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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 Jan 1995

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 …


The Use Of Titanium In Dentistry, Toru Okabe, Hakon Hero Jan 1995

The Use Of Titanium In Dentistry, Toru Okabe, Hakon Hero

Cells and Materials

The aerospace, energy, and chemical industries have benefitted from favorable applications of titanium and titanium alloys since the 1950's. Only about 15 years ago, researchers began investigating titanium as a material with the potential for various uses in the dental field, mainly because of its proven biocompatibility and other attractive properties. The present review examines updated information on the use of titanium in a major area of dentistry. Titanium-based alloys used for casting, casting equipment and procedures, casting investment materials, and porcelain veneering are discussed. Information about advances made in techniques other than casting, which could widen the applications of …


Room Temperature Aging Of Pd-Cu-Ga Dental Alloys, William A. Brantley, Zhuo Cai, Qiang Wu, Alan B. Carr, John C. Mitchell Jan 1995

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.


Adsorption Of Proteins At Solid-Liquid Interfaces, Willem Norde Jan 1995

Adsorption Of Proteins At Solid-Liquid Interfaces, Willem Norde

Cells and Materials

This paper concisely reviews the general principles underlying protein adsorption from aqueous solution onto a solid surface. The discussion includes the various stages of the adsorption process, i. e., transport of the protein molecules towards the surface, the absorbed amount under equilibrium conditions, desorption and re-adsorption. Among the interactions that determine the overall protein adsorption process (1 ) redistribution of charged groups in the interfacial layer, (2) changes in the hydration of the sorbent and the protein surface, and (3) structural rearrangements in the protein molecule play major roles. Special attention is given to the relation between the structural stability …


Reliability Of Human Fresh And Frozen Gingiva Explant Culture In Assessing Dental Materials Cytocompatibility, R. Warocquier-Clerout, G. C. Hachom-Nitcheu, M. F. Sigot-Luizard Jan 1995

Reliability Of Human Fresh And Frozen Gingiva Explant Culture In Assessing Dental Materials Cytocompatibility, R. Warocquier-Clerout, G. C. Hachom-Nitcheu, M. F. Sigot-Luizard

Cells and Materials

An explant culture of human gingival epithelium has been set up in order to provide a valuable test for evaluating the cytocompatibility of dental material s. In an attempt to supply a bank of gingiva ex plants, frozen and freshly excised specimens were cultured in parallel. Optical and scanning electron microscopy showed an early release of cuboidal cells forming a dense layer around the explants. Afterwards, cultures evolved differently . Spread cells grew and migrated more rap idly in fresh than in frozen explant cultures but their adhesion to substratum increased earlier in frozen ones. Epithelial phenotype of cells had …


Biomaterials Associated Infections: The Scale Of The Problem, David J. Stickler, Robert J. C. Mclean Jan 1995

Biomaterials Associated Infections: The Scale Of The Problem, David J. Stickler, Robert J. C. Mclean

Cells and Materials

The biomaterials used in the manufacture of implanted prosthetic devices profoundly impair the host's ability to opsonise and phagocytose invading microbes. As a result, while these devices generally provide effective relief from painful, crippling and life-threatening disorders, they can also induce vulnerability to infection in the recipients. The surfaces of the implants are susceptible to colonisation by microbial biofilms. The cells in the biofilm.s are further protected against opsonophagocytosis and are also resistant to antibacterials. Device associated infections thus tend to be refractile to antibiotic therapy and in many cases the device has to be removed before the infection will …


Feasability Of Preventing Encrustation Of Urinary Catheters, J. M. Bibby, A. J. Cox, D. W. L. Hukins Jan 1995

Feasability Of Preventing Encrustation Of Urinary Catheters, J. M. Bibby, A. J. Cox, D. W. L. Hukins

Cells and Materials

Colonization of urinary catheters by bacteria which produce urease leads to an increase in urine pH, followed by deposition of the minerals struvite and hydroxyapatite. Adhesion of these encrusting deposits can be reduced, but not prevented, by using catheters with a smooth surface finish. Chemical methods for preventing encrustation are not completely satisfactory. A better way of preventing encrustation would be to prevent colonization of the catheter by bacteria. This might be achieved by controlled release of antimicrobial agents directly into the urine from the catheter itself. Preliminary experiments have demonstrated the feasibility of controlled release from solid silicone. However, …


Some Biological And Physical Properties Of Laser Deposited Hydroxyapatite Based Films, Tatjana Dostalova, Lucie Himmlova, Miroslav Jelinek, Jirina Bartova Jan 1995

Some Biological And Physical Properties Of Laser Deposited Hydroxyapatite Based Films, Tatjana Dostalova, Lucie Himmlova, Miroslav Jelinek, Jirina Bartova

Cells and Materials

The preliminary results of biological and physical tests of hydroxyapatite thin films deposited on dental implants by a new technology with the KrF excimer laser ablation method were evaluated. Biological and physical properties were studied and analyzed by the lymphocyte proliferation test and scanning electron microscopy (SEM), X-ray analysis, Rutherford backscattering analysis (RBS) and particle induced X-ray emission (PIXE) methods. Ten bioceramic films from 45 samples had very good physical and biological properties. Creation of hydroxyapatite thin films with laser ablation can have a positive effect on adhesion of the film and protection for corrosion.


Optical Bone Chambers As Tools For Studying The Bone-Implant Interface: A Review, Howard Winet Jan 1995

Optical Bone Chambers As Tools For Studying The Bone-Implant Interface: A Review, Howard Winet

Cells and Materials

Bone chamber intravital microscopy combines the control volume of in vitro models and the chemical complexity of in vivo models to optimize the study of bone physiology in situ. As an optical tool it provides a window to dynamic events at the tissue level of magnification. In particular, it allows measures of microvascular events: (1) in space by magnifying local perfused vasculature and microcirculation at any instant, and (2) in time by providing the same volume of tissue for weekly viewing of an evolving process such as bone healing. This quartz-bearing titanium screw has revealed a consistent order for …