Color variations in PMMA acrylic resins after thermocycling and mouthwash simulation / Variações de cor em resinas acrílicas de PMMA após termociclagem e simulação de enxaguatório bucal

Estabilidade de cor é um requisito estético fundamental das resinas acrílicas provisórias, em especial quando esses materiais são submetidos a longos períodos na cavidade oral. Embora resinas acrílicas temporárias novas e aprimoradas estejam disponíveis, os efeitos da variação térmica e de soluções antissépticas na estabilidade de cor de resinas acrílicas provisórias ainda não foram completamente elucidados. Portanto, este estudo avaliou a coloração de resinas autopolimerizáveis polimetilmetacrilato (PMMA) e bis-acrilo submetidas à termociclagem e imersão em clorexidina. Amostras padronizadas (n=10) foram preparadas de duas resinas acrílicas temporárias a base de PMMA (Alike® e Duralay®). Foram realizadas três avaliações de cor (T1 ­ 24h após o preparo da amostra, T2 ­ após termociclagem e T3 ­ após termociclagem e imersão em clorexidina) por meio de espectrofotômetro eletrônico de seleção de sombra (Vita Easy Shade). Os dados obtidos foram analisados por ANOVA e teste t (α=0,05). As resinas de PMMA Alike e Duralay apresentaram alteração de cor após a termociclagem e também após a imersão em clorexidina.

Color stability is a fundamental aesthetic requirement for temporary acrylic resins, especially when these materials are subjected to long periods in the oral cavity. Although new and improved temporary acrylic resins are available, the effects of thermal variation and antiseptic solutions on the color stability of temporary acrylic resins have not yet been fully elucidated. Therefore, this study evaluated the color of self-polymerizing resins polymethyl methacrylate (PMMA) and bis-acryl subjected to thermocycling and immersion in chlorhexidine. Standardized samples (n=10) were prepared from two PMMA-based temporary acrylic resins (Alike® and Duralay®). Three color evaluations were carried out (T1 ­ 24h after sample preparation, T2 ­ after thermocycling and T3 ­ after thermocycling and immersion in chlorhexidine) using an electronic shade selection spectrophotometer (Vita Easy Shade). The data obtained were analyzed by ANOVA and t test (α=0.05). PMMA Alike and Duralay resins showed color changes after thermocycling and also after immersion in chlorhexidine.

Multifunctional MOF: Cold/hot adapted sustainable oxidase-like MOF nanozyme with ratiometric and color tonality for nitrite ions detection.

Integrating multiple functionalities into a single entity is highly important, especially when a broad spectrum of application is required. In the present work, we synthesized a novel manganese-based MOF (denoted as UoZ-6) that functions as a cold/hot-adapted and recyclable oxidase nanozyme (Km 0.085 mM) further developed for ratiometric-based colorimetric and color tonality visual-mode detection of nitrite in water and food. Nitrite ions promote the diazotization process of the oxTMB product, resulting in a decay in the absorbance signal at 652 nm and the emergence of a new signal at 461 nm. The dual-absorbance ratiometric platform for nitrite ion detection functions effectively across a wide temperature range (0 °C to 100 °C), offering a linear detection range of 5-45 µM with a detection limit of 0.15 µM using visual-mode. This approach is sensitive, reliable, and selective, making it effective for detecting nitrite ions in processed meat and water.

Rapid detection of colored and colorless macro- and micro-plastics in complex environment via near-infrared spectroscopy and machine learning.

To better understand the migration behavior of plastic fragments in the environment, development of rapid non-destructive methods for in-situ identification and characterization of plastic fragments is necessary. However, most of the studies had focused only on colored plastic fragments, ignoring colorless plastic fragments and the effects of different environmental media (backgrounds), thus underestimating their abundance. To address this issue, the present study used near-infrared spectroscopy to compare the identification of colored and colorless plastic fragments based on partial least squares-discriminant analysis (PLS-DA), extreme gradient boost, support vector machine and random forest classifier. The effects of polymer color, type, thickness, and background on the plastic fragments classification were evaluated. PLS-DA presented the best and most stable outcome, with higher robustness and lower misclassification rate. All models frequently misinterpreted colorless plastic fragments and its background when the fragment thickness was less than 0.1mm. A two-stage modeling method, which first distinguishes the plastic types and then identifies colorless plastic fragments that had been misclassified as background, was proposed. The method presented an accuracy higher than 99% in different backgrounds. In summary, this study developed a novel method for rapid and synchronous identification of colored and colorless plastic fragments under complex environmental backgrounds.

