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Tronco MC, Cassel JB, Dos Santos LA. α-TCP-based Calcium Phosphate Cements: a critical review. Acta Biomater 2022; 151:70-87. [PMID: 36028195 DOI: 10.1016/j.actbio.2022.08.040] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 08/04/2022] [Accepted: 08/17/2022] [Indexed: 11/18/2022]
Abstract
Calcium phosphates are promising materials for applications in bone repair and substitution, particularly for their bioactivity and ability to form self-setting cements. Among them, α-tricalcium phosphate (α-TCP) stands out due to its high solubility, its hydration reaction and bioresorbability. The synthesis of α-TCP is particularly complex and the interactions between some of the synthesis parameters are still not completely understood. The variety of methods available to synthesize α-TCP has provided a substantial variance in the properties of α-TCP-based cements and the decision about which method, parameters and starting reagents will be used for the powder's synthesis is determinant of the properties of the resulting material. Therefore, this review paper focuses on α-TCP's synthesis and properties, presenting the synthesis methods currently in use as well as a discussion of how the synthesis parameters and the cement preparation affect the reactivity and mechanical properties of the material, providing a guide for the selection of the most suitable process for each α-TCP application. STATEMENT OF SIGNIFICANCE: α-TCP is a calcium phosphate and it is currently one of the most investigated bioceramics for applications that explore its bioresorbability and the hydration reaction of α-TCP-based cements. Despite the increasing number of publications on the topic, there are still aspects not well understood. This review article aims at contributing to this fascinating subject by offering an update on the state of the art of α-TCP's synthesis methods, while also addressing topics that are not often discussed about this material, such as the preparation of α-TCP-based cements and how its parameters affect the properties of the resulting cements.
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Affiliation(s)
- Matheus C Tronco
- Biomaterials Laboratory, Materials Department, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 91501-970, Brazil.
| | - Júlia B Cassel
- Biomaterials Laboratory, Materials Department, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 91501-970, Brazil.
| | - Luís A Dos Santos
- Biomaterials Laboratory, Materials Department, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 91501-970, Brazil.
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2
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Schröter L, Kaiser F, Stein S, Gbureck U, Ignatius A. Biological and mechanical performance and degradation characteristics of calcium phosphate cements in large animals and humans. Acta Biomater 2020; 117:1-20. [PMID: 32979583 DOI: 10.1016/j.actbio.2020.09.031] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/21/2020] [Accepted: 09/15/2020] [Indexed: 12/11/2022]
Abstract
Calcium phosphate cements (CPCs) have been used to treat bone defects and support bone regeneration because of their good biocompatibility and osteointegrative behavior. Since their introduction in the 1980s, remarkable clinical success has been achieved with these biomaterials, because they offer the unique feature of being moldable and even injectable into implant sites, where they harden through a low-temperature setting reaction. However, despite decades of research efforts, two major limitations concerning their biological and mechanical performance hamper a broader clinical use. Firstly, achieving a degradation rate that is well adjusted to the dynamics of bone formation remains a challenging issue. While apatite-forming CPCs frequently remain for years at the implant site without major signs of degradation, brushite-forming CPCs are considered to degrade to a greater extent. However, the latter tend to convert into lower soluble phases under physiological conditions, which makes their degradation behavior rather unpredictable. Secondly, CPCs exhibit insufficient mechanical properties for load bearing applications because of their inherent brittleness. This review places an emphasis on these limitations and provides an overview of studies that have investigated the biological and biomechanical performance as well as the degradation characteristics of different CPCs after implantation into trabecular bone. We reviewed studies performed in large animals, because they mimic human bone physiology more closely in terms of bone metabolism and mechanical loading conditions compared with small laboratory animals. We compared the results of these studies with clinical trials that have dealt with the degradation behavior of CPCs after vertebroplasty and kyphoplasty.
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Affiliation(s)
- Lena Schröter
- Institute for Orthopedic Research and Biomechanics, Ulm University Medical Center, Helmholtzstrasse 14, D-89081 Ulm, Germany
| | - Friederike Kaiser
- Department for Functional Materials in Medicine and Dentistry, University of Würzburg, Pleicherwall 2, D-97070 Würzburg, Germany
| | - Svenja Stein
- Institute for Orthopedic Research and Biomechanics, Ulm University Medical Center, Helmholtzstrasse 14, D-89081 Ulm, Germany
| | - Uwe Gbureck
- Department for Functional Materials in Medicine and Dentistry, University of Würzburg, Pleicherwall 2, D-97070 Würzburg, Germany.
| | - Anita Ignatius
- Institute for Orthopedic Research and Biomechanics, Ulm University Medical Center, Helmholtzstrasse 14, D-89081 Ulm, Germany
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3
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Boehm AV, Meininger S, Gbureck U, Müller FA. Self-healing capacity of fiber-reinforced calcium phosphate cements. Sci Rep 2020; 10:9430. [PMID: 32523063 PMCID: PMC7287135 DOI: 10.1038/s41598-020-66207-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 05/15/2020] [Indexed: 11/23/2022] Open
Abstract
A major problem concerning the mechanical properties of calcium phosphate cements (CPC) is related to their inherent brittleness, which limits their applicability to non-load bearing bone defects. In this work the preparation of a damage tolerant CPC is presented, where the incorporation of functionalized carbon fibers facilitates steady state flat crack propagation with crack openings below 10 µm. A subsequent self-healing process in simulated body fluid, that mimics the in vivo mineralization of bioactive surfaces, closes the cracks and completely restores the mechanical properties. Hereby, two pathways of self-healing are presented: i) intrinsic healing that bases on the inherent bioactive properties of the cement matrix and chemically treated fibers, and ii) capsule based extrinsic healing, where H2PO4- is released as an initiator for the apatite formation. Such damage tolerant CPCs with self-healing capacity are of particular interest to increase the lifetime of implants as well as in the field of load-bearing bioceramics.
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Affiliation(s)
- Anne V Boehm
- Otto Schott Institute of Materials Research (OSIM), Friedrich Schiller University Jena, Löbdergraben 32, 07743, Jena, Germany
| | - Susanne Meininger
- Department for Functional Materials in Medicine and Dentistry (FMZ), University of Würzburg, Pleicherwall 2, 97070, Würzburg, Germany
| | - Uwe Gbureck
- Department for Functional Materials in Medicine and Dentistry (FMZ), University of Würzburg, Pleicherwall 2, 97070, Würzburg, Germany
| | - Frank A Müller
- Otto Schott Institute of Materials Research (OSIM), Friedrich Schiller University Jena, Löbdergraben 32, 07743, Jena, Germany.
