- Rio de Janeiro, Brazil
The aim of this study was to characterize implants coated with hydroxyapatite (HA) using 2 different processes. Commercially pure titanium implants were coated with HA using a modified biomimetic process and the plasma spray process.... more
The aim of this study was to characterize implants coated with hydroxyapatite (HA) using 2 different processes. Commercially pure titanium implants were coated with HA using a modified biomimetic process and the plasma spray process. These implants were characterized by scanning electron microscopy, Fourier-transformed infrared spectroscopy, and x-ray photoelectron spectroscopy. The plasma spray process generates a typical rough topography mainly consisting of HA. The HA coating produced by biomimetic process was partially dissolved in water and only a very thin layer of calcium titanate plus calcium phosphate and probably beta-tricalcium phosphate remained. In vitro test showed that both coatings can be considered bioactive. The modified biomimetic process seems to be a simple and low-cost alternative to coat titanium with a high potential of In vitro application.
Research Interests: Dentistry, Biomimetics, Hydroxyapatite, Scanning Electron Microscopy, Titanium, and 12 moreDental Implants, Plasma spray coatings, Fourier transform infrared spectroscopy, Implant, Surface Properties, Spectrum analysis, Implant Dentistry, Surface characterization, Dental Implant, Materials Testing, Durapatite, and In Vitro Techniques
Hydroxyapatite coatings are commonly applied to metallic biomedical implants to accelerate osseointegration. These coatings, usually produced by plasma spray techniques, can be obtained by alternative processes, like biomimetic process,... more
Hydroxyapatite coatings are commonly applied to metallic biomedical implants to accelerate osseointegration. These coatings, usually produced by plasma spray techniques, can be obtained by alternative processes, like biomimetic process, electrolytic deposition, or electrophoretic process as well. Electrophoretic deposition of hydroxyapatite exhibits several advantages like simplicity and low cost. In this article, titanium sheets with three different surface finishing were coated with hydroxyapatite by using electrophoresis. Surface treatments include: (1) abrading with SiC paper; (2) abrading with SiC paper plus electrolytic etch with H3PO4 solution; and (3) blasting with alumina powder followed by etch with a solution containing H2O2 and HF. Stoichiometric hydroxyapatite was used to coat titanium sheets. Blasted samples were also coated using a calcium-deficient hydroxyapatite. SEM, XRD, and FTIR were employed to characterize titanium substrates and coatings produced. Results show that electrophoretic process can produce a uniform thin layer, satisfactorily adhered, of hydroxyapatite on treated titanium samples. Furthermore, sintering at 800 degrees C do not promote the decomposition of calcium-deficient hydroxyapatite.
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... Publications Effect of Electrophoretic Apatite Coating on Osseointegration of Titanium Dental Implants Cristina C. Almeida 1 , Lídia A. Sena 1 , Alexandre M. Rossi 2 , Marcelo Pinto 3 , Carlos A. Muller 3 and Gloria A. Soares 1 ...
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página 1 de 1, 1 / 1, LILACS, seleciona. para imprimir. Fotocópia. Texto completo. experimental, Documentos relacionados. Id: 358859. Autor: Almeida, Jorge Maurício Vieira de; Sena, LídiaÁgata de; Vidigal Junior, Guaracilei Maciel;... more
página 1 de 1, 1 / 1, LILACS, seleciona. para imprimir. Fotocópia. Texto completo. experimental, Documentos relacionados. Id: 358859. Autor: Almeida, Jorge Maurício Vieira de; Sena, LídiaÁgata de; Vidigal Junior, Guaracilei Maciel; Soares, Gloria de Almeida. ...
