Purpose: The present study aimed to elucidate how saliva contamination affects microtensile bond strength of resin cement to CAD/CAM resin blocks and identify a decontamination method that can restore original bond strength.
Methods: The KATANA AVENCIA block (Kuraray Noritake Dental) was sandblasted on the adherend surface (P-Co group). Then, the block was contaminated with artificial saliva (Saliveht Aerosol, Teijin). Air dry (N-Co), sandblasting (Sb) and phosphate acid cleaning (AT) groups were prepared. After silane treatment, PANAVIA V5 (Kuraray Noritake Dental) was built up and microtensile bond strength (μTBS) was measured after immersion in water (n=24 per group). Scanning electron microscopy (SEM) analysis, surface roughness and contact angle measurement of each surface were performed.
Results: The P-Co group showed the highest μTBS value, and bond strength was significantly lower in the N-Co group than the other groups (P<0.001). In all groups, decreased bond strength resulted from long-term water storage. In the N-Co group, a contaminated layer was observed on the surface by SEM and the contact angle was significantly smaller than the other groups (P<0.001). In Sb and AT groups, μTBS values that were reduced by artificial saliva contamination significantly increased but did not recover to P-Co group values (P<0.001). SEM showed no morphological difference between P-Co, Sb and AT groups. The Sb group showed increased surface roughness.
Conclusion: The long-term durability of bonds between CAD/CAM resin blocks and luting agent cement was significantly reduced by artificial saliva contamination. However, sandblasting or phosphoric acid cleaning can recover bonding effectiveness by 75-85%.
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http://dx.doi.org/10.1016/j.jpor.2017.08.006 | 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.
View Article and Find Full Text PDFPhys Chem Chem Phys
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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