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Yousefi AM. A review of calcium phosphate cements and acrylic bone cements as injectable materials for bone repair and implant fixation. J Appl Biomater Funct Mater 2020; 17:2280800019872594. [PMID: 31718388 DOI: 10.1177/2280800019872594] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Treatment of bone defects caused by trauma or disease is a major burden on human healthcare systems. Although autologous bone grafts are considered as the gold standard, they are limited in availability and are associated with post-operative complications. Minimally invasive alternatives using injectable bone cements are currently used in certain clinical procedures, such as vertebroplasty and balloon kyphoplasty. Nevertheless, given the high incidence of fractures and pathologies that result in bone voids, there is an unmet need for injectable materials with desired properties for minimally invasive procedures. This paper provides an overview of the most common injectable bone cement materials for clinical use. The emphasis has been placed on calcium phosphate cements and acrylic bone cements, while enabling the readers to compare the opportunities and challenges for these two classes of bone cements. This paper also briefly reviews antibiotic-loaded bone cements used in bone repair and implant fixation, including their efficacy and cost for healthcare systems. A summary of the current challenges and recommendations for future directions has been brought in the concluding section of this paper.
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Affiliation(s)
- Azizeh-Mitra Yousefi
- Department of Chemical, Paper and Biomedical Engineering, Miami University, Oxford, OH, USA
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5
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Tanodekaew S, Channasanon S, Kaewkong P. Heat-curing polylactide for bone implants: Preparation and investigation on properties relevant to degradation. J BIOACT COMPAT POL 2019. [DOI: 10.1177/0883911519881715] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Several processes have been used to produce polylactide for bone replacement. The challenge remains, however, to produce these devices by a simpler and more economical process. In this study, a method of combining powder and liquid parts was introduced. Star-shaped polylactides with molecular weights ranging from 3 to 16 kg/mol were synthesized and blended with a linear polylactide (Mw = 188 kg/mol) using the technique of emulsion solvent evaporation. The blends in a form of spherical powder were characterized by scanning electron microscopy, gel permeation chromatography, and particle size analysis. The heat-curing polylactide was fabricated by mixing the powder with triethylene glycol dimethacrylate, molded, and then heated in a hot water bath to solidify. The effects of powder composition in terms of amount and molecular weight of the star-shaped polylactide on mechanical properties were investigated. The results showed an increase in flexural strength with increase in the amount of star-shaped polylactide. The powder comprised star-shaped polylactide having the molecular weight of 10,770 g/mol, not less than 80wt%, offered the fabricated heat-curing polylactide with high strength ranging from 95 to 100 MPa. This formulation was further incorporated with hydroxyapatite to improve biocompatibility and subjected to degradation at 37°C. Mechanical test and weight loss determination together with biological test were conducted at certain times during degradation of the materials. Both materials with and without hydroxyapatite showed mechanical stability upon degradation for at least 6 months, but the one with hydroxyapatite revealed significantly better bioactivity at the end of 1-year follow-up study, making it the most promising material for bone implants.
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Affiliation(s)
| | | | - Pakkanun Kaewkong
- National Metal and Materials Technology Center, Pathum Thani, Thailand
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6
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Weichhold J, Gbureck U, Goetz-Neunhoeffer F, Hurle K. Setting Mechanism of a CDHA Forming α-TCP Cement Modified with Sodium Phytate for Improved Injectability. MATERIALS 2019; 12:ma12132098. [PMID: 31261865 PMCID: PMC6651550 DOI: 10.3390/ma12132098] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 06/21/2019] [Accepted: 06/27/2019] [Indexed: 02/02/2023]
Abstract
A calcium deficient hydroxyapatite (CDHA) forming cement with a bimodal grain size distribution, composed of α-TCP and fine grained CDHA at a weight ratio of 9:1, was modified by the addition of sodium phytate (IP6) in variable amounts ranging from 0.25 to 2 wt.%, related to the powder content. The injectability of the cement paste was drastically increased by the IP6 addition, independent of the amount of added IP6. Additionally, the cement paste viscosity during the first minutes decreased. These effects could be clearly related to a slightly more negative zeta potential. Furthermore, IP6 was shown to strongly retard the setting reaction, as can be seen both in the calorimetry and X-ray diffraction measurements. In addition, octacalcium phosphate (OCP) was identified as a further setting product. All measurements were performed at 23 °C and 37 °C to assess the effect of temperature on the setting reaction for both clinical handling by the surgeon and the final hardening in the bone defect.
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Affiliation(s)
- Jan Weichhold
- Department for Functional Materials in Medicine and Dentistry, University of Wuerzburg, Pleicherwall 2, 97070 Würzburg, Germany
| | - Uwe Gbureck
- Department for Functional Materials in Medicine and Dentistry, University of Wuerzburg, Pleicherwall 2, 97070 Würzburg, Germany.
| | - Friedlinde Goetz-Neunhoeffer
- GeoZentrum Nordbayern-Mineralogy, Friedrich-Alexander-University of Erlangen-Nuernberg, Schlossgarten 5a, 91054 Erlangen, Germany
| | - Katrin Hurle
- GeoZentrum Nordbayern-Mineralogy, Friedrich-Alexander-University of Erlangen-Nuernberg, Schlossgarten 5a, 91054 Erlangen, Germany.
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7
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Luo J, Engqvist H, Persson C. A ready-to-use acidic, brushite-forming calcium phosphate cement. Acta Biomater 2018; 81:304-314. [PMID: 30291976 DOI: 10.1016/j.actbio.2018.10.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 09/07/2018] [Accepted: 10/01/2018] [Indexed: 10/28/2022]
Abstract
Premixed calcium phosphate cements have been developed to simplify the usage of traditional calcium phosphate cements and reduce the influence of the setting reaction on the delivery process. However, difficulties in achieving a good cohesion, adequate shelf life and sufficient mechanical properties have so far impeded their use in clinical applications, especially for the more degradable acidic calcium phosphate cements. In this study, a brushite cement was developed from a series of ready-to-use calcium phosphate pastes. The brushite cement paste was formed via mixing of a monocalcium phosphate monohydrate (MCPM) paste and a β-tricalcium phosphate (β-TCP) paste with good injectability and adequate shelf life. The MCPM paste was based on a water-immiscible liquid with two surfactants and the β-TCP paste on a sodium hyaluronate aqueous solution. The effect of citric acid as a retardant was assessed. Formulations with suitable amounts of citric acid showed good cohesion and mechanical performance with potential for future clinical applications. STATEMENT OF SIGNIFICANCE: Acidic calcium phosphate cements have attracted extensive attention as bone substitute materials due to their ability to resorb faster than basic calcium phosphate cements in vivo. However, traditionally, short working times and low mechanical strength have limited their clinical application. Premixed cements could simplify the clinical use as well as improve property reproducibility, but short shelf lives, low cohesion and low mechanical properties have restricted the development. In this study, an injectable ready-to-use two-phase system consisting of an MCPM paste and a β-TCP paste was developed based on acidic cement. It shows good cohesion, compressive strength and adequate shelf life, which has the potential to be used in a dual chamber system for simplified and fast filling of bone defects in a minimally invasive manner. This will reduce surgery time, decrease the risk of contamination and ensure repeatable results.
