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High‐translucency restorative materials are commonly used in the restoration of anterior teeth where aesthetics is a critical factor. In this in vitro study, the impact of mouthwash on the colour stability and surface characteristics of high‐translucency computer‐aided design and computer‐aided manufacturing (CAD‐CAM) dental restorative materials was evaluated. Two‐hundred specimens were fabricated from five high‐translucency CAD‐CAM materials: a resin nano ceramic; a polymer‐infiltrated ceramic network; a feldspathic ceramic; a lithium disilicate glass ceramic; and high‐translucency zirconia. Each group of ceramic specimens was then divided into four subgroups: conventional mouthwash (LISTERINE); whitening mouthwash (LISTERINE Healthy White); chlorhexidine gluconate; and distilled water. Oral rinsing was simulated at 100 rpm for 180 h, representing 15 yr of clinical simulation. The specimens were then evaluated for colour, translucency, gloss, roughness, and surface morphology. Two‐way ANOVA and linear mixed models were used for intergroup comparisons (α = 0.05). The polymer‐infiltrated ceramic network and feldspathic ceramic became brighter, more opaque, less glossy, and rougher after rinsing with the whitening mouthwash. The long‐term use of specific mouthwashes can cause deterioration of the optical and surface properties of high‐translucency CAD‐CAM dental restorations. [ABSTRACT FROM AUTHOR]

Objective: The aim of this in vitro study was to evaluate the effects of substrate colors, different levels of ceramic thickness and translucency, and cement shades on the color difference from a reference color of lithium‐disilicate crowns. Materials and Methods: A premolar tooth preparation was made on a study model for 1.0 and 1.5 mm thick full‐ceramic crowns. Digital impressions were taken (3Shape TRIOS) and crowns designed in a CAD program (DentalDesigner). Shade A1 crowns were milled (Everest, Kavo) from high‐translucency (HT) and low‐translucency IPS e.max (Ivoclar Vivadent) blocks. Twelve substrates were made of different colors and materials (Natural Die Material, Co‐Cr, zirconia, and gold‐colored alloy). Three different shades of try‐in pastes were used to simulate the effect of cements (Variolink Esthetic try‐in paste; Ivoclar). Shade measurement was done three times for each crown by a spectrophotometer (VITA Easyshade Advance); averages were compared to a reference crown (A1, HT, 1.5 mm, ND2 abutment, neutral try‐in paste) with ΔE00 (CIEDE2000, according to the CIE latest standard) calculated. Results: All the examined parameters influenced the ΔE00 of the crowns. The weakest effect was exerted by the try‐in paste. Conclusions: All examined parameters influenced the final color of e.max CAD lithium‐disilicate ceramic crowns. Clinical Significance: Matching the shade of ceramic crowns to the natural tooth color is a great challenge in dentistry. To meet patients' increasing esthetical expectations, CAD/CAM methods are very popular for full‐ceramic crowns. However, several factors such as the shade of the abutment, luting cement color, ceramic thickness, and translucency may influence the final color. Our objective was to measure the optical effect of these factors on the final shade of CAD/CAM lithium‐disilicate ceramic crowns. [ABSTRACT FROM AUTHOR]

This paper is devoted to ocean images. First we propose a complete geometrical model accounting for refraction, diffraction, reflection, transmission and multiwave trains. Then we describe a specific algorithm for the rendering of coastal scenes. Copyright © 2000 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In the context of personalized medicine, there is a growing interest in materials bearing at the same time diagnostic and therapy functions. This article reports a cheap and easily reproducible procedure to obtain materials with a high potential for these applications. Three new strontium iodide-fructose-based metal-organic frameworks with formulae [Sr(C 6 H 12 O 6 ) 2 ]I 2 , [Sr 2 (C 6 H 12 O 6 ) 3 (H 2 O) 3 ]I 4 ·0.5H 2 O and [Sr(C 6 H 12 O 6 )(H 2 O) 3 I]I differing in stoichiometry, symmetry and crystal packing, were obtained and characterized by X-ray diffraction. Bulk quantum simulations show that both the ions and the sugar are crucial in determining the predicted nonlinear response; also, the relative arrangement of various functional groups in the unit cell plays a role in the computed optical properties. Small fragments of the three compounds were selected for in vacuo calculations, proving that the reduced dimensions of the particles have a great influence on the nonlinear optical response. Despite the similar chemical composition of the three compounds, second harmonic generation measurements and in crystal and in vacuo theoretical calculations agree that one of the compounds is a much more efficient second harmonic emitter than the other two, and is thus a suitable candidate for bio-sensor applications.

