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Acrylic Bone Cement
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Gladius Lewis – One of the best experts on this subject based on the ideXlab platform.
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Probabilistic characteristics of random damage events and their quantification in Acrylic Bone Cement
Journal of Materials Science: Materials in Medicine, 2010Co-Authors: Gang Qi, Gladius Lewis, Steven F. Wayne, Oliver Penrose, John I. Hochstein, Kenneth A. MannAbstract:The failure of brittle and quasi-brittle polymers can be attributed to a multitude of random microscopic damage modes, such as fibril breakage, crazing, and microfracture. As the load increases, new damage modes appear, and existing ones can transition into others. In the example polymer used in this study—a commercially available Acrylic Bone Cement—these modes, as revealed by scanning electron microscopy of fracture surfaces, include nucleation of voids, cracking, and local detachment of the beads from the matrix. Here, we made acoustic measurements of the randomly generated microscopic events (RGME) that occurred in the material under pure tension and under three-point bending, and characterized the severity of the damage by the entropy ( s ) of the probability distribution of the observed acoustic signal amplitudes. We correlated s with the applied stress (σ) by establishing an empirical s–σ relationship, which quantifies the activities of RGME under Mode I stress. It reveals the state of random damage modes: when d s /dσ > 0, the number of damage modes present increases with increasing stress, whereas it decreases when d s /dσ
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probabilistic characteristics of random damage events and their quantification in Acrylic Bone Cement
Journal of Materials Science: Materials in Medicine, 2010Co-Authors: Steven F. Wayne, Gladius Lewis, Oliver Penrose, John I. Hochstein, Kenneth A. MannAbstract:The failure of brittle and quasi-brittle polymers can be attributed to a multitude of random microscopic damage modes, such as fibril breakage, crazing, and microfracture. As the load increases, new damage modes appear, and existing ones can transition into others. In the example polymer used in this study—a commercially available Acrylic Bone Cement—these modes, as revealed by scanning electron microscopy of fracture surfaces, include nucleation of voids, cracking, and local detachment of the beads from the matrix. Here, we made acoustic measurements of the randomly generated microscopic events (RGME) that occurred in the material under pure tension and under three-point bending, and characterized the severity of the damage by the entropy (s) of the probability distribution of the observed acoustic signal amplitudes. We correlated s with the applied stress (σ) by establishing an empirical s–σ relationship, which quantifies the activities of RGME under Mode I stress. It reveals the state of random damage modes: when ds/dσ > 0, the number of damage modes present increases with increasing stress, whereas it decreases when ds/dσ < 0. When ds/dσ ≈ 0, no new random damage modes occur. In the s–σ curve, there exists a transition zone, with the stress at the “knee point” in this zone (center of the zone) corresponding to ~30 and ~35% of the Cement’s tensile and bending strengths, respectively. This finding explains the effects of RGME on material fatigue performance and may be used to approximate fatigue limit.
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alternative Acrylic Bone Cement formulations for Cemented arthroplasties present status key issues and future prospects
Journal of Biomedical Materials Research Part B, 2008Co-Authors: Gladius LewisAbstract:All the commercially available plain Acrylic Bone Cement brands that are used in Cemented arthroplasties are based on poly (methyl methacrylate) and, with a few exceptions, have the same constituents. It is well known that these brands are beset with many drawbacks, such as high maximum exotherm temperature, lack of bioactivity, and volumetric shrinkage upon curing. Furthermore, concerns have been raised about a number of the constituents, such as toxicity of the activator (N,N,dimethyl-p-toluidine) and possible involvement of the radiopacifier (BaSO4 or ZrO2 particles) in third-body wear. Thus, over the years, many research efforts have been expended to address these drawbacks, culminating in a large number of alternative formulations, which may be grouped into 16 categories. Although there are a number of reviews of the large literature that now exists on these formulations, each covers only some of the categories and none contains a detailed discussion of the germane issues. The objective of the present work, therefore, was to present a comprehensive and critical review of the whole field. In addition to succinct descriptions of the Cements in each category, there are explicative summaries of literature reports, a detailed discussion of several key issues surrounding the potential for use of these Cements in Cemented arthroplasties, and a presentation of numerous ideas for future studies. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
Mervi Puska – One of the best experts on this subject based on the ideXlab platform.
