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Acrylic Bone Cement (acrylic + bone_cement)
Selected AbstractsAcrylic Bone Cements Modified With Bioactive FillerMACROMOLECULAR SYMPOSIA, Issue 1 2009Carlos Federico Jasso-Gastinel Abstract Bioactive cuttlebone Sepia officinalis particles that contain collagen were used to fill poly (methyl methacrylate- co -styrene) bone cements, varying size and concentration of filler particles. Cuttlebone was characterized by X-ray diffraction and plasma atomic emission spectrophotometer. Maximum reaction temperature and cement setting time were determined for composites and reference (copolymer without filler), along with NMR determination of residual monomer concentration. Mechanical properties characterization included stress-strain, bending, compression, fracture toughness and storage modulus tests. Mechanical results for composites filled with 10 and 30% weight of cuttlebone, complied with norm requirements which opens the possibility for using cuttlebone particles as bioactive filler. [source] Intermittent watt-level ultrasonication facilitates vancomycin release from therapeutic acrylic bone cementJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2009Xun-Zi Cai Abstract Ultrasound holds promise for enhancing the vancomycin release from cement though the length of time when local drug level exceeded the minimum inhibitory concentration (T>MIC) was not prolonged by the previous protocol of milliwatt-level ultrasonication. Here vancomycin-loaded cements were subjected to continuous watt-level ultrasonication (CUG), intermittent watt-level ultrasonication (IUG) or no ultrasonication (NUG) for 14 d during immersion in 40-ml phosphate buffered saline (PBS) for 28 d. The T>MIC for IUG was more than three times that for NUG. In contrast, T>MIC for CUG was slightly shortened. The subtherapeutic release of vancomycin between 15 d and 28 d for IUG was one-ninth that for NUG. The fitting equations indicated a significant enhancement on the burst release and the slow release for IUG; however, the continuous ultrasonication hampered the slow release. SEM images exhibited denser craters and pores with larger diameters and less residual drug in specimens from IUG relative to those from both CUG and NUG. Intermittent watt-level ultrasonication improved the ultrasound-enhanced vancomycin release from cement in view of the prolonged T>MIC and the inhibited subtherapeutic release compared with continuous ultrasonication. The mechanisms may be associated with the distinctive effects of detaching forces and pushing forces by acoustic microstreams. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009 [source] Influence of powder particle size distribution on complex viscosity and other properties of acrylic bone cement for vertebroplasty and kyphoplasty,JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2006Lidia Hernández Abstract For use in vertebroplasty and kyphoplasty, an acrylic bone cement should possess many characteristics, such as high radiopacity, low and constant viscosity during its application, low value of the maximum temperature reached during the polymerization process (Tmax), a setting time (tset) that is neither too low nor too high, and high compressive strength. The objective of this study was to investigate the influence of the powder particle distribution on various properties of one acrylic bone cement; namely, residual monomer content, Tmax, tset, complex viscosity, storage and loss moduli, injectability, and quasi-static compressive strength and modulus. It was found that the formulations that possessed the most suitable complex viscosity-versus-mixing time characteristics are those in which the ratio of the large poly(methyl methacrylate) beads (of mean diameter 118.4 ,m) to the small ones (of mean diameter 69.7 ,m) was at least 90% w/w. For these formulations, the values of the other properties determined were acceptable. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006 [source] Rheological properties of acrylic bone cement during curing and the role of the size of the powder particlesJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2002Gladius Lewis Abstract A dynamic compressive rheometric technique was used to determine the true or complex viscosity (,*) of three poly (methyl methacrylate), PMMA-based bone cement formulations (one commercially available and two experimental), as a function of the time that elapsed from commencement of hand mixing of the cement constituents (t). For each cement, two rheological parameters [namely, the time of onset of cure (tons) and the critical cure rate (CCR), which is herein defined as the complex viscosity rate computed at tons] were determined from the ,*,t data. For each cement, particle analysis was used to obtain the powder particle size distribution, from which the following parameters were obtained: (a) the overall mean particle diameter Dm, and (b) the relative amounts of small-sized PMMA beads (mean diameter d between 0 and 40 ,m) (,) and large-sized PMMA beads (d > 75 ,m) (,). It is seen that the key particle parameter is not Dmper se but , and ,. Thus, the highest values of tons and CCR were obtained from a cement with the highest values of , and ,. An explanation for these trends is given, and two areas for further research work in this field are outlined. © 2002 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 63: 191,199, 2002; DOI 10.1002/jbm.10127 [source] Graft copolymers of methyl methacrylate and poly([R]-3-hydroxybutyrate) macromonomers as candidates for inclusion in acrylic bone cement formulations: Compression testingJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2006Sophie