Louis-philippe Lefebvre - Academia.edu (original) (raw)
Papers by Louis-philippe Lefebvre
Key Engineering Materials, 2007
The aim of this study was to evaluate the cytocompatibility, cell ingrowth and extracellular matr... more The aim of this study was to evaluate the cytocompatibility, cell ingrowth and extracellular matrix deposition of a newly developed porous bioactive glass as a bone substitute. Two types of bioactive glass, different in their pore size (75 and 20 ppi, resp. ~350 and ~1200 $m), were used in this study. The materials were seeded with human osteoblastic (MG63) and fibroblastic (M-228 F01 and M-191 F01) cell lines. The cells were visualized by two techniques, scanning electron microscopy and confocal microscopy. For confocal microscopy cell nuclei were labeled with propidium iodide (IP) and the extracellular matrix components (type I collagen and osteocalcin) by specific antibodies. Cells and matrix were visualized by fluorescence. The bioactive glass used in this study was shown to be non cytotoxic. Cell growth and colonization at the surface and in the depth of the material were observed. Extracellular matrix deposition was also demonstrated which proved the proper biofunctionality of...
Journal of materials research and technology, Jul 1, 2023
International journal of ceramic engineering & science, Jul 1, 2020
Bioactive glasses have been used for many years as bone graft substitutes in orthopedic and denta... more Bioactive glasses have been used for many years as bone graft substitutes in orthopedic and dental applications as well as an additive in tooth pastes, cosmetics and cosmeceutical products. The interest of using bioactive glass comes from its ability to dissolve and release dissolution products that stimulate bone regeneration. Porous bioactive glass scaffolds that can provide structural support while bone is growing into the structure have generated interest. However, little data is available in the literature on the effect of the environmental conditions or sterilization treatments on the structure and properties of these materials. This study presents the evolution of the structure and microstructure of bioactive foams exposed to different accelerated and real-time aging conditions and sterilization treatments. The results indicate that the material is relatively stable. For example, different sterilization methods (steam, ethylene oxide, hydrogen peroxide, gamma-rays) have limited effect on the structure and properties of the foams. However, carbonate species may form on the surface of the material when exposed to CO 2 and humidity. The carbonates dissolve rapidly in water and may impact the pH of the solution. Adequate packaging should limit the reaction of the bioactive glass with CO 2 and humidity and the formation of carbonate.
International Journal of Oral and Maxillofacial Surgery, Sep 1, 2012
Journal of Materials Science: Materials in Medicine, Apr 22, 2011
The utility of porous metals for the integration of orthopaedic implants with host bone has been ... more The utility of porous metals for the integration of orthopaedic implants with host bone has been well established. Quantification of the tissue response to cementless implants is laborious and time consuming process requiring tissue processing, embedding, sectioning, polishing, imaging and image analysis. Micro-computed tomography (lCT) is a promising three dimensional (3D) imaging technique to quantify the tissue response to porous metals. However, the suitability and effectiveness of lCT for the quantification of bone ingrowth remains unknown. The purpose of this study was to evaluate and compare bone growth within porous titanium implants using both lCT and traditional hard-tissue histology techniques. Cylindrical implants were implanted in the distal femora and proximal tibiae of a rabbit. After 6 weeks, bone ingrowth was quantified and compared by lCT, light microscopy and backscattered electron microscopy. Quantification of bone volume and implant porosity as determined by lCT compared well with data obtained by traditional histology techniques. Analysis of the 3D dataset showed that bone was present in the pores connected with openings larger 9.4 lm. For pore openings greater than 28.2 lm, the size of the interconnection had little impact on the bone density within the porosity for the titanium foams.
