Objectives: Color coordinates of translucent esthetic materials measured by traditional spectrophotometers (SP) would deviate from those measured by newly introduced spectroradiometers (SR), which might simulate the clinical viewing condition better. This study aimed to determine the correlations in the SP- and SR-based color coordinates and color differences of all-ceramic materials.
Methods: Specimens for seven A2 shade core ceramics (n=7) and corresponding A2 and A3 shades veneer ceramics (n=7) were fabricated in clinically relevant thicknesses (1.5mm after layering). Color of layered specimens was measured according to the CIELAB color scale by a SP and a SR. Color differences (ΔE(ab)(*)) between the reference ceramics and the corresponding layered ceramics were calculated. Correlations between SP- and SR-based color coordinates and color difference values were determined (α=0.05).
Results: SR-based color coordinates were significantly different from the SP-based values; however, general shifting trends by the instrument were observed. SP- and SR-based CIE a*, b* and chroma values showed significant correlations (p<0.05); however, the CIE L* values and the color differences with the reference showed no significant correlations (p>0.05).
Significance: The color coordinates representing the hue attribute (CIE a*, b* and chroma) measured by a spectrophotometer and a spectroradiometer showed significant correlations; however, the color coordinates and the color difference values were significantly different by the instrument. Therefore, color coordinates and the color difference values based on different instruments should not be compared directly.
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http://dx.doi.org/10.1016/j.dental.2010.07.005 | DOI Listing |
Nanoscale
January 2025
Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares and Departamento de Química Orgánica Universidade de Santiago de Compostela Santiago de Compostela, Spain.
Poly(phenylacetylene)s (PPAs) bearing -substituted anilide pendant groups are sensitive to the presence of oxidizing metal ions such as Cu, Hg, Fe, Au or Ce due to a redox reaction between the anilide-PPA and the metal ion. Using a library of six different PPAs containing diverse chiral pendant groups connected to the PPA backbone through the N (anilide) or C (benzamide) atoms of an amide group used as a linker, it was found that anilide-PPAs are sensitive to oxidizing metal ions. In these polymers, and through a redox reaction, a radical species is delocalized along the polyene backbone, resulting in a color change of the solution from yellow to blue.
View Article and Find Full Text PDFBiophys J
January 2025
Department of Biology, New York University, New York, New York, 10003, USA. Electronic address:
The outer membrane is the defining structure of Gram-negative bacteria. We previously demonstrated that it is a major load-bearing component of the cell envelope and is therefore critical to the mechanical robustness of the bacterial cell. Here, to determine the key molecules and moieties within the outer membrane that underlie its contribution to cell envelope mechanics, we measured cell-envelope stiffness across several sets of mutants with altered outer-membrane sugar content, protein content, and electric charge.
View Article and Find Full Text PDFJ Dent
January 2025
Department of Dentistry, School of Medicine, University of Salamanca, Spain. Electronic address:
Objective: to evaluate the efficacy and chromatic stability after 4weeks, in all three thirds of the central incisor of two whitening treatments: in-office 37.5% hydrogen peroxide (HP) treatment alone, and 37.5% in-office HP followed by use of 6% HP whitening strips (WS).
View Article and Find Full Text PDFSensors (Basel)
January 2025
Department of Civil Engineering and Engineering Management, National Quemoy University, Kinmen 89250, Taiwan.
Ground-based LiDAR technology has been widely applied in various fields for acquiring 3D point cloud data, including spatial coordinates, digital color information, and laser reflectance intensities (I-values). These datasets preserve the digital information of scanned objects, supporting value-added applications. However, raw point cloud data visually represent spatial features but lack attribute information, posing challenges for automated object classification and effective management.
View Article and Find Full Text PDFMolecules
January 2025
Department of Analytical Chemistry and Applied Spectroscopy, Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarina 7, 87-100 Toruń, Poland.
In this study, biodegradable and active films based on sodium alginate incorporated with different concentrations of oils (25% and 50%) from fruit seeds were developed for potential applications in food packaging. The ultraviolet and visible (UV-VIS) spectra of raspberry seed oil (RSO) and black currant seed oil (BCSO) indicated differences in bioactive compounds, such as tocopherols, phenolic compounds, carotenoids, chlorophyll, and oxidative status (amounts of dienes, trienes, and tetraenes) of active components added to alginate films. The study encompassed the color, structure, and thermal stability analysis of sodium alginate films incorporated with RSO and BCSO and their mixtures.
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