled either with MBCP alone, BM alone or a mixture of MBCP and BM. Six weeks after implantation, animals were sacrificed: bone repair and ceramic degradation were evaluated by qualitative and quantitative study. Results showed that bioceramics were well osteointegrated. Filling the defects with BM alone showed a significant increased of newly-formed bone formation but only after irradiation, whereas filling defects with MBCP alone increased new-bone formation only without previous irradiation. Associating MBCP to BM provided the best new-bone formation rates after irradiation. Degradation of the ceramic was the most important in case of BM grafting. This study demonstrated that BM added to MBCP constitute an appropriate material to be considered in case of bone defect occurring in irradiated tissue, and could be foreseen for use after bone removal for oncologic obligations.
In Vitro and In Vivo Behavior of Coral Treated by Hydrogen Peroxide, Supercritical Ethanol, or Heat
Authors: Souillac Vincent , Fricain Jean Christophe , Lepetitcorps Y. , Bureau V. , Chauveaux Dominique
Published: March 2009

In this study we focus on the use of coral Porites Lutea and the various treatments
used to remove proteins while assessing the impact of the various removal methods on the in vitro and in vivo coral behavior. No significant differences were observed in vitro among all materials. In vivo, no histological differences were observed between BiocoralÒ and samples treated by either hydrogen peroxide or a thermal procedure. The implants made from supercritical fluid treated coral were more resistant to resorption (50% more resistant after one month).
Fabricating Hydroxyapatite Spherulites with Characteristic Microporous Structure by Chitin Sol Emulsified in Oil and Gelatinized In Situ
Authors: Peng Qian , Qu Shao Xing , Lu Xiao Ying , Weng Jie
Published: March 2009

Hydroxyapatite (HA) spherulites had been fabricated successfully through a novel approach including chitin emulsion and geletion processes. The freeze-dried nano-HA powder was firstly dispersed in the chitin solvent before chitin dissolves in its solvent completely. The chitin sol containing nano-HA particles was dropped into oil and emulsified making use of liquids immiscibility effect between oil and chitin sol by stirring. The n-HA/Chitin sol spherulites gelled in situ with the existence of water molecules. Subsequently, the spherular gel granules were rinsed in distilled water to leach the solvent and dried in room circumstance. Finally, special sintering
routines were carried to harvest spherular HA granules. The size and porosity of HA spherulites were controlled by the rate of nano-HA to chitin, the chitin concentration in the starting slurry, the stirring rate and the temperature of oil etc. In addition porosifier such as sugar was used in order to adjust the macro- and micro-porous structures in the HA spherulites. The morphological observation showed that the HA spherulites had good sphericity and characteristic microporous
structure which were favorable for medical application.
XRD, SEM/EDX and FTIR Characterization of Brazilian Natural Coral
Authors: Mansur Herman S. , Mansur Alexandra A.P. , Pereira Marivalda
Published: March 2009

In the present work, natural coral from Brazilian reefs were studied according to their
crystallography by X-ray diffraction and microstructure by Scanning Electron Microscopy (SEM/EDX). FTIR spectroscopy was also used to evaluate the chemical functionalities and major components present in the material. The SEM morphology results have shown a tri-dimensional coral structure with porous ranging from 50 to 200 µm. Aragonite was identified as the major crystalline phase through XRD analysis and FTIR spectroscopy. Strontium calcium carbonate,
(Sr,Ca)CO3, was also identified by XRD analysis. After sintering at 900º/1h, the conversion from aragonite to CaO and calcite was observed. These results have endorsed the high potential application of natural coral materials as 3D scaffolds for biomedical application, because of calcium carbonate compounds can be converted to HA by hydrothermal and biomimetic coating processes.
Fast Apatite-Forming Ability of Magnetron Co-Sputtered Silicon-Containing Hydroxyapatite (Si-HA) Thin Films
Authors: Thian E.S. , Huang Jie , Best Serena , Barber Zoe H. , Bonfield William
Published: March 2009

0.8 wt.% silicon-containing hydroxyapatite (Si-HA) thin films of thickness 600 nm have been successfully developed using a magnetron co-sputtering technique, through careful selection and control of the processing conditions. These films were immersed in simulated body fluid (SBF) to investigate the nucleation and growth of an apatite layer on their surfaces. A newly-formed apatite layer with similar characteristics to that of the biological bone apatite, was observed after 4 days of
immersion in SBF. X-ray diffraction and infrared analyses confirmed this layer to be calciumdeficient micro-crystalline carbonate HA. These results demonstrated that the novel Si-HA films were highly bioactive and the time frame required for apatite formation was reduced by approximately 76 % (from 17 days to 4 days).
Effect of Some Physical-Chemical Variables in the Synthesis of Hydroxyapatite by the Precipitation Route
Authors: García Claudia P. , Paucar C. , Gaviria J. , Durán Alicia
Published: March 2009

