Biphasic Calcium Phosphate (biphasic + calcium_phosphate)

Distribution by Scientific Domains
Polymers and Materials Science50%

Kinds of Biphasic Calcium Phosphate

  • novel biphasic calcium phosphate
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    Selected Abstracts

    Effect of Co-Precipitation on the Low-Temperature Sintering of Biphasic Calcium Phosphate

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2006
    Youn-Ki Jun
    Three types of biphasic calcium phosphate (BCP) powders were prepared and their sintering behavior was investigated. The specific surface area and HA/TCP ratio were similar in all three specimens. Most of the densification in the co-precipitated s-BCP occurred before the ,- to ,-TCP phase transformation, and a maximum density of ,95% was obtained at 1100°C. The mixture of separately precipitated and calcined hydroxyapatite (HA) and tricalcium phosphate (TCP) (m-BCP) showed a poor sintering behavior, and the apparent density was below 70% at temperatures up to 1200°C. In the commercial HA and TCP mixture (c-BCP), the low temperature sintering was poor, but densification continued without the phase transformation due to the presence of MgO, achieving almost full densification at 1200°C. [source]

    Retention of 125I-labeled recombinant human bone morphogenetic protein-2 by biphasic calcium phosphate or a composite sponge in a rabbit posterolateral spine arthrodesis model

    JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 5 2002
    John Louis-Ugbo
    The purpose of this study was to characterize the retention kinetics of recombinant human bone morphogenetic protein-2 (rhBMP-2) applied to two calcium-based delivery matrices. Biphasic calcium phosphate (BCP) and a composite containing BCP in an absorbable collagen sponge (BCP/ACS) were evaluated using a spinal fusion model in rabbits. rhBMP-2 labeled with radioactive iodine (125I) was used as a tracer to assess in vivo retention of rhBMP-2 in the presence of these materials (nine animals per material studied). Over a 36 day study period, animals were assessed for the following: percent administered dose retained at the implant site as measured by scintigraphic imaging (counting) with a gamma camera (all animals), radiography of the implant site (all animals), radioactivity in blood and plasma (all animals), and radioactivity in the urine and feces (three animals for each material). Radioactivity data were corrected for the decay of 125I and the attenuation between the implant in vivo and the gamma camera. Differences observed between the two materials for the area under the retention vs. time profile (AUC; 988%day for BCP vs. 1070%day for BCP/ACS, p = 0.57) and the mean residence time (MRT; 10.2 days for BCP vs. 7.6 days for BCP/ACS, p = 0.06) were not statistically significant. Initial retention/incorporation of rhBMP-2 was slightly higher for rhBMP-2/BCP/ACS than for rhBMP-2/BCP (96.8% vs. 86.0%, p lt; 0.05). Animals receiving rhBMP-2/BCP showed a longer terminal retention half-life (t1/2) than did those receiving rhBMP-2/BCP/ACS (7.5 vs. 4.5 days, p < 0.05). The urinary radioactivity recovery data supported the data obtained by scintigraphy. Over the 36 day collection period, essentially complete recovery of radioactivity (dose) in urine was observed for rhBMP-2/BCP and rhBMP-2/BCP/ACS and the majority of the radioactivity (approximately 95%) was soluble in trichloroacetic acid, suggesting extensive catabolism of rhBMP-2 before renal excretion. Fecal recovery of radioactivity was low, approximately 2,3%. In conclusion, rhBMP-2 was retained at the implant site when delivered with either BCP or BCP/ACS based on mean residence time and area under the retention curve vs. time profile. Use of these matrices resulted in detectable rhBMP-2 levels at the surgical site for over a week in contrast to data reported with several other matrices that lasted less time. Systemic catabolism and elimination of the rhBMP-2 was extensive and systemic presence of the protein was negligible. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source]

    In Vitro Characteristics of Surface-Modified Biphasic Calcium Phosphate/Poly(L -Lactide) Biocomposite

    ADVANCED ENGINEERING MATERIALS, Issue 4 2010
    Weizhong Yang
    Abstract Surface-modified biphasic calcium phosphate (BCP)/poly(L -lactide) (PLLA) biocomposite is shown to have improved microstructure and mechanical properties compared to the unmodified system. In vitro biodegradation and bioactivity of the composite are investigated in simulate body fluid for up to four weeks. Weight changes of the samples and the pH changes of the SBF are recorded. Surface properties of the composite after immersion are characterized by XRD, SEM and EDX analyses. Cyto-compatibility was determined by MTT assay with L929 mouse fibroblasts. The difference of the degradation behavior between modified BCP/PLLA and the reference unmodified composite are investigated, and mBCP/PLLA composite is proved to be a better as a scaffold material. The surface formed bio-apatite layer after immersion shows the excellent bioactivity of the mBCP/PLLA composite. L929 cells show a high growth rate and proliferation, demonstrating the good cytocompatibility of mBCP/PLLA composite. [source]