A comparative study of shade-matching performance using intraoral scanner, spectrophotometer, and visual assessment.

This study aimed to explore the clinical applicability of the shade-matching function in intraoral scanners. This study measured the tooth colors of maxillary anterior dentitions of 83 adults using visual matching, a spectrophotometer, and a scanner according to two color systems: VITA Classical (VC) and VITA 3D-Master (V3D). Agreement between each method was assessed by weighted Cohen's kappa coefficient (KW, α = 0.05). For V3D, the overall agreement between the scanner and spectrophotometer (KW = 0.498) was higher than that between the scanner and visual matching (KW = 0.473). Similarly, the agreement between the scanner and spectrophotometer (KW = 0.283) was higher than that between a scanner and visual matching (KW = 0.140) for VC. Regarding tooth position, the highest agreement between the scanner and spectrophotometer was observed on the right central incisor (KW = 0.542) for V3D. Tooth color measurement with a scanner was comparable to that with a spectrophotometer, especially on the central incisors when using the VITA 3D-Master system. A scanner could serve as an alternative to a spectrophotometer for shade selection. However, color matching should still be visually verified.

Enrichment of shortcrust pastry cookies with bee products: polyphenol profile, in vitro bioactive potential, heat-induced compounds content, colour parameters and sensory changes.

Bee products, including bee pollen (BP) and bee bread (BB) are natural sources that contain a diverse range of bioactive compounds. The objective of this study was to investigate the potential of BP and BB to enhance the functional properties of shortcrust pastry cookies. The impact on BP and BB on the colour parameters, polyphenolic compounds content, heat-induced compounds content (acrylamide, furfural, 5-hydroxymethylfurfural (HMF)), antioxidant properties, and inhibitory effects against advanced glycation end products (AGEs) formation and acetylcholinesterase (AChE) activity was examine by enriching cookies with 3 and 10% of BP or BB. The incorporation of BP or BB resulted in a notable darkening of the cookies. The spectroscopic and chromatographic analyses revealed that the cookies enriched with bee products exhibited an elevated content of phenolic compounds. The antioxidant activity (AA) of the enriched cookies exhibited an average increase of 2- to 3-fold in the ABTS test and 2-fold in the DPPH test. All cookies exhibited inhibitory potential against AGEs formation, witch inhibitory rates ranging from 10.64 to 46.22% in the BSA-GLU model and 1.75-19.33% in BSA-MGO model. The cookies enriched with 10% BP were characterised by to the highest level of AChE activity inhibition (13.72%). The incorporation of BB and BP resulted in elevated concentration of acrylamide, furfural, and HMF. Our findings suggest that bee products may serve as a valuable addition to food ingredients, significantly enhancing the functional properties of shortcrust pastry cookies. However, further investigation is necessary to address the increased level of heat-induced compounds.

Novel EBT3 film calibration using an integrated HSV color space analysis.

PURPOSE: Radiochromic EBT3 films are commonly used as dosimeter for clinical practice and research on radiotherapy. In principle, they are associated with a flatbed scanner to determine the optical density change, which can be correlated to the absorbed dose after calibration. Several approaches have been proposed to reduce the uncertainties during acquisition and to compensate the lighting inhomogeneities, thus improving the dose measurement. Those works have shown that good accuracy can be achieved for absorbed dose using EBT3 films, at the expense of complex data processing and time-consuming acquisition protocols. METHOD: We introduce the new method to determine the calibration curve based on the HSV color space analysis, which provides robustness and invariance to illumination changes. RESULTS: With this new approach, it allows to compute the calibration curve by performing only a single scan of film pieces regardless either the lateral positions or control points on the scanner bed. Using the hue channel in HSV color space, we prove that the dose can be accurately reconstructed with a much simpler protocol than when using RGB channels with blank scans rectification. Our HSV approach includes comparative gamma index for conventional film analysis. It achieves a gamma index (3%/3mm) over 99% when comparing measurement and AAA computation for a modulated beam. CONCLUSION: Compared to most existing approaches, our approach does not rely on complex mathematical reconstructions or additional scans. Instead, it uses another color model representation to rectify the scanner response, coping the dose measurement homogeneity problem over the scanner window. It facilitates the overall scan calibration to be much simpler, save time, and less manipulations, which also decreases the risk of human error.

