Дисертації з теми "Tricalcium silicates"
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Begarin, Farid. "Etude de paramètres endogènes et exogènes au ciment Portland ordinaire influençant l'hydratation de sa phase principale : le silicate tricalcique." Phd thesis, Université de Bourgogne, 2012. http://tel.archives-ouvertes.fr/tel-00845948.
Повний текст джерелаQueiroz, Marcela Borsatto. "Physicochemical and biological properties of tricalcium silicate-based reparative materials with alternative radiopacifiers and Biosilicate /." Araraquara, 2018. http://hdl.handle.net/11449/153908.
Повний текст джерелаAbstract: Tricalcium silicate cements associated with radiopacifiers are used as repair materials. Publication 1: Evaluation of tricalcium silicate-based cements (TCS) associated with zirconium oxide (ZrO2), calcium tungstate (CaWO4) or niobium oxide (Nb2O5) radiopacifiers compared to MTA Repair HP (MTA HP). Publication 2: Evaluation of tricalcium silicate-based cements (TCS) associated with zirconium oxide (ZrO2) radiopacifier with 10% or 20% of Biosilicate (TCS ZrO2 + 10% Biosilicate and TCS ZrO2 + 20% Biosilicate) compared to Biodentine. Setting Time (ST) and radiopacity were evaluated based on ISO 6876/2002 standard. Solubility was evaluated according to the method proposed by Carvalho-Júnior et al. (2007) modified. pH was measured at 3, 12 and 24 hours and 7, 14 and 21 days after immersion in distilled water. Cellular cytotoxicity and bioactivity were evaluated by methyltetrazolium (MTT), neutral red (NR), alkaline phosphatase (ALP), alizarin red (ARS) and real time PCR (qPCR) (Publication 1) assays in different periods of contact with eluates of the materials in Saos-2 cells. Antibacterial activity was evaluated by direct contact on Enterococcus faecalis in the planktonic form. For the physico-chemical and ARS tests, the data were submitted to ANOVA and Tukey tests; for MTT, NR and ALP tests the data were analyzed by the Two-Way ANOVA and Bonferroni tests; the antibacterial activity, were submitted to Kruskall-Wallis and Dunn tests (α = 0.05). Publication 1: TCS + CaWO4 presented... (Complete abstract click electronic access below)
Resumo: Cimentos de silicato tricálcico com radiopacificadores são utilizados como materiais reparadores. Publicação 1: Avaliação de cimento à base de silicato tricálcico (STC) associado aos radiopacificadores óxido de zircônio (ZrO2), tungstato de cálcio (CaWO4) ou óxido de nióbio (Nb2O5) em comparação ao MTA Repair HP (MTA HP). Publicação 2: Avaliação de material à base de silicato tricálcico (STC) e radiopacificador óxido de zircônio (ZrO2) e 10% ou 20% de Biosilicato (STC ZrO2 + 10% de Biosilicato e STC ZrO2 + 20% de Biosilicato) em comparação ao Biodentine. Tempo de presa e a radiopacidade foram avaliados seguindo ISO 6876/2002. A solubilidade foi avaliada de acordo com o método proposto por Carvalho-Júnior et al. (2007) modificado. pH foi avaliado 3, 12 e 24 horas, 7, 14 e 21 dias após imersão em água destilada. A citotoxidade e bioatividade celular foram avaliadas pelos testes metiltetrazólio (MTT), vermelho neutro (VN), atividade de fosfatase alcalina (ALP), ensaio de vermelho de alizarina (ARS) e PCR em tempo real (qPCR) (Publicação1), em diferentes períodos de contato com eluídos dos materiais em células Saos-2. Atividade antimicrobiana dos materiais foi avaliada por meio do teste de contato direto com Enterococcus faecalis na forma planctônica. Para os testes físicoquímicos e ARS, os dados foram submetidos aos testes ANOVA e Tukey; para os ensaios do MTT, VN e ALP e qPCR os dados foram analisados aos testes Two Way ANOVA e Bonferroni; os dados da atividade antimicrobiana f... (Resumo completo, clicar acesso eletrônico abaixo)
Mestre
Claverie, Jérôme. "Molecular dynamics investigation of the mechanical, thermal and surface properties of tricalcium silicate and its early hydration /." Ilha Solteira, 2019. http://hdl.handle.net/11449/191301.