    Preparation and characterization of novel biphasic calcium phosphate powders (,-TCP/HA) derived from carbonated amorphous calcium phosphates

    JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2009
    Yanbao Li
    Abstract Novel biphasic calcium phosphate (BCP) powders composed of ,-tricalcium phosphate (,-TCP) and hydroxyapatite (HA) were prepared by thermal decomposition of carbonated amorphous calcium phosphates (CACP). At first, the CACP precipitates were synthesized by adding ammonium carbonate in the presence of poly(ethylene glycol) at pH 10 with an initial Ca/P molar ratio of 1.60 at 5°C. The Ca/P molar ratios of the CACP precursors are between 1.50 and 1.67 investigated by ICP. Then BCP (,-TCP/HA) powders were obtained after heating the CACP precursors at relatively low temperature (800°C) for 3 h. ,-TCP/HA powders were characterized by X-ray diffractometry, Fourier transform infrared spectra, transmission electron microscopy/scanning electron microscopy, and sedimentation experiment. The results show that ,-TCP and HA phases form in one powder, ,-TCP/HA powders are sphere with the diameter of 300 nm to less than 100 nm varied with their chemical compositions and the ratio of ,-TCP and HA in the powders can be adjusted by the adding amount of carbonates. The possible formation process of biphasic ,-TCP/HA powders was proposed. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009 [source]

    Retention of 125I-labeled recombinant human bone morphogenetic protein-2 by biphasic calcium phosphate or a composite sponge in a rabbit posterolateral spine arthrodesis model

    JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 5 2002
    John Louis-Ugbo
    The purpose of this study was to characterize the retention kinetics of recombinant human bone morphogenetic protein-2 (rhBMP-2) applied to two calcium-based delivery matrices. Biphasic calcium phosphate (BCP) and a composite containing BCP in an absorbable collagen sponge (BCP/ACS) were evaluated using a spinal fusion model in rabbits. rhBMP-2 labeled with radioactive iodine (125I) was used as a tracer to assess in vivo retention of rhBMP-2 in the presence of these materials (nine animals per material studied). Over a 36 day study period, animals were assessed for the following: percent administered dose retained at the implant site as measured by scintigraphic imaging (counting) with a gamma camera (all animals), radiography of the implant site (all animals), radioactivity in blood and plasma (all animals), and radioactivity in the urine and feces (three animals for each material). Radioactivity data were corrected for the decay of 125I and the attenuation between the implant in vivo and the gamma camera. Differences observed between the two materials for the area under the retention vs. time profile (AUC; 988%day for BCP vs. 1070%day for BCP/ACS, p = 0.57) and the mean residence time (MRT; 10.2 days for BCP vs. 7.6 days for BCP/ACS, p = 0.06) were not statistically significant. Initial retention/incorporation of rhBMP-2 was slightly higher for rhBMP-2/BCP/ACS than for rhBMP-2/BCP (96.8% vs. 86.0%, p lt; 0.05). Animals receiving rhBMP-2/BCP showed a longer terminal retention half-life (t1/2) than did those receiving rhBMP-2/BCP/ACS (7.5 vs. 4.5 days, p < 0.05). The urinary radioactivity recovery data supported the data obtained by scintigraphy. Over the 36 day collection period, essentially complete recovery of radioactivity (dose) in urine was observed for rhBMP-2/BCP and rhBMP-2/BCP/ACS and the majority of the radioactivity (approximately 95%) was soluble in trichloroacetic acid, suggesting extensive catabolism of rhBMP-2 before renal excretion. Fecal recovery of radioactivity was low, approximately 2,3%. In conclusion, rhBMP-2 was retained at the implant site when delivered with either BCP or BCP/ACS based on mean residence time and area under the retention curve vs. time profile. Use of these matrices resulted in detectable rhBMP-2 levels at the surgical site for over a week in contrast to data reported with several other matrices that lasted less time. Systemic catabolism and elimination of the rhBMP-2 was extensive and systemic presence of the protein was negligible. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source]

    A Novel Biphasic Bone Scaffold: ,-Calcium Phosphate and Amorphous Calcium Polyphosphate