The synthetic hydroxyapatite is a very useful material for numerous applications in
medicine as a biomaterial. One of the most economic manufacturing process is the
precipitation route. In the present work, synthetic hydroxyapatite was prepared using the precipitation route, starting with aqueous solutions of calcium nitrate (Ca(NO3).4H2O ) and ammonium phosphate (H2(PO4)NH4). The effects of physical-chemical variables such as pH, temperature, time of agitation, ageing time and heat treatment of the mixture were evaluated.
The characterization of the samples obtained in different conditions made possible to
conclude about the optimal values of the studied variables for the synthesis of this material in laboratory conditions.
Effect of Phase Components on Apatite Formation on the Surface of Ca-P Bioceramics
Authors: Deng Chun Lin , Chen Ji Yong , Fan Hong Song , Zhang Xing Dong
Published: March 2009

Dense hydroxyapatite (HA) and hydroxyapatite/tricalcium (HA/TCP) were immersed in Fast calcified solution (FCS) at 37°C in constant temperature culture box for 7 days. It was observed that the phase components of dense ceramics affected the composition, crystallinity and phase components of formed apatites on the surface of ceramics. It is a mixture of hydroxyapatite with a strong preferential crystallographic direction of 002 and octacalcium phosphate (OCP) on the surface of HA/TCP ceramics, whereas only an HA phase was detected on the surface of HA ceramics.
In Vitro Characterization of Bioactive Glasses
Authors: Zhang Di , Vedel Erik , Hupa Leena , Ylänen Heimo O. , Hupa Mikko
Published: March 2009

In vitro behavior of 30 new glasses in the system Na2O-K2O-MgO-CaO-B2O3
-P2O5-SiO2 was investigated by immersing them into a simulated body fluid for 4 to168 hours. This study involved the observation of both the changes in the properties of the immersion solution and on the glasses surface after immersion. In vitro reactivity was different for each experimental glass depending on its chemical composition. By comparing these glasses to four established bioactive glasses showing different in vivo bioactivity, a fast estimation of the bioactivity of glasses can be done; thereby the optimization of bioactive glasses for various clinical applications can be developed.
Effect of Concentrated Sulfuric Acid-Etching on Apatite-Forming Ability of Alkaline-Treated Titanium
Authors: Ban Seiji , Kono Hiroshi , Iwaya Y. , Yuda Akihiko , Izumi Yuichi
Published: March 2009

Concentrated H2SO4 acid was applied to pretreatment for the alkaline treatment of
commercially pure titanium, and the effect of acid-etching on apatite-forming ability of
alkaline-treated titanium in a simulated body fluid (SBF) was investigated. Characterization analysis revealed that the concentrated H2SO4 etching formed much amount of sodium titanate, resulting a large amount of formation of apatite in SBF. It is confirmed that the etching in concentrated H2SO4 enhance apatite-forming ability of alkaline-treated titanium.
Osteoclast Response of Biomimetically Processed Silica and Carbonate Containing Calcium Phosphate Layers on Bioactive Glass S53P4
Authors: Vaahtio Minna , Peltola Timo , Hentunen Teuvo , Ylänen Heimo O. , Areva Sami , Salonen Jukka I.
Published: March 2009

Different silica and carbonate containing calcium phosphate (CaP) layers were prepared on bioactive glass S53P4 in conventional C-SBF and revised R-SBF. In R-SBF the CaP layer formed faster compared to C-SBF, and the CaP layer formed in R-SBF was amorphous compared to the poorly crystalline bonelike HCA formed in C-SBF. In addition, the influence of chemical composition, dissolution and structure of biomimetically processed CaP layers on osteoclast and osteoblast activity was studied. In general, biomimetic CaP layers on bioactive glass S53P4 did not
affect so much on bone cell activity as it was expected compared to the untreated glass. Additionally, it was observed that the mechanism for good osteoclast activity is multifactorial. The optimal surface for osteoclast adhesion and growth was an amorphous CaP having mesoporous nanotopography and proper dissolution rate of calcium and silica. Also osteoblasts grew well on such surface.
The Influence of Geometrically Configured Sol-Gel Derived Hydroxyapatite Substrates on Osteoblast Response
Authors: Adams Daniel , Smith Regina D. , Malgas Gerald F. , Massia S.P. , Alford T.L. , Mayer J.W.
Published: March 2009

Good quality crystalline sol-derived Hydroxyapatite (HA) thin films of thickness ~350 nm on titanium substrates with underlying micro-channels were prepared by microwave annealing at a temperature of 400 °C for 30 min. A comprehensive in-vitro study was conducted to assess the osteoblast adhesive response to the well-defined micro-scale topographical features on HA coated and uncoated surfaces. The study confirmed the osteoblast’s response to the HA coated micro-channels with an elongated morphology. The effects to morphology suggest that osteoblast adhesion can be improved through optimal micro-channel design and may provide baseline design cues for improving the longterm performance of prosthetic orthopedic and dental implants.
Culturing Human Mesenchymal Stem Cells on Bioceramics for Hard Tissue Regeneration (Validation of In Vitro Bone Matrix Formed on Ceramics for Clinical Application)
Authors: Ohgushi Hajime , Kitamura Shigeyuki , Kotobuki Noriko , Hirose Motohiro , Machida Hiroko , Oshima Akira , Tanaka Yasuhito , Takakura Yoshinori
Published: March 2009