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Biomineralization of Glass Fibre Reinforced Porous Acrylic Bone Cement
Key Engineering Materials, 2007Co-Authors: Mervi Puska, Ari-pekka Forsback, Antti Yli-urpo, Jukka Seppälä, Pekka K. VallittuAbstract:Acrylic Bone Cements are used to fix joint replaCements to Bone. The main substance in Acrylic Bone Cement is biologically inert poly(methylmethacrylate), PMMA. The dense PMMA polymer structure of Cement does not allow Bone ingrowth into Cement. Therefore, the main focus of our studies is to modify Acrylic Bone Cement in order to improve its biological properties e.g., by creating porosity in the Cement matrix. The porous structure is in situ created using pore-generating filler (i.e., 20 wt% of an experimental biodegradable polyamide) that is incorporated in Acrylic Bone Cement. The aim of this in vitro study was to investigate the biomineralization of Acrylic Bone Cement modified using an experimental biodegradable polyamide.
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Synthesis and Characterization of Polyamide of Trans-4-hydroxy-L-proline used as Porogen Filler in Acrylic Bone Cement
Journal of Biomaterials Applications, 2005Co-Authors: Mervi Puska, Antti Yli-urpo, Pekka Vallittu, Karri AirolaAbstract:The aim of this study was to synthesize on a larger scale, an experimental polyamide based on an amino acid of trans-4-hydroxy-L-proline. The polyamide of trans-4-hydroxy-L-proline has been used as porogen filler (i.e., a hydrophilic pore generating material) in nondegradable Acrylic Bone Cement. In in vitro studies, this hydrophilic filling component has been shown to form porosity within the Acrylic Bone Cement in an aqueous environment. The formation of in situ porosity in the Acrylic polymer matrix is believed to improve the fixation between the Cement and the living Bone. Namely, a porous structure can support Bone ingrowth and strengthen the mechanical connection between the Acrylic Bone Cement and the Bone. The monomer, trans-4-hydroxy-L-proline methyl ester, was prepared from trans-4-hydroxy-L-proline by means of two steps, and the monomer was then polymerized to polyamide of trans-4-hydroxy-L-proline. The polymerization was carried out using a melt polycondensation method. The molecular weights (M) of the produced polyamides were between 1800 and 3600. The products were characterized by FTIR and H-NMR spectroscopy.
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Synthesis and Characterization of Polyamide of Trans-4-hydroxy-L-proline used as Porogen Filler in Acrylic Bone Cement
Journal of biomaterials applications, 2005Co-Authors: Mervi Puska, Pekka K. Vallittu, Antti Yli-urpo, Karri AirolaAbstract:The aim of this study was to synthesize on a larger scale, an experimental polyamide based on an amino acid of trans-4-hydroxy-L-proline. The polyamide of trans-4-hydroxy-L-proline has been used as porogen filler (i.e., a hydrophilic pore generating material) in nondegradable Acrylic Bone Cement. In in vitro studies, this hydrophilic filling component has been shown to form porosity within the Acrylic Bone Cement in an aqueous environment. The formation of in situ porosity in the Acrylic polymer matrix is believed to improve the fixation between the Cement and the living Bone. Namely, a porous structure can support Bone ingrowth and strengthen the mechanical connection between the Acrylic Bone Cement and the Bone. The monomer, trans-4-hydroxy-L-proline methyl ester, was prepared from trans-4-hydroxy-L-proline by means of two steps, and the monomer was then polymerized to polyamide of trans-4-hydroxy- L-proline. The polymerization was carried out using a melt polycondensation method. The molecular weights (M) of the produced polyamides were between
Karri Airola – One of the best experts on this subject based on the ideXlab platform.
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Synthesis and Characterization of Polyamide of Trans-4-hydroxy-L-proline used as Porogen Filler in Acrylic Bone Cement
Journal of Biomaterials Applications, 2005Co-Authors: Mervi Puska, Antti Yli-urpo, Pekka Vallittu, Karri AirolaAbstract:The aim of this study was to synthesize on a larger scale, an experimental polyamide based on an amino acid of trans-4-hydroxy-L-proline. The polyamide of trans-4-hydroxy-L-proline has been used as porogen filler (i.e., a hydrophilic pore generating material) in nondegradable Acrylic Bone Cement. In in vitro studies, this hydrophilic filling component has been shown to form porosity within the Acrylic Bone Cement in an aqueous environment. The formation of in situ porosity in the Acrylic polymer matrix is believed to improve the fixation between the Cement and the living Bone. Namely, a porous structure can support Bone ingrowth and strengthen the mechanical connection between the Acrylic Bone Cement and the Bone. The monomer, trans-4-hydroxy-L-proline methyl ester, was prepared from trans-4-hydroxy-L-proline by means of two steps, and the monomer was then polymerized to polyamide of trans-4-hydroxy-L-proline. The polymerization was carried out using a melt polycondensation method. The molecular weights (M) of the produced polyamides were between 1800 and 3600. The products were characterized by FTIR and H-NMR spectroscopy.