Whiteness, redness, blueness and greenness profile assessment and design of experiments approach to microwave-aided sensitive and green spectrofluorophotometric determination of baclofen.

As a gamma amino butyric acid-ergic agonist, Baclofen is often prescribed to adults and children for the treatment of severe spasticity that originates in the brain or spinal cord. Even after reviewing the literature extensively, no one has documented a method for estimating baclofen using microwave-assisted stability-indicating spectrofluorimetric techniques, despite the abundance of options for baclofen stability, assay, and bioanalysis. Organic solvents, which are typically necessary for current procedures but may be costly and toxic, have a severe effect on aquatic life and the environment. Using green solvents and 4-chloro-7-nitrobezofuran as a fluorescent probe, this work conducted a stability-indicating spectrofluorimetric estimate of baclofen. Through the use of a design-of-experiments technique, a reliable microwave-aided spectrofluorimetric method was developed, with little solvent consumption and time for sample analysis. Prior to conducting response surface analysis and optimizing important variables and responses, a fractional factorial design was used to screen method variables and responses. A central composite design was then employed for these purposes. This flexible spectrofluorimetric technique was used to assess baclofen concentrations in forced degraded samples and marketed formulations. For baclofen determination, the suggested spectrofluorimetric approach was found to be green, quick, easy to use, economical, and user-friendly.

Development of a smartphone enabled, paper-based quantitative diagnostic assay using the HueDx color correction system.

Color correction is an important methodology where a digital image's colors undergo a transformation to more accurately represent their appearance using a predefined set of illumination conditions. Colorimetric measurements in diagnostics are sensitive to very small changes in colors and therefore require consistent, reproducible illumination conditions to produce accurate results, making color correction a necessity. This paper presents an image color correction pipeline developed by HueDx, Inc., using transfer algorithms that improve upon existing methodologies and demonstrates real-world applications of this pipeline in colorimetric clinical chemistry using a smartphone enabled, paper-based total protein diagnostic assay. Our pipeline is able to compensate for a variety of illumination conditions to provide consistent imaging for quantitative colorimetric measurements using white-balancing, multivariate gaussian distributions and histogram regression via dynamic, non-linear interpolating lookup tables. We empirically demonstrate that each point in the color correction pipeline provides a theoretical basis for achieving consistent and precise color correction. To show this, we measure color difference with deltaE (ΔE00), alongside quantifying performance of the HueDx color correction system, including the phone hardware, color sticker manufacturing quality and software correction capabilities. The results show that the HueDx color correction system is capable of restoring images to near-imperceptible levels of difference independent of their original illumination conditions including brightness and color temperature. Comparisons drawn from the paper-based total protein assay calibrated and quantified with and without using the HueDx color correction pipeline show that the coefficient of variation in precision testing is almost twice as high without color-correcting. Limits of blank, detection and quantitation were also higher without color-correction. Overall, we were able to demonstrate the HueDx platform improves reading and outcome of the total protein diagnostic assay and is useful for the development of smartphone-based quantitative colorimetric diagnostic assays for point-of-care testing.

Can wheel polishers improve surface properties and color stability of monochromatic resin composites?

