Saeed Hesaraki; Masoud Hafezi Ardakani; Kolsoum Rajabi Monavar; Hosein Mohammadi
Volume 7, Issue 3 , June 2013, , Pages 201-207
Abstract
In this research, effect of temperature and calcium to phosphorus (Ca/P) ratio of raw materials on the type and the amounts of formed phases were investigated by solid state method. Calcium carbonate and dicalcium phosphate were provided as raw materials and mixed with different percentages in a way ...
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In this research, effect of temperature and calcium to phosphorus (Ca/P) ratio of raw materials on the type and the amounts of formed phases were investigated by solid state method. Calcium carbonate and dicalcium phosphate were provided as raw materials and mixed with different percentages in a way that final (Ca/P) ratio was between 1.50 to 1.67 in different batches. Then each of these mixtures was heated at temperatures of 800 to 1200 ° C for 3 hours. Phases were identified with XRD technique and quantitative assessment of phases was evaluated by RIR method and Chung relation. Results showed that in all relations and desired temperatures sintered below 1100 ° C beta tri-calcium phosphate is the dominant phase and hydroxyapatite present as second phase in the composition. In samples which sintered at 1200° C, beta TCP is transferred significantly to alpha TCP. In samples with Ca/p ratio: 1.62, 1.67, hydroxyapatite is dominant phase at 1200° C.
Nano-Biomaterials
Shekufe Borhan; Saeed Hesaraki
Volume 6, Issue 3 , June 2012, , Pages 163-168
Abstract
Bioactive glasses with different compositions have been extensively used as substitute for defective bones. Injectable biomaterial is important in clinical applications that involve defects with limited accessibility or when using minimally invasive surgical techniques. In this study bioactive glass ...
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Bioactive glasses with different compositions have been extensively used as substitute for defective bones. Injectable biomaterial is important in clinical applications that involve defects with limited accessibility or when using minimally invasive surgical techniques. In this study bioactive glass nano-powder was synthesized by acid-base catalyzed sol-gel process and used as solid phase of injectable non-setting pastes. Morphological characteristics of powder were found by TEM. To prepare paste the powder was mixed with hyaluronic acid and polyvinyl alcohol solutions. Stability of pastes was determined by soaking in simulated body fluid. Rheological behaviours of paste in both rotation and oscillation modes were also measured. The results showed that particle size of glass powder was 20-30 nm. According to rheometry, these nano composites exhibited non-Newtonian shear thinning behaviour. By adding polyvinyl alcohol more stable paste with increased hysteresis loop area is obtained. The oscillatory tests revealed that these pastes were viscoelastic with more elastic character. The biocomposite can potentially be used as bioactive paste for the treatment of hard and even soft tissues.
Biopolymers
Hadis Bandegani; Saeed Hesaraki; Masoud Alizadeh
Volume 3, Issue 2 , June 2009, , Pages 99-109
Abstract
The aim of the present paper is to investigate the effect of incorporating various amounts of strontium ions (0.19 - 2.23 wt%) into calcium sulfate bio ceramics on the physical, structural properties and in vitro bioactivity and compare these properties with those of a pure calcium sulfate dehydrate ...
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The aim of the present paper is to investigate the effect of incorporating various amounts of strontium ions (0.19 - 2.23 wt%) into calcium sulfate bio ceramics on the physical, structural properties and in vitro bioactivity and compare these properties with those of a pure calcium sulfate dehydrate (gypsum) as control. Strontium-doped gypsum (Sr-gypsum) was obtained by mixing calcium sulfate hemihydrates powder and solutions of strontium nitrate followed by washing the specimens with distilled water for the removal of residual salts. Gypsum was the only phase found in the composition of both pure and Sr-gypsum meanwhile a shift into lower diffraction angles was observed in the x-ray diffraction patterns of doped specimens. The Sr-doped sampled exhibited higher compressive strength and lower solubility than pure gypsum. Microstructure of all gypsum specimens had been composed of many rod-like small crystals entangled to each others with more elongation and higher thickness in the cases of Sr-gypsum. EDXA pattern of Sr-gypsum showed the presence of calcium and sulfur ions as the main elements of gypsum as well as slight amount of strontium ion. A continuous release of strontium was observed from the Sr-gypsum after soaking in simulated body fluid for 14 days. Proliferation rate of cultured osteoblasts and higher alkaline phosphatase activity on doped samples was better compared to pure gypsum.
