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This study assessed the impact of beverage temperature on the surface roughness, microhardness, and color stability of monoshade composite resin. A batch of 70 monoshade composite resin specimens manufactured by Charisma Diamond ONE (Kulzer, Hanau, Germany) was prepared. Initial readings for surface roughness, microhardness, and color were recorded. The specimens were then divided into seven groupings of ten each: Distilled water (control group), Nescafe coffee at 70 °C and 5 °C, Arabic coffee at 70 °C and 37 °C, and cola at 7 °C and 24 °C. These samples underwent 30-min daily immersion in their respective beverages for a duration of 30 days. Final measurements were then taken. A non-contact profilometer was used for measuring surface roughness, a Vickers microhardness machine from Contour GT-I (Bruker Nano GmbH, Berlin, Germany) for microhardness, and a Color-Eye 7000A Spectrophotometer (X-Rite, GretagMacbeth, Michigan USA) for color stability. Statistical analyses, including repeated measure ANOVA for microhardness, roughness, and color, were executed using SPSS version 23. All beverages led to changes in composite color and properties. Notably, coffee at 70 °C resulted in significant discoloration of the composite resin surface (p < 0.0001). The beverage that most affected the surface hardness and roughness of the monoshade composite resin was cola at 7 °C (p = 0.008) The inherent chemicals in beverages, coupled with their temperatures, can influence the composite properties of resin, specifically surface discoloration, hardness, and roughness. Clinicians may, therefore, consider instructing patients about the potential negative effects of these beverages. [ABSTRACT FROM AUTHOR]

Additive manufacturing is a newly developed method that provides a compelling and practical alternative to conventional subtractive manufacturing methods. Therefore, this study evaluates and compares the color stability and microhardness of two types of 3D-printed definitive hybrid ceramic materials after storage in different staining solutions. A total of 180 rectangular shape samples were fabricated from Crowntec, VarseoSmile Crown Plus and Vita Enamic. 90 samples (14×12×1 mm) were stored in different staining solutions. The color measurements were taken at the baseline and after three different periods (one week, two weeks and one month) using an Easyshade advance 4.0 spectrophotometer. Another 90 samples (14×12×5 mm) were subjected to a one-week storage period. The Microhardness measurements were taken at the baseline and after a one-week staining period using a digital Vickers microhardness tester. Three-way ANOVA test at a 0.05 significance level followed by Tukey's for pairwise comparison among the groups. The CT had the highest color change (ΔE) compared to VS and VE. VE displayed the lowest ΔE value among different materials. Coffee caused a greater color change compared to tea and distilled water. In contrast, the lowest (ΔE) was observed in the distilled water. Regarding the microhardness test, the results showed a significant difference (P<0.05) between VE and 3D printed materials, with no significant difference between CT and VS. VE displayed the highest Microhardness value, while the lowest Microhardness was observed in VS material. 3D-printed hybrid materials seem to offer less color stability and lower microhardness when compared to CAD CAM material. [ABSTRACT FROM AUTHOR]

This study aimed to use spectrophotometry to assess the color stability of composite resins polished with different polishing techniques and scanning electron microscopy (SEM) to evaluate the surface micromorphology of the specimens. In this in vitro experimental study, a total of 96 disc-shaped specimens were fabricated from microfilled (Renamel Microfill, shade SB3) and natiohybrid (Estelite Sigma Quick, shade BW) composite resins in bright white shades (n = 48). Each group was randomized into 1 control and 2 experimental subgroups (n = 16): no polishing (control), polishing with aluminum oxide discs (experimental), or polishing with diamond-impregnated spiral wheels (experimental). In each subgroup, half of the specimens were immersed in a coffee solution and the other half in a tea solution for 48 hours after finishing (control) or polishing (experimental). Spectrophotometry was used to measure the color of the specimens at baseline, after finishing, after polishing (experimental groups only), and after immersion in tea and coffee. The surface micromorphology of a randomly selected specimen from each subgroup was assessed under SEM. The color change (AF) of the specimens between measurements was calculated and analyzed using 1-way, 2-way, and 3-way analyses of variance (ANOVAs) and the Tukey test. Both tea and coffee caused significant color change in the composite resin specimens, with specimens immersed in coffee undergoing significantly greater color change than those immersed in tea (P < 0.001; 2-way ANOVA). The nanohybrid composite specimens polished with polishing discs had a significantly greater color change than nanohybrid specimens polished with spiral wheels (P = 0.041). The Tukey test revealed that there was no overall significant difference between the 2 polishing techniques (P = 0.505), but both of these subgroups exhibited a significantly lower color change than the control group (P < 0.001). In general, SEM did not reveal substantial differences between the 2 polishing techniques, but specimens polished by spiral wheels appeared to have a smoother surface. All polished specimens demonstrated clinically acceptable mean color change values (AF < 3.5). The type of coloring agent had a greater effect on color stability than either the polishing technique or type of composite resin, with coffee causing a greater color change than tea. [ABSTRACT FROM AUTHOR]