BACKGROUND: To overcome the color layering procedure, monochromatic resin composites have been introduced. However, little is known about their polishability, gloss and color stability. This study aimed to investigate the surface roughness, gloss, and color change of monochromatic resin composites polished with wheel systems after being immersed in coffee. MATERIALS AND METHODS: Omnichroma, Zenchroma, Essentia Universal, Charisma Diamond One and NeoSpectra ST were used to obtain 120-disc samples of 8 × 2 mm. Only one side of the sample was polished with Twist Dia (TWD) or Nova Twist (NOV). The samples were examined for surface roughness, gloss, and color (ΔE and ΔE00) before and after 7 days of immersion in coffee and subsequent repolishing. The discs were examined via SEM. Surface roughness and gloss values were analyzed using ANOVA, Tukey and Pearson correlation tests. ΔE and ΔE00 values were evaluated using T tests, multivariate ANOVA, and Dunnett's post-hoc tests. RESULTS: For TWD groups, the smoothest material was Omnichroma (p < 0.05), while for NOV groups, it was Omnichroma and Zenchroma. Omnichroma was the glossiest, while Charisma Diamond One was the least glossy. In TWD groups, Charisma Diamond One and Essentia Universal were the most discolored, while Zenchroma and Omnichroma were the least. For NOV groups, Essentia Universal and Charisma Diamond One were the most discolored, while NeoSpectra ST, Omnichroma and Zenchroma were the least. After repolishing, Charisma Diamond One did not reach the level of ΔE < 2, while the other groups showed values below. Color evaluation with the CIELab and CIEDE2000 systems revealed similar results for the TWD groups after post-staining. CONCLUSIONS: Smooth and glossy surfaces could be achieved with the wheel system regardless of the composite resin. Repolishing after discoloration ensures that the color recovery is below the acceptable limit. Color evaluations with CIELab and CIEDE2000 yielded similar results.

Masking ability of CAD-CAM resin-matrix ceramics with different translucencies and thicknesses combined with four cement shades against varying background colors when facing veneer restorations.

BACKGROUND: To evaluate the comprehensive effect of translucency, thickness, cement shades, and background color on the masking ability of resin-matrix ceramic veneer restorations. METHODS: Resin-matrix ceramic specimens with 2 translucencies (LT, HT) and 3 thicknesses (0.5, 1.0, and 1.5 mm) were made of Upcera Hyramic (A2 shade). Cement specimens were made of Variolink N in 4 shades (yellow, white, transparent, and bleach XL). Five background specimens were made of IPS Natural Die Material in 5 shades (ND1, ND2, ND3, ND4, and ND5). Color coordinates of 120 subgroups (n = 5) of combined specimens composed of different ceramic, cement, and background specimens were obtained using a spectroradiometer. Color difference (ΔE00) compared with a 4-mm thick specimen of LT and HT ceramics was calculated and four-way ANOVA was used for statistical analysis (α = 0.05). RESULTS: Translucency, thickness, cement shade, background color, and their interaction had significant effects on ΔE00 (p < 0.001). ΔE00 values of HT groups were always higher than that of LT groups and were greater than 1.8 against all background colors. ΔE00 values of LT groups could be achieved to be less than 1.8 with appropriate thickness and cement shade. ΔE00 value decreased with increasing ceramic thickness. The effect of cement shade on ΔE00 had no obvious regularity, but ΔE00 values of bleach XL cement shade group were always lower than other cement shade groups under ND3 and ND5 background color. CONCLUSIONS: The masking ability of CAD-CAM resin-matrix ceramics can be simultaneously affected by translucency, thickness, cement shade, and background color. Resin-matrix ceramics with low translucency has a better masking ability than that with high translucency. The masking ability of CAD-CAM resin-matrix ceramics increase with increasing thickness. Cement shade has less impact on the final color of resin-matrix ceramic restorations.

Highly Sensitive Detection of Sulfur Ion in Water by Four-Color Fluorescence Based on Cu-Containing Metal-Organic Framework.

In this paper, a highly sensitive method for sulfur ion (S2-) detection was developed based on a four-color fluorescence probe constructed from copper-containing metal-organic framework (CuBDC) and four dye-labeled single-strand DNA (ssDNA). In the absence of S2-, dye-labeled ssDNA can be adsorbed on the surface of CuBDC, and the dyes are close to copper ion on the CuBDC surface, their fluorescence is quenched by copper ion, and their fluorescence signals are weak. In the presence of S2- in the system, S2- reacts with copper ion in CuBDC to form CuS, which has a more stable structure than complex CuBDC, resulting in the decomposition of CuBDC. In this case, dye-labeled ssDNA are detached from the CuBDC surface and dissolved in the solution, and the fluorescence of the dyes is restored. Under the optimized conditions, there is a good linear relationship between the total fluorescence intensity of four dyes and the concentration of S2- in the range of 2 × 10-9 to 5 × 10-8 mol/L; the detection limit is 2.2 × 10-10 mol/L. The method has a good selectivity and accuracy, and it can be applied to the analysis and detection of S2- in actual water samples.