Повний текст джерелаAbstract: The energetical and environmental problematic related to the cement production is a very sensitive issue. As every other field, the construction industry must go through drastic change in the design of concrete and cement-based materials. The understanding of the physical and chemical properties of the Portland cement (PC) clinker is important to improve its design. Tricalcium silicate C3S, or alite, is the main phase of PC clinker and has been largely studied since it is the first responsible for the strength development of the cement paste. On the other hand, the development of computational methods at the molecular scale has made possible the modelling of structural, dynamical and energetic properties, sometimes hardly measurable by experimental means. Such methods are relatively new in the field of cement chemistry, but have been increasingly employed over the last 15 years. In this project, density functional theory (DFT), classical molecular dynamics (MD), and ab initio molecular dynamics (AIMD) are employed towards a better understanding of mechanical, thermal, and superficial properties of monoclinic C3S, as well as C3S/water interface features. The present thesis consists of five chapters. The first chapter presents a review of the literature on the chemistry of cement, and more particularly on the hydration process modeling. The various phases which compose the Portland cement clinker are introduced, then the the different polymorphs of C3S are described, in particu... (Complete abstract click electronic access below)
Resumo: A produção de cimento envolve questões energéticas e ambientais muito relevantes. Em função disso, a indústria da construção deve sofrer mudanças radicais na concepção de concreto de materiais cimentícios. A compreensão das propriedades físicas e químicas do clínquer de cimento Portland (PC) é importante para melhorar seu design. O silicato tricálcico (C3S), ou alita, é a fase principal do clínquer de PC e tem sido amplamente estudado uma vez que é o principal responsável pelo desenvolvimento da resistência da pasta de cimento. Por outro lado, o desenvolvimento de métodos de cálculo na escala molecular possibilitou a modelagem de propriedades estruturais, dinâmicas e energéticas, às vezes difícil de medir por meios experimentais. Esses métodos são relativamente novos no campo da química do cimento, mas tem sido cada vez mais empregados nos últimos 15 anos anos. Neste trabalho, a teoria de funcional da densidade (DFT), a dinâmica molecular clássica (MD) e a dinâmica molecular ab initio (AIMD) são utilizadas para permitir uma melhor compreensão das características mecânicas, térmicas e de superfície do C3S monoclinico, bem como propriedades da interface C3S/água. Esta tese consiste em cinco capítulos: O primeiro capítulo apresenta uma revisão da literatura sobre a química dos cimento e, mais particularmente, sobre o processo de hidratação e sua modelagem. Introduzimos as diferentes fases que compõem o clínquer de cimento Portland, em seguida, a estrutura e os diferentes polimor... (Resumo completo, clicar acesso eletrônico abaixo)
Doutor
Peterson, Vanessa Kate. "Diffraction investigations of cement clinker and tricalcium silicate using Rietveld analysis /." Electronic version, 2003. http://adt.lib.uts.edu.au/public/adt-NTSM20040830.173127/index.html.
Повний текст джерела"Submited for the degree of Doctor of Philosophy, University of Technology, Sydney, Dept. of Chemistry, Materials and Forensic Sciences, August 2003" Bibliographic references: leaves 224-232.
Whitfield, Troy T. "Effect of Tricalcium Silicate Content on Expansion in Internal Sulfate Attack." Scholar Commons, 2006. http://scholarcommons.usf.edu/etd/3802.
Повний текст джерелаRastoul, Juillan Katy. "Interaction polymère associatif - ciment en milieu pâteux Adsorption - Stabilité - Rhéologie." Paris 6, 2003. http://www.theses.fr/2003PA066479.
Повний текст джерелаMishra, Ratan K. "Simulation of Interfaces in Construction Materials: Tricalcium Silicate, Gypsum, and Organic Modifiers." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1333037184.
Повний текст джерелаDamidot, Denis. "Etude de l'hydratation du silicate tricalcique en suspensions diluées par microcalorimétrie isotherme." Dijon, 1990. http://www.theses.fr/1990DIJOS036.
Повний текст джерелаMaggion, Renaud. "Etude de l'evolution de la microtexture de pates de silicate tricalcique hydrate." Orléans, 1992. http://www.theses.fr/1992ORLE2026.
Повний текст джерелаMansoutre, Sandrine. "Des suspensions concentrees aux milieux granulaires lubrifies : etude de pates de silicate tricalcique." Orléans, 2000. http://www.theses.fr/2000ORLE2014.
Повний текст джерелаNoirfontaine, Marie-Noëlle de. "Etude structurale et cristallographie du compose majoritaire du ciment anhydre : le silicate tricalcique." Palaiseau, Ecole polytechnique, 2000. https://pastel.archives-ouvertes.fr/pastel-00003675.
Повний текст джерелаHusson, Sophie. "Etude physicochimique et mécanique des interactions ciment-fillers : Application aux mortiers." Grenoble INPG, 1991. http://tel.archives-ouvertes.fr/tel-00844622.
Повний текст джерелаSowoidnich, Thomas Verfasser], and Horst-Michael [Akademischer Betreuer] [Ludwig. "A Study of Retarding Effects on Cement and Tricalcium Silicate Hydration induced by Superplasticizers / Thomas Sowoidnich ; Betreuer: Horst-Michael Ludwig." Weimar : F. A. Finger-Institut für Baustoffkunde, 2016. http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20160224-25444.
