The Experts below are selected from a list of 24216 Experts worldwide ranked by ideXlab platform
Marianna Peroglio - One of the best experts on this subject based on the ideXlab platform.
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Human primary osteoblast behaviour on microrough zirconia-toughened alumina and on selectively etched microrough zirconia-toughened alumina
Journal of the European Ceramic Society, 2018Co-Authors: Ana-maria Stanciuc, Meinhard Kuntz, Quentin Flamant, Katia Biotteau-deheuvels, Martin Stoddart, Alessandro Porporati, Laurent Gremillard, Marc Anglada, Mauro Alini, Marianna PeroglioAbstract:Hip arthroplasty cementless acetabular components require excellent mechanical properties, biocompatibility, low friction and good osseointegration with Surrounding Bone tissue. Zirconia-toughened alumina (ZTA) fulfils these demands but requires combination with a rough metal shell for adequate osseointegration. Surface modifications of ZTA could allow a metal-free solution, thus preserving the Bone stock for an eventual revision surgery. In this study, selective chemical etching proved to be an innovative method for the introduction of nano-features on micro-rough surfaces obtained by injection moulding. Results suggest that micro-roughness, fluorine enrichment and nano-porosity at the surface of ZTA play a synergistic role on human osteoblast (hOb) maturation. Among the tested groups, hydrofluoric acid etched “medium” roughness (Sa = 330 nm) ZTA showed the highest and/or earliest ALP expression at both the protein and gene level, while microroughness alone induced only minor effects on hOb maturation on ZTA.
Thomas J. Webster - One of the best experts on this subject based on the ideXlab platform.
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the influence of nano mgo and baso4 particle size additives on properties of pmma Bone cement
International Journal of Nanomedicine, 2008Co-Authors: Alyssa Ricker, Peishan Liusnyder, Thomas J. WebsterAbstract:A common technique to aid in implant fixation into Surrounding Bone is to inject Bone cement into the space between the implant and Surrounding Bone. The most common Bone cement material used clinically today is poly(methyl methacrylate), or PMMA. Although promising, there are numerous disadvantages of using PMMA in Bone fixation applications which has limited its wide spread use. Specifically, the PMMA polymerization reaction is highly exothermic in situ, thus, damaging Surrounding Bone tissue while curing. In addition, PMMA by itself is not visible using typical medical imaging techniques (such as X-rays required to assess new Bone formation Surrounding the implant). Lastly, although PMMA does support new Bone growth, studies have highlighted decreased osteoblast (Bone forming cell) functions on PMMA compared to other common orthopedic coating materials, such as calcium phosphates and hydroxyapatite. For these reasons, the goal of this study was to begin to investigate novel additives to PMMA which can enhance its cytocompatibility properties with osteoblasts, decrease its exothermic reaction when curing, and increase its radiopacity. Results of this study demonstrated that compared to conventional (or micron) equivalents, PMMA with nanoparticles of MgO and BaSO4 reduced harmful exothermic reactions of PMMA during solidification and increased radiopacity, respectively. Moreover, osteoblast adhesion increased on PMMA with nanoparticles of MgO and BaSO4 compared with PMMA alone. This study, thus, suggests that nanoparticles of MgO and BaSO4 should be further studied for improving properties of PMMA for orthopedic applications.