Alumina ceramics have excellent mechanical and biocompatible properties, but are bioinert and hence have no bone-bonding properties. We took a tissue engineering approach in an attempt to modify the ceramic surface and so provide an osteogenic/osteoconductive milieu. We used fresh human bone marrow cells obtained from the iliac crest by needle aspiration for culture expansion of
mesenchymal stem cells (MSC) followed by in vitro osteogenic differentiation on both tissue culture polystyrene (TCPS) and alumina ceramics. We have succeeded in expanding the number of MSC from all 35 cases and compared the differentiation capability of selected MSC on alumina ceramics to that on TCPS. The cells on both substrata showed extensive alkaline phosphatase staining and
mineralization as evidenced by calcein uptake. Biochemical analyses revealed high levels of alkaline phosphatase activity, osteocalcin expression, and calcium content. These data indicate that an alumina ceramic surface can support a differentiation cascade of MSC resulting in osteoblastic phenotype expression of the cells. Based on these results, we have performed clinical applications of tissue engineered total joint replacements for osteoarthritic patients.
Development of Controlled Heterogeneity on a Polymer-Ceramic Hydrogel Scaffold for Osteochondral Repair
Authors: Lu H.H. , Jiang J. , Tang Aitao , Hung C.T. , Guo X.E.
Published: March 2009

Due to its intrinsically poor repair potential, injuries to articular cartilage do not heal and clinical intervention is required. Osteochondral grafts may improve healing while promoting integration with host tissue. We report here the development of an osteochondral graft based on a hybrid of a hyrogel and a polymer-bioactive glass composite (PLAGA-BG) microsphere scaffold. This novel osteochondral construct consists of three regions: gel-only, gel/composite interface, and a composite-only-region. The three phases differ in calcium phospate (Ca-P) or BG content. The objective of the current study is to investigate the effects of scaffold composition on chondrocyte response, and to evaluate the effects of co-culture on osteoblasts and chondrocyte growh and differentiation on the hybrid scaffold. The PLAGA-BG microsphere scaffold supported the growth of chondrocytes and initial results indicate that in the presence of BG, chondrocyte-mediated mineralization may be stimulated. Co-culture of osteoblasts and chondrocytes on the multi-phased scaffold with varied Ca-P content facilitated the formation of multiple matrix zones: a GAGrich chondrocyte region, an interfacial matrix rich in GAG+collagen, and a mineralized collagen matrix with osteoblasts. In summary, chondrocyte response has been optimized as a function of scaffold composition and the novel osteochondral graft has the potential to support the simultaneous formation of multiple types of tissue in vitro.
Biomimetic Hydroxyapatite Micro-Tube Tissue Scaffold
Authors: Kolos Elizabeth C. , Ruys Andrew John , Rohanizadeh Ramin , Muir M.M. , Roger Greg J.
Published: March 2009

The aim of this study was to fabricate a micro-tube scaffold using a biomimetic method (immersion in Simulated Body Fluid, SBF) to coat apatite on cotton fibres. The cotton fibres were first pre-treated using a phosphorylation technique and then apatite crystals were deposited on the fibres by immersing in SBF. Micro-tubes were then formed by burning out the cotton fibres at various temperatures between 950-1250°C. The scaffolds were fabricated by compaction of the micro-tubes in a mould. The compacted micro-tubes were then sintered at various temperatures
between 900-1200°C. The biocompatibility and the effects of the surface morphology of scaffolds on cell coverage and proliferation were determined using osteoblast cell culture. The results showed that these scaddolds were biocompatible and able to support cell growth. Future studies include animal studies for biomimetic tissue scaffold as a bone filler substitute material.
In Vitro Culture of Osteoblasts with Three Dimensionally Ordered Macroporous Sol-Gel Bioactive Glass (3DOM-BG) Particles
Authors: Zhang Kai , Washburn Newell R. , Antonucci Joseph M. , Simon Carl G.
Published: March 2009

Three dimensionally ordered macroporous sol-gel bioactive glasses (3DOM-BGs)are a type of biomaterial that is both bioactive and resorbable. In this study, 80 % SiO2 – 20 % CaO (molar fraction) 3DOM-BG particles were prepared using a colloidal crystal templating method via a sol-gel process. The as-prepared 3DOM-BG particles can quickly convert to a calcium-deficient, bone-like apatite after soaking in a simulated body fluid (SBF). MC3T3-E1 osteoblastic cells were cultured in the presence of 3DOM-BG particles. Preliminary results from cell studies showed that 3DOM-BG particles are not cytotoxic and are compatible with
MC3T3-E1 osteoblast-like cells in vitro.
Preparation of Hydroxyapatite Ceramic Unit with a Trap for 2-D Cultured Cells
Authors: Teraoka Kay , Saito Takao , Yokogawa Yoshiyuki
Published: March 2009