Повний текст джерелаSowoidnich, Thomas [Verfasser], and Horst-Michael [Akademischer Betreuer] Ludwig. "A Study of Retarding Effects on Cement and Tricalcium Silicate Hydration induced by Superplasticizers / Thomas Sowoidnich ; Betreuer: Horst-Michael Ludwig." Weimar : F. A. Finger-Institut für Baustoffkunde, 2016. http://d-nb.info/1116609118/34.
Повний текст джерелаPignat, Christian. "Simulation numérique de l'hydratation du silicate tricalcique, caractérisation de la structure poreuse et de la perméabilité /." [S.l.] : [s.n.], 2003. http://library.epfl.ch/theses/?nr=2763.
Повний текст джерелаRASSEM, RACHA. "Apport de la rmn a l'etude du mecanisme d'hydratation du silicate tricalcique, composant majoritaire du ciment portland." Paris 6, 1990. http://www.theses.fr/1990PA066287.
Повний текст джерелаTran, Xuan Vinh. "Effet d'un nouveau ciment de restauration à base de silicate tricalcique sur la réparation pulpo-dentinaire : Etude In Vivo." Thesis, Paris 5, 2013. http://www.theses.fr/2013PA05T005.
Повний текст джерелаPas de résumé en anglais
Lecoq, Xavier. "Etude de l'hydratation à concentration contrôlée du silicate tricalcique ca#3sio#5 et des caractéristiques de ses produits de réaction." Dijon, 1993. http://www.theses.fr/1993DIJOS063.
Повний текст джерелаNeji, Mejdi. "Modélisation chimie mécanique et simulation numérique du comportement expansif de résines échangeuses d’ions enrobées dans une matrice cimentaire." Thesis, Lille 1, 2014. http://www.theses.fr/2014LIL10106/document.
Повний текст джерелаIon exchange resins (IER) are widely used in the nuclear industry to purge non directly storable infected effluents. IER then become a solid waste which could be stored as any classical nuclear waste. One way of conditioning consists in embedding it into a cement paste matrix. This process raises some concerns regarding the cohesiveness of the composite. Once embedded, the IER might indeed interact with the cement paste which would lead, in some cases, to the swelling of the composite. This thesis has been set up to address this potential issue, with the aim to develop a numerical tool able to predict the mechanical behavior of this kind of material. This work only focuses on the long term behavior and more specifically on the potential degradations of the cement paste /IER composite due to cationic IER
Naber, Christoph [Verfasser], Jürgen [Akademischer Betreuer] Neubauer, and Jürgen [Gutachter] Neubauer. "Hydration kinetics of tricalcium silicate: A dataset for reaction rate calculations and nanoscale analysis employing atom probe tomography / Christoph Naber ; Gutachter: Jürgen Neubauer ; Betreuer: Jürgen Neubauer." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2019. http://d-nb.info/1176809806/34.
Повний текст джерелаSpannagel, Philippe. "Contribution à l'étude du système silicate décalcique-phosphate tricalcique et son intérêt dans la caractérisation et la valorisation de scories d'aciéries." Nancy 1, 1996. http://www.theses.fr/1996NAN10371.
Повний текст джерелаMASSE-BARBIER, BARBIER SYLVIE. "Synthese hydrothermale d'hydrates de silicate tricalcique analyse structurale en phase solide etude comparative avec les ciments utilises pour chemiser les puits de petrole." Paris 6, 1993. http://www.theses.fr/1993PA066606.
Повний текст джерелаGarrault-Gauffinet, Sandrine. "Etude expérimentale et par simulation numérique de la cinétique de croissance et de la structure des hydrosilicates de calcium, produits d'hydratation des silicates tricalcique et dicalcique." Dijon, 1998. http://www.theses.fr/1998DIJOS057.
Повний текст джерелаHusson, Sophie. "Étude physicochimique et mécanique des interactions ciment-fillers. Application aux mortiers." Phd thesis, Ecole Nationale Supérieure des Mines de Saint-Etienne, 1991. http://tel.archives-ouvertes.fr/tel-00844622.
Повний текст джерелаGirod-Labianca, Caroline. "Modélisation thermodynamique des diagrammes de phases des clinkers de ciments Portland : étude de l'influence des éléments mineurs : cas du phosphore." Paris 6, 2008. http://www.theses.fr/2008PA066158.
Повний текст джерелаNachbaur, Laurent. "Etude de l'influence d'électrolytes sur l'hydratation et la prise du silicate tricalcique, composant principal du ciment Portland : Caractérisation des interactions à l'origine de la prise." Dijon, 1997. http://www.theses.fr/1997DIJOS055.
Повний текст джерелаPlassais, Arnaud. "Nanoporosité, texture et propriétés mécaniques de pâtes de ciments." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2003. http://tel.archives-ouvertes.fr/tel-00007576.