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Recent studies show that similarity between synthetic scaffolds and original tissue is an important characteristic for bone replacement materials. The hydroxyapatite-collagen type I (HA- Col I) composites were prepared by in vitro... more
Recent studies show that similarity between synthetic scaffolds and original tissue is an important characteristic for bone replacement materials. The hydroxyapatite-collagen type I (HA- Col I) composites were prepared by in vitro fibrilogenesis of Col I fibrils simultaneously with HA precipitation. Composites obtained were lyophilized and sterilized by γγγγ radiation, and some samples were chemically treated with glutaraldehyde (GTA). By
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The growth of titanium oxide layer on titanium surface by the micro-arc oxidation technique was investigated. Ca(CH 3COO) 2 (0.3M), Na 2CO 3 (0.6M) and Na 2HPO 4 (0.1M) solutions were employed as electrolytes. SEM and EDS microanalysis... more
The growth of titanium oxide layer on titanium surface by the micro-arc oxidation technique was investigated. Ca(CH 3COO) 2 (0.3M), Na 2CO 3 (0.6M) and Na 2HPO 4 (0.1M) solutions were employed as electrolytes. SEM and EDS microanalysis were used for morphology, composition characterization and low-angle X-ray diffraction to describe titanium oxide crystallogra phic orientation. TiO 2 films formed by using 0.3M Ca(CH 3COO) 2 and 0.1M Na 2HPO 4 solutions showed a porous, homogeneous surface structure, with presenc e of phosphorous and after an hydrothermical treatment using a Ca(OH) 2 suspension during 24h at 60ºC was observed phosphorous and calcium.
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SHINERS and SHINEF from Ag@SiO2 and Au@SiO2 excited in the near-infrared are presented, with high enhancement factors, together to TEM/EDX evidences of silica coverage over Au and Au nanoparticles.
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To evaluate the probability of survival and failure modes of implant-supported resin nanoceramic relative to metal-ceramic crowns. Resin nanoceramic molar crowns (LU) (Lava Ultimate, 3M ESPE, USA) were milled and metal-ceramic (MC) (Co-Cr... more
To evaluate the probability of survival and failure modes of implant-supported resin nanoceramic relative to metal-ceramic crowns. Resin nanoceramic molar crowns (LU) (Lava Ultimate, 3M ESPE, USA) were milled and metal-ceramic (MC) (Co-Cr alloy, Wirobond C+, Bego, USA) with identical anatomy were fabricated (n=21). The metal coping and a burnout-resin veneer were created by CAD/CAM, using an abutment (Stealth-abutment, Bicon LLC, USA) and a milled crown from the LU group as models for porcelain hot-pressing (GC-Initial IQ-Press, GC, USA). Crowns were cemented, the implants (n=42, Bicon) embedded in acrylic-resin for mechanical testing, and subjected to single-load to fracture (SLF, n=3 each) for determination of step-stress profiles for accelerated-life testing in water (n=18 each). Weibull curves (50,000 cycles at 200N, 90% CI) were plotted. Weibull modulus (m) and characteristic strength (η) were calculated and a contour plot used (m versus η) for determining differences between groups. Fractography was performed in SEM and polarized-light microscopy. SLF mean values were 1871N (±54.03) for MC and 1748N (±50.71) for LU. Beta values were 0.11 for MC and 0.49 for LU. Weibull modulus was 9.56 and η=1038.8N for LU, and m=4.57 and η=945.42N for MC (p>0.10). Probability of survival (50,000 and 100,000 cycles at 200 and 300N) was 100% for LU and 99% for MC. Failures were cohesive within LU. In MC crowns, porcelain veneer fractures frequently extended to the supporting metal coping. Probability of survival was not different between crown materials, but failure modes differed. In load bearing regions, similar reliability should be expected for metal ceramics, known as the gold standard, and resin nanoceramic crowns over implants. Failure modes involving porcelain veneer fracture and delamination in MC crowns are less likely to be successfully repaired compared to cohesive failures in resin nanoceramic material.
Research Interests: Engineering, Computer Aided Design, Scanning Electron Microscopy, Scanning Transmission Electron Microscopy, Dental Materials, and 10 moreCeramics, Nanostructures, Dental Prosthesis Design, Reproducibility of Results, Dental Implant-Abutment Design, Crowns, Dental Stress Analysis, Materials Testing, Medical and Health Sciences, and Dental restoration failure
Carbon–oxygen functional groups dominate over different spatial regions in nanoscale carbon grains from ancient Amazonian anthrosols (Terra Preta de Índio).
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Composites based on hydroxyapatite (HA) and collagen are being used for bone engineering applications. Synthetic composites were produced by precipitating hydroxyapatite in a reaction medium containing collagen fibers. The effect of... more
Composites based on hydroxyapatite (HA) and collagen are being used for bone engineering applications. Synthetic composites were produced by precipitating hydroxyapatite in a reaction medium containing collagen fibers. The effect of saline treatment during the procedure of fibrils extraction on the composite morphology, phases presented and in vitro stability was evaluated. The FTIR analysis showed collagen bands well preserved. By Rietveld analysis, additional peaks of sodium chloride were identified on sample made from collagen submitted to saline precipitation. Besides that, the mineral formed phase is a carbonated apatite. This step during fibrils extraction results in larger areas of collagen uncoated and higher stability in culture medium. Despite of this, a cross-linking agent will be necessary to maintain the composite in culture for longer times.
