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Facial epistasis represent facial prosthetic components made of acrylic or silicone plastics, which have no other function than to rebuild the lost region of the face in order to partially restore the physiognomy. A mandatory step in the manufacturing process of epistasis is represented by fingerprinting the tissue defect and the entire facial region and making a study model as basis for designing the epistasis . Keywords: facial episthesis, prosthetic components, acrylic or silicone plastics

Metal-composite crowns or metal-polymeric crown are an intermediary option from the mechanical and esthetical characteristics between acrylic resin and ceramic materials. Same as in the case of other types of fix partial dentures, the esthetic veneer may present fissures or fractures. The replacement of a fix partial denture is time consuming and involves high costs. In specific clinical cases, the metal-composite fix partial dentures can be repaired with plastic materials like diacrylic composite resin. Metal-acrylic and metal-ceramic fix partial dentures can also take advantage of the diacrylic composite resin in similar situations- fracture. The repairing maneuver can be considered temporary for a longer period of time. The key of reparation’s success is the interface integrity between the two materials. Imagistic investigation methods, like Atomic Force Microscopy gives important information about the surface roughness of different materials. The purpose of the present study is the investigation of the new interface obtained after the direct reparation of metal-composite crowns with diacrylic composite resins. Keywords: crown, acrylic resins, ceramic materilas

This paper is about obtaining polyolefin composites with antibacterial properties for the manufacture of hollow blown bodies (vials, bottles, jars) used for the packaging of medical products, cosmetics and food. As main polymer, it was used polypropylene, and as biocide active agent, it was used silver chloride deposited on a support of titanium dioxide or of silica. Antimicrobial silver was added as a premix, using for this purpose the co-polymer ethylene-1-octene. Hollow bodies were obtained by extrusion-blowing and were tested for their mechanical properties and biocompatibility. Keywords: polypropylene, co-(ethylene-1-octene), hollow blown bodies, extrusion

The utilization of waste rubber powder in polymer matrices provides an attractive strategy for polymer waste disposal. In this study lead free composite material samples for anti– radiation purposes were produced. To attain this goal, 15 wt. % of recycled acrylonitrile-butadiene rubber (NBRr) were added to Naturalrubber (NR) to prepare the composite’s matrix part. Then the matrix was incorporated with various hard materials wastes such as iron particulates, iron fillings and slags brought from different industry zones. The amounts of the added particulates were ranged from 15–75 wt%. All fabricated samples were assessed for their anti-radiation attenuation properties. The attenuation measurements were performed using gamma spectrometer of NaI (Tl) detector. The utilized radiation sources comprised 137Cs and 60Co radioactive elements with photon energies of 0.662 MeV for 137Cs and two energy levels of 1.17 and 1.33MeV for 60Co. Likewise theHalf-Value Layer (HVL) and the mean free paths (Mfp) for the tested samples were obtained. The aim of this work is to investigate the effects of the waste loading rates, the particulate types and their dispersive manner within the rubber blends on the attenuation coefficients. The maximum linear attenuation coefficient (m)was attained for rubber incorporates iron particulates wastes of 65 wt. %. They were of 0.0510± 3.2123 ×10-3for 137Cs and 0.0346± 6.973×10-3and 0.0182±1.297×10-3 for 60Cofor the energies of 0.662, 1.17and 1.33 MeV respectively. A Significant improvement of attenuation performance was achieved by 25%–30% for rubber samples incorporate iron particulate. The tested samples were examined using different techniques, metallographic facilities, optical microscopy, scanning electron microscopy (SEM), Fourier Transform Infrared (FTIR) Spectroscopy, and hardness and measurement facilities. The microstructure, homogeneity, particulate dispersion, porosity and structure defects, and the mechanical properties of the fabricated samples were studied and evaluated. Keywords: Attenuation coefficient, radioactive, wastes iron filings, NR/NBRr blends, SEM, NaI (Tl), steel slag

