Background: Reduced time and appropriate bond strength of brackets is one of the most important aspects of orthodontic treatments. Prolonged halogen light curing for bonding of brackets is undesirable, so the purpose of this study was to compare the shear bond strength of brackets bonded with halogen light and plasma arc system. MATERIALS AND MEHODS: This was an experimental in vitro study. A total of 60 intact premolar teeth were collected and divided into four groups. Stainless steel orthodontic brackets were bonded to them. In groups 1 and 2, curing was done using halogen light given for 20 seconds from two and four angles. In groups 3 and 4, curing was carried out using the plasma arc system for 6 seconds from two and four angles. The shear bond strength was recorded by Instron. The statistics of ANOVA, Tukey's test, and T-test were used in data analysis.
Results: There was a statistically significant difference in shear bond strength among the four groups (P = 0.043) and between group 1 with group 2 (P = 0.035). Yet, there was no statistically significant difference between brackets bonded with plasma arc and those bonded with halogen light or between the two groups of plasma arc.
Conclusion: Using the plasma arc system is superior to other methods due to reduced curing time. Also, since in using the halogen light system, an increase in curing periods from different angles resulted in a significant increase in shear bond strength; it is advisable to apply the halogen light from different angles.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3469900 | PMC |
Inorg Chem
January 2025
Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States.
Three new hexagonal perovskites with CsMMRhCl (M = Na, Ag; M = Mn, Fe) stoichiometry have been synthesized from solution precipitation reactions. These air-stable compounds crystallize as triply cation-ordered variants of the 6H perovskite structure. This structure contains octahedra that share a common face to form MRhCl dimers that are arranged on a two-dimensional triangular network.
View Article and Find Full Text PDFSmall
January 2025
Department of Polymer Materials and Engineering, School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin, 300401, P. R. China.
Nowadays, much attention is paid to the development of high-performance and multifunctional materials, but it is still a great challenge to obtain polymer materials with high mechanical properties, high self-healing properties, and multifunctionality in one. Herein, an innovative strategy is proposed to obtain a satisfactory waterborne polyurethane (PMWPU-Bx) by in situ anchoring 3-aminophenylboronic acid (3-APBA) in a pyrene-capped waterborne polyurethane (PMWPU) via supramolecular interactions. The multiple functional sites inherent in 3-APBA can produce supramolecular interactions with groups on PMWPU, promoting the aggregation of hard domains in the polymer network, which confers the PMWPU-Bx strength (7.
View Article and Find Full Text PDFAdv Healthc Mater
January 2025
College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, China.
The hydrogel adhesives with strong tissue adhesion and biological characteristics adhm202404447are urgently needed for injury sealing and tissue repair. However, the negative correlation between tissue adhesion and the mechanical strength poses a challenge for their practical application. Herein, a bio-inspired cohesive enhancement strategy is developed to prepare the hydrogel adhesive with simultaneously enhanced mechanical strength and tissue adhesion.
View Article and Find Full Text PDFThis study examines the intricate area of refractory-based high entropy alloys (RHEAs), focusing on a series of complex compositions involving nine diverse refractory elements: Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W. We investigate the phase stability, bonding interactions, electronic structures, lattice distortions, mechanical, and thermal properties of six RHEAs with varying elemental ratios using VASP and OLCAO DFT calculations. Through comprehensive analysis, we investigate the impact of elemental variations on the electronic structure, interacting bond dynamics, lattice distortion, thermodynamic, mechanical, and thermal properties within these RHEAs, providing an insight into how these specific elemental variations in composition give rise to changes in the calculated properties in ways that would guide future experimental and computational efforts.
View Article and Find Full Text PDFSmall
January 2025
Key Laboratory of Organic Optoelectronics & Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China.
A microwave-strengthened supramolecular adhesive by introducing maleic acid amide bonds into the cross-linked networks of catechol-based monomers and iron oxide nanoparticles is reported. Under microwave irradiation, the supramolecular adhesive can be rapidly heated up, causing the transformation from maleic acid amide bonds to maleimide bonds and thus the increase of its cohesive strength. The supramolecular adhesive can flexibly bond substrates like pressure sensitive adhesives during the bonding procedure and shows an adhesion strength of 0.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!