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Synthesis and Characterization of Polyamide of Trans-4-hydroxy-L-proline used as Porogen Filler in Acrylic Bone Cement
Journal of biomaterials applications, 2005Co-Authors: Mervi Puska, Pekka K. Vallittu, Antti Yli-urpo, Karri AirolaAbstract:The aim of this study was to synthesize on a larger scale, an experimental polyamide based on an amino acid of trans-4-hydroxy-L-proline. The polyamide of trans-4-hydroxy-L-proline has been used as porogen filler (i.e., a hydrophilic pore generating material) in nondegradable Acrylic Bone Cement. In in vitro studies, this hydrophilic filling component has been shown to form porosity within the Acrylic Bone Cement in an aqueous environment. The formation of in situ porosity in the Acrylic polymer matrix is believed to improve the fixation between the Cement and the living Bone. Namely, a porous structure can support Bone ingrowth and strengthen the mechanical connection between the Acrylic Bone Cement and the Bone. The monomer, trans-4-hydroxy-L-proline methyl ester, was prepared from trans-4-hydroxy-L-proline by means of two steps, and the monomer was then polymerized to polyamide of trans-4-hydroxy- L-proline. The polymerization was carried out using a melt polycondensation method. The molecular weights (M) of the produced polyamides were between
Kenneth A. Mann – One of the best experts on this subject based on the ideXlab platform.
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Probabilistic characteristics of random damage events and their quantification in Acrylic Bone Cement
Journal of Materials Science: Materials in Medicine, 2010Co-Authors: Gang Qi, Gladius Lewis, Steven F. Wayne, Oliver Penrose, John I. Hochstein, Kenneth A. MannAbstract:The failure of brittle and quasi-brittle polymers can be attributed to a multitude of random microscopic damage modes, such as fibril breakage, crazing, and microfracture. As the load increases, new damage modes appear, and existing ones can transition into others. In the example polymer used in this study—a commercially available Acrylic Bone Cement—these modes, as revealed by scanning electron microscopy of fracture surfaces, include nucleation of voids, cracking, and local detachment of the beads from the matrix. Here, we made acoustic measurements of the randomly generated microscopic events (RGME) that occurred in the material under pure tension and under three-point bending, and characterized the severity of the damage by the entropy ( s ) of the probability distribution of the observed acoustic signal amplitudes. We correlated s with the applied stress (σ) by establishing an empirical s–σ relationship, which quantifies the activities of RGME under Mode I stress. It reveals the state of random damage modes: when d s /dσ > 0, the number of damage modes present increases with increasing stress, whereas it decreases when d s /dσ
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probabilistic characteristics of random damage events and their quantification in Acrylic Bone Cement
Journal of Materials Science: Materials in Medicine, 2010Co-Authors: Steven F. Wayne, Gladius Lewis, Oliver Penrose, John I. Hochstein, Kenneth A. MannAbstract:The failure of brittle and quasi-brittle polymers can be attributed to a multitude of random microscopic damage modes, such as fibril breakage, crazing, and microfracture. As the load increases, new damage modes appear, and existing ones can transition into others. In the example polymer used in this study—a commercially available Acrylic Bone Cement—these modes, as revealed by scanning electron microscopy of fracture surfaces, include nucleation of voids, cracking, and local detachment of the beads from the matrix. Here, we made acoustic measurements of the randomly generated microscopic events (RGME) that occurred in the material under pure tension and under three-point bending, and characterized the severity of the damage by the entropy (s) of the probability distribution of the observed acoustic signal amplitudes. We correlated s with the applied stress (σ) by establishing an empirical s–σ relationship, which quantifies the activities of RGME under Mode I stress. It reveals the state of random damage modes: when ds/dσ > 0, the number of damage modes present increases with increasing stress, whereas it decreases when ds/dσ < 0. When ds/dσ ≈ 0, no new random damage modes occur. In the s–σ curve, there exists a transition zone, with the stress at the “knee point” in this zone (center of the zone) corresponding to ~30 and ~35% of the Cement’s tensile and bending strengths, respectively. This finding explains the effects of RGME on material fatigue performance and may be used to approximate fatigue limit.
