ObjectiveThe aim of the study reported here was to evaluate the performance of a self-adhesive flowable composite and two self-etching adhesive systems, when subjected to cyclic loading, in preventing the nanoleakage of Class V restorations.MethodsWedge-shape Class V cavities were prepared (4×2×2 mm [length × width × depth]) on the buccal surfaces of 90 sound human premolars. Cavities were divided randomly into three groups (n=30) according to the used adhesive (Xeno® V [self-etching adhesive system]) and BOND-1® SF (solvent-free self-etching adhesive system) in conjunction with Artiste® Nano Composite resin, and Fusio™ Liquid Dentin (self-adhesive flowable composite), consecutively. Each group was further divided into three subgroups (n=10): (A) control, (B) subjected to occlusal cyclic loading (90N for 5,000 cycles), and (C) subjected to occlusal cyclic loading (90N for 10,000 cycles). Teeth then were coated with nail polish up to 1 mm from the interface, immersed in 50% silver nitrate solution for 24 hours and tested for nanoleakage using the environmental scanning electron microscopy and energy dispersive analysis X-ray analysis. Data were statistically analyzed using two-way analysis of variance and Tukey’s post hoc tests (P≤0.05).ResultsThe Fusio Liquid Dentin group showed statistically significant lower percentages of silver penetration (0.55 μ) compared with the BOND-1 SF (3.45 μ) and Xeno V (3.82 μ) groups, which were not statistically different from each other, as they both showed higher silver penetration.ConclusionUnder the test conditions, the self-adhesive flowable composite provided better sealing ability. Aging of the two tested adhesive systems, as a function of cyclic loading, increased nanoleakage.

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Objectives:The aim of this in-vitro study was to compare the stresses transmitted to the abutments in mandibular Kennedy class I restored with telescopic-retained removable partial denture (RPD) made from two different materials; PolyEther Ether Ketone (PEEK) and Co-Cr alloy. Materials and Methods:One mandibular model representing Kennedy class I, with second premolars as the last standing abutments, was fabricated using epoxy resin. Poly Vinyl Siloxane (PVS) impression material was used to simulate the mucosa and the periodontal ligament. The acrylic first and second premolar teeth bilaterally were prepared to receive primary telescopic copings. The latter and two removable partial denture (RPD) frameworks were fabricated out of PEEK and Co-Cr alloy. The 2 frameworks were then processed into fully finished RPDs using heat cured acrylic resin and acrylic teeth following the conventional techniques. Four strain gauges were installed in the epoxy resin model 1 mm mesial to the socket of the 1 st premolar and 1 mm distal to that of the 2 nd premolar, on the right and left sides respectively; channel 1, 2, 3 and 4. A load of 100 N was applied to the area of the first molar unilaterally on the right side and then bilaterally. The same procedure was repeated six times. Data on stresses were then collected, tabulated and statistically analyzed using one-way ANOVA and Tukey HSD Test (P≤0.05). Results:In the unilateral loading condition, the highest compressive micro-strains were recorded at channel 3 for the Co-Cr alloy-group (-40±3.16 µm/m). While the least compressive micro-strains were recorded at channel 3 for the PEEK-group (-10±3.16 µm/m). The highest tensile micro-strains were recorded at channel 2 for the PEEK-group (540±10 µm/m). While the least tensile micro-strains were recorded at channel 4 for the PEEK-group (15±4.47 µm/m). In the bilateral loading condition, the highest tensile micro-strains were recorded at channel 2 for the PEEK-group (355±11.83 µm/m). While the least tensile micro-strains were recorded at the same channel for the Co-Cr alloy-group (50±3.16 µm/m). The highest compressive micro-strains were recorded at channel 1 for the PEEK-group (-170±11.4 µm/m). While the least compressive microstrains were recorded at channel 3 for the Co-Cr alloy-group (-95±8.94 µm/m).

Herein, versatile, and reproducible method to prepare binary metal oxides via microwave assisted synthesis. Catalysts are substances that basically speeds up chemical reactions. Ideally, bonds are formed between the catalysts and the reactants. Also, catalysts permits formation of products from the reactants. These formed products, splits off the catalyst without affecting or changing it. Catalytic kinetics studies the correlate chemical reaction rate with some properties of reactants and/or products for instance; temperature, concentration and pressure. The aim of the project is to prepare pure and bi-metal iron based catalyst by co-precipitation method and to characterize the prepared sample using X-ray diffraction .Metal oxides nanoparticles is a field of interest in catalysis, such that these oxides are used to oxidize carbon monoxide. The samples were prepared through co-precipitation method in laboratory scale. The metals used was copper, iron and cobalt. After preparing pure sample of each metal a mix of two metals were introduced in different ratios. The samples were characterized via X-ray diffraction (XRD) and then the results were compared to exist data introduced from others research, the prepared samples XRD was having a great matching with the data retrieved from internet and we found that the metal could exist in two form of oxides and even could exist as pure metal. Each peak in the XRD figure could indicate one or more phase of the metal.

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