This paper demonstrated a simple technique to seed the hydroxyapatite (HA) ceramic with 2-D cultured cells to establish an advanced mode of HA grafting. The HA beads with a through-hole were fabricated to have an oblate shape to keep an opening of the through-hole contact with 2-D cultured cells layer. The seeding was performed by leaving the HA beads in a culture dish with MG63 cells in culture. The through-hole trapped MG63 cells in a sheet form by 1-day seeding. After 5 days,
the number of trapped cells increased about nine fold, forming cell clumps in the through-hole. The seeding of the HA beads was considered an easy and practical method to provide HA/Cell hybrids that would realize active bone forming orthopedic treatment.
Effect of Calcium Phosphate Addition to Alginate Microspheres: Modulation of Enzyme Release Kinetics and Improvement of Cell Adhesion
Authors: Barrias C.C. , Ribeiro C.C. , Rodrigues Daniel , Sá Miranda M.C. , Barbosa Mario A.
Published: March 2009

In this study, the addition of calcium phosphate powders to an alginate matrix was
evaluated as a strategy to modulate enzyme release-kinetics from alginate microspheres and, simultaneously, to improve cell adhesion to the polymer. Pre-adsorption of the enzyme to the ceramic powders resulted in a more adequate release pattern. The ratio of ceramic-to-polymer had a pronounced effect on osteoblast adhesion to microspheres. Cells were only able to spread on
microspheres with the highest percentage of ceramic (0.4 w/w using a 1.5% w/v alginate solution).
Carboxymethylchitosan/Calcium Phosphate Hybrid Materials Prepared by an Innovative Auto-Catalytic Co-Precipitation Method
Authors: Costa S.A. , Oliveira J. Miguel , Leonor Isabel B. , Reis Rui L.
Published: March 2009

In this study, it is shown that it is possible to prepare carboxymethyl-chitosan/Ca-P
hybrids using an innovative “auto-catalytic” co-precipitation method, namely by using an acid and an oxidant bath. The X-ray diffraction (XRD) patterns evidenced the formation of crystalline calcium-phosphate precipitates when using an acid bath, while amorphous ones were obtained for those produced in the oxidant bath. The Fourier Transform Infrared spectroscopy (FTIR) and Scanning Electron Microscopy (SEM/EDS) studies revealed that the extent of the polymer
precipitation and formation of calcium-phosphates is directly dependent on the pH and composition of the baths. Furthermore, by conducting bioactivity tests in a simulated body fluid (SBF) followed by the SEM/EDS analysis it was possible to detect the formation of an apatite layer with a cauliflower-like morphology on the surface of hybrids prepared by the acid bath, after 7 days of immersion. These results are quite promising because they can allow for the production of bioactive
and biodegradable 3D porous scaffolds to be used in bone tissue engineering applications.
Synthesis of Biodegradable Hybrid Consisting of Hydroxyapatite and Alginate
Authors: Ohtsuki Chikara , Hosoya K. , Kawai Takahiro , Kamitakahara Masanobu , Ogata Shinichi , Miyazaki Toshiki , Tanihara Masao
Published: March 2009

Hybrids consisting of hydroxyapatite and biodegradable polymers are attractive materials for bone repair. We recently developed hydroxyapatite-alginate hybrids through a soaking process of alginate modified with 3-aminopropyltriethoxysilane (APES), ethylenediamine (EDA) and CaCl2 in a solution mimicking body fluid such as SBF, 1.5SBF proposed by Kokubo et al.. In this study, biological behavior of the apatite-alginate hybrid fabricated through modification with APES and
CaCl2 were evaluated after implantation in a rat tibia, in comparison with that of alginate gel without hydroxyapatite. The higher degree of calcification was observed for the hydroxyapatitealginate hybrid than the alginate gel without hydroxyapatite. The hydroxyapatite precipitated on and inside alginate allowed the hybrid to show not only osteoconduction but also suitable biodegradation after implantation in bony defect.
Calcium Polyphosphate/Polyvinyl Acid-Carbonate Copolymer Based Composites for Use in Biodegradable Load-Bearing Composites for Orthopaedic Implant Fabrication
Authors: Ramsay S.D. , Pilliar R.M. , Yang Liu , Santerre J.P.
Published: March 2009

Particle filled composite and interpetrating phase composite (IPC) structures are investigated for the production of a biodegradable composite for use as a fixation device in various osteosynthesis applications. The composites consist of calcium polyphosphate, present as either a dispersion of 106 – 150 µm particles or as a sintered scaffold-like structure having open porosity in the range of 18 – 35 volume percent, and a polyvinyl acid-carbonate copolymer that is cured in situ via free
radical polymerization. The performance of each composite structure is evaluated in terms of its three-point bend strength and elastic constant. Plane strain fracture toughness values are also
presented for IPC samples based on CPP sintered to have 30 volume percent porosity.
Repairing of Osteochondral Defects in Joint Using Beta-TCP/ Carboxymethyl Chitin Composite
Authors: Masuda Shingo , Yoshihara Yusuke , Muramatsu Kazuaki , Wakebe Izumi
Published: March 2009

