Behaviour of Calcium Alkali Orthophosphate Cements under Simulated Implantation Conditions

2008 ◽  
Vol 396-398 ◽  
pp. 213-216 ◽  
Author(s):  
Daniela Jörn ◽  
Renate Gildenhaar ◽  
Georg Berger ◽  
Michael Stiller ◽  
Christine Knabe

The setting behaviour, the compressive strength and the porosity of four calcium alkali orthophosphate cements were examined under laboratory conditions (dry) and under conditions similar to those during clinical application (37°C, contact with body fluid). The results showed an increase of the setting times when specimens were covered with simulated body fluid. Especially, the final setting time (FHZ) was significantly higher for three of the four cements. Furthermore, when specimens were stored in SBF for 16h, an extensive decrease of the compressive strength was noted. The porosity was more than twice as high after 16h in SBF and this may be the cause for the great decrease of the compressive strength.

2006 ◽  
Vol 309-311 ◽  
pp. 861-864 ◽  
Author(s):  
Byung Hyun Lee ◽  
Min Chul Kim ◽  
Kyoung Nam Kim ◽  
Kwang Mahn Kim ◽  
Seong Ho Choi ◽  
...  

In preliminary ageing test, the cement using only calcium phosphate glass as power phase cracked with 1 day in simulated body fluid because of high dissolution rate of the cement. We added 30 wt% of either β-TCP or HA to 70 wt% calcium phosphate glass as powder phase to control the dissolution rate of the cement and performed in vitro ageing test in simulated body fluid by dynamic protocol as well as static protocol to confirm the possibility of controlling. Adding either β-TCP or HA to the cement increases the setting time and decreases the compressive strength. In dynamic assay, the pH of extract is maintained over 7. However, pH decreased to around 5 in static assay. Therefore, weight loss by static protocol continuously increased for 14 days, while weight loss by dynamic protocol almost saturated. In XRD patterns of ageing cements, CaO peaks appeared. CaO peak was maximized most lately in dynamic assay of the cement adding HA and within 7 days, the cement adding HA showed higher weight loss. It is indicated that CaO formed in surface of the cement hinder the dissolution of the cement. In addition, compressive strength increased when the CaO peak was maximized.


2011 ◽  
Vol 46 (13) ◽  
pp. 1571-1581 ◽  
Author(s):  
Song Zhao ◽  
Zhufa Zhou ◽  
Jiang Wu ◽  
Shumei Wang ◽  
Xinshuang Guo ◽  
...  

A novel hydroxyapatite-wollastonite/silk fibroin (AW/SF) composite was prepared for bone repair and replacement by a modified coprecipitation method. The wollastonite powders introduced in the composite were sintered with full crytallinity and ground to the diameter of 30–50 nm. The FT-IR and XRD analyses showed that the silk fibroin, wollastonite, and hydroxyapatite co-existed in the composite, but the newly formed hydroxyapatite had low crystallinity ascribing to the low temperature procedure. The composite exhibited both higher compressive strength (84.4 MPa) and Barcol hardness (48.5) than the hydroxyapatite/silk fibroin (HA/SF) composite without any wallostonite involved. And the composite in this work showed excellent bioactivities while held in simulated body fluid (SBF).


2021 ◽  
Vol 25 (1) ◽  
Author(s):  
Jei Kim ◽  
Hyun-Jung Kim ◽  
Seok Woo Chang ◽  
Soram Oh ◽  
Sun-Young Kim ◽  
...  

Abstract Background The addition of bioactive glass (BG), a highly bioactive material with remineralization potential, might improve the drawback of weakening property of mineral trioxide aggregates (MTA) when it encounters with body fluid. This study aims to evaluate the effect of BG addition on physical properties of MTA. Methods ProRoot (MTA), and MTA with various concentrations of BG (1, 2, 5 and 10% BG/MTA) were prepared. Simulated body fluid (SBF) was used to investigate the effect of the storage solution on dentin remineralization. Prepared specimens were examined as following; the push-out bond strength to dentin, compressive strength, setting time solubility and X-ray diffraction (XRD) analysis. Results The 2% BG/MTA showed higher push-out bond strengths than control group after 7 days of SBF storage. The 2% BG/MTA exhibited the highest compressive strength. Setting times were reduced in the 1 and 2% BG/MTA groups, and solubility of all experimental groups were clinically acceptable. In all groups, precipitates were observed in dentinal tubules via SEM. XRD showed the increased hydroxyapatite peaks in the 2, 5 and 10% BG/MTA groups. Conclusion It was verified that the BG-added MTA increased dentin push-out bond strength and compressive strength under SBF storage. The addition of BG did not negatively affect the MTA maturation reaction; it increased the amount of hydroxyapatite during SBF maturation.