Purpose: To evaluate the radiopacity of luting cements submitted to different aging procedures., Materials and Methods: Twenty discs (1 × 4 mm) of each of the following cements were prepared: zinc phosphate, RelyX Luting 2, Variolink 2, AllCem, RelyX U200, Multilink, Panavia F2.0, and RelyX ARC. Then, they were randomly divided into two groups (n = 10/group), according to the aging procedure: thermal cycling group and water storage group. Before and after aging procedures, specimens were x-rayed with an aluminum step-wedge (11 steps, 1 mm thick each) and three dental slices (1 mm thick). The radiopacity was evaluated by means of optical density, which was measured using ImageJ software. The values were converted into millimeters of aluminum with a logistic regression calibration curve. The data were analyzed by one-way ANOVA and Tukey post-hoc test (α = 0.05)., Results: In the thermal cycling group, RelyX Luting 2, RelyX U200, and Panavia F2.0 showed a statistically significant reduction in radiopacity (p < 0.05). In the water storage group, all cements showed a significant reduction in radiopacity (p < 0.05), and RelyX Luting 2 and Panavia F2.0 performed below the desired ISO 4049 standard., Conclusions: The radiopacity of luting cements can decrease after aging, especially after 1-year water storage., (© 2018 by the American College of Prosthodontists.)

Active pharmaceutical ingredients (APIs), through their favourable donor/acceptor spatial distribution and synthon formation flexibility, are attractive building blocks in modern materials crystallography. The optical properties of a crystal strongly depend on two factors, i.e. the spatial distribution of molecules in the crystal structure and the electronic properties of molecular building blocks (dipole moments, polarizabilities, hyperpolarizabilities). Although the latter are easy to predict through ab initio calculations, the former are not. Only a combination of experimental and theoretical charge density studies together with prediction and measurement of optical properties enable full analysis of the obtained functional material in terms of its usefulness in practical applications. This article presents design strategies of optical materials based on selected pharmaceutical molecules. Factors that contribute to molecular recognition in the four selected polar/chiral crystal phases (derived through charge density and Hirshfeld surfaces analysis) have been determined. Theoretically predicted optical properties of the molecular/ionic building blocks as well as bulk effects have been confirmed experimentally. This research is a first step in the design of novel optical materials based on push-pull molecules and APIs.

This study concentrates on the potential application of conjugated polyelectrolytes (CPEs) to cell imaging and DNA delivery. Four different types of polyfluorene copolymers, namely, PAHFP-Br, PAEFP-Br, PAHFbT-Br, and PSBFP-Na, which have the same π-conjugated backbone but different side chains, were synthesized. For cytotoxicity testing, L-929 fibroblastic cells were treated with increasing concentrations (0-50 µM) of each CPE and then cell viability was determined by WST-8 assay. Cellular uptake of CPEs into cultured L-929 cells was observed by fluorescence microscopy. To examine DNA delivery by CPEs, the cells were incubated for 1 H with PAHFP-Br/fluorescein (Fl)-labeled single-stranded DNA (ssDNA-Fl) complex and then visualized by fluorescence microscopy. Cytotoxicity of CPEs was increased in a dose-dependent manner but at lower than 10 µM, PAHFP-Br, PAEFP-Br, and PSBFP-Na did not show any cytotoxic effects on the cells. When added to cell cultures at 1 µM, PAHFP-Br/ssDNA-Fl complex was delivered and then dissociated into PAHFP-Br and ssDNA-Fl within the cells. This result implies that PAHFP-Br can enable cell imaging and DNA delivery into fibroblastic cells. Therefore, it is suggested that PAHFP-Br with various advantages such as low cytotoxicity and high fluorescence efficiency can be extensively used as a potential agent for cell imaging and gene delivery., (© 2013 International Union of Biochemistry and Molecular Biology, Inc.)

