Browse Articles

Marginal adaptation at composite enamel interface was assessed through direct clinical method, three-dimensional scanning and optical microscopy respectively for three composite materials with Nano filler: Tetric EvoCeram® (Ivoclar Vivadent-), Premise™ (Kerr Corp.) and experimental material C20 (“Raluca Ripan” Chemistry Research Institute, Cluj-Napoca). Clinical evaluation of marginal adaptation highlights at 6 months and at 12 months a rate of 25-40% marginal defects, regardless the Nano composite material used. Characterisation of interface between Nano-composite material and dental tissue requires a complex multifactorial assessment.

Modified cement composites were prepared by dispersing commercially available PMMA powders and chitosan/ tricalcium phosphate (TCP) or chitosan / hydroxyapatite (HA) fillers into a PMMA matrix. SEM and EDX were used to determine the compounds and the morphology of the composite. The characteristics of these materials indicate that the addition of chitosan/TCP and chitosan /HA as a constituent into the PMMA cement significantly decreases the curing peak temperature. Furthermore, the setting time increases from 4 min to 7 min, as compared to the PMMA cement. These changes could be beneficial for the handling of the bone cement paste and causing less damage to the surrounding tissues.

The paper aims to find solutions to some of the problems the staff operating the natural gas networks have to face, which are the low, medium and high pressure, and the corrosion of the steel pipelines. This metal corrosion can be dealt with by insulating it through various procedures, the latest being the different thickness polyethylene strips insulation. The goal of the paper is to observe the insulation areas on the pipeline which can be destroyed by mechanical factors during operation and the method of remedying these faults with high density polyethylene strips.

Composite sandwich structures with Nomex honeycomb core are commonly used in industrial applications. This paper was focused on the study of the mechanical properties of sandwich structures with CFRP (carbon fibre reinforced polymer) skin and a phenolic resin-impregnated aramid paper core, known as Nomex. The paper analyzes behaviour and determines the mechanical properties of the CFRP-Nomex specimens to different types of tests, such as: three - point bending, compression, impact. The exceptional fatigue resistance of the composite structures is responsible for their success in a variety of industrial applications. For this reason, in this paper were implemented accelerated testing techniques for CFRP-Nomex sandwich structures, resulting in a significant reduction of the test time (of 13.9 times). The main indicator that was determined using the accelerated testing methodology was the mean life that has value of 268554 cycles.

The use of polylactic acid (PLA) for food packaging is limited because it has poor mechanical and thermal properties, low ductility, and its oxygen barrier property is quite poor compared with polymers obtained from petrochemical resources. One main task of processors is to modify these properties in such a way that PLA to be able to compete with conventional polymers such as polyethylene, polypropylene or poly(vinylchloride). Our studies were conducted to test the effect of different types of plasticizers on the PLA melt processing and also on its mechanical and thermal performance.

The present study evaluates the radiologic particularities of deformities in valgus that are necessary for a correct positioning in frontal and rotational plane of the prosthetic components and for a long term life of the polyethylene and the prosthetic implant. Long leg X-ray performed in orthostatism can evaluate the type and degree of the deformity in frontal plane, it can establish the osteotomy cuts and the necessity of ligament release. The anterior-posterior radiologic incidence of the knee in flexion of 900 evaluates the individual rotational profile by calculating the torsion of the distal femoral. Although the frequency of deformity in valgus is more reduced, it presents important clinical and radiologic particularities for the surgical technique.

The paper is focused on designing a novel silk fibroin-magnetite biomaterial scaffold for wounds healing in terms of: synthesis, physico-chemical and morphological characterization and in vitro biological behaviour assessment. Magnetic scaffolds were prepared from silk fibroin solutions and magnetic nanoparticles with various concentrations by solvent casting technique. Specimens were investigated by FTIR-ATR spectroscopy and XRD measurements. Morphological investigation including internal structure was employed by AFM and TEM/HRTEM analyses. Biological assay was performed on human adipose derived stem cells isolated from subcutaneous adipose tissue. Results suggested that all the tested magnetic silk-magnetite scaffolds display a good biocompatibility in vitro on hASCs and could be promising candidates for further wound dressing testing.

This paper aims to present the benefits and results of using TCA of high concentration of 50%, in conjunction with the presentation of adverse reactions and complications. The study was conducted in Arestetic Clinic Galai during the period 10 Dec. 2015-1 Nov. 2016, on a group of 12 patients, of which 10 women and 2 men. The product used was Easy TCA 50% manufactured by SkinTech laboratories. Three coats of TCA were applied at intervals of 4 minutes each. The end result was assessed at 21 days, when the entire surface of the skin was peeled and re-epithelized. Patients were asked to assess the degree of satisfaction on a scale of 1 to 10, with 1 being the least satisfactory and 10 being the most satisfactory. As a result of this assessment, 10 patients rated the degree of satisfaction with 10 (83%) and 2 patients rated the degree of satisfaction with 9 (17%), with an average degree of satisfaction of 9.83. At 21 days, dyschromias and hyperpigmentations completely disappeared in 9 patients, while a female patient and 2 male patients still presented with barely noticeable spots. These three persons were subjected to the second peeling after 2 months, this time in two layers, and these hyperpigmentations disappeared at the end.

The positive attributes of excellent biocompatibility and biodegradability of biocomposites with the addition of versatile nanocellulose from agriculture wastes have provided plenty opportunities for further development of functional biocomposite in various fields. Therefore, solvent casting was selected as a reinforcement method in order to produce biocomposite comprise of nanocrystalline cellulose and PLA polymer. Modification of nanocrystalline cellulose through acetylation reaction was conducted upon reinforcement to reduce its surface polarity and hidrophilicity. Biocomposite films prepared at various unmodified (uNC) and acetylated nanocrytalline cellulose (aNC) loading were exposed to morphological (FESEM), tensile test and thermal analysis (TGA). Reinforcement of aNC shows a better dispersion in PLA polymer due to the decreasing of surface polarity, thus increasing inter-facial interaction between both materials. This is proven by greater performance of biocomposite films in tensile strength, Young’s modulus and thermal stability of aNC reinforced PLA as compared to uNC reinforced PLA. Overall, it can be concluded that these research findings can widen the scope of biocomposites research area and have significant implications for the commercial application of biomass products.

Since the development of 3D printing, over the past decades, the domain of application has evolved significantly! Concerning the orthosis and prosthesis manufacturing, the 3D printing offers many possibilities for developing new medical devices for people with disabilities. Our paper wish to synthetize the main 3D printing methods and the biomaterial properties which can be used in orthosis and prosthesis manufacturing, like polylactic acid or acrylonitrile butadiene styrene. Fused Deposition Modeling and Stereo lithography are most used for medical devices manufacturing and usually using polylactic acid, considering the properties of this polymer and de organic componence.