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The adsorption of the p-phenylenediamine (PPD(+)) radical cation on gold or copper nanoparticle (NP) surfaces was studied through surface-enhanced Raman scattering (SERS) spectroscopy, excited at 1064 nm. The SERS spectra were obtained... more
The adsorption of the p-phenylenediamine (PPD(+)) radical cation on gold or copper nanoparticle (NP) surfaces was studied through surface-enhanced Raman scattering (SERS) spectroscopy, excited at 1064 nm. The SERS spectra were obtained from gold or copper NPs after exposure to non-oxidized p-phenylenediamine (PPD) aqueous solution, in millimolar concentration. The gold NPs were synthesized as nanoshells involving silica cores (SiO(2)@Au) and the copper NPs were obtained in aqueous medium, undergoing surface oxidation with the formation of Cu(II) oxide nanoshell (Cu@CuO). In the latter, the oxidative adsorption of PPD(+) led to the reduction of the copper oxide, present on NP surface, allowing obtaining the PPD(+) SERS spectrum. The vibrational assignments of the SERS spectra of the adsorbate were performed using the results of Density Functional Theory calculations of the Raman frequencies, which together with the SERS surface selection rules, allowed to infer the adsorption geometry of PPD(+) radical cation on both metallic surfaces. This work stress the investigation of redox processes involved in the molecular adsorption is imperative for the interpretation of the SERS results, which is even more important when copper surfaces are studied.
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... of the adsorption of the anthraquinone pigment alizarin on Ag nanoparticles MV Ca namares, JV Garcia-Ramos, C. Domingo and S. Sanchez-Cortes ∗ ... Phys. 1985; 57: 783. 7. Creighton JA. In Spectroscopy of Surfaces, Clark RJH, Hester... more
... of the adsorption of the anthraquinone pigment alizarin on Ag nanoparticles MV Ca namares, JV Garcia-Ramos, C. Domingo and S. Sanchez-Cortes ∗ ... Phys. 1985; 57: 783. 7. Creighton JA. In Spectroscopy of Surfaces, Clark RJH, Hester RE (eds). Wiley: Chichester, 1988; 37. ...
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In this work, a porous and homogeneous titanium dioxide layer was grown on commercially pure titanium substrate using a micro-arc oxidation (MAO) process and Ca-P-based electrolyte. The structure and morphology of the TiO2 coatings were... more
In this work, a porous and homogeneous titanium dioxide layer was grown on commercially pure titanium substrate using a micro-arc oxidation (MAO) process and Ca-P-based electrolyte. The structure and morphology of the TiO2 coatings were characterized by X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy, and profilometry. The chemical properties were studied using electron dispersive X-ray spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy. The wettability of the coating was evaluated using contact angle measurements. During the MAO process, Ca and P ions were incorporated into the oxide layer. The TiO2 coating was composed of a mixture of crystalline and amorphous structures. The crystalline part of the sample consisted of a major anatase phase and a minor rutile phase. A cross-sectional image of the coating-substrate interface reveals the presence of voids elongated along the interface. An osteoblast culture was performed to verify the cytocompatibility of the anodized surface. The results of the cytotoxicity tests show satisfactory cell viability of the titanium dioxide films produced in this study.
