Post and core build-ups provide resilience and retention for future tooth restorations. In this study we intend to assess the resistance to fracture of two types of aesthetic post, using a testing machine after the application of a paraxial force. The results show that no specific material from the ones used shows a better behavior. Fiber quartz posts AAA Fiber Post had the highest resistance and the fiberglass posts Matrix Plus 2 were rated with the lowest values. Further laboratory and clinical studies are necessary to the in which one type of post material is favorable for a specific type case.
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The Gold standard in parietal wall hernias is represented by mesh implantation. Both wall repair and hernia-associated complications are related to the anatomic location and biomechanics of the structures involved specificity. This work reports the results of the intraoperative and postoperative evaluation of synthetic polypropylene mesh integration. The mesh and the surrounding tissue, previously removed and preserved, have been analyzed macroscopically and at microscopic level. The tissue invaded the pores of the mesh and coated the monofilaments. The right balance between the mesh type and tissular response is hard to evaluate preoperatively, due to individual variations, but we can upgrade the criteria used to personalize the treatment for the best possible outcome.
The article presents the procurance of an apparatus intended for the stage of reading and writing , used both by the pre- school children and the persons who present speaking deficiencies ,obtained from plastic parts marked and processed using a laser equipment. The learning equipment of writing and reading consists in a carcass of a triangular prism which has on a lateral side two visualization windows and a magnetic plate for writing, placed one below the other, at an appropriate distance, each visualization window being equipped with several illumination sources, disposed in a lineal way along the window, having an independent performance.
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.