In order to improve the reliability and the mechanical properties of orthopaedic hip prosthesis, new ceramic composites starting with nanosized powders of alumina and zirconia have been recently developed. The aim of the present study was to investigate the biological tolerance of one of these sintered ceramics and of its alumina and zirconia constitutive nanosized powders with both in vitro and in vivo approaches. At first, osteoblasts and fibroblasts were cultured either upon sintered ceramic discs with polished or rough surfaces or in the presence of the corresponding alumina or zirconia powders at various concentrations. Thereafter, we chronically injected these powders in the knee articulation of rats. In vitro, the materials showed no deleterious effect on cell proliferation, extra-cellular matrix production (human type I collagen and fibronectin) or on cell morphology. In vivo, the histological examination showed only a very moderate and non-specific granulomatous response of the synovial membrane but no major inflammation as clinically described with metals or polyethylene wear debris. Besides its improved physical properties, this recently developed alumina-zirconia composite showed satisfactory biocompatibility.
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http://dx.doi.org/10.1016/j.biomaterials.2009.11.107 | DOI Listing |
Small
January 2025
Department of Chemistry and Life Science, Yokohama National University, Yokohama, 240-8501, Japan.
Hydrogen spillover, particularly when involving "interparticle" hydrogen spillover, offers a unique opportunity to enhance catalytic efficiency by remote activation of surface acidity. Building on this concept, this study aims to investigate physically mixed alumina-supported platinum nanoparticles (Pt/AlO) and zirconia-supported tungsten oxide (WO/ZrO) in promoting the direct synthesis of cumene from benzene and propane at 300 °C. The reaction with Pt/AlO alone afforded propylene as the only product, indicating the successive reaction route of Pt-catalyzed dehydrogenation of propane, followed by acid-catalyzed alkylation.
View Article and Find Full Text PDFSci Rep
January 2025
Biomedical Engineering Department, Faculty of Engineering, Helwan University, Cairo, Egypt.
Car accidents, infections caused by bacteria or viruses, metastatic lesions, tumors, and malignancies are the most frequent causes of chest wall damage, leading to the removal of the affected area. After excision, artificial bone or synthetic materials are used in chest wall reconstruction to restore the skeletal structure of the chest. Chest implants have traditionally been made from metallic materials like titanium alloys due to their biocompatibility and durability.
View Article and Find Full Text PDFJ Prosthodont Res
January 2025
Department of Gerodontology and Oral Rehabilitation, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
Purpose: This study investigated the effects of femtosecond laser (FL) irradiation on the surface roughness and shear bond strength of high-translucency zirconia (6 mol% yttria-partially stabilized zirconia [6Y-PSZ]) and lithium disilicate (LiSiO) glass ceramics.
Methods: Fully sintered square-shaped specimens of 6Y-PSZ (7 groups; 20 specimens/group) and LiSiO (8 groups; 20 specimens/group) were surface-treated via sandblasting (50-μm alumina sand or glass beads) or FL irradiation (20- or 40-μm dot or cross-line patterns) or using Monobond Etch & Prime (Ivoclar Vivadent AG; only for LiSiO specimens). The surface roughness (arithmetic average [Sa] and developed interfacial area ratio [Sdr]) and shear bond strength after 24 h and 10,000 thermal cycles were measured and statistically analyzed.
BMC Oral Health
January 2025
Department of Basic Medical Science, Faculty of Medicine, Yozgat Bozok University, Yozgat, 66100, Türkiye, Turkey.
Background: Although surface finishing processes are effective against Streptococcus mutans biofilm, the mechanism of action of saliva with different acidity values has not been studied in detail. This study aims to produce four different all-ceramic materials in a single session with CAD/CAM devices and apply two different surface finishing processes, glazing and polishing, and then determine the retention of Streptococcus mutants on the surfaces of the materials in saliva with varying levels of acidity.
Methods: Zirconia-reinforced lithium silicate (Vita Suprinity, Vita Zahnfabrik, Bad Saöckingen, Germany), monochromatic feldspar (Vitablocs Mark 2, Vita Zahnfabrik, Bad Saöckingen, Germany), leucite glass ceramic (IPS Empress CAD, Ivoclar Vivadent, Liechtenstein), and monolithic zirconia (Incoris TZI (Cerec) Sirona, Germany) were used in the study.
Adv Mater
December 2024
Centre for Advanced Structural Ceramics, Department of Materials, Imperial College London, London, SW7 2AZ, UK.
Inorganic/inorganic composites are found in multiple applications crucial for the energy transition, from nuclear reactors to energy storage devices. Their microstructures dictate their properties from mass transport to fracture resistance. Consequently, there has been a multitude of processes developed to control them, from powder mixing and the use of short or long fibers, to tape casting for laminates up to recent 3D printing.
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