All social and economic systems worldwide, including the educational one have been disrupted by escalating the global COVID-19 pandemic. One of the most impacted areas were the medical and dental education fields, due to the forced break from clinical practice during the lockdown, which affected both the educational part, as well as the patients. Thus, the main goal of our research was to investigate the impact of the COVID-19 pandemic on the dental students’ education as related to their perceptions and evaluations, in Carol Davila University of Medicine and Pharmacy, Bucharest, Romania. A cross-sectional study was conducted on 878 dental students who reported their perception of the psychological and educational impact of this period by completing a Google Forms questionnaire. Collected data were statistically analyzed using Stata/IC 16. There was a severe psychological impact among the respondents, the levels of stress being perceived as high and very high (33.83%, n = 297; 28.59%, n = 251), similar to high and very high anxiety feelings (26.54%, n = 233; 24.26%, n = 213). Very high educational impact from the point of view of the acquisition of practical skills (48.52%, n = 426) and future professional perspectives (38.95%, n = 342) were recorded. While online theoretical learning ability was principally low (37.93%, n = 333) despite consistently modified time allocated to the individual study (44.35%, n = 389), most of the students evaluated the efficiency of lecturers in online courses as neutral (41.12%, n = 361). New dentistry teaching programs will have to be adopted taking into account the dynamics of the pandemic and its strong impact on our students, in order to improve both their wellbeing and the sustainability of dental education.

The influence of complex thermo-mechanical processing (TMP) on the mechanical properties of a Ti-Nb-Zr-Fe-O bio-alloy was investigated in this study. The proposed TMP program involves a schema featuring a series of severe plastic deformation (SPD) and solution treatment (STs). The purpose of this study was to find the proper parameter combination for the applied TMP and thus enhance the mechanical strength and diminish the Young’s modulus. The proposed chemical composition of the studied β-type Ti-alloy was conceived from already-appreciated Ti-Nb-Ta-Zr alloys with high β-stability by replacing the expensive Ta with more accessible Fe and O. These chemical additions are expected to better enhance β-stability and thus avoid the generation of ω, α’, and α” during complex TMP, as well as allow for the processing of a single bcc β-phase with significant grain diminution, increased mechanical strength, and a low elasticity value/Young’s modulus. The proposed TMP program considers two research directions of TMP experiments. For comparisons using structural and mechanical perspectives, the two categories of the experimental samples were analyzed using SEM microscopy and a series of tensile tests. The comparison also included some already published results for similar alloys. The analysis revealed the advantages and disadvantages for all compared categories, with the conclusions highlighting that the studied alloys are suitable for expanding the database of possible β-Ti bio-alloys that could be used depending on the specific requirements of different biomedical implant applications.

One of the most important requirements for a metallic biomaterial is the mechanical biocompatibility, which means excellent mechanical properties—high strength and fatigue strength, but low elastic modulus, to be mechanically harmonized with hard tissues. In order to improve the mechanical and biocompatible performance of the Ti-25.5Nb-4.5Ta-8.0Zr wt% alloy, the influence of cold plastic deformation and solution treatment on its properties were investigated. The Ti-25.5Nb-4.5Ta-8.0Zr wt% alloy was fabricated by melting in a cold crucible furnace (in levitation) and then subjected to several treatment schemes, which include cold rolling and different solution treatments. Microstructural and mechanical characteristics of specimens in as-cast and thermo-mechanically processed condition were determined by SEM microscopy and tensile testing, for different structural states: initial as-cast/as-received, cold rolled and solution treated at different temperatures (800, 900, and 1000 °C) and durations (5, 10, 15, and 20 min), with water quenching. It was concluded that both cold rolling and solution treatment have important positive effects on structural and mechanical properties of the biomaterial, increasing mechanical strength and decreasing the elastic modulus. Samples in different structural states were also corrosion tested and the results provided important information on determining the optimal processing scheme to obtain a high-performance biomaterial. The final processing route chosen consists of a cold rolling deformation with a total deformation degree of 60%, followed by a solution heat treatment at 900 °C with maintenance duration of 5 min and water quenching. By applying this thermo-mechanical processing scheme, the Ti-25.5Nb-4.5Ta-8.0Zr wt% alloy showed an elastic modulus of 56 GPa (5% higher than in the as-cast state), an ultimate tensile strength of 1004 MPa (41.8% higher than in the as-cast state), a yield strength of 718 MPa (40.6% higher than in the as-cast state), and increased corrosion resistance (the corrosion rate decreased by 50% compared to the as-cast state).

It is generally accepted that severe plastic deformation (SPD) has the ability to produce ultrafinegrained (UFG) and nanocrystalline materials in bulk. Recent developments in high pressure torsion (HPT) processes have led to the production of bimetallic composites using copper, aluminum or magnesium alloys. This article outlines a new approach to fabricate multilayered Ni-Ti nanocomposites by a patented SPD technique, namely, high speed high pressure torsion (HSHPT). The multilayered composite discs consist of Ni-Ti alloys of different composition: a shape memory alloy (SMA) Ti-rich, whose Mf > RT, and an SMA Ni-rich, whose Af < RT. The composites were designed to have 2 to 32 layers of both alloys. The layers were arranged in different sequences to improve the shape recovery on both heating and cooling of nickel-titanium alloys. The manufacturing process of Ni-Ti multilayers is explained in this work. The evolution of the microstructure was traced using optical, scanning electron and transmission electron microscopes. The effectiveness of the bonding of the multilayered composites was investigated. The shape memory characteristics and the martensitic transition of the nickel-titanium nanocomposites were studied by differential scanning calorimetry (DSC). This method opens up new possibilities for designing various layered metal-matrix composites achieving the best combination of shape memory, deformability and tensile strength.

Dental pulp vitality preservation in dental caries treatment is a major goal in odontotherapy. The main objective of this study was to compare dental pulp tissue responses to vital therapies in deep carious lesions, using different calcium-based materials. An ambispective study was conducted on 47 patients. Ninety-five teeth with deep carious lesions were treated. Among them, 25 (26.32%) were diagnosed with pulpal exposures and treated by direct pulp capping. Indirect pulp capping was applied when pulp exposure was absent (n = 70; 73.68%). Fifty teeth (52.63%) were treated with TheraCal LC (prospective study), 31 teeth (32.63%) with Calcimol LC, and 14 teeth (14.74%) with Life Kerr AC (retrospective study). The results show that the survival rate for dental pulp was 100% for Life Kerr AC, 92% for TheraCal LC, and 83.87% for Calcimol LC, without significant differences. Apparently, self-setting calcium hydroxide material provided better dental pulp response than the two light-cured materials, regardless of their composition, that is, either calcium -hydroxide or calcium silicate-based. We will need a significant number of long-term clinical studies with the highest levels of evidence to determine the most adequate biomaterials for vital pulp therapies.