Beta-tricalcium phosphate/carboxymethyl chitin composites [TCP/CMCh] of various
ratios of TCP granules and CMCh were made and their mechanical properties, handling properties and repair performance for bone defects and for osteochondral defects were investigated. Water pooling ratio of CMCh was approximately 40 times the weight itself. TCP/CMCh of a higher TCP ratio had higher stress at 50%-strain. The stress at 50%-strain of TCP/CMCh with 0, 2.5, 5.0, 7.5, 10 TCP ratios was 0.12, 0.51, 1.08, 1.46, 1.67 (MPa, n=5), respectively. The TCP/CMCh with 5.0 TCP ratios had the best total scores in handling tests. The bone repair rate of TCP/CMCh was TCP ratio 2.5< Blank= TCP ratio 7.5< TCP ratio 5.0. In the implantation test for osteochondral defects, TCP/CMCh was completely absorbed at four weeks after surgery. Regeneration of the articular cartilage was seen with TCP/CMCh and HA/CMCh but not with TCP granules, which remained eight
weeks after implantation. The regenerated articular cartilage had remained 32 weeks after implantation. In conclusion, it was demonstrated that this TCP/CMCh composite was a promising material for repairing osteochondral defects.
In Vivo Biocompatibility of a Novel Ceramic-Metal Biocomposite
Authors: Ying Danyang , Luo L.X. , Young B. , Julian A.F.
Published: March 2009

An in vivo biocompatibility test of a novel biocomposite, with major phases of CaTiO3 and Ti2O, and minor phases of AlTi3, TiO, CaO and Al2O3, was conducted on rats using subcutaneous implantation. The biocomposite and titanium alloy control specimens were removed at 6 and 14 weeks post-implantation. Histological examination revealed no significant adverse reaction of the
surrounding tissue to the either the biocomposite or the control material. We conclude that the
composite is well tolerated in a physiological environment.
In Vitro Biodegradability of Chitosan-Organosiloxane Hybrid Membrane
Authors: Tsuru Kanji , Shirosaki Yuki , Hayakawa Satoshi , Osaka Akiyoshi , Lopes M.A. , Santos José D. , Fernandes Maria Helena F.V.
Published: March 2009

Chitosan-silicate hybrid membranes were prepared using g-glycidoxy-propyltrimethoxysilane (GPSM) through a sol-gel process. The amino groups of chitosan chains were reacted with the epoxy groups of GPSM and GPSM have a function as the agent to cross-link the chitosan chains. The cross-linking degree of the hybrid membranes was determined by ninhydrin assay. Fourier-transform infrared (FT-IR) spectroscopy and 29Si cross-polarization (CP)
magic-angle spinning (MAS)-NMR spectroscopy were used to assess the structure of the hybrid membranes. The biodegradability of the hybrid membranes in phosphate-buffered saline solution or lysozyme solution was investigated as a function of the GPSM concentration.
Si, Zn-Modified Tricalcium Phosphates: A Phase Composition and Crystal Structure Study
Authors: Wei Xiang , Akinc Mufit
Published: March 2009

Tricalcium phosphate modified by silicon and zinc was synthesized as a candidate for resorbable temporal bone implant having a controlled solubility and improved biocompatibility. Since Si and Zn are essential trace elements with stimulatory effects on bone formation, Si,Znmodified tricalcium phosphate can also promote bone formation. From XRD and ICP analyses, it was shown that up to 10 mol% Si and Zn can be incorporated in the tricalcium phosphate lattice without formation of a second phase. Changes in lattice parameters and unit volume of TCP as
calculated by Rietveld refinement analysis indicate that Si and Zn substitute for P and Ca respectively.
Assessment of the Potential of Bonelike® Graft for Bone Regeneration by Using an Animal Model
Authors: Lobato J.V. , Sooraj Hussain Nandyala , Botelho C.M. , Rodrigues J.M. , Luís A.L. , Maurício Ana Colette , Lopes M.A. , Santos José D.
Published: March 2009

BonelikeÒ graft that mimics the inorganic composition of bone tissue has been developed and characterized over the last decade. To evaluate the osteoconductivity of BonelikeÒ two granule size ranges, one ranging from 150-250µm and the other from 250-500µm were implanted in the femurs of New Zealand White rabbits, aiming at being clinically used in different medical applications, such as dentistry and orthopaedics. In order to facilitate the medical application of the
BonelikeÒ graft the use of a commercially available polymeric vehicle was also analyzed. Radiological examination, histological studies and scanning electron microscopy (SEM) analyses revealed that the surface of Bonelike® granules was almost completely surrounded by new bone formation after 12 weeks of implantation, which proves its highly osteoconductive behaviour.
The Effect of Li2O and B2O3 on Thermal Properties and Chemical Solubility of Low-Fusing Dental Porcelain
Authors: Ko Dae Jin , Kim Kyoung Nam , Lee Yong Keun , Kim B.H. , Kim Kwang Mahn
Published: March 2009

