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Modern coronary restorative materials have a vulnerable aspect, represented by the excessive wear, which determines the severe limitations of applications in the areas of the occlusal contact. In this study, the experimental researches on the abrasive wear behaviour were performed on five direct restorative dental materials belonging to some different classes from the structural point of view: compomer (Compoglass), ceramic (Empress), silver amalgam (Ventura Plus), poly-glass (Artglass), light-cured lining composite resin (Herculite 1). The analysis of the abrasive wear behaviour of direct restorative dental materials imposed their initial characterization from the microstructural point of view and according to the Vickers hardness. Experimental determinations pointed out absolute and relative mass loss, mass intensity and wear speed. The results of the study are useful in choosing a direct resistant and esthetical restoration material.

The aim of this study was to evaluate the potential of coloring of two commercial beverages: coffee and wine, and cigarette smoke, on three materials (ICON infiltration resin, MI Varnish Recaldent, and a sealant based on composite resin) currently used in incipient caries therapy. The study group included 75 extracted teeth that were divided into 3 groups corresponding to each material used. The groups were divided into 5 subgroups that corresponded to each colorant (A. red wine, B. coffee, C. cigarette smoke, D. association of the three colorants, E. control group). The coloration degree of the samples was measured both after the moment of coloring (M3) and after polishing (M4). The results showed a significant increase of the coloring degree for the samples subjected to the combined action of the three colorants (M3), for all the three materials used (DE1*: Id = 23.56, IId = 25.87, IIId = 19.87), and in terms of the coloring degree after the polishing procedure (M4), a decrease of the values was observed (DE2*: Id = 17.56, IId = 21.67, IIId = 16.78). In conclusion, both exposure to the two beverages used in the study and cigarette smoke (C) leads to the appearance of color changes, but the most significant changes were obtained by combining the three colorants (D). Also, the polishing procedure leaded to an improvement of the color variation for all three materials.

Since the discovery of exceptional properties of graphene, a lot of researchers focused on the discovery of another nobel two-dimensional (2D) materials. Recently, an elegant exfoliation approaches was proposed as a method to synthesis a new family of transitional 2D metal carbide or nitrades of MXene from a layered MAX phase. A layered MAX phase of Ti3AlC2 was synthesized through pressureless sintering (PLS) the initial powder of 3TiH2/1.1Al/2C without preliminary dehydrogenation under argon atmosphere at 1350 oC. An elegant exfoliation approach was used to eliminates Al from its precursor to form a layered-structure of Ti3C2. In this study, thermal conductivity of MAX phase and MXene were studied using absolute axial heat flow method to measure the abilities sample to conduct heat and the data was collected using Picolog 1216 Data Logger. Electrical conductivity of these two materials was also compared by using two-point probe, due to its simplicity. Radiation properties of 2D MXene Ti3C2 was studied by using an established radon monitor, placed in closed, fabricated container. Morphological and structural properties of this 2D material were also studied using an established FESEM and XRD apparatus. SEM images shows two types of morphology which is a layer of Ti3C2 and the agglomerates Al2O3 with graphite. XRD pattern reveals three phases in this material which is a rhombohedral Al2O3, rhombohedral graphite and rhombohedral Ti3C2 phases, respectively. Thermal and electrical conductivity of MXene were proven higher than MAX phase. Radon concentration for this material for five consecutive days explains the radiation level of this material which is under the suggestion value from US Environmental Protection Agency (EPA). From this finding, it is can conveniently say that the MXene material can be promising material for electronic application.

The current trend is the introduction of antimicrobial agents for the purpose of inhibiting or avoiding (adherence) adhesion and (increasing) the multiplication of their microorganisms on the surface of the impression materials. This study aims to determine the properties of antibacterial and antifungal elastic impression materials in full agreement with (bacterial flora) microflora specific for every patient ( with identification of existing species ). In the same time there are considered modern methods of sterilization and insertion of antiseptics, trajectories with profound impact in the field of biocompatibility. The obtained microorganisms were transplanted on differentiated and selective (differentiated) culture medium in order to obtain pure cultures.Each microbial strain obtained was tested to identify several characteristics. The examinations carried out by means of the electron microscopy very accurately detect the microbial load in the structure of the impression materials, sounding an alarm signal on its use in particular clinical situations. Alginates present in their structure polysaccharide structures that represent an excellent substrate of microorganisms.