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8
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9
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Self-Setting Calcium Orthophosphate (CaPO4) Formulations. SPRINGER SERIES IN BIOMATERIALS SCIENCE AND ENGINEERING 2018. [DOI: 10.1007/978-981-10-5975-9_2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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10
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Elastic properties and strain-to-crack-initiation of calcium phosphate bone cements: Revelations of a high-resolution measurement technique. J Mech Behav Biomed Mater 2017; 74:428-437. [DOI: 10.1016/j.jmbbm.2017.06.023] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 06/16/2017] [Accepted: 06/20/2017] [Indexed: 11/18/2022]
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11
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O'Neill R, McCarthy HO, Montufar EB, Ginebra MP, Wilson DI, Lennon A, Dunne N. Critical review: Injectability of calcium phosphate pastes and cements. Acta Biomater 2017; 50:1-19. [PMID: 27838464 DOI: 10.1016/j.actbio.2016.11.019] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 11/03/2016] [Accepted: 11/08/2016] [Indexed: 12/26/2022]
Abstract
Calcium phosphate cements (CPC) have seen clinical success in many dental and orthopaedic applications in recent years. The properties of CPC essential for clinical success are reviewed in this article, which includes properties of the set cement (e.g. bioresorbability, biocompatibility, porosity and mechanical properties) and unset cement (e.g. setting time, cohesion, flow properties and ease of delivery to the surgical site). Emphasis is on the delivery of calcium phosphate (CaP) pastes and CPC, in particular the occurrence of separation of the liquid and solid components of the pastes and cements during injection; and established methods to reduce this phase separation. In addition a review of phase separation mechanisms observed during the extrusion of other biphasic paste systems and the theoretical models used to describe these mechanisms are discussed. STATEMENT OF SIGNIFICANCE Occurrence of phase separation of calcium phosphate pastes and cements during injection limits their full exploitation as a bone substitute in minimally invasive surgical applications. Due to lack of theoretical understanding of the phase separation mechanism(s), optimisation of an injectable CPC that satisfies clinical requirements has proven difficult. However, phase separation of pastes during delivery has been the focus across several research fields. Therefore in addition to a review of methods to reduce phase separation of CPC and the associated constraints, a review of phase separation mechanisms observed during extrusion of other pastes and the theoretical models used to describe these mechanisms is presented. It is anticipated this review will benefit future attempts to develop injectable calcium phosphate based systems.
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Affiliation(s)
- R O'Neill
- School of Mechanical and Aerospace Engineering, Queen's University Belfast, Ashby Building, Stranmillis Rd, Belfast BT9 5AH, United Kingdom
| | - H O McCarthy
- School of Pharmacy, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, United Kingdom
| | - E B Montufar
- Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgical Engineering, Universitat Politècnica de Catalunya. BarcelonaTech (UPC), Av. Diagonal 647, 08028 Barcelona, Spain; Institute for Bioengineering of Catalonia, C. Baldiri Reixach 10, 08028 Barcelona, Spain
| | - M-P Ginebra
- Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgical Engineering, Universitat Politècnica de Catalunya. BarcelonaTech (UPC), Av. Diagonal 647, 08028 Barcelona, Spain; Institute for Bioengineering of Catalonia, C. Baldiri Reixach 10, 08028 Barcelona, Spain
| | - D I Wilson
- Department of Chemical Engineering and Biotechnology, New Museums Site, Pembroke Street, University of Cambridge, CB2 3RA, United Kingdom
| | - A Lennon
- School of Mechanical and Aerospace Engineering, Queen's University Belfast, Ashby Building, Stranmillis Rd, Belfast BT9 5AH, United Kingdom
| | - N Dunne
- School of Pharmacy, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, United Kingdom; Centre for Medical Engineering Research, School of Mechanical and Manufacturing Engineering, Dublin City University, Stokes Building, Collins Avenue, Dublin 9, Ireland; Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland.
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12
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Self-hardening and thermoresponsive alpha tricalcium phosphate/pluronic pastes. Acta Biomater 2017; 49:563-574. [PMID: 27872015 DOI: 10.1016/j.actbio.2016.11.043] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 11/14/2016] [Accepted: 11/17/2016] [Indexed: 11/21/2022]
Abstract
Although calcium phosphate cements (CPCs) are used for bone regeneration in a wide range of clinical applications, various physicochemical phenomena are known to hinder their potential use in minimally invasive surgery or in highly vascularized surgical sites, mainly because of their lack of injectability or their low washout resistance. The present work shows that the combination of CPCs with an inverse-thermoresponsive hydrogel is a good strategy for finely tuning the cohesive and rheological properties of CPCs to achieve clinical acceptable injectability to prevent phase separation during implantation and cohesion to avoid washout of the paste. The thermoresponsive CPC developed combines alpha-tricalcium phosphate with an aqueous solution of pluronic F127, which exhibits an inverse thermoresponsive behaviour, with a gelling transformation at around body temperature. These novel CPCs exhibited temperature-dependent properties. Addition of the polymer enhanced the injectability of the paste, even at a low liquid-to-powder ratio, and allowed the rheological properties of the cement to be tuned, with the injection force decreasing with the temperature of the paste. Moreover, the cohesion of the paste was also temperature-dependent and increased as the temperature of the host medium increased due to gelling induced in the paste. The thermoresponsive cement exhibited excellent cohesion and clinically acceptable setting times at 37°C, irrespective of the initial temperature of the paste. The addition of pluronic F127 slightly delayed the setting reaction in the early stages but did not hinder the full transformation to calcium-deficient hydroxyapatite. Moreover, the frozen storage of premixed thermoresponsive cement pastes was explored, the main physicochemical properties of the cements being maintained upon thawing, even after 18months of frozen storage. This avoids the need to mix the cement in the operating theatre and allows its use off-the-shelf. The reverse thermoresponsive cements studied herein open up new perspectives in the surgical field, where the sequential gelling/hardening of these novel cements could allow for a better and safer clinical application. STATEMENT OF SIGNIFICANCE Calcium phosphate cements are attractive bone substitutes due to their similarity to the bone mineral phase. Although they can be injectable, cohesion and stability of the paste are crucial in terms of performance and safety. A common strategy is the combination with hydrogels. However, this often results in a decrease of viscosity with increasing temperature, which can lead to extravasation and particle leakage from the bone defect. The preferred evolution would be the opposite: a low viscosity would enhance mixing and injection, and an instantaneous increase of viscosity after injection would ensure washout resistance to the blood flow. Here we develop for the first time a calcium phosphate cement exhibiting reverse thermoresponsive properties using a poloxamer featuring inverse thermal gelling.
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13
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Unosson J, Montufar EB, Engqvist H, Ginebra MP, Persson C. Brushite foams--the effect of Tween® 80 and Pluronic® F-127 on foam porosity and mechanical properties. J Biomed Mater Res B Appl Biomater 2016; 104:67-77. [PMID: 25615405 PMCID: PMC5024005 DOI: 10.1002/jbm.b.33355] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 11/19/2014] [Accepted: 12/02/2014] [Indexed: 11/30/2022]
Abstract
Resorbable calcium phosphate based bone void fillers should work as temporary templates for new bone formation. The incorporation of macropores with sizes of 100 -300 µm has been shown to increase the resorption rate of the implant and speed up bone ingrowth. In this work, macroporous brushite cements were fabricated through foaming of the cement paste, using two different synthetic surfactants, Tween® 80 and Pluronic® F-127. The macropores formed in the Pluronic samples were both smaller and less homogeneously distributed compared with the pores formed in the Tween samples. The porosity and compressive strength (CS) were comparable to previously developed hydroxyapatite foams. The cement foam containing Tween, 0.5M citric acid in the liquid, 1 mass% of disodium dihydrogen pyrophosphate mixed in the powder and a liquid to powder ratio of 0.43 mL/g, showed the highest porosity values (76% total and 56% macroporosity), while the CS was >1 MPa, that is, the hardened cement could be handled without rupture of the foamed structure. The investigated brushite foams show potential for future clinical use, both as bone void fillers and as scaffolds for in vitro bone regeneration.