We previously proposed a new strategy to fabricate a novel foldable capsular vitreous body (FCVB) as a vitreous substitute and found that the FCVB was a very good replacement for closely mimicking the morphology and restoring the physiologic function of the rabbit vitreous body. The aim of this article was to assess the mechanical, optical, and biocompatible properties of a FCVB made from liquid silicone rubber. The mechanical properties show that the shore hardness is 37.80 degrees, the tear strength is 47.14 N/mm, the tensile strength is more than 7.28 MPa, and the elongation ratio is more than 1200%; in addition, the FCVB has 300 nm mili apertures in the capsule. The optical properties reveal that transmittances are 92%, hazes are 5.74%, and spectral transmittance is 97%. The transmittance mission is 2.3% and can sustain a 1500 mW, 0.2 s, 532 nm green laser. The biocompatible properties are shown in the stable extracts experiment, no significant fever, good genetic safety, and no structural abnormality or apoptosis in the cornea, ciliary body, and retina over a 6-month observation period. These results indicate that the FCVB has good mechanical, optical, and biocompatible properties, and the assessment results can be recommended as the FCVB technical standards for industrial manufacturing and inspection., (© 2010, Copyright Zhongshan Ophthalmic Center, Sun Yat-sen University. Artificial Organs © 2010, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.)

Purpose: This study compared the color parameters and total luminous transmittance of disc specimens by different veneering techniques in order to examine the effect of veneering technique on esthetics of yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) all-ceramic restorations., Materials and Methods: Thirty disc specimens (10-mm diameter, 0.50 +/- 0.01 mm thick) were fabricated of IPS e.max ZirCAD core material, and ZL1 IPS e.max ZirLiner (0.10-mm thick) was layered. The specimens were randomly divided into three groups (n = 10/group). Group ZP (fully anatomical technique) was veneered 0.60 mm by heat-pressing IPS e.max ZirPress fluorapatite glass-ceramic ingots; Group ZC (traditional layering technique) was veneered 0.60 mm by condensing and sintering IPS e.max Ceram low-fusing nano-fluorapatite veneering porcelain; Group ZPC (cutback technique) was veneered by partially pressed ingots and subsequently layered 0.30 mm with veneering porcelain. Color parameters (L*, a*, b*) and total luminous transmittance (tau) of zirconia core discs and core and veneer specimens were measured with ShadeEye NCC dental colorimeter and spectrophotometer, respectively. Color saturation (C*ab) and color difference (DeltaE) were calculated using color difference formula. One-way analysis of variance (ANOVA) combined with a Tukey multiple-range test were used to analyze the data (alpha= 0.05)., Results: As to ZP, ZPC, and ZC groups, the value of a* increased (-1.35 +/- 0.07, -0.64 +/- 0.06, -0.36 +/- 0.05, respectively) (p < 0.05); b* decreased (27.01 +/- 0.07, 25.48 +/- 0.11, 23.28 +/- 0.25, respectively) (p < 0.05); and C*ab decreased (27.04 +/- 0.08, 25.49 +/- 0.11, 23.28 +/- 0.25, respectively) (p < 0.05). L* value and total luminous transmittance were highest in ZP group (87.53 +/- 0.48, 1.64 +/- 0.03, respectively), and lowest in ZPC group (82.14 +/- 0.18, 1.47 +/- 0.01, respectively) (p < 0.05)., Conclusions: Y-TZP all-ceramic restoration veneered by fully anatomical technique was the most transparent and lightest, while restorations veneered by cutback technique were the least translucent and the darkest.