The developement and regeneration of healthy bone tissue is a complex process that includes the interaction of different cell types and requires a set of coordinated processes. The loss of bone tissue may occur due to various reasons: surgical removal, bone trauma (i.e., fractures) or systemic bone loss (i.e., osteoporosis). When the natural bone tissue is destroyed, the regeneration capacity of the bone is not always satisfactory. The result consists therefore in many functional and structural aberrations. In order to improve and accelerate the healing process, bone substitutes have been developed. Hydroxyapatite has been widely used in bone applications due to its excellent biocompatibility, osteoconductivity and bioactivity [1,2]. The objective of this research is to obtain a new composite biomaterial that can be used as bone substitute. In this study, bovine hydroxyapatite obtained from freshly calcined bovine femur was used. The objective of this research is to obtain a new composite biomaterial that can be used as bone substitute. The experimental composite samples were obtained using bovine hydroxyapatite as matrix and tricalcium phosphate, respectively, magnesium oxide as reinforcement materials. The synthesis process of these new biomaterial composites, the effect of chemical composition, surface structure, chemical and phase composition as well as mechanical features have been investigated.

The current study relates to the immobilization of the nasal region with splints using modern materials such as thermoplastic compounds in patients that have undergone rhinoplasty. The objectives of the research are to highlight the main characteristics of thermoplastic splints and to perform a comparative analysis in relation with traditional splints. The research was conducted on 2 batches, the first batch involving 24 patients that have undergone rhinoplasty, the postoperative immobilization being performed using metallic splints and the second batch involving 29 patients, thermoplastic splints being used for immobilization after the surgery. The results of the study are focused on evaluating both thermoplastic and traditional splints based on several criteria, such as modeling capacity, toxicity, surgical risks and patients’ degree of satisfaction.

Zinc oxide (ZnO) is an inorganic compound used for its antiseptic and skin healing properties. It is an excellent protective filter against UV radiation and it can be used as white pigment in pharmaceutical preparations. In this study, nano-ZnO particles were obtained by ultrasound treatment, and respectively by repeated freezing/heating process. The influence of synthesis method and of ultrasound generator parameters on the particles size and stability was observed. The results reveal that were obtained samples with a very good stability and sizes between 15 and 96 nm. It was found that synthesis based on ultrasound treatment lead to the formation of nanoparticles with lower sizes.

With technology becoming more and more advanced, the medical system is being consistently improved. From intraoral scanners that started to replace conventionally impressions technique to printed surgical guides that directs the drilling systems of implants, dentistry is one of the beneficiars of new and advanced treatments that are ergonomic, safe and put both the medical team and the patient in a more pleasant experience. The purpose of our article is to summarize the application of acrylic and metacrylic resin in 3D printing of surgical guides used in orthodontics.

Thermoplastic polymers have found widespread applicability in electronic industry owing to their facile processing and relatively low costs. Transparent polymer foils, like polyethylene terephthalate (PET), can be utilized in manufacturing components for liquid crystal display (LCD) devices. This work is focused on surface processing of PET through different procedures. The induced surface modifications of polymer samples were analyzed by optical microscopy. Contact angles of nematic drops on PET film are measured to evaluate how the method of surface modification reveals that the surface texturing affects the interactions of polymer with the liquid crystal. The influence of created surface anisotropy on the work of adhesion at polymer/liquid crystal interface is analyzed. Preliminary assessment of nematic orientation on the surface of modified PET foils is performed using polarized light. The results were discussed in regard with the used methodology to adapt the surface of the PET films to achieve optimal orientation of nematic molecules. The obtained data will open new perspectives on processing polymer foils as alignment layers used in LCD devices.

Abstract.The paper aims to present research on the determination of the coefficient of acoustic absorption as a function of frequency, for composite monolayer plates (made of: MDF - wooden dried agglomerated fibres with medium density, RWB – rebated wood from dried beech, PS - extruded polystyrene) and multilayer (with outer coatings of: MDF, RWB and polymeric core of extruded polystyrene). The sound-absorbing behavior of such plates is highlighted in the cabins made of multilayer structures.