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Objectives: The purpose of this study is to evaluate the remineralization potential of primary teeth enamel after being exposed to different laser diode therapies. Methods: Ninety-six vestibular primary teeth enamel samples were divided into eight groups (n = 12) with varying treatments: control (G1), CPP-ACP-fluoride varnish (G2), diode lasers at 980 nm (G3), 808 nm (G4), 450 nm (G5), 980 nm + CPP-ACP-fluoride varnish (G6), 808 nm + CPP-ACP-fluoride varnish (G7), and 450 nm + CPP-ACP-fluoride varnish (G8). Each sample was assessed using a DIAGNOdent® (KaVo Dental, Biberach, Germany), at baseline, post-treatment, and post-pH cycle remineralization. SEM imaging was performed before and after treatment and following the pH cycle. Results: The results indicated that the 980 nm and 808 nm diode lasers, both alone and in combination with CPP-ACP-fluoride varnish, either maintained or increased the calcium (Ca) weight percentage (Wt%) in the enamel. The 980 nm diode laser combined with CPP-ACP-fluoride varnish (G6) showed a significant increase in Ca Wt%, suggesting a strong remineralization effect. Similarly, the 808 nm diode laser alone (G4) also promoted a substantial increase in Ca Wt%. In contrast, the 450 nm diode laser, whether applied alone or in combination with CPP-ACP-fluoride varnish, resulted in a lower Ca Wt% and an increase in phosphorus (P) Wt%. Most groups, except for the CPP-ACP-fluoride varnish alone (G2), demonstrated an increase in P Wt%, indicating a complex interaction between laser therapy and enamel remineralization. Conclusions: The combined use of laser therapy with CPP-ACP-fluoride varnish significantly enhanced the remineralization of temporary teeth enamel. The 980 nm diode laser + CPP-ACP-fluoride varnish showed the most pronounced improvement in remineralization, while the 808 nm diode laser alone also effectively increased calcium solubility. These findings suggest that higher-wavelength diode lasers, particularly when combined with remineralizing agents, can effectively enhance the mineral content of primary teeth and promote enamel remineralization. [ABSTRACT FROM AUTHOR]

This article presents a study on the influence of the intensity of the welding current on the properties of the mechanical strain strength of welded joints made by using submerged arc welding technology. The influence of the welding current on the microstructure of the welded joints was also observed in different regions of the cross-section of the welding seam. Also subject to observation was the mode of influence of the welding current on the geometry and dimensions of the welding seams. The welded samples were obtained using five different welding regimes whose main variable was the intensity of the welding current, which had values between 300 A and 700 A. The criterion used as a reference for comparing the effects produced by the studied welding regimes was a standard welding regime that is used in the industry for welding railway tank wagons, with a welding current intensity of 480 A. The base material used in the experiments was a fine-grained carbon steel specially intended for the manufacture of pressure vessels identified as P355 N; the semi-finished product from which the samples were made consisted of 6 mm thick laminated sheets used in the manufacture of the covers of the vessels that make up the railway tank wagon. The aim of this study was to highlight the differences that may appear through varying the current welding parameter and identify welding regimes that can provide welded joints with superior mechanical properties compared to what is currently employed in the industry. This study focused on the most widespread technology of welding pressure vessels: the submerged electric arc welding method. [ABSTRACT FROM AUTHOR]

Ti alloys have been widely used in biomedical applications due to their special properties. They have specific properties such as biocompatibility, biofunctionality and high corrosion resistance, which enable them to function inside the human body. Among them, Ti-6Al-4V is probably one of the most widely used alloys for implants. However, aluminum and vanadium ions have been reported to cause problems and adverse reactions in the human body over long periods. Thus, in the present study, Ti–15Zr–10Nb alloy synthesized by high vacuum melting was manufactured and characterized by different techniques. The phase composition was determined by XRD. This showed the presence of α and β phases in the alloy, consistent with the microstructural study. From a microstructural point of view, the alloy shows lamellar and acicular structures with α-grain boundaries. Vickers microhardness measurements showed an increased hardness compared to Ti-CP. Furthermore, the electrochemical behavior was evaluated using HCl as an electrolyte. The obtained results were compared to Ti-CP tested in the same electrochemical condition. The studies indicated that Ti-CP presents a nobler electrochemical behavior than Ti-15Zr-5Nb. Thus, despite the very good corrosion properties of Ti-15Zr-5Nb in a simulated oral environment and Ringer's solutions, the present study reveals that the Ti-15Zr-5Nb alloy has lower corrosion resistance in aggressive media when compared to Ti-CP. [ABSTRACT FROM AUTHOR]