2014 ◽  
Vol 906 ◽  
pp. 45-50
Author(s):  
Enori Gemelli ◽  
Fabio Nery ◽  
Nelson Heriberto Almeida Camargo ◽  
Vinicius André Rodrigues Henriques ◽  
Daiara Floriano da Silva

Titanium-based composites with bioactive phases were produced with TiH2and 10% in volume of calcium phosphate. The mixtures were prepared either by conventional powder metallurgy processing or by ultrasound, dried in a rotary evaporator, pressed at 600 MPa and vacuum-sintered at 1200 °C for 2 hours. Crystal phases of the as-fabricated composites are found to be α-Ti, CaTiO3and TixPyphase (s). The TixPyand CaTiO3phases resulted from the reaction between titanium and tricalcium phosphate at about 1130 °C. Calcium phosphate was better dispersed by ultrasound leading to a higher compressive strength of the composite and a more uniform Ca-P deposition in simulated body fluid solution.


2017 ◽  
Vol 898 ◽  
pp. 1990-1995 ◽  
Author(s):  
Ming Zhang Lan ◽  
Bin Feng Xiang ◽  
Jian Feng Wang ◽  
Xu Dong Zhao ◽  
Xiao Ying Wang

In order to investigate the early hydration behavior of rapid setting and hardening belite sulfoaluminate cements, the methods of X-ray Diffraction, Scanning Electron Microscope, Compressive Strength test and Setting Times test were used to identify and quantify the hydration kinetics and microstructure of this new-found cements in China. The results showed that the main mineral compositions of high belite sulfoaluminate cement clinker included calcium sulfoaluminate (4CaO·3Al2O3·CaSO4), belite (2CaO·SiO2), ferrite phase, free gypsum and free lime. It was found that not only the setting time and compressive strength but also the composition of hydration products were influenced by anhydrite to some extent. Meanwhile, a mass of AFt and AFm generated along with the hydration process at different ages, overlapped, crossed and penetrated through calcium silicate hydrate gel and aluminum oxide to form a relatively dense structure which could contribute to the high strength of cement.


2010 ◽  
Vol 654-656 ◽  
pp. 2192-2195 ◽  
Author(s):  
Yun Cang Li ◽  
Mei Heng Li ◽  
Wang Yu Hu ◽  
Peter D. Hodgson ◽  
Cui E Wen

In this study, Mg-xCa (x = 0.5, 1.0, 2.0, 5.0, 10.0, 15.0 and 20.0 %, wt.%, hereafter) and Mg-1Ca-1Y alloys were investigated as new biodegradable bone implant materials. The compressive strength, ultimate strength and hardness of the Mg-Ca alloys increased, whilst the corrosion rate and biocompatibility decreased, with the increase of the Ca content in the Mg-Ca alloys; higher Ca content caused the Mg-Ca alloy to become brittle. Solutions of simulated body fluid (SBF) and modified minimum essential media (MMEM) with the immersion of Mg-xCa and Mg-1Ca-1Y alloys showed strong alkalisation. The yttrium addition to the Mg-Ca alloys does not improve the corrosion resistance of the Mg-1Ca-1Y alloy as expected compared to the Mg-1Ca alloy. It is suggested that Mg-Ca alloys with Ca additions less than 1.0 wt.% exhibited good biocompatibility and low corrosion rate.


2014 ◽  
Vol 2014 ◽  
pp. 1-11
Author(s):  
El-Sayed Negim ◽  
Latipa Kozhamzharova ◽  
Yeligbayeva Gulzhakhan ◽  
Jamal Khatib ◽  
Lyazzat Bekbayeva ◽  
...  