Повний текст джерелаŠvéda, Matěj. "Vliv různé technologie mletí na vlastnosti Portlandského cementu." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-295660.
Повний текст джерелаWu, Yi-Chung, and 吳懿君. "Study of collagen/tricalcium silicate bone glue." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/5z77v2.
Повний текст джерела國立臺北科技大學
生物科技研究所
100
In this study, the aim is to develop a novel bone glue composed of tricalcium silicate and high proportion of type I collagen. The bone glue has plasticity in the early stage and will self-set after hydration to provide mechanical strength. Tricalcium silicate (C3S) is one of the main components of Portland cement, with the ability of rapid hydration to harden in a short period of time. It was reported to induce the formation of bone-like apatite and with excellent bone binding capacity in vitro and in vivo. Type I collagen, the main distribution of the majority of connective tissue in the skin, hard bone and blood vessels, plays important roles in tissue remodeling, wound healing and bone reconstruction. Carboxymethyl cellulose (CMC) is a cellulose-based ring hydroxyl methyl substituted derivative. Depending on the degree of substitution, CMC provides different levels of the sticky property and has been widely used in biomedical products in the recent years. In this experiment, sodium carboxymethyl cellulose with medium degree of substitution was applied to increase the adhesion property of the bone glue. Mechanical property test, surface morphology observation, crystalline phase analysis, in vitro pH value measurement, ions releasing, cytotoxicity test with MG 63 cell line and the drug releasing test including antibiotics and nonsteroidal anti-inflammatory were carried out. The results indicated that bone glue containing 40% collagen, Glue 40, had the following advantages, including shorter working time and setting time, about 11 and 150 minutes, respectively; better adhesion ability in vitro; higher adhesive strength about 416 Kpa; higher tensile strength about 167 Kpa. After seven days curing in the simulated body fluid, Glue 40 was cemented to be block and the changes of pH value was controlled between 7~9. Furthermore, Glue 40 was selected for advanced investigations. After seven days of curing in the saturated vapor of water, the compressive strength of Glue 40 increased with time and reached the maximum value of 500 Kpa. In addition, the additive of CMC not only enhanced the viscosity of the material, but also promoted the proliferation of MG 63 cells. Results of tetracycline releasing test showed that Glue 40 had the ability of initial burst, from 4% to 13%, and then maintained about 20%. Results of diclofenac sodium releasing test showed that after two days the release increased from 46% to 53%, and then maintained about 53%. Concluding the results of tests, Glue 40 has great potential to be a novel bone glue carrying with drugs.
Chuang, Ya-Chien, and 莊雅茜. "Synthesis and structural elucidation of tricalcium silicate biomaterials." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/94491665419929982727.
Повний текст джерела國立臺灣大學
化學研究所
100
Tricalcium silicate (Ca3SiO5, C3S), the main component of mineral trioxide aggregate (MTA), is a potential dental material because of its favorable sealing ability, bioactivity, and biocompatibility. Pure phase of C3S, however, could only be obtained at 1400 degreeC or above. The requirement of high temperature and the poor compressive strength of C3S are undesirable for its clinical applications. Fluoride ions, as a fluxing reagent, can significantly lower the calcination temperature for C3S formation. In this study, C3S are prepared in the presence of NaF by co-precipitation method. By adding 0 to 2 wt% of NaF, different polymorphs of C3S are obtained from 1100 to 1400 degreeC. At 1400 degreeC, the triclinic phase of C3S is the major product, with or without the addition of fluoride. At a temperature of 1100 to 1250 degreeC, the rhombohedral phase of C3S could be obtained by doping 1 to 2 wt% of NaF. In the absence of fluoride ions, however, only dicalcium silicate (C2S) would be formed. In addition to lowering the formation temperature, the setting time and microhardness of C3S can also be improved by the addition of fluorides. The 29Si magic-angle spinning NMR spectra of the rhombohedral C3S show a broad Q0 peak spanning the range from -69 to -75 ppm, whereas there are seven distinct sharp peaks (FWHM ~0.5 ppm) in the same chemical shift range of the Q0 site for the triclinic C3S samples. In other words, the triclinic phase of C3S has significantly higher crystallinity than the rhombohedral phase. Based on a series of 29Si–29Si double-quantum/single-quantum spectra, we have narrowed down the spectral assignments of the resolved seven resonances to two possible scenarios.
Lin, Kuan-Hung, та 林官鴻. "Study of γ-Polyglutamic Acid/Tricalcium Silicate Composite Bone Cement". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/er8au5.
