High-strength apatitic cement by modification with superplasticizers

Fernández, E.; Sarda, Stéphanie; Hamcerencu, Mihaela; Vlad, Maria; Gel, Maria Montserrat; Valls, S.; Torres, Ricardo; López, José López

doi:10.1016/j.biomaterials.2004.07.043

Cited by 34 publications

(30 citation statements)

References 19 publications

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“…Similar strengthening effect was achieved by addition of some commercial superplasticizers [457]. The results showed that small additions, i.e., 0.5 vol%, in the aqueous liquid phase improved the maximum compressive strength (35 MPa) of Biocement-H © by 71%, i.e., till ~60 MPa.…”

Section: Nonporous Formulationssupporting

confidence: 57%

“…Moreover, the addition of high amounts of superplasticizers, i.e., 50 vol%, allowed for a significant increasing of the P/L ratio from 3.13 to 3.91 g/mL, without affecting the maximum strength and/or the workability [457]. This effect was explained by an inhibiting effect of the aforementioned additives on the crystal growth kinetics of newly forming crystals of calcium orthophosphates, which resulted in smaller crystallites and, hence, a denser and more interdigitated microstructure.…”

Section: Nonporous Formulationsmentioning

confidence: 99%

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Self-Setting Calcium Orthophosphate Formulations

Dorozhkin¹

2012

Calcium Orthophosphates

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Abstract:In early 1980s, researchers discovered self-setting calcium orthophosphate cements, which are bioactive and biodegradable grafting bioceramics in the form of a powder and a liquid. After mixing, both phases form pastes, which set and harden forming either a non-stoichiometric calcium deficient hydroxyapatite or brushite. Since both of them are remarkably biocompartible, bioresorbable and osteoconductive, self-setting calcium orthophosphate formulations appear to be promising bioceramics for bone grafting. Furthermore, such formulations possess excellent molding capabilities, easy manipulation and nearly perfect adaptation to the complex shapes of bone defects, followed by gradual bioresorption and new bone formation. In addition, reinforced formulations have been introduced, which might be described as calcium orthophosphate concretes. The discovery of self-setting properties opened up a new era in the medical application of calcium orthophosphates and many commercial trademarks have been introduced as a result. Currently such formulations are widely used as synthetic bone grafts, with several advantages, such as pourability and injectability. Moreover, their low-temperature setting reactions and intrinsic porosity allow loading by drugs, biomolecules and even cells for tissue engineering purposes. In this review, an insight into the self-setting calcium orthophosphate formulations, as excellent bioceramics suitable for both dental and bone grafting applications, has been provided.

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Section: Nonporous Formulationssupporting

confidence: 57%

Section: Nonporous Formulationsmentioning

confidence: 99%

Self-Setting Calcium Orthophosphate Formulations

Dorozhkin¹

2012

Calcium Orthophosphates

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“…In previous studies, several different compositions of CPC were developed [8][9][10][11][12][13][14][15]. A number of other studies investigated the setting reaction [8], in vitro aging [12], macroporous scaffolds [22][23][24][25][26][32][33][34][35], and shelf life of CPC [38].…”

Section: Discussionmentioning

confidence: 99%

“…It consisted of tetracalcium phosphate (TTCP, Ca 4 (PO 4 ) 2 O) and dicalcium phosphate anhydrous (DCPA, CaHPO 4 ) [7]. Since then, several different CPC have been developed [8][9][10][11][12][13][14][15]. The CPC paste can intimately adapt to neighboring bone even for irregularly shaped cavities, and then harden in situ to form hydroxyapatite [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Strong, macroporous, and in situ-setting calcium phosphate cement-layered structures