Research Interests: Materials Engineering, Biomedical Engineering, Calcium, Osseointegration, Scanning Electron Microscopy, and 15 moreTitanium, Transmission Electron Microscopy, Phosphorus, Wettability, Calcium Phosphates, Electrons, Electrolytes, Oxygen, X ray diffraction, Fourier transform infrared spectroscopy, Time Factors, Phosphates, Osteoblasts, Materials Testing, and Ions
Wollastonite-poly(n-butyl-2-cyanoacrylate) composite (W-BCA) has been proposed to immobilize anatomically bone fragments in order to achieve an optimal healing process. The present study evaluated the in vitro and in vivo behavior of... more
Wollastonite-poly(n-butyl-2-cyanoacrylate) composite (W-BCA) has been proposed to immobilize anatomically bone fragments in order to achieve an optimal healing process. The present study evaluated the in vitro and in vivo behavior of three types of fillers: powdered natural wollastonite (Wn), synthetic pseudowollastonite powder (Ws), and synthetic pseudowollastonite powder coated with 5% acetyl tributyl citrate (Wst). The Wst-BCA composite underwent a higher degradability in the real-time degradation test and a superior cytotoxic effect; whereas the Wn-BCA composite showed a higher degradability in the accelerated test with no cytotoxicity. The formation of an extracellular collagenous matrix deposit on its surface and the most favorable new bone formation on Wn-BCA indicate its potential for bone adhesive use in unstable orthopedic traumas.
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Hydroxyapatite (HA)-type I collagen (Col) composite is a tissue-engineered bone graft which can act as a carrier or a template structure for cells or any other agents. In this paper, the effect of Col ratio on the scaffold structure and... more
Hydroxyapatite (HA)-type I collagen (Col) composite is a tissue-engineered bone graft which can act as a carrier or a template structure for cells or any other agents. In this paper, the effect of Col ratio on the scaffold structure and composition was analyzed. Scaffolds composed by HA/Col with different weight ratios (80:20; 50:50; 20:80, and 10:90) were produced by the precipitation method at pH 8-9, 37 degrees C and 6 h of ripening. Using X-ray diffraction data, the Rietveld structure refinement showed that the size of HA crystals along the c-axis direction (002) decreases significantly in the presence of Col. Thus, the HA crystal shape turned from needle-like in pure HA, into spherical, in the 10:90 composite due to Col fibrillogenesis. The homogeneity of the composite was significantly dependent on the amount of Col in it. HA/Col 20/80 composite presented HA particles in a more homogenous way. Such a biocomposite was successfully produced in a rapid way and it is potentially useful for both small tissue repairs and engineering.
Research Interests: Materials Engineering, Biomedical Engineering, Tissue Engineering, Hydroxyapatite, Materials, and 11 moreScanning Electron Microscopy, Transmission Electron Microscopy, Tissue repair, Bone graft, Collagen, X ray diffraction, Fourier transform infrared spectroscopy, Durapatite, Structure Refinement, COL, and Type I Collagen
... The asymmetry on the high-energy side of the O 1s peak has previously been observed on rutile surfaces and it has been attributed to surface defects [17] although it can also be assigned to hydrogen-bonded oxygen due to the hydroxides... more
... The asymmetry on the high-energy side of the O 1s peak has previously been observed on rutile surfaces and it has been attributed to surface defects [17] although it can also be assigned to hydrogen-bonded oxygen due to the hydroxides and ... [5] LA Sena, MC Andrade, AM ...
Research Interests: Materials Engineering, Condensed Matter Physics, Hydroxyapatite, Scanning Electron Microscopy, PHOTOELECTRON SPECTROSCOPY, and 12 moreTitanium, Phosphorus, Surface Coatings, Surface and Coatings Technology, Calcium Phosphate, Surface treatment, Fourier transform infrared spectroscopy, Binding Energy, Titanium oxide, Bone Formation, Simulated Body Fluid, and P/BV Ratio
Research Interests: Engineering, Chemical Engineering, Condensed Matter Physics, Technology, Materials Chemistry, and 34 moreHydroxyapatite, Nanoparticle, Scanning Electron Microscopy, China, Biophysical Chemistry, Biological Sciences, Ceramics, Compressive Strength, Metalurgia, Bone Cement, Chemical Analysis, High Performance Liquid Chromatography, Energy Dispersive X-Ray Analysis, CHEMICAL SCIENCES, Optical physics, Thermal Analysis, Calcium Phosphate, Chemical Precipitation, X ray diffraction, Particle Size, Scanning Electron Microscope, Microstructures, AAPS PharmSciTech, Calcium Carbonate, THEORETICAL AND COMPUTATIONAL CHEMISTRY, Microspheres, FT IR Spectroscopy, Calcium Phosphate Cement, Simulated Body Fluid, Particle Size Distribution, Chemical Synthesis, Clinical Application, Molecular Structure, and Nanoscience and nanotechnology
Calcium phosphate salts, or more specifically hydroxyapatite, are products of great interest in the fields of medical and dental science due to their biocompatibility and osteoconduction property. Deproteinized xenografts are primarily... more
Calcium phosphate salts, or more specifically hydroxyapatite, are products of great interest in the fields of medical and dental science due to their biocompatibility and osteoconduction property. Deproteinized xenografts are primarily constituted of natural apatites, sintered or not. Variations in the industrial process may affect physicochemical properties and, therefore, the biological outcome. The purpose of this work was to characterize the physical and chemical properties of deproteinized xenogenic biomaterials, Bio-Oss (Geistlich Biomaterials, Wolhuser, Switzerland) and Gen-Ox (Baumer S.A., Brazil), widely used as bone grafts. Scanning electron microscopy, infrared region spectroscopy, X-ray diffraction, thermogravimetry and degradation analysis were conducted. The results show that both materials presented porous granules, composed of crystalline hydroxyapatite without apparent presence of other phases. Bio-Oss presented greater dissolution in Tris-HCl than Gen-Ox in the degradation test, possibly due to the low crystallinity and the presence of organic residues. In conclusion, both commercial materials are hydroxyapatite compounds, Bio-Oss being less crystalline than Gen-Ox and, therefore, more prone to degradation.