Повний текст джерела國立臺北科技大學
生化與生醫工程研究所
102
Bone cement, a biomaterial with self-curing properties, is used to fill bone defects of different sizes for its injectability and plasticity. Tricalcium silicate (C3S), the main component of Portland cement, is also widely used in terms of biomedical materials. It has good biocompatibility and ability of self-curing to serve as bone cement as a result. And after curing it has certain mechanical strength but easily being broken. γ-PGA is a natural, non-toxic, highly biocompatible and edible polymer. In order to improve the physical properties of tricalcium silicate cement, in the study we prepared γ-polyglutamic acid/tricalcium silicate composite bone cement and tested its properties. Tricalcium silicate was synthesized by sol-gel method. The C3S powder was grinded and calcined in electrically heated furnace in an air atmosphere at 1400oC for 4h. The C3S powder was passed through a No. 400 sieve and mixed with different proportions of γ-PGA. With a ratio of powder/liquid 2:1, the powder was mixed with 10-wt % NaH2PO4 solution to make of the composite bone cement. Due to PGA containing carboxyl, the chelation reaction carried out when combined with tricalcium silicate. After a serious of materials characteristics and biocompatibility evaluations, the potential of the composite to be an ideal bone cement was investigated.
Wang, Wei-chuan, and 王偉全. "Development of new sol-gel tricalcium silicate cements in endodontic applications." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/65627014853310195330.
Повний текст джерела國立臺灣大學
臨床牙醫學研究所
99
An ideal repair material plays an important role in the success of endodontic repair therapy including retrograde filling, perforation repair and vital pulp therapy. There are many repair materials have been used in endodontic applications, but none of these could fit the requirements of ideal material. Mineral trioxide aggregate (MTA) has been currently considered as a potential material used in endodontic repair treatments with promising results, which may caused by its major component - the tricalcium silicate (C3S). However, several disadvantages of MTA have been reported such as long setting time, difficulty in handling, and the high arsenic levels contained. Calcium silicate ceramics (CSCs) without toxic ingredients, developed by our research team, are surface bioactive ceramics presenting the similar behaviors in hydration, cell-material interaction and bioactivity to MTA. But the large amount of CaO remained in the high temperature sintering CSCs caused the low chemical reactivity and long setting time. In this study, we developed the porous C3S to enhance their setting reaction by applying sol-gel process, and further investigated their potential using in endodontic applications. This study was conducted to two sections. In the first section, we synthesized tricalcium silicate via sol-gel process (sC3S) following Tsai’s protocol, and evaluated its physical-chemical and clinical properties with commercial MTA and conventional-sintered C3S as compared groups. The results of X-ray diffraction (XRD) analysis showed the similar patterns in sC3S and C3S powders. After hydrated, peaks corresponding to reactants decreased, and peaks corresponding to hydration products of calcium hydroxide and calcium carbonate were recorded by XRD in both groups. Furthermore, the microstructures of C3S and sC3S hydrates were similar, which became more compact structure when time increased. Scanning electron microscope indicated the smaller particle size and porous texture of sC3S powder. In addition, sC3S presented the significant short setting time (12±0.8min) than those of C3S (177±10min), WMTA (172±8min) and GMTA (114±5min) gourps. In the push-out bonding test, there was no significant difference between sC3S (12.96±4.1 MPa), C3S (11.11±3.9MPa), WMTA (16.2±4.5 MPa) and GMTA (15.78±3.8 MPa). To consider the high level content of residual calcium oxide and unacceptable compressive strength (20.21±3.26 MPa) of previous synthesized sC3S, the protocols of sol-gel process were be modified by changing the mixing order (r ratio) and the concentration of catalyst to improve the properties of the material in the second section. The results showed that the changes in r ratio and the concentration of catalyst would not affect the porous texture and crystal phases of the produced sC3S powder, except the decline of the intensities of the peaks corresponded to calcium oxide. After hydration, the crystals over the outer surface changed their shapes form bar-like crystals to plate-like crystals with 3D structure when the catalyst decreased in concentration. In comparison to the previous synthesized sC3S in first section, the modification of sol-gel process by changing the r ratio and the concentration of catalyst would slightly prolong the setting time of products (28min~34min), but still significantly shorter than that of commercial MTA (p<0.001). Meanwhile, the decrease of the concentration of catalyst in sol-gel process would also improve the compressive strength of products (68.14±7.12MPa), which was much better than that of MTA (p<0.001). In conclusion, sol-gel process could produce porous sC3S with a clinical significant short setting time. Furthermore, the modification of r ratio and the concentration of catalyst in sol-gel process could improve the gelation and the purity of products, and enhance their compressive strength after hydration. Based on these findings, sol-gel synthesized tricalcium silicate is a potential ideal material in endodontic applications.
Su, Yu-Chieh, and 蘇育傑. "Study of Polymethylmethacrylate / Tricalcium Silicate Paste Organic-inorganic Hybrid Bone Cement." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/3dje6y.