Nano-Biomaterials
Rouzbeh Kazemzadeh; Ali Asghar Behnamghader; Saeed Hesaraki; Fateme Hazrati
Volume 3, Issue 2 , June 2009, , Pages 127-133
Abstract
Magnesium-contained Hydroxyapatite Nano powder was synthesized by wet chemical method using calcium nitrate tetra hydrate, magnesium nitrate hexa hydrate and di ammonium hydrogen phosphate in the presence of Glutamic acid. According to thermal analysis (STA) findings the samples were calcinated at specific ...
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Magnesium-contained Hydroxyapatite Nano powder was synthesized by wet chemical method using calcium nitrate tetra hydrate, magnesium nitrate hexa hydrate and di ammonium hydrogen phosphate in the presence of Glutamic acid. According to thermal analysis (STA) findings the samples were calcinated at specific temperatures and characterized by XRD, FTIR and TEM analysis. XRD results showed the that b-TCP ((Ca1-xMgx)3(PO4)2) was the dominant phase at 920°C. No characteristic peaks of hydroxyapatite were observed at that temperature. In contrast, the sample which was synthesized in the absence of Glutamic acid, contained both hydroxyapatite and b-TCP phase. The Findings showed a rapid decline in degree of crystallinity at 90°C with presence of Glutamic acid in reaction media. Transmission electron microscopy (TEM) observations on heat treated samples at 480°C revealed that using Glutamic acid has noticeable effect on crystallite size instead of its growth orientation. Dimensions of biomimetic nanoparticles as observed by TEM were 150x60nm and in the witness sample was 500x150nm. According to Scherrer formula for crystallite size, the size of the witness sample was calculated about 40nm. However, because of low degree of crystallinity it was impossible to calculate the size of Glutamic contained samples.
Nader Nezafati; Fathollah Moztarzadeh; Saeed Hesaraki; Nasim Nosoudi
Volume 2, Issue 4 , June 2008, , Pages 277-283
Abstract
Calcium phosphate cements are among the formable calcium phosphate cements which are widely used for reconstruction of hard tissue injuries. Unfortunately, due to low mechanical strength, the application of such materials is only limited to non-load bearing like skull. We have investigated some mechanical ...
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Calcium phosphate cements are among the formable calcium phosphate cements which are widely used for reconstruction of hard tissue injuries. Unfortunately, due to low mechanical strength, the application of such materials is only limited to non-load bearing like skull. We have investigated some mechanical and characteristics of a calcium phosphate cement which was reinforced with glass fiber. Compressed strength, setting time, phase composition and microstructure of the composite cement were among the cases which were investigated using appropriate techniques. The results indicated that adding only 15 weight percent of glass fiber (with about 100µm diameter) which was prepared using sol-gel method, does not show any meaningful change in the setting time of calcium phosphate cement This period of time was estimated about 20 minutes. Compressed strength of the cements without any fibers was 0.635MPa which was increased by adding fiber to 3.69MPa.The toughness of the cement was changed from 0.098KJ/m2 for cement without any fibers to 0.545KJ/m2 cement containing fibers. The XRD pattern of the composite samples which were maintained in the Ringer's solution showed that the reactant materials of the cement have almost thoroughly converted to hydroxyapatite which in this case does not show much difference with the non-fiber samples. As a whole, it seems that using glass fiber prepared by sol-gel method can considerably increase mechanical strength and toughness of calcium phosphate. This occurs without any effect on the quality of the cement.
Biomechanics of Bone / Bone Biomechanics
Seyed Mahmoud Rabiei; Fathollah Moztarzadeh; Mehran Solati Hashjin; Saeed Hesaraki
Volume 1, Issue 2 , June 2007, , Pages 105-110
Abstract
In this research, the influence of NaH2PO4.2H2O with different concentrations on setting time and compressive strength of bone cement based on hydroxyapatite was investigated. Hydroxyapatite cement is of calcium phosphate bone cements, which can be considered as the best substitute for hard tissues. ...
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In this research, the influence of NaH2PO4.2H2O with different concentrations on setting time and compressive strength of bone cement based on hydroxyapatite was investigated. Hydroxyapatite cement is of calcium phosphate bone cements, which can be considered as the best substitute for hard tissues. The powder phase of the cement was prepared from various compositions of calcium phosphates such: tricalcium phosphate (TCP), calcium carbonate (CaCO3) and montite (CaHPO4) as constant and the liquid part using NaH2PO4.2H2O solution with different concentrations. The influences of liquid/powder ratio L/P (ml/g) was investigated on the initial and final setting times and compressive strengths of the cement. According to the obtained results, with optimum concentrations of the liquid phase, this cement seems suitable for clinical applications.
