scholarly journals Nanostructured Strontium-Doped Calcium Phosphate Cements: A Multifactorial Design

2021 ◽  
Vol 11 (5) ◽  
pp. 2075
Author(s):  
Massimiliano Dapporto ◽  
Davide Gardini ◽  
Anna Tampieri ◽  
Simone Sprio
Keyword(s):  
Calcium Phosphate ◽  
Setting Time ◽  
Processing Parameters ◽  
High Energy ◽  
Powder Particle Size ◽  
Extrusion Force ◽  
Precise Control ◽  
Calcium Phosphate Cements ◽  
Shear Mixing ◽  
Mixing Techniques

Calcium phosphate cements (CPCs) have been extensively studied in last decades as nanostructured biomaterials for the regeneration of bone defects, both for dental and orthopedic applications. However, the precise control of their handling properties (setting time, viscosity, and injectability) still represents a remarkable challenge because a complicated adjustment of multiple correlated processing parameters is requested, including powder particle size and the chemical composition of solid and liquid components. This study proposes, for the first time, a multifactorial investigation about the effects of powder and liquid variation on the final performance of Sr-doped apatitic CPCs, based on the Design of Experiment approach. In addition, the effects of two mixing techniques, hand spatula (low-energy) and planetary shear mixing (high-energy), on viscosity and extrusion force were compared. This work aims to shed light on the various steps involved in the processing of CPCs, thus enabling a more precise and tailored design of the device, based on the clinical need.

Development of Alkali Containing Calcium Phosphate Cements

2007 ◽  
Vol 361-363 ◽  
pp. 331-334 ◽  
Author(s):  
Renate Gildenhaar ◽  
Georg Berger ◽  
E. Lehmann ◽  
Christine Knabe
Keyword(s):  
Calcium Phosphate ◽  
Sodium Phosphate ◽  
Biological Fluids ◽  
Setting Time ◽  
Tris Buffer ◽  
Apatite Formation ◽  
Potassium Sodium ◽  
Final Setting Time ◽  
Calcium Phosphate Cements ◽  
Sbf Solution

Commercially available calcium phosphate cements set by precipitation of nanoapatite or brushite. The goal of this study was to elucidate the most suitable conditions for forming cements from calcium potassium sodium phosphate. Furthermore, the behaviour of these cements after immersion in SBF and/or TRIS solution was investigated. Using varying additives resulted in differences in solubility kinetics. The XRD spectra of all investigated cement compositions displayed Ca2KNa(PO4)2 after setting. However, the various cement compositions differed with respect to apatite formation when immersed in TRIS buffer in and/or SBF solution. Therefore, when investigating calcium phosphate cements we consider it necessary to clearly differentiate between the phases which form after completion of the final setting time when these materials set in air, and the phases which form in a time dependant manner after immersion in different biological fluids.

Evaluation of α-Tricalcium Phosphate Cement Obtained at Different Temperatures

2012 ◽  
Vol 727-728 ◽  
pp. 1187-1192 ◽  
Author(s):  
Rafaela Silveira Vieira ◽  
Wilbur Trajano Guerin Coelho ◽  
Mônica Beatriz Thürmer ◽  
Juliana Machado Fernandes ◽  
Luis Alberto Santos
Keyword(s):  
Calcium Phosphate ◽  
Tricalcium Phosphate ◽  
Setting Time ◽  
Calcium Pyrophosphate ◽  
In Vitro Test ◽  
Calcium Phosphate Cements ◽  
Similar Chemical ◽  
Different Temperatures ◽  
Vitro Test

The calcium phosphate cements (CPCs) based on α-tricalcium phosphate (α-TCP) are highly attractive for use in medicine and odontology, since they have similar chemical and phase composition of mineral phase of bones (calcium deficient hydroxyapatite (CDHA)). However, one of the biggest difficulties for use of this type of cement is its low mechanical strength due to the presence of undesirable phases, such as β-tricalcium phosphate. The route for obtaining α-TCP is at high temperature by solid state reaction, mixing calcium carbonate and calcium pyrophosphate. The aim of this work was to obtain calcium phosphate cements with improved strength, by studying the obtaining of α-TCP at temperatures of 1300, 1400 and 1500°C. The samples were analyzed by crystalline phases, pH, setting time, particle size, in vitro test (Simulated Body Fluid), porosity, density and compressive strength. The results show that the synthesis temperatures influence strongly the phases of powders obtained and the mechanical properties of cement, being unnecessary quenching for obtaining pure α-TCP.