Alkali oxides were added to glass frit in order to lower the firing temperature of dental
porcelain, and the effects of Li2O and B2O3 on the thermal properties and chemical solubility of low-fusing dental porcelain were investigated.
The glass transition temperature(Tg) and softening temperature(Ts) of glass frits were decreased remarkably by adding Li2O, but the coefficient of thermal expansion(CTE) was increased with Li2O. In the case of adding B2O3, the thermal properties were unchanged. Tg of B0L4, B2L4 and B4L4 specimens were lower than 500°C and Ts were lower than 550°C. The chemical solubility of prepared low-fusing dental porcelain with these glass frits were 37.3,
43.9, and 49.2µg·cm-2 respectively. The chemical solubility was increased by adding Li2O and B2O3, but all the results were below 100µg·cm-2 and satisfactory to ISO Standards. Further, the chemical solubility of the commercial low-fusing dental porcelains were 52.6µg·cm-2 for Ceramco Finesse(Clear), 70.8µg·cm-2 for Duceram-LFC(TC) and that of conventional dental porcelain, CeraMax(T-C), was 34.8µg·cm-2.
Bioactive Glass Compositions Suitable for Repeated Heat-Treatments
Authors: Arstila Hanna , Zhang Di , Vedel Erik , Hupa Leena , Ylänen Heimo O. , Hupa Mikko
Published: March 2009

The crystallization tendency for 30 experimental glasses in the system Na2O-K2O-MgOCaO-B2O3-P2O5-SiO2 was studied with thermal methods, DTA, HSM and XRD. The glasses were also immersed into simulated body fluid for 8 and 72 hours. The formation of the silica-rich gel and calcium phosphate layer on the glasses were analyzed with SEM. The in vitro behavior and crystallization tendency for heat-treated glasses were then related. This information is essential for choosing glass compositions that can be manufactured to desired products with controlled
bioactivity for different applications. In general, glasses with low alkali content can tolerate heattreatment without crystallization but have less initial Si-gel formation ability and show less in vitro bioactivity than glasses with high alkali content.
Preparation and In Vivo Studies of β-TCP Based Bone Cement Containing Polyphosphate
Authors: Oh Kyung Sik , Jeong Young Keun , Yu Jae Pil , Chae Soo-Kyung , Kim Hong Yeoul , Lee Ho Yeon , Jeun Sin-Soo
Published: March 2009

b-Ca3(PO4)2 (TCP) based cement combined with polyphosphate was investigated. In the bone cement composed of b-TCP, monocalcium monophosphate (MCPM) and calcium sulfate hemihydrate (CSH), effect of the amount of setting agent on workability, setting time, temperature rise and compressive strength was evaluated. The polyphosphate, which was selected as a growth enhancer, could be introduced without affecting the properties of cement. The polyphosphate
containing cement was introduced at the calvarial defect in a rabbit. After three months, the defect was covered with newly formed bone, in contrast with the case of polyphosphate free bone cement.
These results suggest that the bone cement containing inorganic polyphosphate can be used as effective bone filler with considerable potential of bone regeneration for bony defects.
The Osteogenic Potential of Stem Cell- and BMP2 Gene-Activating Bioceramic In Vivo
Authors: Yan Wei Qi , Feng Jie , Chen Q. , Yang Di Sheng , Zhao Ying , Yan Shi Gui
Published: March 2009

Stimulation of bone healing through local application of growth factors from implants
may improve the clinical outcome in fracture treatments. However, the growth factors in reconstructive application require supraphysiologic dosing and considerable expense while hampering their clinical application. Genetic modification of mesenchymal stem cells (MSCs) to both produce and respond to osteogenic factors may have potential for use in enhancing bone healing. In this study, MSCs were genetically modified by a recombinant adenoviral containing the gene for human bone morphogenetic protein 2 (hBMP-2). The gene-transduced cells were
incorporated with a porous beta-tricalcium phosphate (TCP) as a novel complex. We investigated osteogeneic potential of gene-transduced MSCs/ceramic and the ability of the complex on facilitating bone formation in a radius segmental defect of rabbits. In vitro results showed that there were apparent hBMP2 gene expression and protein synthesis in MSCs with hBMP2 stably transfection, whereas negative expression of hBMP2 in controls. Histological studies demonstrated that gene-transfected MSCs/ceramic composite appeared an ability of heterotopic osteogenesis. In the segmental bone defects, endochondrial ossification at fracture sites was found in both transfected and untransfected MSCs-ceramic composites. While the composite with hBMP2 transfection showed the earliest and the most effective healing of the segmental bone defects both radiographically and morphologically. Our results show that genetically modified MSCs/ceramics
had enhanced osteogeneic capacity relative to unmodified MSCs or only ceramic implants. This study suggests that use of cell-and gene-activated bioceramics may offer promise for molecular design of implants to induce osteogenesis and enhance bone regeneration.
The Effects of Hydroxyapatite on Bonding Strength between Dental Luting Cement and Human Teeth
Authors: Yoon S.I. , Lee Yong Keun , Kim Yeon Ung , Kim Min Chul , Kim Kyoung Nam , Kim S.O. , Choi H.J.
Published: March 2009

