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This study compares, by means of the finite element method (FEM), the behaviour of the restorations done with the same material, the same adhesive system and under the action of the same force values applied to four 3-D lower premolar finite element models, representing four different cavity shapes. An extracted lower premolar which presented an abfraction lesion has been used. The restoration was achieved by using etch–and-rinse adhesive systems and Giomers. The premolar was scanned and the resulting sections were processed and converted into a 3D digital format. Thus, a model of finite elements which presented a restored wedge-shaped cavity in the cervical dental area was obtained. Then, by modifying the shape and dimensions, there were created another 3 modified-shape cavities. Forces of different magnitudes (90-150N), exerted at a 45 degree angle on buccal cusp, have been applied. If adhesive system tensile strength is about 25MPa, this limit is reached at 120N only for the third model. For Beautifil FO2 the tensile strength is not reached when maximum forces are applied (150N) and for Beautifil II, the tensile strength is reached only for model 4, when a force of 150N is applied. In order to increase the retention of the abfraction restoration, changing the shape of the cavity should be associated with the use of Giomers and adhesive system with tensile strength exceeding 25MPa.

Structural and morphological features of compositions based on LDPE which contains different types of fillers for creation of conductive polymer products are presented in this article. Different types of fine metallic fillers, such as Al, Br, Cu, and flake-like graphite were used in this work. Comparative assessment of morphometric characteristics of particulate fillers: area, perimeter, equivalent diameter, shape factor and their distribution on these indicators were performed by methods of optical microscopy and image analysis. Composite films based on LDPE, containing 5% vol. with different types of conductive fillers were obtained by pressing method. It was found that the nature of the filler quantitatively influences on the uniformity of distribution of its particles in composite films. The most structural homogeneity was observed in PE-Gr and PE-Cu composites, while the least - in PE-Br composite. It was shown that the increasing of average particle anisotropy for investigated fillers reduces their heterogeneity of distribution in composite films.

The purpose of this study was to develop and characterize the in vitro release kinetics of erythromycin from water-in-oil microemulsion preparations for dermal application. The results obtained confirm that the water-in-oil microemulsion systems based on avocado oil can be used as incorporation and delivery systems for the topical administration of ER in the treatment of skin disorders.

This study reports on the in vitro erosive capacity of three different pH chlorinated waters on dental enamel, and the anti-erosive protection conferred by three dental materials (toothpaste, remineralising cream, and fluoride varnish), assessed by scanning electron microscopy. Fluoride varnish provided the best protection, forming a resistant thin film on the enamel’s surface. The observed ultrastructural changes of the enamel surface were low when the tooth paste was used, and more pronounced when the remineralising cream was used.

Cobalt based alloys are widely used in medicine, the system CoCrMo being used for partial removable dentures realization. The extension of the applications for these alloys is based either on alloying of the tertiary system with new elements, or to the using of the plastic forming components. Titanium, which is well-known for its biocompatibility property, was used as an alloying element for the system CoCrMo in order to increase the physical-chemical properties of these alloys. Present paper has the aim of establishing the plastic forming behavior of the new alloy from the system CoCrMoTi, with 5.5%Ti, which will be possible used in dentistry. The experiments were realized in laboratory conditions, on a free falling dawn hammer, with high of free falling about H = 0.2 m,, and the falling dawn mass about 71 kg. The determinations were made in the range of temperatures about 1100 – 1250°C, at every 50°C. Finally, the graphics of plastic forming versus temperature and mechanical working versus temperature were drawn. The final conclusion was that the optimum range of temperature for hot working of the CoCrMoTi alloy is 1150 ÷ 1250°C, in which the plastic forming resistance and specific hot working are optimum.

The superior machining of waste involves their reuse as raw material for new products. In the research there was aimed to improve the known technological process to reduce costs and increase productivity. Thus, the process was redesigned by introducing new technologies related to shredding of waste respectively de-vulcanization in autoclaves. Shredding technological process has been redesigned by using shredding tools, ultrasonic activated in order to increase productivity, durability of these tools respectively the decrease of energy consumption. There were also conducted researches on the autoclave vacuum after rubber de-vulcanization which allows an increase of reclaimed rubber qualities.

The paper aims to approach a problem which occurs when welding the high density polyethylene fittings and pipes used in the natural gas distribution networks. The work presents a finite element numerical analysis of the polyethylene fitting. The geometric modeling was performed using the Catia software, which includes the finite element module and thus eliminating the risk of the possible inconsistencies between the Catia files and other finite element software. There is presented, in parallel, the thermal analysis of the polyethylene fitting employing an infrared camera. Reading both, finite element analysis and thermal analysis conclusions may lead to the solution that should be taken in order to avoid the fracture of the polyethylene fittings during welding or immediately after that.

This study has been carried out to investigate a new method to improve metallic implant bioactivity for osseointegration by producing a calcium phosphate (Ca–P) surface layer using an immersion process in the Simulated Body Fluid (SBF) of Polypyrrole (PPy) and Polypyrrole/poly(sodium-4styrensulfonate) (NaPSS) conductive hybrid polymers electrochemically synthesized on Ti6Al7Nb alloy. As formed PPy/Ca-P and PPy/PSS-/Ca-P films were characterized electrochemically by Cyclic Voltammetry (CV), Tafel plots and spectroscopically using FT-IR technique. Also, in vitro cytotoxicity of these new organic/inorganic hybrids films was evaluated by yellow 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay after cultivation in a primary culture of osteoblast cells. The PPy/Ca-P hybrid film showed the best electrochemical stability and the highest value of cell viability.

In this work, two commercial block copolymers namely, styrene–ethylene/butylene–styrene (SEBS) and styrene–butadiene–styrene (SBS) with the same amount of styrene were investigated to enhance the properties of recycled polypropylene (RPP) from post-consumer boxes. The amount of elastomer varied from 10 wt.% to 30 wt.% relative to RPP. The elastomer content influence on structural (MFI, DSC, VICAT, HDT, XRD) and mechanical properties (tensile properties, IZOD impact, hardness) of the RPP/SEBS and RPP/SBS blends was studied. The obtained resuls showed that the addition of both elastomers into recycled polypropylene had a similar effect on modification the RPP properties, but SEBS exhibited a higher increase of elongation at break and IZOD impact than SBS, due to a good compatibility with polymeric matrix.

The present paper aims to assess the quality of materials used in the field of removable dentures namely classic acrylate and crosslinked acrylate with improved polymerization using as template vitamin B12 (cyanocobalamin). A major task is the trajectory of Candida albicans biofilm formation and their adherence to the surface of these materials.