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Affiliation(s)
- Johanna Unosson
- Department of Engineering Sciences, Division of Applied Materials Science, Uppsala University, Sweden
- Department of Engineering Sciences, Uppsala University, Sweden
| | - Edgar B Montufar
- Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), ETSEIB, Spain
- Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Spain
| | - Håkan Engqvist
- Department of Engineering Sciences, Division of Applied Materials Science, Uppsala University, Sweden
- Department of Engineering Sciences, Uppsala University, Sweden
| | - Maria-Pau Ginebra
- Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), ETSEIB, Spain
- Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Spain
| | - Cecilia Persson
- Department of Engineering Sciences, Division of Applied Materials Science, Uppsala University, Sweden
- Department of Engineering Sciences, Uppsala University, Sweden
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14
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Hurle K, Christel T, Gbureck U, Moseke C, Neubauer J, Goetz-Neunhoeffer F. Reaction kinetics of dual setting α-tricalcium phosphate cements. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2016; 27:1. [PMID: 26610924 DOI: 10.1007/s10856-015-5616-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 10/28/2015] [Indexed: 06/05/2023]
Abstract
Addition of ductile polymers to calcium-deficient hydroxyapatite (CDHA)-forming bone cements based on α-tricalcium phosphate (α-TCP) is a promising approach to improve the mechanical performance of α-TCP cements and extend their application to load-bearing defects, which is else impeded by the brittleness of the hardened cement. One suitable polymer is poly-(2-hydroxyethylmethacrylate) (p-HEMA), which forms during cement setting by radical polymerisation of the monomer. In this study the hydration kinetics and the mechanical performance of α-TCP cements modified with addition of different HEMA concentrations (0-50 wt% in the cement liquid) was investigated by quantitative in situ XRD and four-point bending tests. Morphology of CDHA crystals was monitored by scanning electron microscopy. The hydration of α-TCP to CDHA was increasingly impeded and the visible crystal size of CDHA increasingly reduced with increasing HEMA concentration. Modification of the cements by adding 50 wt% HEMA to the cement liquid changed the brittle performance of the hardened cement to a pseudoplastic behaviour, reduced the flexural modulus and increased the work of fracture, while lower HEMA concentrations had no significant effect on these parameters. In such a composite, the extent of CDHA formation was considerably reduced (34.0 ± 1.8 wt% CDHA with 50 % HEMA compared to 54.1 ± 2.4 wt% CDHA in the reference formed after 48 h), while the general reaction kinetics were not changed. In conclusion, while the extent of CDHA formation was decreased, the mechanical properties were noticeably improved by addition of HEMA. Hence, α-TCP/HEMA composites might be suitable for application in some load-bearing defects and have adequate properties for mechanical treatment after implantation, like insertion of screws.
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Affiliation(s)
- Katrin Hurle
- GeoZentrum Nordbayern - Mineralogy, Friedrich-Alexander-University of Erlangen-Nuremberg, Schlossgarten 5a, 91054, Erlangen, Germany.
| | - Theresa Christel
- Department for Functional Materials in Medicine and Dentistry, University of Würzburg, Pleicherwall 2, 97070, Würzburg, Germany
| | - Uwe Gbureck
- Department for Functional Materials in Medicine and Dentistry, University of Würzburg, Pleicherwall 2, 97070, Würzburg, Germany
| | - Claus Moseke
- Department for Functional Materials in Medicine and Dentistry, University of Würzburg, Pleicherwall 2, 97070, Würzburg, Germany
| | - Juergen Neubauer
- GeoZentrum Nordbayern - Mineralogy, Friedrich-Alexander-University of Erlangen-Nuremberg, Schlossgarten 5a, 91054, Erlangen, Germany
| | - Friedlinde Goetz-Neunhoeffer
- GeoZentrum Nordbayern - Mineralogy, Friedrich-Alexander-University of Erlangen-Nuremberg, Schlossgarten 5a, 91054, Erlangen, Germany
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15
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Torres P, Gouveia S, Olhero S, Kaushal A, Ferreira J. Injectability of calcium phosphate pastes: Effects of particle size and state of aggregation of β-tricalcium phosphate powders. Acta Biomater 2015; 21:204-16. [PMID: 25870171 DOI: 10.1016/j.actbio.2015.04.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 03/10/2015] [Accepted: 04/07/2015] [Indexed: 10/23/2022]
Abstract
The present study discloses a systematic study about the influence of some relevant experimental variables on injectability of calcium phosphate cements. Non-reactive and reactive pastes were prepared, based on tricalcium phosphate doped with 5 mol% (Sr-TCP) that was synthesised by co-precipitation. The varied experimental parameters included: (i) the heat treatment temperature within the range of 800-1100°C; (ii) different milling extents of calcined powders; (iii) the liquid-to-powder ratio (LPR); (iv) the use of powder blends with different particle sizes (PS) and particle size distributions (PSD); (v) the partial replacement of fine powders by large spherical dense granules prepared via freeze granulation method to simulate coarse individual particles. The aim was contributing to better understanding of the effects of PS, PSD, morphology and state of aggregation of the starting powders on injectability of pastes produced thereof. Powders heat treated at 800 and 1000°C with different morphologies but with similar apparent PSD curves obtained by milling/blending originated completely injectable reactive cement pastes at low LPR. This contrasted with non-reactive systems prepared thereof under the same conditions. Hypotheses were put forward to explain why the injectability results collected upon extruding non-reactive pastes cannot be directly transposed to reactive systems. The results obtained underline the interdependent roles of the different powder features and ionic strength in the liquid media on determining the flow and injectability behaviours.
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16
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Abstract
Calcium phosphate biocements based on calcium phosphate chemistry are well-established biomaterials for the repair of non-load bearing bone defects due to the brittle nature and low flexural strength of such cements. This article features reinforcement strategies of biocements based on various intrinsic or extrinsic material modifications to improve their strength and toughness. Altering particle size distribution in conjunction with using liquefiers reduces the amount of cement liquid necessary for cement paste preparation. This in turn decreases cement porosity and increases the mechanical performance, but does not change the brittle nature of the cements. The use of fibers may lead to a reinforcement of the matrix with a toughness increase of up to two orders of magnitude, but restricts at the same time cement injection for minimal invasive application techniques. A novel promising approach is the concept of dual-setting cements, in which a second hydrogel phase is simultaneously formed during setting, leading to more ductile cement–hydrogel composites with largely unaffected application properties.