This study aimed to investigate the effects of hydroxyapatite on bonding strength between dental luting cement and human teeth. In the previous study, bonelike forming ability by mixing hydroxyapatite with several bone cements was reported in a protein-free acellular simulated body fluid with ion concentrations nearly equal to those of the human blood plasma. Therefore in this experiment, we assumed that if bonelike apatite layer could form between dental luting cement and human teeth, the bonding strength between the two would improve. In addition, we expected the HA
mixed dental luting cement to improve the physical properties. Fuji I glass ionomer and Relyx™ glass ionomer cement were the selected dental luting cements and the film thickness, setting time and compressive strength were measured mixing various concentrations of hydroxyapatite. Glass ionomer cement with the most superior physical properties(Fuji I ; 20% hydroxyapatite, Relyx™ ; 15% hydroxyapatite) was immersed in the simulated body fluid for three weeks and the surface was
observed under SEM after measuring the bonding strength. As the concentration of HA increased, the film thickness of hydroxyapatite-glass ionomer cement decreased, the setting time increased, and the compressive strength increased. The most noteworthy results were that bonding strength increased, and that bonelike apatite formed on the tooth surface when observed under SEM.
Bone Formation of Intrabony Defects in Beagle Dogs Using Calcium Phosphate Glass and Glass-Ceramics
Authors: Choi Seong Ho , Baik D.H. , Kim C.S. , Kim Chong Kwan , Kim Kyoung Nam , Kim Kwang Mahn , LeGeros Racquel Z. , Lee Yong Keun
Published: March 2009

The purpose of this study was to compare the bone regenerative effect of calcium
phosphate glass and glass-ceramics in the system of CaO-CaF2-P2O5-MgO-ZnO, which is already reported that promoted the bone-like tissue formation in vitro and formed new bone in Sprague-Dawley rats. We prepared calcium phosphate glass and glass-ceramics with Ca/P ratio of 0.6 using the system CaO-CaF2-P2O5-MgO-ZnO and subsequently milled to 400 µm. 4×4 mm 1-wall intrabony defects of six beagle dogs were surgically created and used in this study. 8 weeks after
transplantation of the prepared calcium phosphate glass and glass-ceramics in the experimental group 1 and 2, respectively, the animals were sacrificed. No root resorption or ankylosis were observed in all groups. It can be examined that the prepared glass-ceramics were more effective in alveolar bone regeneration with statistical signigicant difference. In cementum regeneration, both the prepared glass
and glass-ceramics showed significantly different effect. However, there were no statistical significant difference neither in glass nor glass-ceramics in the amounts of junctional epithelium migration and connective tissue adhesion. Further study is required to control the flowability as well as reduce the absorption rate in vivo.
Comparison of Hard Tissue Formation in Two Porous Hydroxyapatite Scaffolds Treated with Hyaluronic Acid Sodium Salt
Authors: Tsuji Norimasa , Yoshikawa Masataka , Toda Tadao , Machida Hiroko , Ohgushi Hajime
Published: March 2009

The purpose of this study was to estimate hard tissue formation in two types of porous columnar hydroxyapatite (HA) in order to use as a scaffold for regeneration of dentine-pulp complex. Hard tissue formation in the columnar HA scaffold with a hollow center was compared to that in the columnar HA scaffold without a hollow center. The scaffolds were immersed in hyaluronic acid sodium salt solution and were soaked in bone marrow cell suspension. They were respectively
implanted into dorsal subcutis of rats for 4 weeks. Serially sectioned paraffin specimens were made and observed histologically. The scaffolds with a hollow center showed new hard tissue formation in many pores between the superficies and the wall of hollow. On the other hand, in the scaffolds without a hollow center, hard tissue formation was observed in only a few pores in the area near the
external superficies. The results of this study suggested that the supply of nutrition and bioactive substance from the surrounding tissue were indispensable for differentiation of bone marrow cells and formation of new hard tissue in scaffold. A large contact area of a scaffold to the surrounding tissue may contribute to nutrition supply into the pores.
Polyethylene Wear Against Alumina and Zirconia Heads in K-Max Total Hip Arthroplasty
Authors: Liang Bojian , Kawanabe Keiichi , Ise Kentaro , Shimizu Motoyuki , Iida Hirokazu , Nakamura Takashi
Published: March 2009

Polyethylene wears of 22.225 mm diameter alumina and zirconia femoral heads in
cemented total hip arthroplasty (THA) were compared at mean follow-up of five years. Ninety-six primary cemented K-MAX THA in eighty-seven patients were observed, forty-six hips with alumina heads and fifty-one hips with zirconia heads. Both of the mean linear wear rate and the mean volumetric wear rate of the polyethylene against zirconia were significantly higher that those of alumina (p<0.01, p<0.01, respectively). The monoclinic phase content and roughness rose up on the surfaces of two retrieved zirconia heads from revision surgeries. This was supposed as the differences of thermal conductivity between alumina and zirconia, for which local temperature was higher in zirconia head, leading to the phase transformation and lower-temperature aging degeneration (LTAD) of zirconia head surface.
Safety Issues in the Use of THR Ceramic Heads and Cups
Authors: Piconi Corrado , Maccauro G. , Logroscino Giandomenico
Published: March 2009

The safety of ceramic bearings are depending not only on the design and characteristics of the ceramic components, but also on the characteristics of the metallic tapers used for their connection to the stem and to the metal back in THRs. The modularity of today’s THRs offer the advantage of selecting the implant size that better suits the patient’s anatomy, but in this selections of the coupling several pitfalls have to be avoided. This paper is aimed to reviews the characteristics of the
ceramic-metal interfaces and their influence on the behavior of the components of ceramic bearings.
Investigation of Monoclinic Content on Clinically Retrieved Zirconia Heads
Authors: Tong Wei Dong , McNulty Don , Smith Todd , Li Pan Jian
Published: March 2009