Antti Yli-urpo – One of the best experts on this subject based on the ideXlab platform.
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Biomineralization of Glass Fibre Reinforced Porous Acrylic Bone Cement
Key Engineering Materials, 2007Co-Authors: Mervi Puska, Ari-pekka Forsback, Antti Yli-urpo, Jukka Seppälä, Pekka K. VallittuAbstract:Acrylic Bone Cements are used to fix joint replaCements to Bone. The main substance in Acrylic Bone Cement is biologically inert poly(methylmethacrylate), PMMA. The dense PMMA polymer structure of Cement does not allow Bone ingrowth into Cement. Therefore, the main focus of our studies is to modify Acrylic Bone Cement in order to improve its biological properties e.g., by creating porosity in the Cement matrix. The porous structure is in situ created using pore-generating filler (i.e., 20 wt% of an experimental biodegradable polyamide) that is incorporated in Acrylic Bone Cement. The aim of this in vitro study was to investigate the biomineralization of Acrylic Bone Cement modified using an experimental biodegradable polyamide.
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Exothermal Characteristics and Release of Residual Monomers from Fiber-reinforced Oligomer-modified Acrylic Bone Cement
Journal of Biomaterials Applications, 2005Co-Authors: Mervi A. Puska, Pekka K. Vallittu, Antti Yli-urpo, Lippo V. Lassila, Allan J. Aho, Ilkka KangasniemiAbstract:The aim of this study is to determine the peak temperature of polymerization, the setting time and the release of residual monomers of a modified Acrylic Bone Cement. PalacosR, a commercial Bone Cement, is used as the main component. The Cement is modified by adding short glass fibers and resorbable oligomer fillers, and an additional cross-linking monomer. The test specimens are classified according to the composition of the Bone Cement matrix (i.e., oligomer-filler, glass-fiber reinforCement, and/or cross-linking monomer). The exothermal characteristics during autopolymerization are analyzed using a transducer connected with a computer. The quantities of residual monomers were analyzed from different test groups using high performance liquid chrochromatography (HPLC). The Δ value for the oligomer filler and the glass-fiber-containing Acrylic Bone Cement is lower than that for the unmodified Bone Cement (2.1±0.8 vs. 23.5±4.2°C). The addition of a cross-linking monomer, EGDMA, shortens the setting time of the autopolymerization of the unmodified Bone Cement (7.1±0.9min vs. 3.3 ±0.3min). The quantity of the residual monomers released is higher in the modified Bone Cement than that in the unmodified Cement. The Cement that contains glass fibers and oligomer fillers has a considerably lower exothermal peak, whereas the total quantity of residual monomers released is increased.
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Synthesis and Characterization of Polyamide of Trans-4-hydroxy-L-proline used as Porogen Filler in Acrylic Bone Cement
Journal of Biomaterials Applications, 2005Co-Authors: Mervi Puska, Antti Yli-urpo, Pekka Vallittu, Karri AirolaAbstract:The aim of this study was to synthesize on a larger scale, an experimental polyamide based on an amino acid of trans-4-hydroxy-L-proline. The polyamide of trans-4-hydroxy-L-proline has been used as porogen filler (i.e., a hydrophilic pore generating material) in nondegradable Acrylic Bone Cement. In in vitro studies, this hydrophilic filling component has been shown to form porosity within the Acrylic Bone Cement in an aqueous environment. The formation of in situ porosity in the Acrylic polymer matrix is believed to improve the fixation between the Cement and the living Bone. Namely, a porous structure can support Bone ingrowth and strengthen the mechanical connection between the Acrylic Bone Cement and the Bone. The monomer, trans-4-hydroxy-L-proline methyl ester, was prepared from trans-4-hydroxy-L-proline by means of two steps, and the monomer was then polymerized to polyamide of trans-4-hydroxy-L-proline. The polymerization was carried out using a melt polycondensation method. The molecular weights (M) of the produced polyamides were between 1800 and 3600. The products were characterized by FTIR and H-NMR spectroscopy.