This paper investigates the physicomechanical properties of mortar containing high volume of fly ash (FA) as partial replacement of cement in presence of copolymer latexes. Portland cement (PC) was partially replaced with 0, 10, 20, 30 50, and 60% FA. Copolymer latexes were used based on 2-hydroxyethyl acrylate (2-HEA) and 2-hydroxymethylacrylate (2-HEMA). Testing included workability, setting time, absorption, chemically combined water content, compressive strength, and scanning electron microscopy (SEM). The addition of FA to mortar as replacement of PC affected the physicomechanical properties of mortar. As the content of FA in the concrete increased, the setting times (initial and final) were elongated. The results obtained at 28 days of curing indicate that the maximum properties of mortar occur at around 30% FA. Beyond 30% FA the properties of mortar reduce and at 60% FA the properties of mortar are lower than those of the reference mortar without FA. However, the addition of polymer latexes into mortar containing FA improved most of the physicomechanical properties of mortar at all curing times. Compressive strength, combined water, and workability of mortar containing FA premixed with latexes are higher than those of mortar containing FA without latexes.


Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2415 ◽  
Author(s):  
Zhu Ding ◽  
Xiaodong Wang ◽  
Jay Sanjayan ◽  
Patrick Zou ◽  
Zhi-Kun Ding

A novel 3D printing material based on hydroxypropyl methylcellulose (HPMC)—improved sulphoaluminate cement (SAC) for rapid 3D construction printing application is reported. The hydration heat, setting time, fluidity of paste and mortar, shape retainability, and compressive strength of extruded SAC mortar were investigated. HPMC dosage, water-to-cement (W/C) ratio, and sand-to-cement (S/C) ratio were studied as the experimental parameters. Hydration heat results reveal HPMC could delay the hydration of SAC. The initial and final setting time measured using Vicat needle would be shortened in the case of W/C ratio of 0.3 and 0.35 with HPMC dosage from 0.5% to 1.5%, W/C ratio of 0.40 with HPMC dosage of 0.5%, 0.75%, and 1.5%, and W/C ratio of 0.45 with HPMC dosage of 0.45, or be extended in the case of W/C ratio of 0.4 with HPMC dosage of 1.0% and W/C ratio of 0.45 with HPMC dosage from 0.75% to 1.5%. Fluidity measurement shows HPMC significantly improves the shape retainability. Furthermore, the addition of HPMC remarkably increased the compressive strength of extruded mortar. The results showed that HPMC could be used to prepare 3D printing SAC having satisfactory shape retainability, setting time and compressive strength.


2005 ◽  
Vol 284-286 ◽  
pp. 153-156 ◽  
Author(s):  
S.B. Cho ◽  
Sang Bae Kim ◽  
Keon Joon Cho ◽  
Ill Yong Kim ◽  
Chikara Ohtsuki ◽  
...  

Novel PMMA-based bone cement using bioactive sol-gel derived CaO-SiO2 powder in order to induce bioactivity as well as to increase its mechanical property. The novel PMMA-based bone cements formed apatite on their surfaces in Simulated Body Fluid(SBF). In the present study, a change in mechanical property of the cement was evaluated using SBF. Before soaking in SBF, its compressive strength showed 80.6±2.1MPa. After soaking in SBF for 2 weeks, 8weeks and 9 weeks, its compressive strength were changed to 83.6±1.6MPa, 87.3±2.4MPa and 85.6±1.8MPa, respectively. It is clear that from the above result, there is no decrease in its compressive strength within 9 weeks soaking in SBF. That it hardly decreases in compressive strength of 7P3S bone cement in SBF is due to the relative small amount of gel powder or its spherical shape and monosize. Therefore, the newly developed PMMA-based cement can bond to the living bone and also be effectively used as bioactive bone cement without decrease in mechanical property.


Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1033 ◽  
Author(s):  
Yuli Wang ◽  
Fengxia He ◽  
Junjie Wang ◽  
Qianku Hu

Carbonates and bicarbonates are two groups of accelerators which can be used in sprayed concrete. In this study, the effects of the two accelerators sodium carbonate (Na2CO3) and sodium bicarbonate (NaHCO3) (0%, 1%, 2%, 3%, and 4% by weight of ordinary Portland cement OPC) on the properties of OPC paste were compared. The results show that both of them could accelerate the initial and final setting time of OPC paste, but the effect of the two accelerators on the compressive strength were different. After 1 day, sodium bicarbonate at 3% had the highest strength while sodium carbonate at 1% had the highest strength. After 7 days, both of the two accelerators at 1% had the highest compressive strength. After 28 days, the compressive strength decreased with the increase of the two. The improved strength at 1 and 7 days was caused by the accelerated formation of ettringite and the formation of CaCO3 through the reactions between the two with portlandite. The decrease of strength was caused by the Na+ could reduce the adhesion between C-S-H gel by replacing the Ca2+. NaHCO3 was found be a better accelerator than Na2CO3.


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