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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

Surface microstructure of BCPCs set for 7 d in Ringer's solution: (a) 0% β-TCP, b) 20% β-TCP, c) 40% β-TCP, d) 60% β-TCP, e) 80% β-TCP, f) 100% β-TCP.
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fig05: Surface microstructure of BCPCs set for 7 d in Ringer's solution: (a) 0% β-TCP, b) 20% β-TCP, c) 40% β-TCP, d) 60% β-TCP, e) 80% β-TCP, f) 100% β-TCP.

Mentions: The surface morphology of the various BCPCs observed by FE-SEM is shown in Fig. 5. The β-TCP particles were not exposed in any of the BCPCs, even those containing large amount (80%) of β-TCP, as they were completely covered with CDHA precipitated crystals. However, a change in morphology of the crystals was observed. On the surface of BCPCs containing low amounts of β-TCP (up to 40%), predominantly plate-like crystals were found [Figs. 5 (a–c)], some acicular crystals were found in the 60% β-TCP [Fig. 5(d)], and most extensively in the 80% β-TCP [Fig. 5(e)], where much smaller needle-like crystals were formed. In the 100% β-TCP sample [Fig. 5(f)], the shape of the initial β-TCP particles was visible, although partially covered with small crystals. Interestingly, in spite of these microstructural changes, the addition of β-TCP resulted in a global decrease of the SSA of the set BCPCs [Fig. 4 (b)], as it resulted from the contribution of both phases, CDHA and β-TCP.


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

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

Surface microstructure of BCPCs set for 7 d in Ringer's solution: (a) 0% β-TCP, b) 20% β-TCP, c) 40% β-TCP, d) 60% β-TCP, e) 80% β-TCP, f) 100% β-TCP.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig05: Surface microstructure of BCPCs set for 7 d in Ringer's solution: (a) 0% β-TCP, b) 20% β-TCP, c) 40% β-TCP, d) 60% β-TCP, e) 80% β-TCP, f) 100% β-TCP.
Mentions: The surface morphology of the various BCPCs observed by FE-SEM is shown in Fig. 5. The β-TCP particles were not exposed in any of the BCPCs, even those containing large amount (80%) of β-TCP, as they were completely covered with CDHA precipitated crystals. However, a change in morphology of the crystals was observed. On the surface of BCPCs containing low amounts of β-TCP (up to 40%), predominantly plate-like crystals were found [Figs. 5 (a–c)], some acicular crystals were found in the 60% β-TCP [Fig. 5(d)], and most extensively in the 80% β-TCP [Fig. 5(e)], where much smaller needle-like crystals were formed. In the 100% β-TCP sample [Fig. 5(f)], the shape of the initial β-TCP particles was visible, although partially covered with small crystals. Interestingly, in spite of these microstructural changes, the addition of β-TCP resulted in a global decrease of the SSA of the set BCPCs [Fig. 4 (b)], as it resulted from the contribution of both phases, CDHA and β-TCP.

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