• Title, Summary, Keyword: Tricalcium phosphate

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Microstructure and Biocompatibility of Porous BCP(HA/β-TCP) Biomaterials Consolidated by SPS Using Space Holder

  • Woo, Kee-Do;Kwak, Seung-Mi;Lee, Tack;Oh, Seong-Tak;Woo, Jeong-Nam
    • Korean Journal of Materials Research
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    • v.26 no.8
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    • pp.449-453
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    • 2016
  • $HA(hydroxyapatite)/{\beta}-TCP$ (tricalcium phosphate) biomaterial (BCP; biphasic calcium phosphate) is widely used as bone cement or scaffolds material due to its superior biocompatibility. Furthermore, $NH_4HCO_3$ as a space holder (SH) has been used to evaluate feasibility assessment of porous structured BCP as bone scaffolds. In this study, using a spark plasma sintering (SPS) process at 393K and 1373K under 20MPa load, porous $HA/{\beta}-TCP$ biomaterials were successfully fabricated using $HA/{\beta}-TCP$ powders with 10~30 wt% SH, TiH2 as a foaming agent, and MgO powder as a binder. The effect of SH content on the pore size and distribution of the BCP biomaterial was observed by scanning electron microscopy (SEM) and a microfocus X-ray computer tomography system (SMX-225CT). The microstructure observations revealed that the volume fraction of the pores increased with increasing SH content and that rough pores were successfully fabricated by adding SH. Accordingly, the cell viabilities of BCP biomaterials were improved with increasing SH content. And, good biological properties were shown after assessment using Hanks balanced salt solution (HBSS).

Use of Wet Chemical Method to Prepare β Tri-Calcium Phosphates having Macro- and Nano-crystallites for Artificial Bone

  • Chang, Myung Chul
    • Journal of the Korean Ceramic Society
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    • v.53 no.6
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    • pp.670-675
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    • 2016
  • Calcium phosphate crystallites were prepared by wet chemical method for use in artificial bone. In order to obtain ${\beta}$-tricalcium phosphate (TCP), nano-crystalline calcium phosphate (CaP) was precipitated at $37^{\circ}C$ and at $pH5.0{\pm}0.1$ under stirring using highly active $Ca(OH)_2$ in DI water and an aqueous solution of $H_3PO_4$. The precipitated nano-crystalline CaP solution was kept at $90^{\circ}C$ for the growth of CaP crystallites. Through the growing process of CaP crystallites, we were able to obtain various sizes of rectangular CaP crystallites according to the crystal growing times. Dry nano-crystalline CaP powders at $37^{\circ}C$ were mixed with dry macro-crystalline CaP crystallites and the shaped mixture sample was fired at $1150^{\circ}C$ to make a ${\beta}-TCP$ block. Several tens of nm powders were uniformly coated on the surface, which was comprised of powders of several tens of ${\mu}m$, using a vibrator. The mixing ratio between the nanometer powders and the micrometer powders greatly affected the mechanical strength of the mixture block; the most appropriate ratio of these two materials was 50 wt% to 50 wt%. The sintered block showed improved mechanical strength, which was caused by the solid state interaction between the nano-crystalline ${\beta}-TCP$ and the macro-crystalline ${\beta}-TCP$.

Suspension Polymerization of Styrene with Tricalcium Phosphate as Stabilizer

  • Hong, Soon-Gil;Park, Moonsoo
    • Macromolecular research
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    • v.8 no.6
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    • pp.247-252
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    • 2000
  • Suspension polymerizations of styrene were conducted in the aqueous phase with tricalcium phosphate (TCP) as a stabilizer and $\alpha$, $\alpha$'-azobis(isobutyronitrile) (AIBN) as an initiator. Various amounts of initiator and stabilizer were selected and the reaction was carried out at a selected temperature between 60 to 80 $\^{C}$. It was found that the combination of 5 wt% stabilizer and 2.427$\times$10$\^$-3/ mol/L of costabilizer is the minimum amount for suspension polymerization reaction to produce particles in the aqueous phase. Particles were found to be polydisperse in diameter, regardless of reaction conditions. Class transitions were observed to be around 95$\^{C}$, nearly independent of reaction temperature and initiator. Homogenizer was found to be essential in forming particles in the proximity of tens of micrometers in diameter in suspension polymerization with TCP as stabilizer.