Purpose: The purpose of this study was to assess the performance of an intraoral dental colorimeter., Materials and Methods: In vivo repeatability of an intraoral colorimeter was assessed by performing color measurements of 30 individuals' right maxillary central incisor. Three consecutive measurements from each individual were made. In the in vitro part of the study, 25 metal-ceramic and 25 all-ceramic specimens were prepared. Five shades of metal-ceramic and all-ceramic specimens were selected for color determination. A widely recognized in vitro colorimeter was used as the control group for the in vitro performance assessment of the in vivo colorimeter. The color differentiation capability of two colorimeters was compared with the readings obtained from ceramic specimens. DeltaE values between shade groups of ceramic specimens were calculated and statistically analyzed with Student's t-test. The repeatability of the intraoral instrument was evaluated statistically with Intraclass correlation coefficient., Results: The in vivo evaluation results showed that the overall repeatability coefficient values of L*, a*, and b* notations of the intraoral colorimeter were "excellent." The color differences (DeltaE) calculated between the colorimeters were significant only between shades A(1)-B(1) for metal-ceramic specimens (p= 0.002); however, from 5 of 10 shade couples of all-ceramic specimens, the color differences obtained from the readings of the in vivo colorimeter were significantly different from that of the in vitro colorimeter (p < 0.001). For all specimens, the differences between DeltaE values were within clinically acceptable limits (<3.5)., Conclusions: Within the limitations of this study, the intraoral colorimeter exhibited successful in vivo repeatability; however, the color difference detection performance of the device varied depending on the translucency of the specimens.

Unlabelled: The regular use of mouthrinses, particularly when combined with the use of air-powder polishing, could affect the appearance of tooth-colored restorations. The current study sought to evaluate the effect of NaHCO(3) powder on translucency of a microfilled composite resin immersed in different mouthrinses, at distinct evaluation periods. Eighty disk-shaped specimens of composite resin (Durafill VS, Heraeus Kulzer GmbH & Co. KG, Hanau, Germany) were prepared. The composite specimens were then randomly allocated into two groups according to the surface treatment: exposure to NaHCO3 powder (10 seconds) or nonexposure, and they were randomly assigned into four subgroups, according to the mouthrinses employed (N = 10): Periogard (Colgate/Palmolive, São Bernardo do Campo, SP, Brazil), Cepacol (Aventis Pharma, São Paulo, SP, Brazil), Plax (Colgate/Palmolive), and distilled water (control group). The samples were immersed for 2 minutes daily, 5 days per week, over a 4-month test period. Translucency was measured with a transmission densitometer at seven evaluation periods. Statistical analyses (analysis of variance and Tukey's test) revealed that: distilled water presented higher translucency values (86.72%); Periogard demonstrated the lowest translucency values (72.70%); and Plax (74.05%) and Cepacol (73.32%) showed intermediate translucency values, which were statistically similar between them (p > 0.01). NaHCO3 air-powder polishing increased the changes in translucency associated with the mouthrinses. Air-powder polishing alone had no effect on material translucency. Translucency percent was gradually decreased from 1 week of immersion up to 4 months. It may be concluded that the NaHCO3 powder and the tested mouthrinses have affected the translucency of microfilled composite resin, according to the tested time., Clinical Significance: During the last decade, the demand for composite resin restorations has grown considerably, however, controversy persists regarding the effect of surface roughness on color stability.

The planar component of 2-{3-cyano-4-[3-(1-decyl-1,4-dihydroquinolin-4-ylidene)prop-1-enyl]-5,5-dimethyl-2,5-dihydrofuran-2-ylidene}malononitrile, C(32)H(46)N(4)O, (I), forms into layers parallel to the (\overline{1}01) plane. The larger of the two spaces between layers is filled by the alkyl chains, giving a ;sandwich stack' appearance. The packing of 2-{3-cyano-4-[5-(1-decyl-1,4-dihydroquinolin-4-ylidene)penta-1,3-dienyl]-5,5-dimethyl-2,5-dihydrofuran-2-ylidene}malononitrile, C(34)H(38)N(4)O, (II), which has partial disorder in the 1-decyl group, utilizes weak C-H...N, C-H...O and C-N...pi interactions in a three-dimensional ;herring-bone' array with molecular segments parallel to the (111) and (\overline{1}1\overline{1}) planes. Different rotational isomers with respect to the polyene chain and the 5,5-dimethyl-2,5-dihydrofuran-2-ylidene link are observed in the two structures. The significance of the study lies in the delocalization of charge along the polyene chain and the supramolecular aggregation present, which highlight the difficulty in obtaining the noncentrosymmetric alignment required for high nonlinear optical (NLO) responses in zwitterionic chromophores.