RESUMEN
In our previous work, TaF5 and VCl3 were added to Mg, leading to the preparation of samples with good hydriding and dehydriding properties. In this work, Ni was added together with TaF5 and VCl3 to increase the reaction rates with hydrogen and the hydrogen-storage capacity of Mg. The addition of Ni together with TaF5 and VCl3 improved the hydriding and dehydriding properties of the TaF5 and VCl3-added Mg. MgH2 was also added with Ni, TaF5, and VCl3 and Mg-x wt% MgH2-1.25 wt% Ni-1.25 wt% TaF5-1.25 wt% VCl3 (x = 0, 1, 5, and 10) were prepared by reactive mechanical milling. The addition of MgH2 decreased the particle size, lowered the temperature at which hydrogen begins to release rapidly, and increased the hydriding and dehydriding rates for the first 5 min. Adding 1 and 5 wt% MgH2 increased the quantity of hydrogen absorbed for 60 min, Ha (60 min), and the quantity of hydrogen released for 60 min, Hd (60 min). The addition of MgH2 improved the hydriding-dehydriding cycling performance. Among the samples, the sample with x = 5 had the highest hydriding and dehydriding rates for the first 5 min and the best cycling performance, with an effective hydrogen-storage capacity of 6.65 wt%.
RESUMEN
This study aimed to assess the effectiveness of ultrasonic vibration and thermo-hydrodynamic obturation (VibraTHO) using two types of root canal sealers, in comparison to the single-cone (SC) technique and a calcium silicate-based root canal sealer in complex root canal anatomies. Thirty single-rooted human maxillary premolars with two canals that had a complex root canal anatomy of transverse anastomoses or ramifications were prepared and assigned to the following three experimental groups, according to the filling method: SE group, SC technique with Endoseal TCS; VE group, VibraTHO with Endoseal TCS; and VG group, VibraTHO with GuttaFlow 2. Each tooth was scanned using micro-computed tomography, and the volume percentages of the filling material were calculated. The analysis of variance was used to analyze the statistical differences between the three groups (p < 0.05). The mean volume of the filling material was higher in the VG and VE groups than that in the SE group (p < 0.05) along the apical to middle-to-coronal thirds, and significant differences were observed between each root canal area (p < 0.05), with the only exception being at the apical thirds between the VE and SE groups. The VibraTHO technique using GuttaFlow 2 can be a more effective root canal filling method for anatomically complex root canal systems than the SC technique with Endoseal TCS. On the other hand, the VibraTHO technique using Endoseal TCS has a limited effect on improving the quality of the root filling at the apical portion of anatomically complex root canal systems, compared to the SC technique with Endoseal TCS.
RESUMEN
INTRODUCTION: The purpose of the current population-based study was to analyze the 5-year survival rate of teeth that received nonsurgical endodontic treatment. Specifically, the variables affecting the 5-year survival rates of endodontically treated teeth were analyzed. METHODS: The present study included all endodontically treated teeth reported in 2010 in the National Health Insurance Cohort database of the Republic of Korea. By tracing the dental records of the sample to the end of 2015, the 5-year survival rates of the initial root canal treatment (RCT) and re-RCT were analyzed. Gender, age, institution type, diagnosis, arch type, tooth type, number of visits, and rubber dam usage were included in the analyses as confounding variables. RESULTS: In total, 2,866,749 teeth received initial RCT, and 173,429 teeth received re-RCT. Five-year survival rates were 90.85% and 88.42%, respectively. The survival rate of teeth that received initial RCT was significantly higher than that of those that received re-RCT. Specifically, re-RCT showed a significantly higher rate of extraction within 12 months than during other intervals. Furthermore, the following characteristics significantly positively affected the 5-year tooth survival rate: being female, <20 years of age, hospital as the institution type, mandibular teeth, anterior teeth, initial RCT, and use of rubber dam. CONCLUSIONS: Because of its high 5-year survival rate, endodontic treatment is an effective method for maintaining natural teeth.