Effect of Common Staining Beverages on Color Stability of Polymer-infiltrated Ceramics and Extra Translucent Zirconia: An In Vitro Study.

AIM: The current study aims to assess the color change of polymer-infiltrated ceramic Vita Enamic (VE) and extra translucent multilayer zirconia (XTML) after being immersed in different types of beverages, which are coffee, tea, and cola in comparison to distilled water as control. MATERIALS AND METHODS: A total of 80 rectangular-shaped specimens were prepared with fixed dimensions (14 × 12 × 0.5 mm) and then were divided into two groups (n = 40) according to ceramic material (VE, XTML). Specimens were sliced as each slice measures about 0.5 mm thick. Each group specimens were divided into four subgroups (n = 10) based on the immersion solutions in which specimens were stored (water, coffee, tea, and cola) for 28 days. The color parameters (L-a-b) of the specimens were recorded before immersion and at the end of the 7th (T1), 14th (T2), 21st (T3) and 28th (T4) days after immersion. Color measurements were statistically analyzed with a significance threshold of p < 0.05. RESULTS: There was a significant difference in color change between VE and XTML in all periods of tea and coffee immersion subgroups and in T3 and T4 in cola immersion subgroups (p < 0.001). Vita Enamic showed the highest differences in ΔE through all storage periods after 28 days of tea immersion (ΔE of VE= 8.06 ± 1.04). Extra translucent multilayer zirconia showed the highest differences in ΔE through all storage periods after 28 days of tea immersion (ΔE of XTML = 3.0 ± 0.33). CONCLUSION: Commonly consumed staining beverages influenced the color stability of the polymer-infiltrated ceramics more than extra translucent zirconia ceramics. CLINICAL SIGNIFICANCE: This study may provide guidance for clinicians to select the appropriate ceramic restorative material with high color stability and low tendency for color change by common staining beverages to achieve long-lasting esthetic results for the patients. How to cite this article: Abdelhafez MHA, Abu-Eittah MRH. Effect of Common Staining Beverages on Color Stability of Polymer-infiltrated Ceramics and Extra Translucent Zirconia: An In Vitro Study. J Contemp Dent Pract 2024;25(5):411-416.

CAM: a novel aid system to analyse the coloration quality of thick blood smears using image processing and machine learning techniques.

BACKGROUND: Battling malaria's morbidity and mortality rates demands innovative methods related to malaria diagnosis. Thick blood smears (TBS) are the gold standard for diagnosing malaria, but their coloration quality is dependent on supplies and adherence to standard protocols. Machine learning has been proposed to automate diagnosis, but the impact of smear coloration on parasite detection has not yet been fully explored. METHODS: To develop Coloration Analysis in Malaria (CAM), an image database containing 600 images was created. The database was randomly divided into training (70%), validation (15%), and test (15%) sets. Nineteen feature vectors were studied based on variances, correlation coefficients, and histograms (specific variables from histograms, full histograms, and principal components from the histograms). The Machine Learning Matlab Toolbox was used to select the best candidate feature vectors and machine learning classifiers. The candidate classifiers were then tuned for validation and tested to ultimately select the best one. RESULTS: This work introduces CAM, a machine learning system designed for automatic TBS image quality analysis. The results demonstrated that the cubic SVM classifier outperformed others in classifying coloration quality in TBS, achieving a true negative rate of 95% and a true positive rate of 97%. CONCLUSIONS: An image-based approach was developed to automatically evaluate the coloration quality of TBS. This finding highlights the potential of image-based analysis to assess TBS coloration quality. CAM is intended to function as a supportive tool for analyzing the coloration quality of thick blood smears.

Enhanced Artificial Intelligence Methods for Liver Steatosis Assessment Using Machine Learning and Color Image Processing: Liver Color Project.