Повний текст джерела國立臺北科技大學
化學工程與生物科技系生化與生醫工程碩士班
105
Bone cement is used as a kind of orthopedic material for surgical filling and bone void filler because of its characteristics of self-hardening, good injectibility and moldability. Tricalcium silicate (TCS), the main component of Portland cement, is widely used in terms of biomedical materials. It has good biocompatibility and self-curing ability to serve as a bone cement. TCS bone cement can reach certain level of mechanical strength after setting, but this is unfortunately a brittle material. Polymethylmethacrylate (PMMA) cement has been used in orthopedics for more than seven decades because of its high compressive strength, viscosity, moldability and rapid setting ability. Nevertheless, the heat produced during polymerization could usually challenge its direct bonding to the surrounding bone tissue, which would eventually lead to aseptic loosening. In this study, bioceramics-TCS was chosen to bond directly to the surrounding bone tissue while PMMA could provide good rigidity. These two materials as a composite would complement each other and reduce the problems of loosening due to the high exothermic reaction of PMMA and brittleness of TCS. Therefore, PMMA was combined with TCS to form a composite bone cement. TCS was synthesized by sol-gel method. TCS was calcined in air at 1400°C for 4h and grinded into powder. TCS powder was then sieved through a 400 mesh size sieve to collect powders ≤ 38µm. TCS powder was mixed with citric acid solution at a powder/liquid ratio of 2:1, and then mixed with PMMA in paste form in different ratios to analyze the material properties and biocompatibility. The results showed that the addition of 0.5M citric acid could effectively reduce the setting time of TCS bone cement. The setting-time is in accordance with the regulation of ISO-5833 (Implants for surgery -- Acrylic resin cements) in the range of 5-15 min. For TCS/PMMA composite bone cement, higher TCS ratio would lead to lower temperature produced during polymerization. The curing temperature of the cement was successfully reduced with TCS addition with the highest temperature from 50.4°C of PMMA to the lowest of 39.1°C of TCS 30. In initial test of biocompatibility, specimens were soaked in artificial simulated body fluid (SBF). The pH of the SBF soaked with pure TCS was strongly alkaline while the addition of PMMA could successfully reduce the pH to the range of 7.0-8.5. In addition, there was bone like apatite precipitated on the material surface in 7 days as confirmed by XRD and SEM observations. In vitro studies were proceeded using human osteoblast cell line (MG-63) cultured directly on the materials or in the extracts. The results of cell viability measured using MTT and alkaline phosphatase (ALP) activity showed that the TCS/PMMA cement had great biocompatibility and osteoconductivity. In conclusion, this composite bone cement of PMMA combined with TCS has great potential in orthopedics to serve as bone restoration material.
"Diffraction investigations of cement clinker and tricalcium silicate using Rietveld analysis." Thesis, University of Technology, Sydney. Department of Chemistry, Materials & Forensic Sciences, 2003. http://hdl.handle.net/10453/20345.
Повний текст джерелаCement is the world's most popular building material, yet surprisingly its composition is not fully understood. Due to the complex nature of cement constituents, there is currently no reliable method to quantitatively determine the composition of cement. Partly this arises from the fact that the crystal structure of the main component of cement, tricalcium silicate, has not been fully determined. There has been an increase in the use of Rietveld refinement of powder diffraction data for the analysis of cement in recent years. The method has emerged as a valuable tool for the quantitative determination of the composition of cement. A further advantage of the method is its ability to refine complex crystal structures, such as tricalcium silicate. Despite the increased application of this method, few publications exist concerning the evaluation or improvement of the method for the purpose of cement analysis. In this work, the Rietveld method has been critically investigated as a tool for the identification and quantification of the different phases in cement clinker. Laboratory X-ray, synchrotron, neutron, and combined diffraction data are all used in the investigations. For the first time, comparisons of analysis results using various sources are made, rather than comparing the results from various methods. Inconsistencies in the results were found, and their causes were investigated and identified. The reliability of this method was shown to be dependent on the quality of the diffraction data, both in terms of the counting statistics and the resolution, and on the ability of the structures used in the Rietveld model to describe the phases in the sample. The only previously existing structural model for triclinic tricalcium silicate is shown, in this work, inadequate as a description of the form found in cement. Consequently, the triclinic crystal structures of tricalcium silicate were re-investigated. Using synchrotron powder diffraction data, the lattice dynamics during the T1-T2 transition were observed in detail for the first time. Superstructure reflections were observed for the two structures. The first model for the average sub-structure of the T2 form is presented. Structural modulation in the T1 form was re-investigated. The parent sub-structure, suitable for Rietveld refinement, corresponding modulation wave-vector, and superspace group of the superstructure, were identified.
"Diffraction Investigations of Cement Clinker and Tricalcium Silicate using Rietveld Analysis." University of Technology, Sydney. Department of Chemistry, Materials & Forensic Sciences, 2003. http://hdl.handle.net/2100/328.
Повний текст джерелаHuang, Ying-Chieh, and 黃瑩潔. "Effect of tricalcium aluminate on material properties, bioactivity and biocompatibility of calcium silicate ceramics." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/10171202611979068102.