Progress in additive manufacturing 2020
42nd Society for Biomaterials Annual Meeting and Exposition 2019: The Pinnacle of Biomaterials Innovation and Excellence, 2019
Ceramics International, 2017
Consolidation processes aimed at manufacturing cellular solids from bioglasses often result in a ... more Consolidation processes aimed at manufacturing cellular solids from bioglasses often result in a glass-ceramic microstructure, whose response to aqueous environment affects their performance. In this study, we evaluated the microstructure and the effect of crystallization on the dissolution mechanism of a Bioglass®-based glassceramic scaffold, produced with a powder metallurgy inspired technology. All the experiments are conducted in a controlled aqueous environment in order to avoid nucleation of different species or unknown chemical interactions between simulated body fluids and bioglass-ceramic material. The presence of a residual silica glass embedding different phases of not fully crystallized particles is highlighted, showing a complex multiscale structure elucidated via Focused Ion Beam (FIB) preparation and Scanning Transmission Electron Microscopy (STEM) observation. Crystalline and amorphous phases dissolved both in water, with different kinetics. The dissolution appears to be a surface phenomenon, which reduces the section of the foam struts without instability of the glass-ceramic material. Amorphization of crystalline phase is observed during immersion of the glass-ceramic material in stirring conditions at room temperature from the ions dissolved in water.
Advanced Engineering Materials, 2008
Porous metals and metallic foams are presently the focus of very active research and development ... more Porous metals and metallic foams are presently the focus of very active research and development activities around the world, both at the academic and industrial levels. These materials are used when the combination of metal properties with the characteristics of porous structures provides significant advantages over other types of materials. Porous, cellular and foamed metals are now produced by various companies and used in numerous applications such as lightweight structures, biomedical implants, filters, heat exchangers, sound absorbers, mechanical damping devices, electrodes, sensors and catalyst substrates.
Journal of the American Ceramic Society, 2012
Bioactive glass 45S5 foams were produced using a powder technology process developed by The Natio... more Bioactive glass 45S5 foams were produced using a powder technology process developed by The National Research Council Canada-Industrial Materials Institute. NRC-IMI's proprietary process, combining powder technology and polymer foam technique, allows the production of materials having different structures and properties. It can be used to produce components into various forms, such as fully porous bodies or coatings on solid structures. During foaming, the foaming agent is decomposed and expands the binder-bioactive glass suspension. Then, the binder is burnt out by heating the sample at 500°C and finally the bioactive glass particle network is sintered to consolidate the material. Foams sintered at various temperatures were characterized from a microstructural and mechanical point of view. The foam structure and properties are affected by the sintering temperature when it is varied between 950°C and 1025°C. Foams exhibited open porosity (64%-79%) and pore size (335-530 lm) optimal for bone ingrowth. In all cases, the glass crystallized during sintering and the material was mostly composed of Na 6 Ca 3 Si 6 O 18 and Na 2 Ca 4 (PO 4) 2 SiO 4 phases. The mechanical strength increased from 1.7 to 5.5 MPa while the density of the material increased from 0.56 to 0.97 g/cm 3 .
Journal of Osseointegration, 2011
Aim This study aimed at determining the effect of different thickness of porous titanium (Ti) coa... more Aim This study aimed at determining the effect of different thickness of porous titanium (Ti) coating, 0.5, 1.0 and 1.5 mm thick (PC-0.5, PC-1.0 and PC-1.5), on osteoblast phenotype expression. Materials and methods Dense Ti discs coated with 0.5, 1.0 and 1.5 mm of porous Ti (PC-0.5, PC-1.0 and PC-1.5, respectively) were fabricated by powder metallurgy process with pore size typically between 50 and 400 μm and porosity of 60%. Osteoblastic cells obtained from human alveolar bone were cultured on dense Ti (D-Ti) and PC-Ti discs for periods of up to 17 days. Results Cultures grown on PC-Ti exhibited higher cell proliferation rate than on D-Ti. By comparing PC-Ti groups, it was observed statistical differences on culture grown only at day 10 (PC- 0.5<PC-1.0 and PC-1.5). Cells cultured on PC-1.5 presented the highest gene expression of type I collagen (COL), alkaline phosphatase (ALP), and osteocalcin (OC). The calcium content was significantly greater on PC-1.5 compared to all other...