This paper is aimed to the identification of the plastics used in the insulation of the conductors and the electrical cables and depending on their characteristics , the influence exercised on power losses in the dielectric of the cables . Solid organic synthetic insulating materials that are used in electrotechnics , represents a sensitive group larger than natural materials . According to current statistics , it is clear that solid synthetic materials are implemented in a majority share in achieving equipment and electrical installations insulation being in the configuration of generation, transmission and distribution of electricity systems. Keywords: plastic , polyvinylchloride , insulation, electrical cable , thermal stability

During the daily activity the orthodontic systems are suffering various loadings which together with saliva lead to a depreciation of bonding material which is used to fix the brackets on the dental surfaces. For this study human incisive shaped bovine bone were used to simulate mastication in a media consisting in a mixture of sesame, poppy and sunflower seeds and water. The aim is to compare the shear resistance of the bond with the one evaluated for fresh mounted brackets. Also a qualitative analysis is aimed based on micro photos took before and after bracket debonding. There are not rare the cases when patients are returning to doctor immediately after orthodontic system installation despite the medical advice because it is almost impossible to inhibit natural habits developed. In the first period after the installation of the orthodontic systems the reflex of biting the food is present in all the cases and that produces the detachment of the incisive bonded brackets. However during the mastication components of the food are interacting with the brackets generating local loads over the brackets themselves and also over the bonding material which can be a polymer or a composite. These loadings together with the ones meant by the doctor are producing in time small fractures and cracks at the bonding level with consequences on shear resistance of brackets on the tooth. Keywords: orthodontics, adhesive, bracket, shear strength

To achieve a modeling of the epithesis as close as possible to the lost organ, information on its size and shape can be registered by using computed tomography and 3D reconstruction. This paper aims to investigate to what extent the recording geometry of facial regions using computed tomography and identify on the sections of computed tomography the contour of the region to be reconstructed for virtual modeling of future silicone epithelium can be achieved. The results were obtained by applying the algorithm described in C + + program and contour detection in computed tomography images recorded preoperatively in patients who were to receive resection surgery of a facial region followed by reconstruction of the defect by facial epithesis. Keywords: acrilic resins, contour detection

The poly (vinyl butyral)/silica (PVB/SiO2) composite fibers were produced by the electrospinning process. The experiments were performed with the PVB solution in concentration of 10 wt.% where ethanol was used as the solvent. The silica nanoparticles were added into the solution in different content of 1, 3 and 5 wt.% SiO2. The PVB fibers with 50 wt.% SiO2 nanoparticles were deposited on p-aramid fabrics which were coated with PVB solution. The effect of the processing parameters on the morphology of PVB/SiO2 composite fibers was analysed. Mechanical properties of the p-aramid fabrics were tested by dynamic mechanical analysis (DMA). Keywords: electrospinning, electrospun composite fibers, silica nanoparticles, p-aramid fabrics

Polyelectrolyte multilayers composed of chitosan and poly(acrylic acid) were constructed onto silicon wafers from solutions of different concentrations of polymer and NaCl. To modulate the film properties, the multilayers were subject to three post-treatment strategies: (i) immersion in an aqueous solution with pH = 2.4 for 1 min, followed by a 15 s immersion step in water and drying at 80 oC for 60 min; (ii) immersion for 30 min in water and (iii) immersion in an aqueous solution with pH = 2.4 for 5 min, followed by immersion for 1 min in water and thermal treatment at 120 oC for 60 min. The changes of the film morphology, thickness, and wetting state as a function of deposition conditions and post-treatment strategies used were followed by atomic force microscopy, spectroscopic ellipsometry and contact angle measurements. Keywords: polyelectrolyte multilayer; chitosan; poly(acrylic acid); post-treatments

The purpose of this study was to evaluate colour changes of aesthetic fixed prosthetic restoration materials, when these materials are exposed to a drink rich in colorants, in this case, cola, coffee and red wine. For the study were required 18 fixed partial dentures: 6 integral polymeric dentures, 6 metal-polymeric dentures and 6 metal-ceramic dentures. To verify the colour there were used: VITA EASYSHADE spectrophotometer and the VITA shade for ceramic restorations. Following the results obtained, it was concluded that prosthetic composite resin changes quickly their colour, compared to the ceramic. Also, the liquid that affect the most in changing the colour of this material is coffee. Keywords: composite resin, colour change, aesthetic restorative materials