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Phase and size separations occurring during the injection of model pastes composed of β-tricalcium phosphate powder, glass beads and aqueous solutions. Acta Biomater 2014; 10:2259-68. [PMID: 24361425 DOI: 10.1016/j.actbio.2013.12.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 12/02/2013] [Accepted: 12/10/2013] [Indexed: 11/21/2022]
Abstract
Glass beads a few hundred micrometers in size were added to aqueous β-tricalcium phosphate pastes to simulate the effect of porogens and drug-loaded microspheres on the injectability of calcium phosphate cements and putties. The composition of the pastes was monitored during the injection process to assess the effect of glass bead content, glass bead size and paste composition on the paste injectability. The results revealed that the injection process led to both liquid and glass bead segregations: the liquid flowed faster than the glass beads, which themselves flowed faster than the β-tricalcium phosphate microparticles. In fact, even the particle size distribution of the glass beads was modified during injection. These results reveal that a good design of multiphasic injectable pastes is essential to prevent phase separation.
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Ishikawa K. Calcium Phosphate Cement. SPRINGER SERIES IN BIOMATERIALS SCIENCE AND ENGINEERING 2014. [DOI: 10.1007/978-3-642-53980-0_7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Werdofa DM, Lewis G. Direct and interactive influence of explanatory variables on properties of a calcium phosphate cement for vertebral body augmentation. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2014; 25:55-66. [PMID: 24046084 DOI: 10.1007/s10856-013-5051-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 09/07/2013] [Indexed: 06/02/2023]
Abstract
We used the response surface methodology to investigate the direct and interactive effects of three explanatory variables on three properties of a calcium phosphate cement (CPC) for use in vertebroplasty (VP) and balloon kyphoplasty (BKP). The variables were poly(ethylene glycol) content of the cement liquid (PEG), powder-to-liquid ratio (PLR), and the amount of Na2HPO4 added to an aqueous solution of 4 wt/wt% poly(acrylic acid) (as the cement liquid) (SPC). The properties were injectability (I), final setting time (F), and 5-day compressive strength (UCS). We found that (1) there was an interactive effect between the variables on I and F but not on UCS; (2) the maximum I (98%) was obtained with PEG = 20 wt/wt% and PLR = 2 g mL(-1); (3) F = 15 min (the proposed optimum value for a CPC for use in VP and BKP) was obtained with PEG = 4 wt/wt% and PLR = 2.9 g mL(-1); and (4) the maximum UCS (39 MPa) was obtained with SPC = 0 and PLR = 3.5 g mL(-1).
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Affiliation(s)
- Daniel M Werdofa
- Department of Mechanical Engineering, The University of Memphis, Memphis, TN, 38152, USA
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20
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Dorozhkin SV. Self-setting calcium orthophosphate formulations. J Funct Biomater 2013; 4:209-311. [PMID: 24956191 PMCID: PMC4030932 DOI: 10.3390/jfb4040209] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 10/18/2013] [Accepted: 10/21/2013] [Indexed: 01/08/2023] Open
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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Engstrand J, Persson C, Engqvist H. The effect of composition on mechanical properties of brushite cements. J Mech Behav Biomed Mater 2013; 29:81-90. [PMID: 24064324 DOI: 10.1016/j.jmbbm.2013.08.024] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 08/20/2013] [Accepted: 08/25/2013] [Indexed: 11/19/2022]
Abstract
Due to a fast setting reaction, good biological properties, and easily available starting materials, there has been extensive research within the field of brushite cements as bone replacing material. However, the fast setting of brushite cement gives them intrinsically low mechanical properties due to the poor crystal compaction during setting. To improve this, many additives such as citric acid, pyrophosphates, and glycolic acid have been added to the cement paste to retard the crystal growth. Furthermore, the incorporation of a filler material could improve the mechanical properties when used in the correct amounts. In this study, the effect of the addition of the two retardants, disodium dihydrogen pyrophosphate and citric acid, together with the addition of β-TCP filler particles, on the mechanical properties of a brushite cement was investigated. The results showed that the addition of low amounts of a filler (up to 10%) can have large effects on the mechanical properties. Furthermore, the addition of citric acid to the liquid phase makes it possible to use lower liquid-to-powder ratios (L/P), which strongly affects the strength of the cements. The maximal compressive strength (41.8MPa) was found for a composition with a molar ratio of 45:55 between monocalcium phosphate monohydrate and beta-tricalcium phosphate, an L/P of 0.25ml/g and a citric acid concentration of 0.5M in the liquid phase.
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Affiliation(s)
- Johanna Engstrand
- Division of Applied Materials Science, Department of Engineering Sciences, Uppsala University, Sweden.
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Strong and tough magnesium wire reinforced phosphate cement composites for load-bearing bone replacement. J Mech Behav Biomed Mater 2013; 20:36-44. [DOI: 10.1016/j.jmbbm.2012.12.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Revised: 12/27/2012] [Accepted: 12/30/2012] [Indexed: 02/02/2023]
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Persson C, Berg S. Strategies towards injectable, load-bearing materials for the intervertebral disc: a review and outlook. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2013; 24:1-10. [PMID: 23053805 DOI: 10.1007/s10856-012-4776-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2011] [Accepted: 09/21/2012] [Indexed: 06/01/2023]
Abstract
Currently available treatments for the degenerated intervertebral disc present disadvantages, such as surgical invasiveness and inadequate load distribution results. Load-bearing, injectable materials may be interesting for future therapies, but have not been studied in depth. In this study, the existing literature was screened for studies on injectable materials for the intervertebral disc and a rationale for load-bearing, injectable materials was formulated. Requirements for such a material were discussed, partly based on the experience of materials used for similar applications. Important properties were discussed and found to include biocompatibility, bioactivity, porosity, handling, injectability, working time, setting time, radiopacity, containment and mechanical properties, where several of these properties are linked to one another. In conclusion, there is a need for consensus on the properties of new materials developed for use in minimally invasive procedures in the spine. A substantial amount of attention may need to be given to non-toxic setting reactions.
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Affiliation(s)
- Cecilia Persson
- Applied Materials Science, Department of Engineering Sciences, Uppsala University, Uppsala, Sweden.
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24
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Mechanical characterization of bone graft substitute ceramic cements. Injury 2012; 43:266-71. [PMID: 21371707 DOI: 10.1016/j.injury.2011.02.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 01/07/2011] [Accepted: 02/08/2011] [Indexed: 02/02/2023]
Abstract
The aim of this laboratory work was to study the compressive and flexural characteristics of various commercially available bone graft substitute (BGS) ceramic cements, in their initial as-mixed condition, and compare them to polymethylmethacrylate (PMMA). The tested biomaterials were two different calcium phosphate cements, two different calcium sulphate cements, one nanocrystalline hydroxyapatite and one PMMA cement. All biomaterials were prepared according to manufacturers instructions and the methodology described in ISO 5833 (2002) for acrylic bone cement was followed, as the one closest approaching in vivo requirements. All BGS cements had a brittle behaviour and when subjected to mechanical stress they all failed under sudden crack propagations in their bulk. Both in compression and bending, all BGS cements failed under loads lower than those of PMMA. In compression, the calcium sulphate extra strength cement showed a strength value of approximately 60% of PMMA, the other cements following at a distance. In bending, all BGS cements showed strengths below 22% of PMMA. However, due to limited number and fragility of specimens, calculated bending strengths can only be considered as indicative figures with limited comparative value. The results of this in vitro study showed a varying mechanical performance between tested BGS ceramic cements, whilst all of them exhibited lower compression and bending strength than the selected PMMA. These findings, of course, cannot be directly extrapolated to surgical or clinical implications, since the adopted in vitro context does not necessarily reflect the actual in vivo conditions met by such biomaterials.