Повний текст джерела國立臺灣大學
臨床牙醫學研究所
99
In dentistry, the goal of vital pulp therapy involves removing diseased pulp tissue and covering the remaining undamaged tissue with appropriate materials to induce pulp regeneration. Although plausible clinical results could often be achieved, the actual mechanism of pulp-dentin repair is still unknown. New materials need to be developed for reliable prognosis. The purpose of this study was to examine the physico-chemical properties and biological performances of novel calcium silicate biomaterials prepared from mixing different ratio of tricalcium silicate(C3S) and tricalcium aluminate(C3A) which aimed to improve the setting time which was compared with that of ProRoot white MTA without any change in biological properties. This study contained three experimental groups which contain C3S and C3A with different ratio (C3S/C3A: 90/10, 70/30, 50/50) and were fabricated with sol-gel technique; white-colored ProRoot MTA (Dentsply) was comparable group. The setting times, micro-hardness value, morphology and phase composition of hydration products and ex vivo bioactivity were evaluated, as well as the biocompatibility and mineralization, which use of MTT assay to evaluate cytotoxicity and use of ALP assay and Alizarin test to evaluate mineralization. As solid phases determined by XRD, the material powder with different C3A content were proved. The initial setting times of 70/30, 50/50 groups were in the range of 10-25 minutes, which are significantly (p<0.05, ANOVA and post-hoc test) lower than those obtained for white-colored ProRoot MTA (165 minutes) and 90/10 group(81 minutes). The micro-hardness of 50/50 and 70/30 were also significantly(p<0.05) higher than ProRoot MTA in the first day. All groups demonstrated ex vivo bioactivity when they came into contact with phosphate ions. The biocompatibility results of all groups were as good as the negative control except 50/50 with mild cytotoxicity. Results of mineralization test showed that all groups could induce hard tissue formation. Then we concluded in this study that, first, 90/10 group has optimal compressive strength, biocompatibility, and mineralization ability. Moreover, its material property is more reactive than white MTA. Second, with C3A increased to 30% to 50% in calcium silicate ceramics significantly improved setting time and early microhardness of the material, however, also exacerbating its material strength and biological properties.
Huang, Xiao-Juan, and 黃筱娟. "Development of Poly-L-Lactic Acid/Tricalcium Silicate Composite Film for Leakage Prevention in Percutaneous Kyphoplasty." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/r58ee4.
Повний текст джерела國立臺北科技大學
化學工程與生物科技系化學工程碩士班(碩士在職專班)
105
For people aged 50 years or over, osteoporosis caused by spinal compression fractures is a common cause of pain. In recent years, percutaneous vertebroplasty and percutaneus balloon kyphoplasty become the most accepted treatments for these fractures. The main concern with percutaneous kyphoplasty is high incidence of bone cement leakage and other resulting complications; therefore, this experiment aimed to make a biodegradable film casing to replace the conventional balloon to improve the leakage problem. Polylactic acid is a biomaterial with good bioabsorbability, biodegradability and good environmental affinity, as a polymeric material, it attracts considerable attention in recent years. Poly-L-lactic acid (PLLA), an optical isomer of polylactic acid, is often used in different industrial or medical applications. Tricalcium silicate (C3S) is the main component of Portland cement, with good biocompatibility and rapid hydration ability, widely used in biomaterials. PLLA was first dissolved in chloroform, and calcium silicate was then added to the polymer solution. The composite film with anti-permeation property was prepared by the solution casting method. In this study, we first explored the effects of different concentrations of tricalcium silicate (C3S) on the mechanical properties of the film. It was found that the addition of 1wt% C3S powder worked best in poly-L-lactic acid solution balancing all parameters. With an increase of C3S content, the Young s modulus of the composite film also increased. The maximum stress of PLLA/C3S film was 13.03 MPa and the fractural strain was 157%. TGA and DSC thermal properties of the film showed no residual chloroform on the film, the thermal cracking temperatures of both PLLA and PLLA/C3S films were around 385°C. The addition of C3S to the film was non-homogeneous nucleation. The cold crystallization peak appeared before Tg point could promote the film to the melting point state. The film was immersed in artificial simulated body fluid (SBF), whereas the pH value was maintained at about 7.4, and the apatite deposited on the material after 8 hours of soaking. Release of silicon from PLLA/C3S film was 15 ppm after 21 days of soaking in SBF. By considering the mechanical properties, in vitro test, cell experiments and other experimental results of the material, this PLLA/C3S film has good biocompatible and anti-leakage potential to be applied to percutaneous balloon kyphoplasty.
Fan, Kuei-Sheng, and 范貴盛. "Study of Tricalcium Silicate Doped with Strontium Prepared through a Sol-gel Process and Its Composite with Hydroxyapatite." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/y6v97d.
