Limits...
Development and Characterization of Biphasic Hydroxyapatite/β-TCP Cements.

Gallinetti S, Canal C, Ginebra MP, Ferreira J - J Am Ceram Soc (2014)

Bottom Line: However, they have some limitations associated to their condition of high-temperature ceramics.The strategy used allowed synthesizing BCPCs with modulated composition, compressive strength, and specific surface area.Increasing amounts of the non-reacting β-TCP phase resulted in a linear decrease of the compressive strength, in association to the decreasing amount of precipitated HA crystals, which are responsible for the mechanical consolidation of apatitic cements.

View Article: PubMed Central - PubMed

Affiliation: Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC) Barcelona, 08028, Spain ; Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN) Barcelona, Spain ; Center for Research in Nanoengineering (CRnE), UPC Barcelona, 08028, Spain.

ABSTRACT

Biphasic calcium phosphate bioceramics composed of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) have relevant properties as synthetic bone grafts, such as tunable resorption, bioactivity, and intrinsic osteoinduction. However, they have some limitations associated to their condition of high-temperature ceramics. In this work self-setting Biphasic Calcium Phosphate Cements (BCPCs) with different HA/β-TCP ratios were obtained from self-setting α-TCP/β-TCP pastes. The strategy used allowed synthesizing BCPCs with modulated composition, compressive strength, and specific surface area. Due to its higher solubility, α-TCP was fully hydrolyzed to a calcium-deficient HA (CDHA), whereas β-TCP remained unreacted and completely embedded in the CDHA matrix. Increasing amounts of the non-reacting β-TCP phase resulted in a linear decrease of the compressive strength, in association to the decreasing amount of precipitated HA crystals, which are responsible for the mechanical consolidation of apatitic cements. Ca(2+) release and degradation in acidic medium was similar in all the BCPCs within the timeframe studied, although differences might be expected in longer term studies once β-TCP, the more soluble phase was exposed to the surrounding media.

No MeSH data available.


Related in: MedlinePlus

Cohesion time, initial setting time, and final setting time of BCPCs composed of α-TCP and β-TCP at different ratios at a L/P = 0.35 mL/g.
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fig02: Cohesion time, initial setting time, and final setting time of BCPCs composed of α-TCP and β-TCP at different ratios at a L/P = 0.35 mL/g.

Mentions: All cement formulations gave a homogeneous paste with good workability. The results obtained for the cohesion time, initial setting time and final setting time are given in Fig. 2. The cohesion time was defined as the minimum time after which the cement did not suffer disintegration when immersed in deionized water at 37°C. All cements presented cohesion in water after a few minutes, and as shown in Fig. 2, cohesion time increased by adding β-TCP, irrespective of the amount. The addition of a second phase (β-TCP) did not alter much the initial setting time but did substantially increase the final setting time. The 100% β-TCP cement showed faster cohesion than the BCPCs but the final setting time was significantly higher.


Development and Characterization of Biphasic Hydroxyapatite/β-TCP Cements.

Gallinetti S, Canal C, Ginebra MP, Ferreira J - J Am Ceram Soc (2014)

Cohesion time, initial setting time, and final setting time of BCPCs composed of α-TCP and β-TCP at different ratios at a L/P = 0.35 mL/g.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4384943&req=5

fig02: Cohesion time, initial setting time, and final setting time of BCPCs composed of α-TCP and β-TCP at different ratios at a L/P = 0.35 mL/g.
Mentions: All cement formulations gave a homogeneous paste with good workability. The results obtained for the cohesion time, initial setting time and final setting time are given in Fig. 2. The cohesion time was defined as the minimum time after which the cement did not suffer disintegration when immersed in deionized water at 37°C. All cements presented cohesion in water after a few minutes, and as shown in Fig. 2, cohesion time increased by adding β-TCP, irrespective of the amount. The addition of a second phase (β-TCP) did not alter much the initial setting time but did substantially increase the final setting time. The 100% β-TCP cement showed faster cohesion than the BCPCs but the final setting time was significantly higher.

Bottom Line: However, they have some limitations associated to their condition of high-temperature ceramics.The strategy used allowed synthesizing BCPCs with modulated composition, compressive strength, and specific surface area.Increasing amounts of the non-reacting β-TCP phase resulted in a linear decrease of the compressive strength, in association to the decreasing amount of precipitated HA crystals, which are responsible for the mechanical consolidation of apatitic cements.

View Article: PubMed Central - PubMed

Affiliation: Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC) Barcelona, 08028, Spain ; Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN) Barcelona, Spain ; Center for Research in Nanoengineering (CRnE), UPC Barcelona, 08028, Spain.

ABSTRACT

Biphasic calcium phosphate bioceramics composed of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) have relevant properties as synthetic bone grafts, such as tunable resorption, bioactivity, and intrinsic osteoinduction. However, they have some limitations associated to their condition of high-temperature ceramics. In this work self-setting Biphasic Calcium Phosphate Cements (BCPCs) with different HA/β-TCP ratios were obtained from self-setting α-TCP/β-TCP pastes. The strategy used allowed synthesizing BCPCs with modulated composition, compressive strength, and specific surface area. Due to its higher solubility, α-TCP was fully hydrolyzed to a calcium-deficient HA (CDHA), whereas β-TCP remained unreacted and completely embedded in the CDHA matrix. Increasing amounts of the non-reacting β-TCP phase resulted in a linear decrease of the compressive strength, in association to the decreasing amount of precipitated HA crystals, which are responsible for the mechanical consolidation of apatitic cements. Ca(2+) release and degradation in acidic medium was similar in all the BCPCs within the timeframe studied, although differences might be expected in longer term studies once β-TCP, the more soluble phase was exposed to the surrounding media.

No MeSH data available.


Related in: MedlinePlus