Burguera

Carey

2007

Biomaterials

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Calcium phosphate cement (CPC) is highly promising for clinical uses due to its in situ-setting ability, excellent osteoconductivity and bone-replacement capability. However, the low strength limits its use to non-load-bearing applications. The objectives of this study were to develop a layered CPC structure by combining a macroporous CPC layer with a strong CPC layer, and to investigate the effects of porosity and layer thickness ratios. The rationale was for the macroporous layer to accept tissue ingrowth, while the fiber-reinforced strong layer would provide the needed early-strength. A biopolymer chitosan was incorporated to strengthen both layers. Flexural strength, S (mean±sd; n = 6) of CPC-scaffold decreased from (9.7±1.2) to (1.8±0.3) MPa (p<0.05), when the porosity increased from 44.6% to 66.2%. However, with a strong-layer reinforcement, S increased to (25.2±6.7) and (10.0±1.4) MPa, respectively, at these two porosities. These strengths matched/exceeded the reported strengths of sintered porous hydroxyapatite implants and cancellous bone. Relationships were established between S and the ratio of strong layer thickness/specimen thickness, a/h:S = (17.6 a/h +3.2) MPa. The scaffold contained macropores with a macropore length (mean±sd; n = 147) of (183 ±73) μm, suitable for cell infiltration and tissue ingrowth. Nano-sized hydroxyapatite crystals were observed to form the scaffold matrix of CPC with chitosan. In summary, a layered CPC implant, combining a macroporous CPC with a strong CPC, was developed. Mechanical strength and macroporosity are conflicting requirements. However, the novel functionally graded CPC enabled a relatively high strength and macroporosity to be simultaneously achieved. Such an in situ-hardening nano-apatite may be useful in moderate stress-bearing applications, with macroporosity to enhance tissue ingrowth and implant resorption.

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“…Estudos já realizados mostram que é possível transformar o cimento em uma pasta injetável pela adição de aditivos sem modificar as reações químicas que ocorrem durante a cura do cimento [4,5,6,7]. Para que um aditivo seja eficiente na promoção de resistência à dissolução do cimento, deve apresentar certas propriedades fundamentais como promover a injetabilidade sem impedir o processo de precipitação de hidroxiapatita [8].…”

Section: Introductionunclassified

Influência de aditivos na injetabilidade de cimento ósseo de fosfato tricálcico

2006

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RESUMOOs cimentos de fosfatos de cálcio são biomateriais formados pela mistura de um pó de fosfato de cálcio com água ou com solução aquosa de sais orgânicos ou inorgânicos formando uma pasta que reage à temperatura ambiente ou corpórea, endurecendo como resultado da reação de precipitação. Cimentos de fosfato de cálcio são usados comumente em cirurgias de preenchimento ósseo na odontologia e ortopedia, que requerem procedimentos extremamente invasivos. A inovação consiste em formular uma pasta injetável pela incorporação de aditivos. Neste estudo, três aditivos (carboxi-metil-celulose, polímero de agar e alginato de sódio) foram incorporados a fosfato tricálcico-alfa, nas concentrações de 0,4%; 0,8%; 1,6%; 3,2%; 6,4% em massa. Os resultados demonstraram que foi possível obter composições de cimento de fosfato tricálcico injetáveis. Verificou-se que a injetabilidade, medida por um método inédito proposto, depende do comportamento reológico das pastas. Neste estudo, as formulações com 1,6% de carboxi-metil-celulose, 1,6% de agar e 0,8% de alginato de sódio, permitiram a obtenção de uma viscosidade suficiente para uma boa homogeneização e injeção do cimento.Palavras chaves: Cimento ósseo, fosfato tricálcico, aditivos, injetabilidade. Additives Influence on the Injectability of Tricalcium Phosphate Bone Cement ABSTRACTCalcium phosphate cements are biomaterials made of a mixture of calcium phosphate powder with water or with aqueous solutions of inorganic or organic salts, forming a paste that reacts at room or body temperature and hardens as a result of precipitation reactions. Calcium phosphate cements are commonly used in both dentistry and orthopedic bone filling surgeries, which require extremely invasive procedures. The innovation consists in formulate an injectable paste by incorporation of additives. In this work, three different additives (carboxymethylcellulose, agar polymer and calcium alginate) were incorporated in alphatricalcium phosphate (α-TCP), in concentrations of 0.4%; 0.8%; 1.6%; 3.2% and 6.4% wt%. Results showed that it was possible to obtain injectable compositions of tricalcium phosphate cement. It was verified that the injectability, measured by a novel method, depends on the rheological behavior of the pastes and injection time. In this study, pastes with sufficient viscosity for good homogenization and injection were obtained. In this study, pastes with 1.6% carboxymethylcellulose, 1.6% agar and 0.8% sodium alginate present sufficient viscosity for good homogenization for cement injection.

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High-strength apatitic cement by modification with superplasticizers

Cited by 34 publications

References 19 publications

Self-Setting Calcium Orthophosphate Formulations

Self-Setting Calcium Orthophosphate Formulations

Strong, macroporous, and in situ-setting calcium phosphate cement-layered structures

Influência de aditivos na injetabilidade de cimento ósseo de fosfato tricálcico

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