BACKGROUND: The use of livers with significant steatosis is associated with worse transplantation outcomes. Brain death donor liver acceptance is mostly based on subjective surgeon assessment of liver appearance, since steatotic livers acquire a yellowish tone. The aim of this study was to develop a rapid, robust, accurate, and cost-effective method to assess liver steatosis. METHODS: From June 1, 2018, to November 30, 2023, photographs and tru-cut needle biopsies were taken from adult brain death donor livers at a single university hospital for the study. All the liver photographs were taken by smartphones then color calibrated, segmented, and divided into patches. Color and texture features were then extracted and used as input, and the machine learning method was applied. This is a collaborative project between Vall d'Hebron University Hospital and Barcelona MedTech, Pompeu Fabra University, and is referred to as LiverColor. RESULTS: A total of 192 livers (362 photographs and 7240 patches) were included. When setting a macrosteatosis threshold of 30%, the best results were obtained using the random forest classifier, achieving an AUROC = 0.74, with 85% accuracy. CONCLUSION: Machine learning coupled with liver texture and color analysis of photographs taken with smartphones provides excellent accuracy for determining liver steatosis.

Identification and functional analysis of GmPasL regulating pod color in vegetable soybean.

BACKGROUND: Vegetable soybean is rich in nutrients and has a unique flavor. It is highly preferred by people because of its pharmacological activities, including those that regulate the intestines and lower blood pressure. The pod color of vegetable soybeans is an important quality that indicates their freshness and has a significant impact on their commercialization. RESULTS: In this study, pod color was evaluated in 301 vegetable soybean accessions collected from various regions. Genome-wide association analysis was carried out using the Mixed linear model (MLM), a total of 18 quantitative trait loci including 117 SNPs were detected. Two significant QTLs located on chromosomes 6 (qGPCL4 /qGPCa1/qGPCb2) and 18 (qGPCL10/qGPCb3) were consistently detected across different variables. Based on gene functional annotation, 30 candidate genes were identified in these two candidate intervals. Combined with transcriptome analysis, Glyma.18g241700 has been identified as a candidate gene for regulating pod color in vegetable soybeans. Glyma.18g241700 encodes a chlorophyll photosystem I subunit XI. which localizes to the chloroplast named GmPsaL, qRT-PCR analysis showed that GmPsaL was specifically highly expressed in developing pods. Furthermore, overexpression of GmPsaL in transgenetic Arabidopsis plants produced dark green pods. CONCLUSIONS: These findings may be useful for clarifying the genetic basis of the pod color of vegetable soybeans. The identified candidate genes may be useful for the genetic improvement of the appearance quality of vegetable soybeans.

Change of bioactive properties, spectral reflectance, and color characteristics of European cranberry (Viburnum opulus L.) juice as affected by foam mat drying technique.

The European cranberry bush, known for its health benefits, can only be consumed through fermentation. This study aimed to develop a fruit leather made from European cranberry bush using quince seed gel and the foam drying method. For this purpose, quince seed gel was added to European cranberry juice to increase consistency. Then, European cranberry fruit leather was obtained by drying at 70, 80, and 90 °C air temperatures using foam mat drying technology. Spectral reflectance, color, drying kinetics, anthocyanin, ascorbic acid, and total phenolic content, antiradical activity, and macro-micronutrient concentrations of the resulting fruit pulp were investigated. The foam mat drying process at 90 °C had the greatest values of ascorbic acid (0.996 mg g- 1), anthocyanin (275.9 mg kg- 1), DPPH (47.77%), and ABTS.+ (68.76 µg TE g- 1). In addition, the highest value of total phenolic content (37.75 mg g- 1) was obtained in the foam mat drying process at 80 °C. The highest concentration of P, Na, Mg, K, Ca, and Mn in fruit leather was obtained at 70 °C, and the highest concentration of S, Cu, and Zn was obtained at 90 °C. The lowest spectral reflectance values were measured at 90 °C. In conclusion, the present study explored the fact that adding quince seed gel, extremely rich in biochemical content, significantly enhanced the bioactivity properties of European cranberry bush fruit leather.

INFLUENCE OF ABUTMENT MATERIAL, CEMENT THICKNESS, AND CROWN TYPE ON THE FINAL COLOR OF IMPLANT-SUPPORTED RESTORATIONS.