Characterization of α/β-TCP Based Injectable Calcium Phosphate Cement as a Potential Bone Substitute

2012 ◽  
Vol 529-530 ◽  
pp. 157-160 ◽  
Author(s):  
Kemal Sariibrahimoglu ◽  
Joop G.C. Wolke ◽  
Sander C.G. Leeuwenburgh ◽  
John A. Jansen
Keyword(s):  
Compressive Strength ◽  
Calcium Phosphate ◽  
Setting Time ◽  
Surrounding Tissue ◽  
Calcium Phosphate Cements ◽  
Apatite Cement ◽  
Tcp Phase

Calcium phosphate cements (CPCs) can be a suitable scaffold material for bone tissue engineering because of their osteoconductivity and perfect fit with the surrounding tissue when injected in situ. However, the main disadvantage of hydroxyapatite (HA) forming CPC is its slow degradation rate, which hinders complete bone regeneration. A new approach is to use hydraulic apatite cement with mainly α/β-tricalciumphosphate (TCP) instead of α-TCP. After hydrolysis the α/β-TCP transforms in a partially non-absorbable HA and a completely resorbable β-TCP phase. Therefore, α-TCP material was thermally treated at several temperatures and times resulting in different α/β-TCP ratios. In this experiment, we developed and evaluated injectable biphasic calcium phosphate cements (BCPC) in vitro. Biphasic α/β-TCP powder was produced by heating α-TCP ranging from 1000-11250°C. Setting time and compressive strength of the CPCs were analyzed after soaking in PBS for 6 weeks. Results demonstrated that the phase composition can be controlled by the sintering temperature. Heat treatment of α-TCP, resulted in 100%, 75% and 25% of α-to β-TCP transformation, respectively. Incorporation of these sintered BCP powder into the cement formulation increased the setting time of the CPC paste. Compressive strength decreased with increasing β-TCP content. In this study, biphasic CPCs were produced and characterized in vitro. This injectable biphasic CPC presented comparable properties to an apatitic CPC.

Polymeric Calcium Phosphate Cements Incorporated with Poly-γ-Glutamic Acid

2008 ◽  
Vol 396-398 ◽  
pp. 265-268
Author(s):  
Sung Soo Kim ◽  
Sung Jae Lee ◽  
Yong Sik Kim ◽  
Kwon Yong Lee
Keyword(s):  
Citric Acid ◽  
Calcium Phosphate ◽  
Glutamic Acid ◽  
Setting Time ◽  
Physiological Saline ◽  
Initial Setting Time ◽  
Calcium Phosphate Cements ◽  
Physiological Saline Solution ◽  
Biodegradable Poly ◽  
Initial Setting

Polymeric calcium phosphate cements (PCPC) derived from biodegradable poly-g-glutamic acid (g-PGA) were prepared in an attempt to improve the mechanical strength of calcium phosphate cement (CPC). The characteristics of the PCPCs were compared to those of cement incorporated with citric acid. The diametral tensile and compressive strengths of the CPC incorporated with g-PGA were significantly higher than that of cement incorporated with citric acid at equivalent concentrations (p<0.05). The maximal diametral tensile and compressive strengths of the CPC incubated for 1 week in physiological saline solution were approximately 18.0 and 50.0 MPa, respectively. However, the initial setting time of the PCPC was much slower than that of CPC incorporated with citric acid. The formation of ionic complexes between calcium ions and g-PGA was observed using FT-IR spectroscopy. Hydroxyapatite (HA) formation was retarded by g-PGA incorporation according to scanning electronic microscopy (SEM) and powder X-ray diffraction (XRD) observations.

Effects of Processing Techniques on Morphology and Mechanical Properties of Epoxy-Clay Nanocomposites

2013 ◽  
Vol 652-654 ◽  
pp. 167-174 ◽  
Author(s):  
Nesar Merah ◽  
Muneer Al-Qadhi
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Physical And Mechanical Properties ◽  
Processing Parameters ◽  
Clay Nanocomposites ◽  
Transmission Electron ◽  
Shear Mixing ◽  
Mixing Techniques ◽  
Processing Techniques ◽  
Morphology And Mechanical Properties

Proper dispersion of nano thin layered structure of nanoclay in polymer matrix offers new and greatly improved properties over pristine polymers. The degree of nanoclay dispersion and hence the improvements in the physical and mechanical properties depend greatly on the technique used and processing parameters. In this work, 2 wt.% epoxy-clay nanocomposites were fabricated using different mixing techniques to study the effect of mixing methods on the nanoclay dispersion and thus on the enhancement of the properties of the resultant nanocomposites. Three mixing techniques were explored: high shear mixing (HSM), ultrasonication and their combination as well as hand mixing. The effect of mixing techniques on morphology and mechanical properties of the resultant nanocomposites was investigated using scanning electron microscope (SEM), X-ray diffraction (XRD), transmission electron microscope (TEM) and tensile testing. The results of XRD and TEM showed that both exfoliated and disordered intercalated morphology were developed for the nanocomposites synthesized by HSM, while ordered intercalated morphology was observed for samples prepared by sonication. The tensile test results show that among the mixing techniques considered in this study HSM results in the optimum mechanical properties as a whole while hand mixing resulted in the worst physical and mechanical properties.