The monoclinic zirconia content in clinically failed ceramic heads was investigated in
order to identify the cause of the failure. High percentages of the monoclinic zirconia were associated with the fractured surface. In vitro, accelerated aging of some components shows that the monoclinic transformation is site related: the closer to the bore, the more the monoclinic transformation. This phenomenon may be associated with the composition and the manufacturing process.
Effect of Aluminium on High-Energy Ball Milling and Spark Plasma Sintering of Silicon Nitride
Authors: Nishimura Toshiyasu , Xu Xin , Hirosaki Naoto , Kimoto K. , Yamamoto Yoo , Tanaka Hiroaki
Published: March 2009

A commercial silicon nitride powder with oxide sintering additives was ground with high-energy ball mill to obtain nano-sized powder. Metallic aluminium powder was added as a grinding additive. Effect of high-energy ball milling was evaluated by X-ray diffraction analysis. After milling, height of background increased and peak height of silicon nitride decreased in XRD chart, which suggested that vitrification and/or decrease in grain size of silicon nitride occurred. The milled powders were sintered by spark plasma sintering system. Aluminium nitride was formed during sintering by reaction of aluminium and atmospheric nitrogen. Dense nano-ceramics, which were composed of silicon nitride and sialon, were obtained by sintering at 1550 oC.
Joining Method of Silicon Nitride to Carbon Steel
Authors: Choi Young Min , Ryu Beyong Hwan , Lee Jae Do
Published: March 2009

We investigated the method of joining silicon nitride having on its surface a thin layer of active silicon metal to carbon steel. The active silicon layer is formed through the thermal dissociation of silicon nitride (Si3N4) into silicon (Si) and nitrogen gas (N2). The active silicon layer is directly joined to carbon steel via an induced eutectic melting reaction between the silicon and iron (Fe) found in carbon steel, or via brazing of two materials using general brazing metal such as Ag-Cu alloys. This joining process does not require the use of expensive active brazing alloys such as Ag-Cu-Ti alloys or a sputtering method designed to coat the active metals on surface of silicon nitride.
Microstructure and Properties of Sintered Reaction Bonded Silicon Nitride with Aligned Whisker Seeds
Authors: Park Dong Soo , Hahn Byung Dong , Baik D.-J.
Published: March 2009

Sintered reaction bonded silicon nitride with aligned whisker seeds was prepared by tape casting silicon slurry with 5 wt% b-Si3N4 whisker seeds followed by nitridation and sintering. Three different sintering additives were used for the samples; 7 wt% Y2O3, 6 wt% Y2O3 + 1 wt% Al2O3 and 5 wt% Y2O3 + 2 wt% Al2O3. The sample with 5 wt% Y2O3 + 2 wt% Al2O3 showed the fastest a to b phase transformation after nitridation and the highest fracture toughness and flexural strength after gas pressure sintering among the samples. It also had finer microstructure than the other samples after sintering at 2248 K and at 2273 K. The finer microstructure was related to the faster phase transformation after nitridation, which resulted in the higher flexural strength.
Highly Ordered Macroporous BN-Based Ceramics Prepared from Templated Preceramic Polymers
Authors: Hong Lan Young , Kim Dong Pyo
Published: March 2009

Macroporous SiCBN and BCN ceramic were prepared by infiltrating these preceramic polymers into the colloidal silica crystalline array, followed by pyrolysis at 1400ı and subsequently etching off the silica spheres. It is generally observed by SEM and TEM that a highly ordered and interconnected 'honeycomb' pore structure was obtained by replicating the three dimensional close packed silica spheres which was fabricated by natural sedimentation. And BET surface areas in range 413 ~ 315 m2/g and pore sizes of 113 ~ 395 nm in the porous materials were tailored by controlling the sacrificial silica sphere sizes in range 145~500 nm even under volume shrinkage involved during pyrolytic step. The porous SiCBN ceramics and BCN ceramic showed a slight weight loss of 0.2~0.8% and 4%, respectively, indicating excellent resistance to oxidation.
Effects of Al, B and C Additives on Microstructure and Mechanical Properties of Spark-Plasma-Sintered SiC Ceramics
Authors: Cho Kyeong Sik , Lee Kwang Soon
Published: March 2009

Densification of the SiC powder without and with additives B+C or Al+B+C was carried out by spark plasma sintering (SPS). The unique features of the process are the possibilities of using a very fast heating rate and a short holding time to obtain fully dense materials. The heating rate and applied pressure were kept at 100°C/ min and 40 MPa, while the sintering temperature and soaking time varied from 1650-1850°C for 10-40 min, respectively. The SPS-sintered specimens with the addition of B+C or Al+B+C at 1850°C reached near-theoretical density. The 3C major crystalline phase of SiC was transformed to 6H at 1800°C and translated to 4H during prolonged annealing at 1850°C. The strength of 531.0 MPa and the fracture toughness of 3.9 MPa·m1/2 were obtained by the addition of Al+B+C to SiC prepared at 1850°C for 10 min.