Browse Articles

In the light of multiple research on dental erosion, by using the spectrophotometry absorption method, we have conducted a in vitro study with the aim to highlight the erosive effect of chlorinated pool water, as well as the protective role of a lacquer and of two different toothpastes with remineralizant effect. Followed targets: the erosive capacity evaluation of three chlorinated waters used for swimming pools, the quantitative determination of the calcium and phosphates concentration absorbed by these waters, the quantitative determination of the remineralization and protection capacity of some dental materials on the enamel exposed to the action of chlorinated waters. After exposing the enamel to the action of these waters, we determined that the swimming pool waters improperly chlorinated represent a risk factor for the performant and casual swimmers. These waters have the capacity to demineralize the dental enamel in vitro, the severity of the demineralization being influenced by the pH and the capacity of extracting different quantities of calcium and phosphates. The three materials used for protection are able to remineralize the dental enamel, the best effect being given by the application of fluorinated lacquers. Optimal maintenance strategies of the swimming pools and specific prophylactic methods for the performant swimmers are necessary.

Genu valgum or valgus knee is a disorder caused by the knee deviation in the frontal plane, when the external angle formed between the thigh and calf is less than 170 degrees. The incidence of this disorder is unknown; it can occur sporadically or inside the family and it is one of the most common causes of joint pain. This study describes the properties and the application of a commercial material, AliPlast™ 10, in the case of a 13-year-old patient which presents bilaterally genu valgum deviations. Important improvement in gait and posture were obtained after a 6 months treatment, in which the patient has used the orthoses, combined with physical therapy.

The superstructure of dental implants represents the portion that is attached to the implant substructure, by a fixed or movable prosthetic restoration, realized in order to restore the disturbed functions oro-facial system. Recently, a new high performance polymer, BioHPP, based on polyether-ether-ketone (PEEK) polymer was introduced as dental material for manufacturing the superstructure dentures on dental implants. The purpose of this article is to present the results of the clinical trials referring to the advantages of BioHPP polymer as superstructure in oral implantology. The research has been carried out on 35 patients. The recordings of the advantages in the using this polymer for superstructure on dental implants, in accordance with six evaluation criteria, were performed in three dental schools from Romania, monthly, during one year. The results of survey demonstrate that BioHPP polymer as superstructure on dental implants present many advantages, therefore this PEEK type of dental material represents a beneficial new acquisition for patients’ oral health.

This study reports the preparation of gelatin – poly(vinyl alcohol) / graphene oxide composites by combining ultrasound treatment, freeze-thawing and freeze drying techniques. Characterization results highlight the positive effect of graphene oxide on materials structure, morphology, swelling degree and biodegradation, as well as rheology.

This paper deals with an input oriented method called Ecological Rucksack applied on two materials –corn starch polylactic acid (PLA) granules (bottle grade) and polyethylene terephthalate (PET) granules (bottle grade). We calculated the total mass of material inputs of PLA (from the cradle to the point of sale) and made comparative analysis with PET. Case study results indicate that Ecological Rucksack of PET granules (bottle grade) in terms of its abiotic material and biotic material requirement is about 44% lower than the Ecological Rucksack of corn starch PLA granules (bottle grade).However, PLA has significantly lower water requirement compared to PET. The study has highlighted some limitations of the Ecological Rucksack method arising from the limited data availability and uncertainties associated with its application.

The column type reactors play a particularly important role in the chemical industry and technology, because they are successfully used in most of the industrial processes. The inner stirring may be achieved by different mechanical means or by bubbling a gas. This study presents some aspects regarding the heat transfer for a process performed in an experimental bubble gas column reactor. The process in a bubble column reactor was performed at different conditions regarding: temperature, pressure of the inlet gas, nozzle diameters for the inlet gas, packing material inside the reactor; choosing in the end the most convenient conditions for the process energetic consumption efficiency.

The aim of this study was to obtain an edible film polymer matrix naturally extracted from tubers of Helianthus tuberosus L and biologically active components extracted from the roasted seeds of Vitis vinifera, in order to protect the active components from oxidation reactions during food conservation. The film was prepared by filling technique. It was evaluated the antioxidant activity of the film by means of DPPH (98.7%) technique, solubility water solubility (20.4%) and Isothermal sorption of water by GAB (Guggenheim, Anderson, de Boer) technique resulting a value of water activity of 0.167 and a value monolayer of 0.026 g water/g film. Through these values the resulting film ensure a sound management of the evolution of biological systems from the point of view of their complexity, especially food whose degradation can impact on their safety.

The main goal of this study was to modify halloysite with polyethylene glycol methacrylate and polyethylene glycol dimethacrylate in order to realize some pH sensitive controlled drug delivery systems. The obtained samples were characterized by spectral techniques (FTIR, XPS) and thermal techniques (TGA, DSC). There was also studied the influence of clay type and initial clay amount onto the drug adsorption process within halloysite. The hydrocortisone release profile was also investigated in simulated gastric fluid and simulated intestinal fluid.

At global scale, the trend of developing new thermoresistant polymeric structures, obtained from a mixture of dynamically cured elastomer/plastomer, and compatibility and curing agents, broadens their area of application and leads to greening of their processing technology and qualitative performance. Through dynamic curing and compatibilization, the elastomeric particles disperse more readily in the mixture thus making it possible to develop new innovative materials and techniques. Polymer structures were obtained by extrusion granulation technology, tested physico-mechanically (hardness, elasticity, tensile strength) according to current standards and morphologically by electron microscopy (SEM).

The aim of this work is to examine the role of alloying elements (Cu, Mg, Zn) in the complex reactions occurring in the heterogeneous system Al-Cu-Mg-Zn/K2TiF6/KBF4 at high temperatures. The paper presents theoretical and experimental studies to obtain aluminothermic reactions of composite AA7xxx/TiB2, putting into evidence the thermodynamic calculations and X-ray diffraction resulting compounds.