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In Pediatric practical dentistry, beside the great variety of direct dental restoration materials the dentist must take into account several factors such as morpho-structural particularities of temporary teeth, the clinical situation, physician performance, behavioural features of children and last but not least the quality of the chosen material. Thus, we investigated the behavior of glass ionomers cements in occlusal stress by determining their mechanical properties. The study aims to determine the vertical compressive strength values, which is one of the mechanical properties of filling materials, the strength of materials being useful in the research of occlusal forces exerted on the future restorations. We had used two glass ionomer cements and a resin modified glass ionomer cement, which then we have tested them to obtain comparative data of the resistance for vertical compression. Keywords: glass ionomers cements, mechanical properties, vertical compression, temporary teeth

The computerized technologies and equipment for obtaining nanofibers impose high training, a large interdisciplinary substantiation, capacity for data storage, memorizing, easy usage, selectivity, fiability, stability, reduced time for analizing / processing of the technological parameters. That is why the computerized electrospinning equipment and technologies for obtaining nanofibers are possible candidates to carry out these requirements owing to the fact that they present both the proper selectivity / sensibility and the increased processing /determining /intervening speed by using the computerized control. This paper aims to present the operation and aplication of equipment for obtaining polimeric nanofibers by electrospinning technology. The designing and accomplishing of the suggested electrospinning equipment has been aimed to obtain a modular system which should allow the control of the technological parameters by means of the computer. Thus, the multitude of the parameters which influence the process of electrospinning, can be independently and automatically varied. The obtained nanofibers were studied by scanning electron microscope. Keywords: nanofibers, equipment, technology, modular conception, electrospinning

Plastination suits very good for 3D reconstruction and morphometric measurements. Digital representation of anatomical features has provided a useful source of data for computer-based instructional development. The validation of 3D reconstructions and measurements needs a thoroughly knowledge about shrinkage. The aim of this paper is to determine the average slice shrinkage rate occurring during sheet plastination (E12 and P40). Fresh human brain slices for P40, pelvis slices for the standard E12 technique and a shoulder tissue block for the E12 thin slice technique were used for this study. In order to determine the shrinkage rate, the slice areas were measured before and after plastination for al samples. For the E12 thin slice technique, the shoulder tissue block was measured before and after plastination and a volumetric shrinkage rate was determined. The shrinkage rate was for P 40 technique 5.74%, for standard E12 technique 6.54% and for the E12 thin slices technique 6.23%. Therefore, plastinated slices showed a decreased shrinkage rate and fit best for research purposes. All shrinkage rates were under 10%, so we believe that every shrinkage below this value is appropriate and actually is fitted for a correct plastination procedure. Keywords: plastination, polymer E12, polymer P40, shrinkage

The surgical approach of the skull base pathology is in a state of constant development. The advancement of the ablative techniques forced the development in the field of reconstructive surgery of the skull base as well. The goal of the reconstructive surgery of the postablative defect of the skull base is to create a stable, watertight limit between the endocranian and the sinusal cavities. New reconstructive materials and adhesives were developed. The purpose of this article is to critically analyze the use of the mixture between the polyethylene glycol ester and trilysine amine solution as a sealant and adhesive in the reconstructive surgery of the skull base. Keywords: polyethylene glycol ester, trilysine amine solution, skull base, reconstructive surgery

Statistical copolymers N-isopropylacrylamide (NIPAM) – 5,6-benzo-2-methylene-1,3-dioxepane (BMDO) with different compositions were prepared by RAFT polymerization and characterized by 1H NMR, GPC and DSC analyses. Their solid-state thermal degradation was investigated for the first time by TGA, showing that the presence of the BMDO units within the PNIPAM chain decreased the thermal stability of the copolymer. In the case of higher BMDO content copolymers the onset decomposition temperature was lower even than that of PBMDO, and also a multistep decomposition process was noticed. The evolution of the global activation energy of the degradation process as a function of degradation conversion was determined by means of the Kissinger-Akahira-Sunose isoconversional method. Keywords: N-isopropylacrylamide; 5,6-benzo-2-methylene-1,3-dioxepane; copolymer; thermosensitive; thermal degradation; Kissinger-Akahira-Sunose isoconversional method