Nguyen Abstract Graft copolymers of methyl methacrylate and biodegradable, biocompatible bacterial poly([R]-3-hydroxybutyrate) (PHB) blocks were synthesized and evaluated as possible constituents in acrylic bone cements for use in orthopaedic applications. The copolymers were produced by conventional free radical copolymerization and incorporated in one commercially available acrylic bone cement brand, Antibiotic Simplex® (AKZ). Cements with formulations containing 6.7 and 13.5 wt % of PMMA- graft -PHB were prepared. The morphology of the graft copolymer particles was suggested to influence the ability of the modified cement to be processed. Formulations containing more than about 20 wt % of the graft copolymer resulted in cement doughs that, both after first preparation and several hours later, were either sandy or soft spongy in texture and, thus, would be unacceptable for use in orthopaedic applications. The morphologies of the powders and the volumetric porosity (p) and ultimate compressive strength (UCS) of the cured cements were determined. Micro computed tomography showed that the cements presented average porosities of 13.5,16.9%. It was found that, while the powder particle shape and size for the experimental cements were markedly different from those of AKZ, there was no significant difference in either p or UCS for these cements. The latter was determined to be about 85 MPa for the modified cements and 84 MPa for Antibiotic Simplex. Furthermore, the UCS of all the cements exceeded the minimum level for acrylic bone cements, as stipulated by ASTM F-451. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006 [source] Injectable acrylic bone cements for vertebroplasty with improved propertiesJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2004Raúl García Carrodeguas Abstract Currently commercially available acrylic bone cements lack adequate radiopacity and viscosity when they are used in percutaneous vertebroplasty (PVP). In this work improved formulations of radiopaque and injectable poly(methyl methacrylate) bone cements were prepared with different amounts (10,50 wt.%) of BaTiO3 or SrTiO3 particles as the radiopaque agent. Two sets of cements were prepared by using untreated or silanated radiopaque particles, respectively. The influence of the content and nature of the radiopaque agent as well as its silanation with 3-(trimethoxysilyl) propyl methacrylate (,-MPS), on the curing parameters, residual monomer content, radiopacity, mechanical properties, and injectability of the resulting materials, was examined. Doughing and setting times, maximum temperature, and compressive strength of all formulations fulfilled the requirements of standard specifications, with values of peak temperature in the range 57,72 °C and those of compressive strength between 114 and 135 MPa. Formulations containing at least 20 wt.% BaTiO3 or SrTiO3 had radiopacities equal to or greater than that corresponding to 2 mm of Al as required for surgical plastics. Injectability of any of the formulations provided 75,80 wt.% of the total mass manually injected through a conventional biopsy needle 4 min after mixing. Silanation of the BaTiO3 or SrTiO3 particles led to formulations with improved mechanical properties and injectability compared to those obtained with the untreated fillers. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 68B: 94,104, 2004 [source] Characterization of new acrylic bone cements prepared with oleic acid derivativesJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2002Blanca Vázquez Abstract Acrylic bone-cement formulations were prepared with the use of a new tertiary aromatic amine derived from oleic acid, and also by incorporating an acrylic monomer derived from the same acid with the aim of reducing the leaching of toxic residuals and improving mechanical properties. 4-N,N dimethylaminobenzyl oleate (DMAO) was used as an activator in the benzoyl-peroxide radical cold curing of polymethyl methacrylate. Cements that contained DMAO exhibited much lower polymerization exotherm values, ranging between 55 and 62 °C, with a setting time around 16,17 min, depending on the amine/BPO molar ratio of the formulation. On curing a commercial bone cement, Palacos® R with DMAO, a decrease of 20 °C in peak temperature and an increase in setting time of 7 min were obtained, the curing parameters remaining well within limits permitted by the standards. In a second stage, partial substitution of MMA by oleyloxyethyl methacrylate (OMA) in the acrylic formulations was performed, the polymerization being initiated with the DMAO/BPO redox system. These formulations exhibited longer setting times and lower peak temperatures with respect to those based on PMMA. The glass transition temperature of the experimental cements were lower than that of PMMA cement because of the presence of long aliphatic chains of both activator and monomer in the cement matrix. Number average molecular weights of the cured cements were in the range of 1.2×105. PMMA cements cured with DMAO/BPO revealed a significant (p<0.001) increase in the strain to failure and a significant (p<0.001) decrease in Young's modulus in comparison to Palacos® R, whereas ultimate tensile strength remained unchanged. When the monomer OMA was incorporated, low concentrations of OMA provided a significant increase in tensile strength and elastic modulus without impairing the strain to failure. The results demonstrate that the experimental cements based on DMAO and OMA have excellent promise for use as orthopaedic and/or dental grouting materials. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 88,97, 2002; DOI 10.1002/jbm.10092 [source] | ||||||||||