Materials Performance and Characterization, 2020
It is recognized that humidity affects the properties of metallic powders (e.g., flowability, den... more It is recognized that humidity affects the properties of metallic powders (e.g., flowability, density, composition). Although standards exist to evaluate the water content in various materials, there is presently no standard method validated or specifically adapted for the evaluation of the water content in metallic powders. This article evaluates the water content in titanium powders using different techniques (gravimetry, Karl Fischer titration, quantification of volatiles with a relative humidity sensor). The effect of measurement conditions, particle size, and types of powder were investigated. The results showed that the adsorption of water is a function of the relative humidity in the environment and the characteristics of the powders. The relative humidity in the laboratory has, however, limited effect if the exposure of the powder to the environment is limited prior to the measurements. Water adsorption/desorption is a function of the surface area of the powder. The measured...
Reducing the amount of admixed lubricant is an attractive route to increase density and improve p... more Reducing the amount of admixed lubricant is an attractive route to increase density and improve properties of P/M components while minimizing the negative effects associated with lubricant burn-off in sintering furnaces. Previous studies have shown that die wall lubrication can be used to reduce the amount of admixed lubricant needed for the compaction and ejection of P/M components. However, this technology must ensure a proper control of the deposition of the lubricant on the die walls. This paper presents a new approach to coat a lubricant on die walls, consisting in the use of a confining block located in the die cavity. An evaluation of this approach on a mechanical production press is presented. Results show the benefit of using this technique combined with warm pressing to produce a relatively thick steel gear with high density under industrial processing conditions.
Additive Manufacturing, 2020
Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, co... more Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous
Materials
Bioactive glasses (BG) possess significant bone-bonding and osteogenic properties that support th... more Bioactive glasses (BG) possess significant bone-bonding and osteogenic properties that support their use for bone defects repair in orthopaedic and dental procedures. Recent advancement enables the manufacturing of BG-based scaffolds providing structural support during bone regeneration. Despite the wide number of studies on BG and BG-based materials, little information on their aging mechanisms and shelf life is available in the literature. In this study, the evolution of chemical species on BG-based foams was investigated via accelerated tests in the presence of CO2 and humidity. The aging process led to the formation of carbonates (Na2CO3 and CaCO3) and hydrocarbonates (NaHCO3). The amount and composition of nucleated species evolved with time, affecting the structure, properties, and bioactivity of the scaffolds. This study provides a first structured report of aging effects on the structure and chemico-physical properties of bioactive glass-based scaffolds, offering an insight ...
Metal Powder Report
ABSTRACT
Key Engineering Materials, 2007
The aim of this study was to evaluate the cytocompatibility, cell ingrowth and extracellular matr... more The aim of this study was to evaluate the cytocompatibility, cell ingrowth and extracellular matrix deposition of a newly developed porous bioactive glass as a bone substitute. Two types of bioactive glass, different in their pore size (75 and 20 ppi, resp. ~350 and ~1200 $m), were used in this study. The materials were seeded with human osteoblastic (MG63) and fibroblastic (M-228 F01 and M-191 F01) cell lines. The cells were visualized by two techniques, scanning electron microscopy and confocal microscopy. For confocal microscopy cell nuclei were labeled with propidium iodide (IP) and the extracellular matrix components (type I collagen and osteocalcin) by specific antibodies. Cells and matrix were visualized by fluorescence. The bioactive glass used in this study was shown to be non cytotoxic. Cell growth and colonization at the surface and in the depth of the material were observed. Extracellular matrix deposition was also demonstrated which proved the proper biofunctionality of...
Journal of materials research and technology, Jul 1, 2023
International journal of ceramic engineering & science, Jul 1, 2020
Bioactive glasses have been used for many years as bone graft substitutes in orthopedic and denta... more Bioactive glasses have been used for many years as bone graft substitutes in orthopedic and dental applications as well as an additive in tooth pastes, cosmetics and cosmeceutical products. The interest of using bioactive glass comes from its ability to dissolve and release dissolution products that stimulate bone regeneration. Porous bioactive glass scaffolds that can provide structural support while bone is growing into the structure have generated interest. However, little data is available in the literature on the effect of the environmental conditions or sterilization treatments on the structure and properties of these materials. This study presents the evolution of the structure and microstructure of bioactive foams exposed to different accelerated and real-time aging conditions and sterilization treatments. The results indicate that the material is relatively stable. For example, different sterilization methods (steam, ethylene oxide, hydrogen peroxide, gamma-rays) have limited effect on the structure and properties of the foams. However, carbonate species may form on the surface of the material when exposed to CO 2 and humidity. The carbonates dissolve rapidly in water and may impact the pH of the solution. Adequate packaging should limit the reaction of the bioactive glass with CO 2 and humidity and the formation of carbonate.