Many studies are concerning with impact properties of composite materials because their large usage in aero-spatial, automotive, marine and sport industry. As the use of composites is continuously increasing the need for more valuable materials becomes essential in designing and producing such materials for a growing market. It is well known that thermoplastic matrix composites show better impact resistance than the thermoset matrix materials but their forming technology is more expensive. This study was designed to analyse the impact behaviour of fabric reinforced thermoset polymer matrix composites with an emphasis on structure of reinforcement. The matrix is an epoxy resin (Epiphen RE4020 – DE 4020, Bostik) while the used fabrics are of carbon fibres, aramid, fibres and glass fibres. Low velocity tests were performed on materials, according to ISO N-6603, and the results were inspected by tomography. Keywords: epoxy resin, fabrics, impact tests

Obstructive sleep apnoea (OSA) is the most common sleep-related breathing disorder that is increasingly recognized as a serious public health issue. The treatment management is determined by the severity of the syndrome. Oral appliances (OAs) are increasingly advocated as a treatment option for mild/moderate obstructive sleep apnoea (OSA). The aim of this paper was to present the two main treatment solutions for OSAS through custom oral appliances made in dental laboratory and to systematically review the available studies in the literature on the efficacy of OAs. Keywords: Obstructive sleep apnea, Oral Appliances, Heat-curing Acrylic resins, Mandible advancement device, Thermoforming method

The aim of the current study was to obtain materials presenting a large scale of applications (polyurethane adhesives and foams) through a one-pot synthesis starting from post-consumer poly(ethylene terephthalate) (PET) bottles. The PET depolymerization was carried out using diethylene glycol (DEG) and catalyst (zinc acetate) in a microwave reactor. Using the obtained depolymerization mixture, different polyurethane adhesives or foams formulations were developed. The adhesives mechanical properties were tested affording samples with tensile shear resistance suitable for commercialization. The polyurethane foams testing confirmed the obtaining of rigid structure with good thermal insulation properties. Keywords: PET, microwaves, adhesives, polyurethane foams, one-pot synthesis

Crown preparation and wax pattern technique are two key factors for the success of a cemented restoration. A poor marginal fit is the main cause of plaque penetration and leakage of oral liquids enhancing thus caries and periodontal disease [1, 2] The present study compares the marginal fit of full metallic crowns restoring caries free extracted molars using different types of marginal preparation as well as different wax-up techniques. The marginal gap was analyzed using scanning technique with an electronic microscope before and after in vitro cementation in several points for every surface of each tooth. Data were statistically analyzed and compared. The scanning technique enhances measurements of the marginal gap without sectioning and provides an objective evaluation of preparation and cementation techniques. Keywords: scanning electron microscopy, marginal gap, crowns, wax pattern techniques, marginal preparation techniques

The fabrication of adsorbent textile fiber materials is of great scientific and industrial interests. In this work a new procedure for fabrication of an anionic compounds adsorbent based on polypropylene nonwoven has been described. Because of using atmospheric pressure plasma as a surface specific pretreatment, the described procedure can be considered as a convenient method without affecting the bulk properties of the fibers. Atmospheric pressure air plasma was used to produce peroxide groups on the surface of polypropylene fibers. Grafting of acrylic acid (AA) was followed to create carboxyl groups on the fibers surfaces and finally the grafted polypropylene fiber samples were aminated using diethylene triamine (DETA) to convert carboxyl groups to amine groups. The effects of various experimental conditions: such as the time for plasma treatment, monomer concentration, temperature and reaction time were investigated. The surface morphology of the fibers was evaluated by SEM. To determine the nitrate and phosphate adsorption on the modified fibers, UV-VIS spectrophotometer was used. Fiber samples modified under optimized conditions showed a high ability to adsorb nitrate and phosphate ions from aqueous media. Keywords: polypropylene, Ion adsorption, Plasma treatment, nitrate, phosphate, acrylic acid