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The influence of nano MgO and BaSO4 particle size additives on properties of PMMA Bone cement
Dove Medical Press, 2008Co-Authors: Alyssa Ricker, Peishan Liu-snyder, Thomas J. WebsterAbstract:Alyssa Ricker, Peishan Liu-Snyder, Thomas J WebsterDivision of Engineering, Brown University, Providence, RI, USAAbstract: A common technique to aid in implant fixation into Surrounding Bone is to inject Bone cement into the space between the implant and Surrounding Bone. The most common Bone cement material used clinically today is poly(methyl methacrylate), or PMMA. Although promising, there are numerous disadvantages of using PMMA in Bone fixation applications which has limited its wide spread use. Specifically, the PMMA polymerization reaction is highly exothermic in situ, thus, damaging Surrounding Bone tissue while curing. In addition, PMMA by itself is not visible using typical medical imaging techniques (such as X-rays required to assess new Bone formation Surrounding the implant). Lastly, although PMMA does support new Bone growth, studies have highlighted decreased osteoblast (Bone forming cell) functions on PMMA compared to other common orthopedic coating materials, such as calcium phosphates and hydroxyapatite. For these reasons, the goal of this study was to begin to investigate novel additives to PMMA which can enhance its cytocompatibility properties with osteoblasts, decrease its exothermic reaction when curing, and increase its radiopacity. Results of this study demonstrated that compared to conventional (or micron) equivalents, PMMA with nanoparticles of MgO and BaSO4 reduced harmful exothermic reactions of PMMA during solidification and increased radiopacity, respectively. Moreover, osteoblast adhesion increased on PMMA with nanoparticles of MgO and BaSO4 compared with PMMA alone. This study, thus, suggests that nanoparticles of MgO and BaSO4 should be further studied for improving properties of PMMA for orthopedic applications.Keywords: Bone cement, PMMA, Poly(methyl methacrylate), osteoblast, nanoparticle
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nanophase ceramics the future orthopedic and dental implant material
Advances in Chemical Engineering, 2001Co-Authors: Thomas J. WebsterAbstract:Abstract Traditional materials utilized for orthopedic and dental applications have been selected based on their mechanical properties and ability to remain inert in vivo; this selection process has provided materials that satifisfy physiological loading conditions but do not duplicate the mechanical, chemical, and architectural properties of Bone. The less than optimal surface properties of conventional materials have resulted in clinical complications that necessitate surgical removal of many such failed Bone implants due to insufficient bonding to juxtaposed Bone. Sufficient bonding of an implant to juxtaposed Bone (i.e., osseointegration) is needed to minimize motion-induced damage to Surrounding tissues and support physiological loading conditions, criteria crucial for implant success. Insufficient osseointegration can be caused by biomaterial surface properties that do not support new Bone synthesis and/or mechanical properties that do not match those of Surrounding Bone; mismatch of mechanical properties between an implant and Surrounding Bone may lead to stress and strain imbalances that cause implant loosening and eventual failure. Clearly, the next generation of biomaterials for orthopedic and dental implant applications must possess both biocompatible surface properties that promote bonding of juxtaposed Bone and mechanical properties similar to those of physiological Bone. Due to unique surface and mechanical properties, as well as the ability to simulate the three-dimensional architecture of physiological Bone, one possible consideration for the next generation of orthopedic and dental implants with improved efficacy are nanophase materials. This chapter presents reports of the design, synthesis, and evaluation of nanophase materials for increased orthopedic and dental implant efficacy.
Antonio Apicella - One of the best experts on this subject based on the ideXlab platform.
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non linear elastic three dimensional finite element analysis on the effect of endocrown material rigidity on alveolar Bone remodeling process
Dental Materials, 2009Co-Authors: Raffaella Aversa, Davide Apicella, Letizia Perillo, Roberto Sorrentino, Fernando Zarone, Marco Ferrari, Antonio ApicellaAbstract:Abstract Objectives In healthy conditions, modeling and remodeling collaborate to obtain a correct shape and function of Bones. Loads on Bones cause Bone strains which generate signals that some cells can detect and respond to. Threshold ranges of such signals are genetically determined and are involved in the control of modeling and remodeling. The present study aimed at assessing the deformations transferred to Surrounding Bone by endodontically treated maxillary central incisors restored with endocrowns made up of high or low elastic modulus materials. Methods The solid model consisted of a maxillary central incisor, the periodontal ligament (PDL) and the Surrounding cortical and cancellous Bone. Both composite and alumina endocrowns were simulated under load and compared to a sound tooth. Dynamic non-linear analyses were performed to validate discretization processes. Non-linear analyses were performed on teeth and Surrounding Bone to estimate strain variations according to restorative techniques. Results Strain values in cortical Bone, spongy Bone, alveolar cortex and tooth were evaluated. PDL allowed models to homogeneously transfer loads to Bone. Strains developing in highly rigid restorations were estimated to activate Bone modeling and remodeling. Significance The higher deformability of composites could enable restorative systems to transfer limited strains to compact and spongy Bone of tooth socket. Although composites could not prevent the physiological resorption of the alveolar Bone, they could successfully reduce strain arising in tooth socket when compared to alumina. The PDL prevented Bone to undergo high deformations, resulting in natural flexural movements of teeth.