PURPOSE: To evaluate the influence of abutment material, cement thickness, and crown type on the esthetics of implant supported restorations. MATERIAL AND METHODS: In total, 60 specimens were prepared to represent six abutment groups: Group PA = pink-anodized Ti; Group GA = gold-anodized Ti; Group T = nonanodized Ti; Group H = hybrid (Ti + zirconia); Group P = PEEK (Ti + PEEK); and Group C = composite resin (control). Crown specimens (n = 120) were obtained from Vita Enamic (VE) and Vita Suprinity (VS). Two cement thicknesses (0.1 and 0.2 mm) were used. The color values of crown configura:ons were measured and ΔE00* values were calculated. Statistical analyses included were Shapiro Wilk, three-way ANOVA, and Tukey HSD tests (P ≤ .05). RESULTS: Abutment (P < .001) and crown materials (P = .001) had a significant effect on ΔE00* values, while cement thickness did not. Groups PA and H resulted in significantly lower mean ΔE00* values than other abutments, whereas Group T revealed the highest. Unlike VS, cement thicknesses created a significant difference on the ΔE00* values for VE (P ≤.05). CONCLUSIONS: Pink-anodized Ti or hybrid abutments for VE and pink- or goldanodized Ti for VS seem to be better options, in terms of color change. Cement thickness of 0.1 mm resulted in higher ΔE00* value than 0.2 mm for VE (P ≤ .05).

The Effect of Cigarettes Smoke on the Color and Properties of a Silicone for Maxillofacial Prostheses.

Although deterioration of silicone maxillofacial prostheses is severely accentuated in smoking patients, the phenomenon has not been systematically studied. To address a gap in the literature concerning the stability of maxillofacial prostheses during service, in this contribution, the effect of cigarette smoke on the aspect and physical properties of M511 silicone elastomer was evaluated. The aspect, surface, and overall properties of the silicone material, pigmented or not, were followed by AFM, color measurements, FTIR, water contact angle measurements, TGA-DTG and DSC, hardness and compression stress-strain measurements. The types of the contaminants adsorbed were assessed by XRF, ESI-MS, MALDI-MS, and NMR spectral analyses. Important modifications in color, contact angle, surface roughness, local mechanical properties, and thermal properties were found in the silicone material for maxillofacial prostheses after exposure to cigarettes smoke. The presence of lead, nicotine, and several other organic compounds adsorbed into the silicone material was emphasized. Slight decrease in hardness and increase in Young's modulus was found. The combined data show important impact of cigarette smoke on the silicone physical properties and could indicate chemical transformations by secondary cross-linking. To our knowledge, this is the first study making use of complementary physical methods to assess the effect of cigarette smoke on the aspect and integrity of silicone materials for maxillofacial prostheses.

3-Ethoxysalicylaldimine-based symmetrical azine-linked luminogen exhibiting ESIPT and bright orange colour AIE behaviour with live cell bioimaging application.

Herein, we describe the design and development of a new cell-permeable aggregation-induced emission (AIE) active 3-ethoxysalicylaldimine-based symmetrical azine molecule HDBE. The synthesized compound underwent comprehensive investigation of different spectroscopic methods, like NMR, mass and single crystal X-ray diffraction analysis. The fluorophore HDBE exhibited the bright orange colour AIE behaviour in THF-H2O mixture. The drastic enhancement of emission was achieved upon adding the water to the THF solution of HDBE, with a concentration of 90%. Along with the dynamic light scattering (DLS) and quantum yield measurements, the formation of aggregates was also verified by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis. Further, HDBE demonstrated excited state intramolecular proton transfer (ESIPT) characteristics in different polarity of solvents, which was corroborated by absorption, emission and lifetime spectroscopical investigations. The detailed scrutiny of X-ray structure of HDBE displayed the two strong intramolecular hydrogen bonding interactions, while solid-state fluorescent spectra showed dual emission that corresponds to enol and keto form confirming the ESIPT feature. Further, the synthesized AIE molecule was non-toxic and cell-permeable, making it easy to label as a biomarker in live HeLa cells via fluorescent bioimaging. These studies offer a quick and easy way to develop both AIE and ESIPT-coupled molecules for live cell bioimaging applications.