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Bending and Compressive Properties of Crystallized TCP/PLLA Composites

  • Kobayashi, Satoshi;Sakamoto, Kazuki
    • Advanced Composite Materials
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    • v.18 no.3
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    • pp.287-295
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    • 2009
  • $\beta$-Tricalcium phosphate ($\beta$-TCP) particles reinforced bioresorbable plastics poly-L-lactide (PLLA) composites were prepared by injection molding. The nominal weight ratio of $\beta$-TCP was selected as 5, 10 and 15%. In order to clarify effects of the PLLA crystallinity on the mechanical properties, the specimens were heat treated isothermally. Results of differential scanning calorimetry indicated that the PLLA crystallinity increased with increasing heat treatment temperature. Bending and compressive tests were conducted on the specimen with different $\beta$-TCP contents and crystallinities. The results show that the bending and compressive moduli increased with increasing $\beta$-TCP contents and crystallinity. On the other hand, bending strength decreased with increasing $\beta$-TCP contents. Maximum bending strength was obtained at the heat treatment of $70^{\circ}C$ for 24 h, whereas compressive 0.2% proof strength increased with increasing heat treatment temperature. This difference is attributed to the difference in the microscopic damages.

Chemical characteristics of mineral trioxide aggregate and its hydration reaction

  • Chang, Seok-Woo
    • Restorative Dentistry and Endodontics
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    • v.37 no.4
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    • pp.188-193
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    • 2012
  • Mineral trioxide aggregate (MTA) was developed in early 1990s and has been successfully used for root perforation repair, root end filling, and one-visit apexification. MTA is composed mainly of tricalcium silicate and dicalcium silicate. When MTA is hydrated, calcium silicate hydrate (CSH) and calcium hydroxide is formed. Formed calcium hydroxide interacts with the phosphate ion in body fluid and form amorphous calcium phosphate (ACP) which finally transforms into calcium deficient hydroxyapatite (CDHA). These mineral precipitate were reported to form the MTA-dentin interfacial layer which enhances the sealing ability of MTA. Clinically, the use of zinc oxide euginol (ZOE) based materials may retard the setting of MTA. Also, the use of acids or contact with excessive blood should be avoided before complete set of MTA, because these conditions could adversely affect the hydration reaction of MTA. Further studies on the chemical nature of MTA hydration reaction are needed.

Processing Optimization of PCL/TCP Composites Produced by Selective Laser Sintering (SLS에 의한 PCL/TCP 복합체 제작공정변수의 최적화)

  • Chung, Ha-Seung;Jee, Hae-Seong
    • Korean Journal of Computational Design and Engineering
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    • v.13 no.6
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    • pp.421-428
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    • 2008
  • This article investigates the fabrication of polycaprolactone (PCL) composites filled with different volume fractions (10-30%) of tricalcium phosphate (TCP) by selective laser sintering (SLS) for tissue engineering scaffolds. Optimal processing parameters for each composition were developed by design of experiments (DOE). Specimens for compressive testing for each composition were fabricated and tested. The results showed that the compressive modulus increases as a function of TCP volume fraction. The experimentally measured compressive moduli were compared with moduli predicted by Halpin's theoretical model and were found to be in excellent agreement. This result proved that experimentally determined processing parameters for each composition were well optimized.

Fabrication of Calcium Phosphate Scaffolds Using Projection-based Microstereolithography and Their Effects on Osteogenesis (투영기반 마이크로 광조형 기술을 이용한 3 차원 인산칼슘 인공지지체 제작 및 골 분화 영향)

  • Seol, Young-Joon;Park, Ju-Young;Cho, Dong-Woo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.35 no.11
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    • pp.1237-1242
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    • 2011
  • Calcium phosphates are very interesting materials for use as scaffolds for bone tissue engineering. These materials include hydroxyapatite (HA) and tricalcium phosphate (TCP), which are inorganic components of human bone tissue and are both biocompatible and osteoconductive. Although these materials have excellent properties for use as bone scaffolds, many researchers have used these materials as additives to synthetic polymer scaffolds for bone tissue regeneration, because they are difficult to manufacture three-dimensional (3D) scaffolds. In this study, we fabricated 3D calcium phosphate scaffolds with the desired inner and outer architectures using solid freeform fabrication technology. To fabricate the scaffold, the sintering behavior was evaluated for various sintering temperatures and slurry concentrations. After the fabrication of the calcium phosphate scaffolds, in-vitro cell proliferation and osteogenic differentiation tests were carried out.