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Habib M, Baroud G, Galea L, Bohner M. Evaluation of the ultrasonication process for injectability of hydraulic calcium phosphate pastes. Acta Biomater 2012; 8:1164-8. [PMID: 22075123 DOI: 10.1016/j.actbio.2011.10.032] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2011] [Revised: 09/28/2011] [Accepted: 10/19/2011] [Indexed: 11/18/2022]
Abstract
This study examined the use of ultrasonication to improve the injectability of an aqueous calcium phosphate paste. Ultrasonication was applied to the paste through the plunger of the delivery syringe. A factorial design of experiments with three investigated factors, liquid to powder ratio (LPR) (38%, 39% and 40%), the size of the delivery syringe (5 and 10 ml) and the amplitude of the 20 kHz power ultrasonication (0-30 μm), was used in this study. The volume fraction of the extruded paste was used to quantify injectability. Small injectability improvements were observed with an increase in LPR and decrease in syringe size, which is consistent with previously published results. The improvements due to ultrasonication were significant and remarkable. For example, when using the 5 ml syringe the injected volume fraction of the 38% LPR paste improved from 63.4 ± 2.3% without ultrasonication to 97.3 ± 2.4% with 30%. This result shows that ultrasonication is an effective solution to improve injectability.
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Affiliation(s)
- Mohamed Habib
- Laboratoire de Biomécanique, Département de Génie, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K 2R1
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Tadier S, Bolay NL, Fullana SG, Cazalbou S, Charvillat C, Labarrère M, Boitel D, Rey C, Combes C. Cogrinding significance for calcium carbonate-calcium phosphate mixed cement. II. Effect on cement properties. J Biomed Mater Res B Appl Biomater 2011; 99:302-12. [DOI: 10.1002/jbm.b.31899] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Revised: 04/02/2011] [Accepted: 05/08/2011] [Indexed: 11/06/2022]
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Tadier S, Le Bolay N, Rey C, Combes C. Co-grinding significance for calcium carbonate-calcium phosphate mixed cement. Part I: effect of particle size and mixing on solid phase reactivity. Acta Biomater 2011; 7:1817-26. [PMID: 21147278 DOI: 10.1016/j.actbio.2010.12.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 11/11/2010] [Accepted: 12/06/2010] [Indexed: 10/18/2022]
Abstract
In part I of this study we aim to evaluate and control the characteristics of the powders constituting the solid phase of a vaterite CaCO(3)-dicalcium phosphate dihydrate cement using a co-grinding process and to determine their impact on cement setting ability. An original methodology involving complementary analytical techniques was implemented to thoroughly investigate the grinding mechanism of separated or mixed reactive powders and the effects on solid phase reactivity. We showed that the association of both reactive powders during co-grinding improves the efficiency of this process in terms of the particle size decrease, thus making co-grinding adaptable to industrial development of the cement. For the first time the usefulness of horizontal attenuated total reflection Fourier transform infrared spectroscopy to follow the chemical setting reaction at 37°C in real time has been demonstrated. We point out the antagonist effects that co-grinding can have on cement setting: the setting time is halved; however, progress of the chemical reaction involving dissolution-reprecipitation is delayed by 30 min, probably due to the increased contact area between the reactive powders, limiting their hydration. More generally, we can take advantage of the co-grinding process to control powder mixing, size and reactivity and this original analytical methodology to better understand its effect on the phenomena involved during powder processing and cement setting, which is decisive for the development of multi-component cements.
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Low KL, Tan SH, Zein SHS, Roether JA, Mouriño V, Boccaccini AR. Calcium phosphate-based composites as injectable bone substitute materials. J Biomed Mater Res B Appl Biomater 2010; 94:273-86. [PMID: 20336722 DOI: 10.1002/jbm.b.31619] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A major weakness of current orthopedic implant materials, for instance sintered hydroxyapatite (HA), is that they exist as a hardened form, requiring the surgeon to fit the surgical site around an implant to the desired shape. This can cause an increase in bone loss, trauma to the surrounding tissue, and longer surgical time. A convenient alternative to harden bone filling materials are injectable bone substitutes (IBS). In this article, recent progress in the development and application of calcium phosphate (CP)-based composites use as IBS is reviewed. CP materials have been used widely for bone replacement because of their similarity to the mineral component of bone. The main limitation of bulk CP materials is their brittle nature and poor mechanical properties. There is significant effort to reinforce or improve the mechanical properties and injectability of calcium phosphate cement (CPC) and this review resumes different alternatives presented in this specialized literature.
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Affiliation(s)
- Kah Ling Low
- School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, Seri Ampangan 14300 Nibong Tebal, Seberang Perai Selatan, Pulau Pinang, Malaysia
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Jiang PJ, Patel S, Gbureck U, Caley R, Grover LM. Comparing the efficacy of three bioceramic matrices for the release of vancomycin hydrochloride. J Biomed Mater Res B Appl Biomater 2010; 93:51-8. [PMID: 20024966 DOI: 10.1002/jbm.b.31557] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A number of calcium phosphate materials have been investigated as drug release matrices for the prophylactic treatment of implant-related osteomyelitis. However, some studies have shown the influence of processing on the efficacy of the delivered drug. The objective of this study was to evaluate the influence of pH during processing on the efficacy of vancomycin hydrochloride (VH) against Staphylococcus aureus. VH was loaded into a brushite cement (CaHPO(4).2H(2)O; pH 2.4); a hydroxyapatite cement (Ca(10)(PO(4))(6)OH(2); pH 9.4); and an apatite xerogel (pH 7.4). The pH of the material during processing had a significant influence on the mechanism of release from the cement. VH released from the apatite cement (pH 9.4) was not released in accordance with the Higuchi model. In addition to affecting release, the basic pH was shown to diminish the antibacterial potency of the released VH. Despite exceeding the minimum inhibitory concentration, the eluent from the apatite cement was ineffective against a culture of S. aureus. The findings of this study reinforce the importance of evaluating not only the release of the drug from the material matrix but also the antibacterial potency of the released drug.