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2009
    Gaoxiang Chen
    Calcium polyphosphate (CPP) was added to hydroxyapatite (HA) to develop a novel biphasic calcium phosphate (BCP). The effects of varying CPP dosage on the sintering property, the mechanical strength, and the phase compositions of HA were investigated. Results showed that CPP reacted with HA and produced ,-calcium phosphate (,-TCP) and H2O and that an excessive dosage of CPP (>10 wt%) obtained a novel BCP of ,-TCP/amorphous-CPP, while a lesser dosage of CPP (<10 wt%) obtained a traditional BCP (HA/,-TCP). The porous ,-TCP/amorphous-CPP scaffolds (porosity of 66.7%, pore diameter of 150,450 ,m, and compressive strength of 6.70±1.5 MPa) were fabricated and their in vitro degradation results showed a significant improvement of degradation with the addition of CPP. [source]

    Effect of Co-Precipitation on the Low-Temperature Sintering of Biphasic Calcium Phosphate

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2006
    Youn-Ki Jun
    Three types of biphasic calcium phosphate (BCP) powders were prepared and their sintering behavior was investigated. The specific surface area and HA/TCP ratio were similar in all three specimens. Most of the densification in the co-precipitated s-BCP occurred before the ,- to ,-TCP phase transformation, and a maximum density of ,95% was obtained at 1100°C. The mixture of separately precipitated and calcined hydroxyapatite (HA) and tricalcium phosphate (TCP) (m-BCP) showed a poor sintering behavior, and the apparent density was below 70% at temperatures up to 1200°C. In the commercial HA and TCP mixture (c-BCP), the low temperature sintering was poor, but densification continued without the phase transformation due to the presence of MgO, achieving almost full densification at 1200°C. [source]

    Histomorphometric analysis of the osseointegration of four different implant surfaces in the femoral epiphyses of rabbits

    CLINICAL ORAL IMPLANTS RESEARCH, Issue 11 2008
    Laurent Le Guehennec
    Abstract Objectives: The surface properties of titanium dental implants are key parameters for rapid and intimate bone,implant contact. The osseointegration of four implant surfaces was studied in the femoral epiphyses of rabbits. Material and methods: Titanium implants were either grit-blasted with alumina or biphasic calcium phosphate (BCP) ceramic particles, coated with a thin octacalcium phosphate (OCP) layer, or prepared by large-grit sand blasting and acid-etched (SLA). After 2 and 8 weeks of implantation, the bone-implant contact and bone growth inside the chambers were compared. Scanning electron microscopy (SEM) and profilometry showed distinct microtopographies. Results: The alumina-Ti, BCP-Ti and OCP-Ti groups had similar average surface roughness in the 1,2 ,m range whereas the SLA surface was significantly higher with a roughness averaging 4.5 ,m. Concerning the osseointegration, the study demonstrated a significantly greater bone-to-implant contact for both the SLA and OCP-Ti surfaces as compared with the grit-blasted surfaces, alumina- and BCP-Ti at both 2 and 8 weeks of healing. Conclusion: In this animal model, a biomimetic calcium phosphate coating gave similar osseointegration to the SLA surface. This biomimetic coating method may enhance the apposition of bone onto titanium dental implants. [source]

    Evaluation of a novel biphasic calcium phosphate in standardized bone defects.

    CLINICAL ORAL IMPLANTS RESEARCH, Issue 6 2007
    A histologic, histomorphometric study in the mandibles of minipigs
    Abstract: Objective: A novel biphasic calcium phosphate (CaP) granulate consisting of hydroxyapatite (HA) and ,-tricalciumphosphate (TCP) was compared with pure HA and pure TCP and with autograft as positive control. Materials and methods: Four standardized bone defects were prepared in both mandibular angles of 16 minipigs and grafted with autogenous bone chips, HA, HA/TCP (60% : 40%), or TCP. Histologic and histomorphometric analysis of bone formation and graft degradation followed healing periods of 2, 4, 8, and 24 weeks. Results: 2 weeks: more bone formation in defects filled with autograft than with the three CaP materials (P<0.05). 4 weeks: bone formation differed significantly (P<0.05) between all four materials (autograft>TCP>HA/TCP>HA). 8 weeks: more bone formation in defects with autograft and TCP than with HA/TCP (P<0.05), and HA/TCP had more bone formation than HA (P<0.05). 24 weeks: no difference in bone formation between the groups. Autograft and TCP resorbed quickly and almost completely over 8 weeks, whereas HA/TCP and HA showed limited degradation over 24 weeks. Conclusion: All defects healed with mature lamellar bone and intimate contact between bone and the remaining graft material. The rate of bone formation corresponded to the content of TCP in the CaP materials. [source]