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Full-Text Articles in Engineering
Scanning Electron Microscopy Studies Of Ceramic Layers And Interfacial Regions For Calcium Phosphate-Coated Titanium Dental Implants, W. A. Brantley, E. Tufecki, J. C. Mitchell, D. W. Foreman, E. A. Mcglumphy
Scanning Electron Microscopy Studies Of Ceramic Layers And Interfacial Regions For Calcium Phosphate-Coated Titanium Dental Implants, W. A. Brantley, E. Tufecki, J. C. Mitchell, D. W. Foreman, E. A. Mcglumphy
Cells and Materials
The surface and cross-section characteristics of the plasma-sprayed calcium phosphate coatings, along with the microstructures and elemental compositions near the titanium alloy interface, were investigated by scanning electron microscopy for two different dental implants of proprietary compositions: Integra!® (Calcitek) and BioVent ® (Dentsply). Elemental concentrations (Ca, P, Ti, AI, and V) near the interfaces were obtained by X-ray energy-dispersive spectroscopy. Coating surfaces exhibited a splat deposition topography of greatly differing microstructural scale for the two implants, along with other features characteristic of the plasma-spraying process; cross-sections of the coatings revealed minimal porosity. Some interdiffusion of principally titanium and calcium was …
Room Temperature Aging Of Pd-Cu-Ga Dental Alloys, William A. Brantley, Zhuo Cai, Qiang Wu, Alan B. Carr, John C. Mitchell
Room Temperature Aging Of Pd-Cu-Ga Dental Alloys, William A. Brantley, Zhuo Cai, Qiang Wu, Alan B. Carr, John C. Mitchell
Cells and Materials
Specimens of three Pd-Cu-Ga dental alloys cast five years ago and subsequently stored at room temperature were reexamined and observed to have lower amounts of the eutectic constituents in the near-surface region than originally present, along with other microstructural changes. This previously unreported room temperature aging behavior of these alloys is attributed to the presence of high-diffusivity paths in the non-equilibrium ascast eutectic structures and to the essential role of the surface for the vacancy diffusion mechanism. These results may have important clinical significance for the ill vivo corrosion resistance and long-term biocompatibility of the Pd-Cu-Ga alloys.
Backscattered Electron Imaging To Enhance Microstructural Contrast In Poly(Methyl Methacrylate) Bone Cement Fracture Analysis, L. D. T. Topoleski, P. Rutledge, X. Lu
Backscattered Electron Imaging To Enhance Microstructural Contrast In Poly(Methyl Methacrylate) Bone Cement Fracture Analysis, L. D. T. Topoleski, P. Rutledge, X. Lu
Cells and Materials
Poly(methyl methacrylate) (PMMA) bone cement is used as a grout to secure joint replacement prostheses into bone. It has a distinct microstructure made up of: prepolymerized beads, an interbead matrix polymer, a radiopacifier {barium sulphate (BaS04) or zirconium dioxide (Zr02)}, and pores or voids; the radiopacifier is found only in the interbead matrix of the cured bone cement. The mechanism of slow or fatigue crack growth appears to be initial micro-cracking through the interbead matrix, followed by coalescence of the microcracks to form a continuous crack. Thus, distinguishing the interbead matrix from the pre-polymerized beads is important for investigating fatigue …
Biodegradation Of Synthetic Biphasic Calcium Phosphate And Biological Calcified Substratum By Cells Of Hemopoietic Origin, A. Soueidan, O. I. Gan, J. M. Bouler, F. Gouin, G. Daculsi
Biodegradation Of Synthetic Biphasic Calcium Phosphate And Biological Calcified Substratum By Cells Of Hemopoietic Origin, A. Soueidan, O. I. Gan, J. M. Bouler, F. Gouin, G. Daculsi
Cells and Materials
Different types of osteoclastic cells (authentic osteoclasit from human giant cell tumor and bone marrow of newborn rats; newly-formed osteoclasts from adult rat bone marrow), giant multinucleated cells and macrophages were studied for their effect on synthetic and natural mineralized substrata. Biphasic calcium phosphate ceramic consisted of hydroxyapatite and beta tricalcium phosphate was chosen for in vitro experiments, and dentine served as a positive control for cell resorbing activity . Our results show the limited capacity of authentic and newly-formed osteoclasts to resorb synthetic ceramic as compared to that of natural substrata. In vitro cell-mediated biodegradation included also modifications of …
A Morphological Assessment Of Bovine Chondrocytes Cultured On Poly(Ethyl Methacrylate)/Tetrahydrofurfuryl Methacrylate, R. M. Sawtell, M. V. Kayser, S. Downes
A Morphological Assessment Of Bovine Chondrocytes Cultured On Poly(Ethyl Methacrylate)/Tetrahydrofurfuryl Methacrylate, R. M. Sawtell, M. V. Kayser, S. Downes
Cells and Materials
A heterocyclic methacrylate polymer system, PEMA/THFMA, has shown potential as a biomaterial for cartilage repair in a rabbit model and has properties making it suitable for use clinically. The ability of the polymer system, PEMA/THFMA, and a related system, PEMA/HEMA, to support chondrocytes in vitro was assessed by scanning electron microscopy. Chondrocytes adhered to the surface of the PEMA/THFMA by day one, having a rounded morphology and clustered appearance opposed to the Thermanox® control, where the cells had spread out and become fibroblastic in appearance. The chondrocytes divided rapidly on the PEMA/ THFMA system by day three and had completely …