International Journal of Oral and Maxillofacial Surgery, Sep 1, 2012
Journal of Materials Science: Materials in Medicine, Apr 22, 2011
The utility of porous metals for the integration of orthopaedic implants with host bone has been ... more The utility of porous metals for the integration of orthopaedic implants with host bone has been well established. Quantification of the tissue response to cementless implants is laborious and time consuming process requiring tissue processing, embedding, sectioning, polishing, imaging and image analysis. Micro-computed tomography (lCT) is a promising three dimensional (3D) imaging technique to quantify the tissue response to porous metals. However, the suitability and effectiveness of lCT for the quantification of bone ingrowth remains unknown. The purpose of this study was to evaluate and compare bone growth within porous titanium implants using both lCT and traditional hard-tissue histology techniques. Cylindrical implants were implanted in the distal femora and proximal tibiae of a rabbit. After 6 weeks, bone ingrowth was quantified and compared by lCT, light microscopy and backscattered electron microscopy. Quantification of bone volume and implant porosity as determined by lCT compared well with data obtained by traditional histology techniques. Analysis of the 3D dataset showed that bone was present in the pores connected with openings larger 9.4 lm. For pore openings greater than 28.2 lm, the size of the interconnection had little impact on the bone density within the porosity for the titanium foams.
Progress in additive manufacturing 2020
42nd Society for Biomaterials Annual Meeting and Exposition 2019: The Pinnacle of Biomaterials Innovation and Excellence, 2019
Ceramics International, 2017
Consolidation processes aimed at manufacturing cellular solids from bioglasses often result in a ... more Consolidation processes aimed at manufacturing cellular solids from bioglasses often result in a glass-ceramic microstructure, whose response to aqueous environment affects their performance. In this study, we evaluated the microstructure and the effect of crystallization on the dissolution mechanism of a Bioglass®-based glassceramic scaffold, produced with a powder metallurgy inspired technology. All the experiments are conducted in a controlled aqueous environment in order to avoid nucleation of different species or unknown chemical interactions between simulated body fluids and bioglass-ceramic material. The presence of a residual silica glass embedding different phases of not fully crystallized particles is highlighted, showing a complex multiscale structure elucidated via Focused Ion Beam (FIB) preparation and Scanning Transmission Electron Microscopy (STEM) observation. Crystalline and amorphous phases dissolved both in water, with different kinetics. The dissolution appears to be a surface phenomenon, which reduces the section of the foam struts without instability of the glass-ceramic material. Amorphization of crystalline phase is observed during immersion of the glass-ceramic material in stirring conditions at room temperature from the ions dissolved in water.
Advanced Engineering Materials, 2008
Porous metals and metallic foams are presently the focus of very active research and development ... more Porous metals and metallic foams are presently the focus of very active research and development activities around the world, both at the academic and industrial levels. These materials are used when the combination of metal properties with the characteristics of porous structures provides significant advantages over other types of materials. Porous, cellular and foamed metals are now produced by various companies and used in numerous applications such as lightweight structures, biomedical implants, filters, heat exchangers, sound absorbers, mechanical damping devices, electrodes, sensors and catalyst substrates.
Journal of the American Ceramic Society, 2012
Bioactive glass 45S5 foams were produced using a powder technology process developed by The Natio... more Bioactive glass 45S5 foams were produced using a powder technology process developed by The National Research Council Canada-Industrial Materials Institute. NRC-IMI's proprietary process, combining powder technology and polymer foam technique, allows the production of materials having different structures and properties. It can be used to produce components into various forms, such as fully porous bodies or coatings on solid structures. During foaming, the foaming agent is decomposed and expands the binder-bioactive glass suspension. Then, the binder is burnt out by heating the sample at 500°C and finally the bioactive glass particle network is sintered to consolidate the material. Foams sintered at various temperatures were characterized from a microstructural and mechanical point of view. The foam structure and properties are affected by the sintering temperature when it is varied between 950°C and 1025°C. Foams exhibited open porosity (64%-79%) and pore size (335-530 lm) optimal for bone ingrowth. In all cases, the glass crystallized during sintering and the material was mostly composed of Na 6 Ca 3 Si 6 O 18 and Na 2 Ca 4 (PO 4) 2 SiO 4 phases. The mechanical strength increased from 1.7 to 5.5 MPa while the density of the material increased from 0.56 to 0.97 g/cm 3 .