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Affiliation(s)
- Peih-Jeng Jiang
- School of Chemical Engineering, University of Birmingham, Birmingham, B15 2TT, UK
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Rheological properties of calcium carbonate self-setting injectable paste. Acta Biomater 2010; 6:920-7. [PMID: 19716448 DOI: 10.1016/j.actbio.2009.08.032] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 08/20/2009] [Accepted: 08/24/2009] [Indexed: 11/21/2022]
Abstract
With the development of minimally invasive surgical techniques, there is growing interest in the research and development of injectable biomaterials with controlled rheological properties. In this context, the rheological properties and injectability characteristics of an original CaCO(3) self-setting paste have been investigated. Two complementary rheometrical procedures have been established using a controlled stress rheometer to follow the structure build-up at rest or during gentle mixing and/or handling on the one hand, and the likely shear-induced breakdown of this structure at 25 or 35 degrees Celsius on the other. The data obtained clearly show the influence of temperature on the development of a cement microstructure during setting, in all cases leading to a microporous cement made of an entangled network of aragonite-CaCO(3) needle-like crystals. Linear viscoelastic measurements arriving from an oscillatory shear at low deformation showed a progressive increase in the viscous modulus (G'') during paste setting, which is enhanced by an increase in temperature. In addition, steady shear measurements revealed the shear-thinning behaviour of this self-setting paste over an extended period after paste preparation and its ability to re-build through progressive paste setting at rest. The shear-thinning behaviour of this self-setting system was confirmed using the injectability system and a procedure we designed. The force needed to extrude a homogeneous and continuous column of paste decreases strongly upon injection and reaches a weight level to apply on the syringe piston around 2.5 kg, revealing the ease of injection of this CaCO(3) self-setting paste.
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Lewis G, Towler MR, Boyd D, German MJ, Wren AW, Clarkin OM, Yates A. Evaluation of two novel aluminum-free, zinc-based glass polyalkenoate cements as alternatives to PMMA bone cement for use in vertebroplasty and balloon kyphoplasty. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2010; 21:59-66. [PMID: 19655232 DOI: 10.1007/s10856-009-3845-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2008] [Accepted: 07/27/2009] [Indexed: 05/28/2023]
Abstract
Vertebroplasty (VP) and balloon kyphoplasty (BKP) are now widely used for treating patients in whom the pain due to vertebral compression fractures is severe and has proved to be refractory to conservative treatment. These procedures involve percutaneous delivery of a bolus of an injectable bone cement either directly to the fractured vertebral body, VB (VP) or to a void created in it by an inflatable bone tamp (BKP). Thus, the cement is a vital component of both procedures. In the vast majority of VPs and BKPs, a poly(methyl methacrylate) (PMMA) bone cement is used. This material has many shortcomings, notably lack of bioactivity and very limited resorbability. Thus, there is room for alternative cements. We report here on two variants of a novel, bioactive, Al-free, Zn-based glass polyalkenoate cement (Zn-GPC), and how their properties compare to those of an injectable PMMA bone cement (SIMPL) that is widely used in VP and BKP. The properties determined were injectability, radiopacity, uniaxial compressive strength, and biaxial flexural modulus. In addition, we compared the compression fatigue lives of a validated synthetic osteoporotic VB model (a polyurethane foam cube with an 8 mm-diameter through-thickness cylindrical hole), at 0-2300 N and 3 Hz, when the hole was filled with each of the three cements. A critical review of the results suggests that the performance of each of the Zn-GPCs is comparable to that of SIMPL; thus, the former cements merit further study with a view to being alternatives to an injectable PMMA cement for use in VP and BKP.
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Affiliation(s)
- Gladius Lewis
- Department of Mechanical Engineering, The University of Memphis, Memphis, TN 38152, USA.
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Habib M, Baroud G, Gitzhofer F, Bohner M. Mechanisms underlying the limited injectability of hydraulic calcium phosphate paste. Part II: particle separation study. Acta Biomater 2010; 6:250-6. [PMID: 19523542 DOI: 10.1016/j.actbio.2009.06.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2009] [Revised: 05/02/2009] [Accepted: 06/08/2009] [Indexed: 11/19/2022]
Abstract
Calcium phosphate cements (CPCs) are of great interest for bone augmentation procedures. In these a hydraulic calcium phosphate paste is injected through a small bore needle into the bone. The injectability of these pastes is relatively poor, resulting into partial injection only. In earlier studies we have shown that phase separation brings the injection process to a halt. Phase separation is characterized by a faster flow of the liquid than of the solid during paste extrusion. So far it is unclear whether or not particle separation contributes to the poor injectability of such hydraulic pastes. It is hypothesized that fine particles behave like a liquid and thus separate under the injection pressure, leaving larger particles behind. A factorial experimental design was used to examine this hypothesis. The particle size distribution (PSD) of the extrudate was measured over the course of each injection experiment using laser diffraction. The solid content of the paste was further inspected using scanning electron microscopy. A total of 48 experiments covering four factors at two levels each were performed. One factor was the ultrasound exposure duration, to ensure the dispersion quality of the particles during the PSD measurements. Another factor was the location of the samples over the course of the injection, so as to compare the extrudate with the PSDs remaining in the syringe. The liquid:powder ratio (LPR) in the injected paste was another factor investigated. Specifically, two different pastes with 40% and 50% LPR were examined. The dispersal medium was a fourth factor investigated, to ensure adequate dispersion of the particles during the PSD measurements. Analysis of variance showed that sample location did not significantly affect PSD. No apparent PSD change for the extruded paste and the paste remaining in the syringe could be detected by scanning electron microscopy. In conclusion, the present study did not show any evidence suggesting that particle separation occurred over the course of injection and thus that phase separation remains the main phenomenon leading to the poor injectability of CPCs.
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Affiliation(s)
- M Habib
- Biomechanics Laboratory, Mechanical Engineering, Université de Sherbrooke, Sherbrooke, QC, Canada J1K 2R1
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Abstract
In early 1980s, researchers discovered self-setting calcium orthophosphate cements, which are a bioactive and biodegradable grafting material in the form of a powder and a liquid. Both phases form after mixing a viscous paste that after being implanted, sets and hardens within the body as either a non-stoichiometric calcium deficient hydroxyapatite (CDHA) or brushite, sometimes blended with unreacted particles and other phases. As both CDHA and brushite are remarkably biocompartible and bioresorbable (therefore, in vivo they can be replaced with newly forming bone), calcium orthophosphate cements represent a good correction technique for non-weight-bearing bone fractures or defects and appear to be very promising materials for bone grafting applications. Besides, these cements possess an excellent osteoconductivity, molding capabilities and easy manipulation. Furthermore, reinforced cement formulations are available, which in a certain sense might be described as calcium orthophosphate concretes. The concepts established by calcium orthophosphate cement pioneers in the early 1980s were used as a platform to initiate a new generation of bone substitute materials for commercialization. Since then, advances have been made in the composition, performance and manufacturing; several beneficial formulations have already been introduced as a result. Many other compositions are in experimental stages. In this review, an insight into calcium orthophosphate cements and concretes, as excellent biomaterials suitable for both dental and bone grafting application, has been provided.
