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In this study, a TiNbCrTa refractory complex concentrated alloy (RCCA) was prepared using vacuum arc remelting. The microstructural evolution and mechanical properties of both as-cast and heat-treated RCCA samples were analyzed. Heat treatment (HT) was performed at 800–1200 °C for 1 h in a vacuum-sealed environment. These samples exhibited a formation of Cr2Nb and Cr2Ti Laves phases. A variation in elemental distribution was observed, with interdendritic (ID) regions showing higher fractions of Ti and Cr, while the dendritic regions had a greater concentration of Ta and Nb. Micro-segregation at the IDs was confirmed through energy dispersive x-ray spectroscopy mapping, which inferred the formation of Cr- and Ti-rich phases during HT at 800–1200 °C. High-temperature HT at 1200 °C for 1 h led to the evolution of the hcp omega phase. Prolonged HT at 1200 °C for 96 h resulted in the evolution of a Cr-rich Laves phase (Cr2Ta), which was homogeneously distributed within the microstructure, indicating an unstable microstructure. Furthermore, despite prolonged HT, a variation in the elemental distribution persisted due to the presence of dendritic and ID regions. Electron backscattered diffraction analysis revealed the presence of bcc and hcp phases in the dendritic and ID regions, respectively, of the as-cast and HTed samples. The as-cast samples demonstrated a high compressive strength of approximately 2 GPa. Micro-hardness values increased with the HT temperature up to 1000 °C. Further increases under HT conditions did not significantly reduce the microhardness value, whereas prolonged HT at 1200 °C led to an increase in the microhardness value. Overall, the newly developed TiNbCrTa RCCA exhibited high-strength behavior even after the phase transformation. [ABSTRACT FROM AUTHOR]

Aim: The study investigated and compared the antimicrobial efficacy of 5%Doxycycline, 5%Tetracycline, 5%Metronidazole and 2.5%NaOCl used alone or in combinations against E.faecalis. Material & Methods: The testorganismE.faecalis was streaked on agar plates.A total of 140 wells, 20 for each group were made in 50 plates.5gms of each powder was mixed with 100ml of ionized water. This 50ìl of the test irrigant solution were pipetted into each well and placed in a CO2incubator at 37°C for 48 hours. The seven groups were are as follows: Group A:2.5%NaOCl,Group B: 5%Tetracycline, Group C: 5%Metronidazole, Group D: 5%Doxycycline, Group E: 5%Doxycycline+2.5%NaOCl, Group F: 5%Tetracycline+2.5%NaOCl, Group G: 5%Metronidazole+2.5%NaOCl. The zones of inhibition were measured using a mm scale. Agar diffusion test was done to evaluate the antimicrobial efficacy of the various intracanal irrigantsand the results was statistically analyzed using ANOVA and Post hoc Tukey's test. Results: Group E showed highly significant differences amongst all the groups and GroupCand GroupAshowed non-significant differences amongst all. Conclusion:Combination of 5%Doxycycline and 2.5%NaOCl is more effective irrigant amongst all the experimental groups againstE.faecalis while Metronidazole and NaOClshows least antimicrobial effect against E.faecalis. [ABSTRACT FROM AUTHOR]

Introduction:-The study investigated and compared the root reinforcement potential of dual cure cement (Luxacore Z - Dual Automix, DMG], light cure glass ionomer cement (GC Light cure GIC), and nano hybrid flowable composite (Tetric-N-Flow, IvoclarVivadent) placed over root canals obturated with gutta-percha and AH plus sealer as intra-orifice barriers. Materials and methods:-Fourty freshly extracted mandibular premolars were instrumented and obturated with corresponding guttapercha cones and AH plus sealer. Except for control group, the coronal 3 mm of root fillings of all other group specimens were removed and randomly divided into 4 groups of 10 specimens each. They were control group (no barrier), dual cure cement, light cure glass ionomercement andnano hybrid flowable composite. After 8 hours, all the groups were subjected to fracture resistance testing by using Universal testing machine. Results:-The fracture resistance testing results obtained showed the following pattern - dual cure cement > light cure glass ionomer cement >nano hybrid flowable composite > Control group. Conclusion:-The placement of an intra-orifice barrier can be regarded as beneficial for the reinforcement of an endodontically treated teeth. [ABSTRACT FROM AUTHOR]