Comparative assessment of durability of compounds of dentin and filling material, when using various adhesive systems and techniques, in persons of young and elderly age

Currently, the success of therapeutic and aesthetic dentistry would not have been possible without adhesive technology. Despite the variety of adhesive systems and techniques available on the market, there are many questions related to reducing the adhesion of filling materials to hard tissues of the tooth. An experimental study of the shearstrength of the joint between dentin and filling material was carried out in patients of young (18-44 years old) and elderly (60-75 years old) age using various adhesive techniques and various adhesive systems (Self Etch, Total Etch, Universal)В настоящее время успехи терапевтической и эстетической стоматологии были бы невозможны без адгезивных технологий. Несмотря на разнообразие представленных на рынке адгезивных систем и методик, остается много вопросов, связанных со снижением адгезии пломбировочных материалов к твердым тканям зуба. Было проведено экспериментальное исследование прочности соединения на сдвиг между дентином и пломбировочным материалом, у пациентов молодого (18-44 года) и пожилого (60-75 лет) возраста, при использовании различных адгезивных техник и различных адгезивных систем (SelfEtch, TotalEtch, Universal

Physical-Mechanical Properties of γ-Irradiated SiC Ceramics for Radioactive Wastes Immobilization

The interest in silicon carbide (SiC-based) ceramics and composites as matrix material for nuclear waste immobilization is grown up. Long-term chemical durability and radiation resistance of SiC are important factors for radionuclides immobilization. Advantages of SiC-based ceramics as structural materials in nuclear applications are the high-temperature properties, high density and reduced neutron activation. The use of radiation resistant materials is a strong requirement for safe and environmentally beneficial energy system. The SiC ceramics stability under irradiation for temperatures up to 1273 K is also very important for nuclear power applications. The SiC matrices doped by additives of Cr, Si were fabricated using High Speed Hot Pressing Method. Additives content was in the range from 0.5 to 3 wt %. Microstructural characteristics of silicon carbide ceramics were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and infra-red spectroscopy (IR) methods. The results of microcracking under indentation conditions were revealed the lack of cracks in the SiC ceramics with Cr additives before and after irradiation process. In addition, it was demonstrated that samples of SiC with alloying additives Cr and Si possess high mechanical parameters under γ-irradiation process. The strength of ceramics increases with the uniform and fine-grained structure formation. The modification of phase composition and mechanical properties of the SiC ceramics with Cr and Si additives under γ-irradiation were analyzed for further development of radiation resistant and matrix materials for radioactive wastes immobilization