scholarly journals Preparation, Physical-Chemical Characterization, and Cytocompatibility of Polymeric Calcium Phosphate Cements

2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
Rania M. Khashaba ◽  
Mervet Moussa ◽  
Christopher Koch ◽  
Arthur R. Jurgensen ◽  
David M. Missimer ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Setting Time ◽  
Chemical Characterization ◽  
Biological Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Type Iii ◽  
Calcium Phosphate Cements ◽  
And Control

Aim. Physicochemical mechanical andin vitrobiological properties of novel formulations of polymeric calcium phosphate cements (CPCs) were investigated.Methods. Monocalcium phosphate, calcium oxide, and synthetic hydroxyapatite were combined with either modified polyacrylic acid, light activated polyalkenoic acid, or polymethyl vinyl ether maleic acid to obtain Types I, II, and III CPCs. Setting time, compressive and diametral strength of CPCs was compared with zinc polycarboxylate cement (control). Specimens were characterized using X-ray diffraction, scanning electron microscopy, and infrared spectroscopy.In vitrocytotoxicity of CPCs and control was assessed.Results. X-ray diffraction analysis showed hydroxyapatite, monetite, and brushite. Acid-base reaction was confirmed by the appearance of stretching peaks in IR spectra of set cements. SEM revealed rod-like crystals and platy crystals. Setting time of cements was 5–12 min. Type III showed significantly higher strength values compared to control. Type III yielded high biocompatibility.Conclusions. Type III CPCs show promise for dental applications.

Calcium phosphate cements as binders for hydroxylapatite particles for bone repair

1987 ◽  
Vol 45 ◽  
pp. 866-867
Author(s):  
J. S. Hanker ◽  
B. L. Giammara ◽  
C. R. Lupton ◽  
L. C. Chow
Keyword(s):  
Calcium Phosphate ◽  
Bone Repair ◽  
Setting Time ◽  
Root Canal Filling ◽  
Calcium Phosphate Cements ◽  
Dense Ceramic ◽  
Mineral Constituent ◽  
Cement Mixture ◽  
Dental Applications ◽  
Calcium Sulfate Hemihydrate

Calcium phosphate cements (CPCs) are under study for dental applications such as root canal filling or sealing and pulp capping. Upon setting they are converted principally to hydroxyapatite, the mineral constituent of bone. The presence of a small amount of fluoride or hydroxyapatite in the cement mixture hastens the setting time. Nevertheless, the CPCs set much more slowly than plaster of Paris (calcium sulfate hemihydrate) when moistened with water or dilute phosphoric acid.Hydroxylapatite (HA) is hydroxyapatite which has been processed either by sintering or firing into a dense ceramic or made into porous particles. Plaster has been found very useful as a binder to prevent the scatter of HA particles implanted for jawbone reconstruction. The composite HA/plaster implants can be tailored to fit the site during surgery or preformed and sterilized prior to surgery.

scholarly journals A bone replacement-type calcium phosphate cement that becomes more porous in vivo by incorporating a degradable polymer

2021 ◽  
Vol 32 (7) ◽  
Author(s):  
Akiyoshi Shimatani ◽  
Hiromitsu Toyoda ◽  
Kumi Orita ◽  
Yuta Ibara ◽  
Yoshiyuki Yokogawa ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Calcium Phosphate Cement ◽  
Alginic Acid ◽  
Setting Time ◽  
Zealand White Rabbit ◽  
Control Group ◽  
Degradable Polymer ◽  
Low Viscosity ◽  
Bone Replacement

AbstractThis study investigated whether mixing low viscosity alginic acid with calcium phosphate cement (CPC) causes interconnected porosity in the CPC and enhances bone replacement by improving the biological interactions. Furthermore, we hypothesized that low viscosity alginic acid would shorten the setting time of CPC and improve its strength. CPC samples were prepared with 0, 5, 10, and 20% low viscosity alginic acid. After immersion in acetate buffer, possible porosification in CPC was monitored in vitro using scanning electron microscopy (SEM), and the setting times and compressive strengths were measured. In vivo study was conducted by placing CPC in a hole created on the femur of New Zealand white rabbit. Microcomputed tomography and histological examination were performed 6 weeks after implantation. SEM images confirmed that alginic acid enhanced the porosity of CPC compared to the control, and the setting time and compressive strength also improved. When incorporating a maximum amount of alginic acid, the new bone mass was significantly higher than the control group (P = 0.0153). These biological responses are promising for the translation of these biomaterials and their commercialization for clinic applications.

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