Повний текст джерела國立臺北科技大學
化學工程研究所
99
In this study, we successfully prepared tricalcium silicate (Ca3SiO5, C3S) doped with a series of strontium (SrxCa3-xSiO5, X= 0.0075 to 0.06) through a sol-gel process. The materials properties including setting property, crystallinity, microstructure and mechanical strength were characterized. Incubation in simulated body fluid was carried out to evaluate the ions releasing and curing behaviors in liquid. Cytotoxcity of the setting block was evaluated with L929 cell-line cultivation. To form a self-setting slurry, the powders were mixed with 10 wt% NaH2PO4 solution. The results showed that the working time of prepared slurries were all less than 10 minutes. Slurry of Sr0.015Ca2.985SiO5 had shortest setting, around 43 minutes. Slurry of Sr0.0525Ca2.9475SiO5 had 69 min setting time, however, and the highest compressive strength 42 MPa after 14 days curing. Results of simulated body fluid incubation study showed that apatite would rapidly form onto the materials, which indicated the well surface bioactivity. The final pH value was 11.7 with high Sr2+ release 135.6 ppm. The cell viability of L929 cell-line was 66% with the treatment of extraction solution using setting block 25 mg/mL, and 98% for 10 mg/mL. Furthermore, a Ca-P-Si composite composed of Sr0.0525Ca2.9475SiO5/Hydroxyapatite (weight ratio of 3) was prepared through a two steps sol-gel process. We successfully decreased pH value and setting time to 8.9 and 43.6 min, respectively. The cell viability of L929 cell-line raised to 107% for 25 mg/mL. The prepared (75 wt%)Sr0.0525Ca2.9475SiO5/(25 wt%)HAp has great potential in bone restoration applications.
Pereira, João António Abreu. "Characterization of dental cements by computed tomography techniques." Master's thesis, 2021. http://hdl.handle.net/10773/30910.
Повний текст джерелаHoje em dia, os cimentos dentários fazem parte dos materiais fundamentais em diversos tratamentos dentários, com o intuito de resolver problemas geralmente relacionados com infeções bacterianas que ocorrem na dentição e que precisam de uma restauração adequada que consiga manter a integridade dessa mesma dentição. O cimento dentário é fundamental em tratamentos de canais radiculares (muitas vezes chamada de desvitalização dentária), e tem como objetivo principal impedir a ocorrência de uma segunda infeção. Desta forma, é necessário que os cimentos utilizados vedem todo o espaço entre o sistema de canais radiculares e os tecidos circundantes de maneira a não permitir a passagem de microorganismos. É também importante que os cimentos apresentem propriedades antimicrobianas. No entanto, esta capacidade dos materiais utilizados na produção dos cimentos acaba por se deteriorar com a passagem do tempo, tornando se difícil a tarefa de inibir uma infeção secundária. A porosidade dos cimentos está diretamente ligada à formação dos biofilmes; quanto mais reduzida esta for, menor será a possibilidade da entrada de bactérias no interior destes, o que torna relacionável a percentagem de porosidade com a probabilidade de formação de um biofilme bacteriano responsável por lesões como a periodontite apical pós-tratamento. A micro-CT, uma tecnologia não-destrutiva (NDT), foi a técnica escolhida para a análise dos cimentos dentários através do Skyscan 2211, e permitiu um estudo cuidado da porosidade por todo o volume das amostras. Esta técnica tornou possível não só a análise da porosidade inerente em cada um dos cimentos dentários analisados, mas também disponibilizou informação de enorme relevo relativamente às dimensões dos poros presentes em cada amostra.
Mestrado em Materiais e Dispositivos Biomédicos
Varela, Montilla María Cristina. "The use of bioinductor materials for vital pulp therapy in immature permanent teeth: narrative review." Master's thesis, 2021. http://hdl.handle.net/10284/10842.
Повний текст джерелаIntrodução: A preservação da polpa dentária é essencial, principalmente em dentes permanentes jovens. Atualmente, com o desenvolvimento dos biomateriais e avanços na biologia pulpar, pode-se alcançar a preservação da polpa dentária baseada em terapias regenerativas com o uso de novos biomateriais. Objetivo: Analisar o uso de materiais bioindutivos na terapia da polpa vital em dentes permanentes imaturos. Materiais e métodos: Uma revisão narrativa de publicações, entre os anos de 2000 e 2021, recuperadas dos motores de busca “PubMed e B-ON” de revistas científicas indexadas. 29 artigos foram selecionados de acordo com os critérios de inclusão de comparação de materiais bioindutivos utilizados no tratamento da polpa, com base nos princípios biológicos e no comportamento desses materiais no tratamento da polpa. Conclusões: A terapia da polpa vital em dentes permanentes imaturos tem tido sucesso, principalmente, com o uso de materiais bioindutivos como o Agregado de Trióxido Mineral que é o mais recomendado.