Objective: The aim of this study was to evaluate the effect of five intracanal irrigants on bond strength of fiber posts cemented with newer self-adhesive resin cement.
Methods: A total of 60 extracted, single-rooted human premolars, sectioned at 14 mm, were prepared with the ProTaper Universal system with a size F3 instrument and filled with an F3 master cone and AH Plus. The root canal filling was partially removed, leaving 4 mm of apical gutta-percha. Specimens were randomly assigned to five groups (n=12), according to the solution used for dentin surface treatment before fiber post cementation, as follows: EDTA 17% (EDTA); QMix (QM); SmearClear (SC); 2.5% sodium hypochlorite (NaOCl), and 0.9% saline solution (SS). Ultrasonic activation was performed (three times, 20 seconds each), and root canals were dried with paper points. Fiber posts were cemented with RelyX U200. In one specimen per group, rhodamine B dye was mixed with RelyX U200 to provide adequate fluorescence for confocal laser scanning microscopy (CLSM) assessment. Specimens were transversally sectioned and three slices were obtained, one for each root third. Next, a push-out test was performed. A stereomicroscope and CLSM were used to analyze the failure modes and to illustrate the pattern of infiltration of RelyX U200 into dentinal tubules, respectively. Bond strength means were calculated, and analysis of variance and Bonferroni tests were used for statistical analysis.
Results: SS showed the highest mean bond strength values (11.5±5.3), superior to QM (5.1±3.1) and SC (5.1±3.3). NaOCl presented intermediary bond strength values (9.7±5.0), similar to EDTA (7.7±2.9) and SS. QM and SC showed the lowest mean bond strength (p<0.05). Adhesive failures between cement/dentin were predominant (53.9%).
Conclusion: SS and NaOCl associated with ultrasonic activation seem to be adequate solutions for root canal cleaning before fiber post cementation with self-adhesive resin cement, whereas chelating solutions, such as EDTA, QM, and SC, cause a decrease in bond strength.
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http://dx.doi.org/10.2341/15-246-L | DOI Listing |
Mater Horiz
January 2025
Department of Materials Science, University of Michigan, Ann Arbor, Michigan 48109, USA.
It is difficult to intuit how electronic structure features-such as band gap magnitude, location of band extrema, effective masses, -arise from the underlying crystal chemistry of a material. Here we present a strategy to distill sparse and chemically-interpretable tight-binding models from density functional theory calculations, enabling us to interpret how multiple orbital interactions in a 3D crystal conspire to shape the overall band structure. Applying this process to silicon, we show that its indirect gap arises from a competition between first and second nearest-neighbor bonds-where second nearest-neighbor interactions pull the conduction band down from Γ to X in a cosine shape, but the first nearest-neighbor bonds push the band up near X, resulting in the characteristic dip of the silicon conduction band.
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January 2025
Department of Chemistry, Dr. Harisingh Gour Vishwavidyalaya (A Central University), Sagar-470003, India.
In a recent communication (A. Shivhare, B. Dehariya, S.
View Article and Find Full Text PDFBeilstein J Org Chem
January 2025
Department of Chemistry, University of Rhode Island, 140 Flagg Rd, Kingston, RI 02881, USA.
The CFH group can act as a hydrogen bond donor, serving as a potential surrogate for OH or SH groups but with a weaker hydrogen bond donation ability. Here, we describe a series of CFH group-containing moieties that facilitate hydrogen bond interactions. We survey hydrogen bond donation ability using several established methods, including H NMR-based hydrogen bond acidity determination, UV-vis spectroscopy titration with Reichardt's dye, and H NMR titration using tri--butylphosphine oxide as a hydrogen bond acceptor.
View Article and Find Full Text PDFMicrosc Res Tech
January 2025
Department of Restorative and Prosthetic Dental Sciences, College of Dentistry, Dar Al Uloom University, Riyadh, Saudi Arabia.
Effect of different root canal irrigation regimes microbubble emulsion (MBE) via riboflavin photosensitizer (RFP), cerium oxide (CeO) nanoparticles (NPs), and Nd: YAP laser on antibacterial efficiency, microhardness (MH), smear layer (SL) removal efficacy, and push-out bond strength (PBS) of AH plus sealer to canal dentin. Sixty single-rooted teeth were selected, disinfected, and categorized into four groups based on the type of disinfection. Following disinfection, a pair of samples were randomly selected and visualized under scanning electron microscope (SEM) for SL evaluation.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu, 210094, China.
After cyclo-pentazolate anion, a 5/6 fused structure of N is constructed, and four novel nitrogen-rich ionic compounds are assembled on its basis. The results of the quantum calculations revealed an uneven distribution of electrons on cyclo-N , with significant charge density near the N5/N9 atoms and an ADCH charge of -0.425.
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