Journal of Osseointegration, 2011
Aim This study aimed at determining the effect of different thickness of porous titanium (Ti) coa... more Aim This study aimed at determining the effect of different thickness of porous titanium (Ti) coating, 0.5, 1.0 and 1.5 mm thick (PC-0.5, PC-1.0 and PC-1.5), on osteoblast phenotype expression. Materials and methods Dense Ti discs coated with 0.5, 1.0 and 1.5 mm of porous Ti (PC-0.5, PC-1.0 and PC-1.5, respectively) were fabricated by powder metallurgy process with pore size typically between 50 and 400 μm and porosity of 60%. Osteoblastic cells obtained from human alveolar bone were cultured on dense Ti (D-Ti) and PC-Ti discs for periods of up to 17 days. Results Cultures grown on PC-Ti exhibited higher cell proliferation rate than on D-Ti. By comparing PC-Ti groups, it was observed statistical differences on culture grown only at day 10 (PC- 0.5<PC-1.0 and PC-1.5). Cells cultured on PC-1.5 presented the highest gene expression of type I collagen (COL), alkaline phosphatase (ALP), and osteocalcin (OC). The calcium content was significantly greater on PC-1.5 compared to all other...
Materials Performance and Characterization, 2020
It is recognized that humidity affects the properties of metallic powders (e.g., flowability, den... more It is recognized that humidity affects the properties of metallic powders (e.g., flowability, density, composition). Although standards exist to evaluate the water content in various materials, there is presently no standard method validated or specifically adapted for the evaluation of the water content in metallic powders. This article evaluates the water content in titanium powders using different techniques (gravimetry, Karl Fischer titration, quantification of volatiles with a relative humidity sensor). The effect of measurement conditions, particle size, and types of powder were investigated. The results showed that the adsorption of water is a function of the relative humidity in the environment and the characteristics of the powders. The relative humidity in the laboratory has, however, limited effect if the exposure of the powder to the environment is limited prior to the measurements. Water adsorption/desorption is a function of the surface area of the powder. The measured...
Reducing the amount of admixed lubricant is an attractive route to increase density and improve p... more Reducing the amount of admixed lubricant is an attractive route to increase density and improve properties of P/M components while minimizing the negative effects associated with lubricant burn-off in sintering furnaces. Previous studies have shown that die wall lubrication can be used to reduce the amount of admixed lubricant needed for the compaction and ejection of P/M components. However, this technology must ensure a proper control of the deposition of the lubricant on the die walls. This paper presents a new approach to coat a lubricant on die walls, consisting in the use of a confining block located in the die cavity. An evaluation of this approach on a mechanical production press is presented. Results show the benefit of using this technique combined with warm pressing to produce a relatively thick steel gear with high density under industrial processing conditions.
Additive Manufacturing, 2020
Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, co... more Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous
Materials
Bioactive glasses (BG) possess significant bone-bonding and osteogenic properties that support th... more Bioactive glasses (BG) possess significant bone-bonding and osteogenic properties that support their use for bone defects repair in orthopaedic and dental procedures. Recent advancement enables the manufacturing of BG-based scaffolds providing structural support during bone regeneration. Despite the wide number of studies on BG and BG-based materials, little information on their aging mechanisms and shelf life is available in the literature. In this study, the evolution of chemical species on BG-based foams was investigated via accelerated tests in the presence of CO2 and humidity. The aging process led to the formation of carbonates (Na2CO3 and CaCO3) and hydrocarbonates (NaHCO3). The amount and composition of nucleated species evolved with time, affecting the structure, properties, and bioactivity of the scaffolds. This study provides a first structured report of aging effects on the structure and chemico-physical properties of bioactive glass-based scaffolds, offering an insight ...
Metal Powder Report
ABSTRACT