This study focuses on the growth of Cu2O/CuO nanowires by one-step thermal oxidation using a flexible copper mesh at oxidation temperatures in the range of 300 to 600 °C in a controlled atmosphere of mixed-flow Ar and O2 gases. Thermal oxidation is one of the simplest used methods to obtain nanowires on a metal surface, offering advantages such as low production costs and the ability to produce metal oxides on a large scale without the use of hazardous chemical compounds. The growth of metal oxides on a conductive substrate, forming metal/oxide structures, has proven to be an effective method for enhancing charge-transfer efficiency. The as-synthesized Cu/Cu2O/CuO (Nw) electrodes were structurally and morphologically characterized using techniques such as XRD and SEM/EDX analysis to investigate the structure modification and morphologies of the materials. The supercapacitor properties of the as-developed Cu/Cu2O/CuO (Nw) electrodes were then examined using cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) measurements, and electrochemical impedance spectroscopy (EIS). The CV curves show that the Cu/Cu2O/CuO (Nw) structure acts as a positive electrode, and, at a scan rate of 5 mV s −1, the highest capacitance values reached 26.158 mF cm−2 for the electrode oxidized at a temperature of 300 °C. The assessment of the flexibility of the electrodes was performed at various bending angles, including 0°, 45°, 90°, 135°, and 180°. The GCD analysis revealed a maximum specific capacitance of 21.198 mF cm−2 at a low power density of 0.5 mA cm−2 for the oxidation temperature of 300 °C. The cycle life assessment of the all of the as-obtained Cu/Cu2O/CuO (Nw) electrodes over 500 cycles was performed by GCD analysis, which confirmed their electrochemical stability. [ABSTRACT FROM AUTHOR]

Carbon aerogels represent a distinctive category of high surface area materials derived from sol-gel chemistry. Functionalizing these aerogels has led to the development of composite aerogels with the potential for a wider range of applications. In this study, the technique of lyophilization was employed to fabricate aerogel composites consisting of inorganic salts and cellulosic fibers. Cellulose carbonization can occur through chemical dehydration by heat treatment in an inert atmosphere. X-ray diffraction analysis spectra and scanning electron microscopy images indicate that the formed polymeric composites contain partially carbonized cellulose fibers, amorphous carbon, and calcium carbonates. CaCO3 primarily forms through the reaction of CaCl2, which moistens cellulose or amorphous carbon fibers with CO2 in ammonia fumes. The water loss in 3D structures was analyzed using thermogravimetric analysis, Fourier Transform Infrared Spectroscopy, and ultraviolet-visible-near-infrared spectroscopy. Depending on the synthesis method, 3D structures can be created from partially or completely dehydrated cellulose fibers. The aerogels were examined for their ability to support the growth of bacterial biofilm and then adorned with metal silver and AgCl to produce bactericidal products. Due to their open pores and CaCO3 content, these aerogels can serve as durable and environmentally friendly thermal insulators with bactericidal properties, as well as a medium for absorbing acidic gases. [ABSTRACT FROM AUTHOR]

Brazing is a joining process that involves melting a filler metal and flowing it into the joint between two closely fitting parts. While brazing is primarily used for joining metals, it can also be adapted for certain coating deposition applications. The present study investigates the microstructure and corrosion behavior and sliding wear resistance of WC (Tungsten Carbide)-CoCr-Ni reinforced Co-based composite coatings deposited onto the surface of AISI 904L stainless steel using a vacuum brazing method. The primary objective of this experimental work was to evaluate the influence of WC-based particles added to the microstructure and the properties of the brazed Co composite coating. The focus was on enhancing the sliding wear resistance of the coatings while ensuring that their corrosion resistance in chloride media was not adversely affected. The morphology and microstructure of the composite coatings were investigated using scanning electron microscopy (SEM) and phase identification by X-ray diffraction (XRD). The SEM analysis revealed in the coating the presence of intermetallic compounds and carbides, which increase the hardness of the material. The sliding wear resistance was assessed using the pin-on-disk method, and the corrosion properties were determined using electrochemical measurements. The results obtained showed that as the WC particle ratio in the Co-based composite coating increased, the mechanical properties improved, the alloy became harder, and the tribological properties were improved. The evaluation of the electrochemical tests revealed no significant alterations of the manufactured composite in comparison with the Co-based alloys. In all cases, the corrosion behavior was better compared with that of the stainless-steel substrate. [ABSTRACT FROM AUTHOR]

All-ceramic restorations are the foundation of modern esthetic dentistry. Clinical approaches for preparation, durability, aesthetics, and repair have been reformed by the idea of adhesive dentistry. The aim of the study and the objective question was to evaluate the impact of heated hydrofluoric acid pretreatment and the application technique's influence on the surface morphology and roughness of leucite-reinforced glass–ceramic materials (IPS Empress CAD, Ivoclar Vivadent), which is fundamental for understanding the adhesive cementation process. Scanning electron microscopy was used to observe the effectiveness of the two HF (Yellow Porcelain Etch, Cerkamed) application techniques and the HF's temperature impact on the surface topography of the ceramic. Based on surface conditioning methods, the adhesive cement (Panavia V5, Kuraray Noritake Dental Inc., Tokyo, Japan) was applied to the conditioned ceramic samples and light-cured. Shear bond strength values were correlated with the micro-retentive surface texture of the ceramic. With universal testing equipment at a 0.5 mm/min crosshead speed, SBS values between the resin cement and the ceramic material were assessed until failure. Analyzing the fractured surfaces of the specimens by digital microscopy, the failure modes were divided into three categories: adhesive, cohesive, and mixed failure. Analysis of variance (ANOVA) was used to statistically analyze the collected data. The results show that alternative treatment methods affected the material's surface characteristics and have an influence on the shear bond strength. [ABSTRACT FROM AUTHOR]