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Mechanisms underlying the limited injectability of hydraulic calcium phosphate paste. Acta Biomater 2008; 4:1465-71. [PMID: 18445539 DOI: 10.1016/j.actbio.2008.03.004] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2007] [Revised: 02/10/2008] [Accepted: 03/20/2008] [Indexed: 11/20/2022]
Abstract
Calcium phosphate (CaP) cements are being increasingly used for minimally invasive hard tissue implantation. Possible approaches to improve the bad injectability of hydraulic calcium phosphate pastes have been discussed and investigated in a number of recent publications. However, the liquid-phase separation mechanism leading to the limited injectability has not yet been addressed. Liquid-phase separation means that the liquid-to-powder ratio (LPR) of the extruded paste is higher than the LPR of the paste left in the syringe. The goal of this paper was to remedy this situation by looking at the liquid-phase migration occurring during the injection of a paste from a syringe through a cannula. Experimentally, it was seen that the liquid content of both the syringe paste and the extrudate decreased during the paste injection. Moreover, a high extrusion velocity, small syringe size, short cannula and high LPR favored a good injectability. These results could be partly explained in light of rheological measurements performed with the investigated paste.
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Boelen EJ, Lewis G, Xu J, Slots T, Koole LH, van Hooy-Corstjens CS. Evaluation of a highly-radiopaque iodine-containing acrylic bone cement for use in augmentation of vertebral compression fractures. J Biomed Mater Res A 2008; 86:76-88. [DOI: 10.1002/jbm.a.31601] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Liu C, Shao H, Chen F, Zheng H. Rheological properties of concentrated aqueous injectable calcium phosphate cement slurry. Biomaterials 2006; 27:5003-13. [PMID: 16787661 DOI: 10.1016/j.biomaterials.2006.05.043] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2006] [Accepted: 05/24/2006] [Indexed: 11/26/2022]
Abstract
In this paper, the steady and dynamic rheological properties of concentrated aqueous injectable calcium phosphate cement (CPC) slurry were investigated. The results indicate that the concentrated aqueous injectable CPC showed both plastic and thixotropic behavior. As the setting process progressed, the yield stress of CPC slurry was raised, the area of the thixotropic hysteresis loop was enlarged, indicating that the strength of the net structure of the slurry had increased. The results of dynamic rheological behavior indicate that the slurry presented the structure similar to viscoelastic body and the property of shear thinning at the beginning. During the setting process, the slurry was transformed from a flocculent structure to a net structure, and the strength increased. Different factors had diverse effects on the rheological properties of the CPC slurry in the setting process, a reflection of the flowing properties (or injection), and the microstructure development of this concentrated suspension. Raising the powder-to-liquid ratio decreased the distance among the particles, increased the initial strength, and shortened the setting time. In addition, raising the temperature improved the initial strength, increased the order of reaction, and shortened the setting time, which was favorable to the setting process. The particle size of the raw material had much to do with the strength of original structure and setting time. The storage module G' of CPC slurry during the setting process followed the rule of power law function G'=A exp(Bt), which could be applied to forecast the setting time, and the calculated results thereafter are in agreement with the experimental data.
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Affiliation(s)
- Changsheng Liu
- Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237, PR China.
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Reid JW, Tuck L, Sayer M, Fargo K, Hendry JA. Synthesis and characterization of single-phase silicon-substituted α-tricalcium phosphate. Biomaterials 2006; 27:2916-25. [PMID: 16448694 DOI: 10.1016/j.biomaterials.2006.01.007] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2005] [Accepted: 01/06/2006] [Indexed: 10/25/2022]
Abstract
Silicon-substituted calcium phosphate (CaP) powders with a Ca/(P+Si) ratio of 1.50 have been prepared by a wet chemical method, with silicon contents up to 2.16 weight percent (wt%). Sintering for 2 h at 1250 degrees C yields single-phase silicon-substituted alpha tricalcium phosphate (Si-alpha-TCP) for compositions between 0.59 and 1.14 wt% silicon. The sintered powders have been characterized with X-ray fluorescence (XRF) spectrometry, X-ray diffraction (XRD), attenuated total reflection infrared spectroscopy (ATR-IR) and transmission electron microscopy (TEM). Compositions with less than 0.59 wt% silicon result in mixtures of Si-alpha-TCP, beta-TCP, and calcium hydroxyapatite (HA), while compositions with more than 1.14 wt% silicon result in mixtures of Si-alpha-TCP and HA. The lattice parameters of single-phase Si-alpha-TCP prepared with 0.87 wt% silicon are a=12.874(1)A, b = 27.372(2) A, c = 15.225(1) A, and beta = 126.38(1) degrees .
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Affiliation(s)
- Joel W Reid
- Millenium Biologix Corp., 785 Midpark Drive, Kingston, Ont., Canada K7M 7G3.
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Lilley KJ, Gbureck U, Wright AJ, Farrar DF, Barralet JE. Cement from nanocrystalline hydroxyapatite: effect of calcium phosphate ratio. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2005; 16:1185-90. [PMID: 16362220 DOI: 10.1007/s10856-005-4727-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2005] [Accepted: 08/19/2005] [Indexed: 05/05/2023]
Abstract
Nanocrystalline hydroxyapatite (nHA) can be mixed with phosphoric acid to form a brushite cement; a degradable inorganic bone filling material. nHA was precipitated from reactants of calcium to phosphate (Ca/P) ratio 0.8 to 2.0 and mixed with phosphoric acid, which resulted in the formation of a brushite cement. Cement was also formed by mixing microcrystalline calcium phosphates, beta-tricalcium phosphate, hydroxyapatite and tetracalcium phosphate with phosphoric acid solution. Cement produced with nHA was stronger in compression than that formed with crystalline calcium phosphate phases. Setting time, strength and composition of cement produced with nHA was dependant on both the Ca/P ratio of nHA and the concentration of phosphoric acid in cement slurry. Increasing phosphoric acid concentration increased compressive strength whilst reducing the initial setting time of cement. Reducing the Ca/P ratio of nHA precipitation reactants retarded the setting and increased the extent of reaction of cements. This finding was unexpected and suggests that Ca/P ratio may strongly affect dissolution behaviour and this parameter is more important than stoichiometry in determining extent of reaction in this system. This study demonstrated that the wide variation in stoichiometry that may be attained in nanocrystalline apatite may be utilised to change cement performance and setting behaviour.
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Affiliation(s)
- K J Lilley
- Biomaterials Unit, School of Dentistry, University of Birmingham, B4 6NN, UK
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Bohner M, Gbureck U, Barralet JE. Technological issues for the development of more efficient calcium phosphate bone cements: a critical assessment. Biomaterials 2005; 26:6423-9. [PMID: 15964620 DOI: 10.1016/j.biomaterials.2005.03.049] [Citation(s) in RCA: 253] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2005] [Accepted: 03/24/2005] [Indexed: 11/19/2022]
Abstract
The first calcium phosphate cements (CPCs) were discovered in the 1980s. Two decades later, the interest for these materials is still rising. The goal of the present document is to review the most recent achievements in the field and to analyze future directions in research and development.
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Affiliation(s)
- M Bohner
- Dr Robert Mathys Foundation, Bischmattstrasse 12, CH-2544 Bettlach, Switzerland.
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