Ana-maria Stanciuc - One of the best experts on this subject based on the ideXlab platform.
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Human primary osteoblast behaviour on microrough zirconia-toughened alumina and on selectively etched microrough zirconia-toughened alumina
Journal of the European Ceramic Society, 2018Co-Authors: Ana-maria Stanciuc, Meinhard Kuntz, Quentin Flamant, Katia Biotteau-deheuvels, Martin Stoddart, Alessandro Porporati, Laurent Gremillard, Marc Anglada, Mauro Alini, Marianna PeroglioAbstract:Hip arthroplasty cementless acetabular components require excellent mechanical properties, biocompatibility, low friction and good osseointegration with Surrounding Bone tissue. Zirconia-toughened alumina (ZTA) fulfils these demands but requires combination with a rough metal shell for adequate osseointegration. Surface modifications of ZTA could allow a metal-free solution, thus preserving the Bone stock for an eventual revision surgery. In this study, selective chemical etching proved to be an innovative method for the introduction of nano-features on micro-rough surfaces obtained by injection moulding. Results suggest that micro-roughness, fluorine enrichment and nano-porosity at the surface of ZTA play a synergistic role on human osteoblast (hOb) maturation. Among the tested groups, hydrofluoric acid etched “medium” roughness (Sa = 330 nm) ZTA showed the highest and/or earliest ALP expression at both the protein and gene level, while microroughness alone induced only minor effects on hOb maturation on ZTA.
Nicholas M. Bernthal - One of the best experts on this subject based on the ideXlab platform.
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the use of a novel antimicrobial implant coating in vivo to prevent spinal implant infection
Spine, 2020Co-Authors: Vishal Hegde, Howard Y. Park, Erik M. Dworsky, Stephen D. Zoller, Weixian Xi, Daniel Johansen, Amanda H. Loftin, Christopher D. Hamad, Tatiana Segura, Nicholas M. BernthalAbstract:STUDY DESIGN: A controlled, interventional animal study OBJECTIVE.: Spinal implant infection is a devastating complication. The objective of this study was to evaluate the efficacy of a novel implant coating that has both a passive antibiotic elution and an active-release mechanism triggered in the presence of bacteria, using an in vivo mouse model of spinal implant infection. SUMMARY OF BACKGROUND DATA: Current methods to minimize the frequency of spinal implant infection include: local antibiotic therapy (vancomycin powder), betadine irrigation, silver nanoparticles, and passive release from antibiotic-loaded cement (PMMA) beads, all of which have notable weaknesses. A novel implant coating has been developed to address some of these limitations but has not been tested in the environment of a spinal implant infection. METHODS: A biodegradable coating using branched poly(ethylene glycol)-poly(propylene sulfide) (PEG-PPS) polymer was designed to deliver antibiotics. The in vivo performance of this coating was tested in the delivery of either vancomycin or tigecycline in a previously established mouse model of spinal implant infection. Noninvasive bioluminescence imaging was used to quantify the bacterial burden, and implant sonication was used to determine bacterial colony forming units from the implant and Surrounding Bone and soft tissue. RESULTS: The PEG-PPS-vancomycin coating significantly lowered the infection burden from post-operative day (POD) 3 onwards (p < 0.05), while PEG-PPS-tigecycline only decreased the infection on POD 5-10 (p < 0.05). Colony-forming units (CFUs) were lower on PEG-PPS-vancomycin pins than PEG-PPS-tigecycline and PEG-PPS pins alone on both the implants (2.4 × 10, 8.5 × 10, and 1.0 × 10 CFUs, respectively) and Surrounding Bone and soft tissue (1.3 × 10, 4.8 × 10, and 5.4 × 10 CFUs, respectively) (p < 0.05). CONCLUSIONS: The biodegradable PEG-PPS coating demonstrates promise in decreasing bacterial burden and preventing spinal implant infection. The vancomycin coating outperformed the tigecycline coating in this model compared to prior work in arthroplasty models, highlighting the uniqueness of the para-spinal infection microenvironment. LEVEL OF EVIDENCE: N/A.