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All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP, www.ttp.net. (ID: 66.249.71.123-18/03/11,17:06:47) ... Bioceramics 14... more
All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP, www.ttp.net. (ID: 66.249.71.123-18/03/11,17:06:47) ... Bioceramics 14 doi:10.4028/www.scientific.net/KEM. ...
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Research Interests: Dentistry, Image Processing, Nonparametric Statistics, Hydroxyapatite, Osseointegration, and 15 moreScanning Electron Microscopy, Titanium, Dental Implants, Tibia, Female, Animals, Male, Electrophoresis, Fourier transform infrared spectroscopy, Dental Implant, Rabbits, Energy Dispersive Spectroscopy, Durapatite, FT IR Spectroscopy, and Fourier transform infrared
All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of the publisher: Trans Tech Publications Ltd, Switzerland, www.ttp.net. (ID:... more
All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of the publisher: Trans Tech Publications Ltd, Switzerland, www.ttp.net. (ID: 66.249.66.33-11/09/10,22:08:19)
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A comparative study of two coating methods on titanium (Ti) substrates, sol-gel and electrophoresis processes, was performed. Before coating, two different surface treatments were employed. The hydroxyapatite (HA) powder were... more
A comparative study of two coating methods on titanium (Ti) substrates, sol-gel and electrophoresis processes, was performed. Before coating, two different surface treatments were employed. The hydroxyapatite (HA) powder were characterized by infrared spectroscopy (FTIR) and X-ray diffraction (XRD) while coated samples were examined by using scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS). Both techniques seem to be suitable to coat Ti. A previous surface treatment on metallic titanium seems to be fundamental to enhance coat uniformity and adhesion that was estimated by the adhesive tape test. The decrease in calcination temperature did not affect the coating adhesion.
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... Publications Effect of Electrophoretic Apatite Coating on Osseointegration of Titanium Dental Implants Cristina C. Almeida 1 , Lídia A. Sena 1 , Alexandre M. Rossi 2 , Marcelo Pinto 3 , Carlos A. Muller 3 and Gloria A. Soares 1 ...
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Synthetic porous ceramics can be used as three-dimensional scaffolds for bone repair. The aim of this work is to correlate process parameters with scaffolds structural characteristics. The factorial 2 level experimental design was chosen... more
Synthetic porous ceramics can be used as three-dimensional scaffolds for bone repair. The aim of this work is to correlate process parameters with scaffolds structural characteristics. The factorial 2 level experimental design was chosen to study the effect of the Ca/P ratio (1.58 or 1.67), calcination temperature (1000 or 1150 °C) and porogen content (20 or 40%) on the calcium phosphate samples characteristics. The influence of such parameters was determined by X-ray diffraction, infrared spectroscopy and image analysis. It was observed that phase composition was basically a function of the Ca/P ratio of the raw material. The use of the porogen did not alter the hydroxyapatite (HA)/tricalcium phosphate (TCP) content, but induced changes in the relative content of TCP phase (a or b). It is possible to design a porous sample with defined characteristics, and the model herein used can be considered as having a good predictive power.