Properties of the Ceramic Composites and Glass-Ceramics Prepared by Using the Natural Hydroxyapatite Derived from Tuna bone (참치 뼈에서 추출한 천연 Hydroxyapatite를 이용한 세라믹 복합체 및 Glass-Ceramics의 특성)

  • Choi, Jin-Sam;Lee, Chang-Kook;Jeon, You-Jin;Byun, Hee-Guk;Kim, Se-Kwon
    • Applied Chemistry for Engineering
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    • v.10 no.3
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    • pp.394-399
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    • 1999
  • As the prosthetic application of natural mineral substituted for chemical reagent, composites and a glass-ceramics containing hydro-xyapatite isolated from tuna bone were prepared by solid state reaction. On x-ray examinations, the major phases of composites were identified as pseudowollastonite(${\alpha}-CaSiO_3$) and ${\beta}$-tricalcium phosphate($\beta$-TCP) and the phase of a glass-ceramics was observed as $\beta$-TCP and fluoroapatite caused by $CaF_2$ respectively. SEM images depict that the microstructures of grain at the composites were a function of temperature. The measured strength of a glass-ceramics prepared at $900^{\circ}C$ for 4 hr in air was 90 MPa as a 4-point bending method and this value was similar to the cortical bone, as 50~150 MPa but it was lower than its maximum strength.

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Bone Healing in Ovariectomized-rabbit Calvarial Defect with Tricalcium Phosphate Coated with Recombinant Human Bone Morphogenetic Protein-2 Genetically Engineered in Escherichia coli

  • Kim, Jung-Han;Kim, Chang-Joo;Shin, Sang-Hun
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.36 no.2
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    • pp.37-49
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    • 2014
  • Purpose: This study compares the bone formation ability of tricalcium phosphate (TCP) with and without recombinant human bone morphogenetic protein-2 (rhBMP-2) and assesses TCP as a carrier of rhBMP-2. Methods: Bilateral round defects (diameter: 8.0 mm) were formed in the cranium of eight New Zealand white rabbits. The defects were grafted with TCP only (control group) or with rhBMP-2-coated TCP (experimental group). The animals were sacrificed at 1st week, 2nd week, 4th week, and 8th week postoperatively; two rabbits sacrificed each time. The skulls were harvested and subjected to radiographic and histological examination. Results: Radiologic evaluation showed faster bone remodeling in the experimental group than in the control group. Histologic evaluation (H&E, Masson's trichrome stain) showed rapid bone formation, remodeling and calcification in the 1st and 2nd week in the experimental group. Immunohistochemical evaluation showed higher expression rate of osteoprotegerin, receptor activator of nuclear factor ${\kappa}B$ ligand, and receptor activator of nuclear factor ${\kappa}B$ in the experimental group at the 1st and 2nd week than in the control group. Conclusion: rhBMP-2 coated TCP resulted in rapid bone formation, remodeling, and calcification due to rhBMP-2's osteogenic effect. TCP performed properly as a carrier for rhBMP-2. Thus, the use of an rhBMP-2 coating on TCP had a synergic effect on bone healing and, especially, bone remodeling and maturation.

Setting Behavior and Drug Release from Brushite Bone Cement prepared with Granulated Hydroxyapatite and β-Tricalcium Phosphate

  • Son, Yeong-Jun;Lee, In-Cheol;Jo, Hyun-Ho;Chung, Tai-Joo;Oh, Kyung-Sik
    • Journal of the Korean Ceramic Society
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    • v.56 no.1
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    • pp.56-64
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    • 2019
  • Calcium phosphate bone cement was prepared to contain antibiotics for release after setting using granulated ${\beta}$-tricalcium phosphate (${\beta}$-TCP) and hydroxyapatite (HA). Gentamicin sulfate (GS) solution was infiltrated within the interconnected pores of the granule to avoid affecting the setting reaction and for protection of GS during the setting. Consequently, the setting time and the temperature increase were not affected, regardless of the loading of GS. The release of the GS from the cement was estimated by measuring the concentration at regular intervals from the cement dipped solution. The ${\beta}$-TCP granule loaded with GS exhibited the saturation of accumulative concentration at 16 h. In contrast, the HA granule with GS exhibited steady increase in accumulative concentration of over $10{\mu}g/ml$ at 144 h. Thus, the granulated cement could release the GS greater than the minimum inhibitory concentration of staphylococcus during the prescription peroid of the oral antibiotics.