A fabric sensitive to acidic vapors has been developed, using cationized cotton with eco-friendly pH-sensitive colorant turmeric. The fabric displays a color change in acidic and alkaline conditions on immersion and to acidic vapors. The fabrics show excellent reversibility on washing and can be used multiple times. [ABSTRACT FROM AUTHOR]

This investigation was carried out to examine the influence of thermocycling aging on the surface roughness (R a , µm), color parameters (L*, a*, b*), lightness change (ΔL*), chroma change (ΔC* ab), color change (ΔE), and microhardness (VH) of three lithium disilicate ceramics. Forty-five specimens were prepared from three lithium disilicate materials (n = 15)—e.max CAD (EC), e.max Press (EP), and GC Initial LiSi Press (LP) ceramics—with dimensions of 6.0 × 1.2 × 16.0 ± 0.2 mm following the manufacturers' instructions. All specimens were exposed to 5000 thermal cycles with bath temperatures ranging between 5 °C and 55 °C. Data of surface roughness, color parameters, and microhardness were obtained using an optical profiler, a spectrophotometer, and a Vickers hardness tester, respectively. One-way ANOVA, a post-hoc Tukey's test, and a paired sample t -test were implemented for statistical analysis (p ≤ 0.05). For surface roughness, insignificant differences were reported between the materials either before or after thermocycling (p > 0.05) while each material displayed a significant increase after being subjected to thermocycling (p < 0.05). For color parameters, LP showed significantly lower L* and b* after thermocycling while EC presented a significant reduction in a* in comparison with other materials (p < 0.05). EP showed a significant decrease in ΔL*, ΔC* ab and ΔE compared with other materials (p < 0.05). Regarding microhardness, LP showed significantly increase value in comparison with other materials (p < 0.05). Thermocycling had a major impact on the surface roughness, microhardness and optical characteristics of the tested materials. E.max Press displayed less changes in (ΔL*), (ΔC* ab) and (ΔE), while GC LiSi Press had better behavior in terms of microhardness. [ABSTRACT FROM AUTHOR]

This study investigated color (E00) and translucency (TP) changed of 3D printing VarseoSmile Crown plus® and milling VITA Enamic® CAD/CAM hybrid material. The 126 rectangular specimens from each material were divided randomly (n=42) to immersed in distilled water, coffee, and cola. E00 and TP were computed before and after immersing at 1 week, 2 weeks, and 1 month using a spectrophotometer, following ISO/TR 28642:2016 standards. Two-way ANOVA followed by Tamhane post-hoc test and a one-way repeated measures ANOVA were performed (P=0.05). The result revealed that the types of material and beverages significantly affected E00 and TP, except for E00 in the first week was not significantly affected by types of material (P = 0.84). The E00 of VS showed more color change than EN after being immersed in coffee and cola at all time points. Also, the TP of VS shows more translucency change statistically significant than EN after being immersed in coffee and water at all time points. Coffee showed the highest discoloration of materials over 30 days. Time is a crucial factor increasing in discoloration. The results concluded that 3D printed resin-ceramic hybrid material prone to have more color and translucency change than milled resin-ceramic hybrid material. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate the influence of brushing with regular or whitening dentifrices on the change in color and micromorphologic surface of ceramic orthodontic brackets subjected to coffee staining. Fifty ceramic brackets were subjected to cycles of coffee staining followed by brushing according to the following groups (n = 10): C, control (no brushing); DW, brushing with distilled water; CT, brushing with Colgate Total 12 Clean Mint (regular toothpaste); COW, brushing with Colgate Optic White (containing 1% hydrogen peroxide); and CUWA, brushing with Close-Up White Attraction (containing blue covarine). The color of the brackets was assessed using the Commission Internationale de l'Eclairage (CIE) L*a*b* system at 5 different timepoints: prior to staining (baseline) and after 1, 7, 14, and 21 days of staining and brushing cycles. The surface micromorphology of the brackets was assessed at the baseline timepoint and after 21 days. Kruskal-Wallis, Dunn, Friedman, and Nemenyi tests were applied (α = 0.05) for the statistical analysis. The C group demonstrated a significant reduction in L* and a significant increase in a* and b* values over time. For the DW group, the L* value was reduced but was higher than in the C group, and there were also significant increases in a* and b* from baseline values. A significant increase in the a* and b* values was observed in all groups (P < 0.05). Total color change (ΔE*) increased over the period of evaluation for all whitening groups, although only the CT group presented significantly lower ΔE* than the other dentifrices. At the end of the test period, only the COW group exhibited a surface with higher porosity. None of the dentifrices prevented the brackets from staining, but they did reduce the magnitude of color change caused by coffee. The most significant difference was found in the CT group. Micromorphologic surface changes were observed when COW was employed. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine the effect of the color stability of acrylic resin dentures and the surface roughness of acrylic resin dentures immersed in denture cleanser agents in the form of effervescent tablets from tobacco leaves (Nicotiana Tabacum L.) 75% for 16 days. The type of this research is a laboratory study with a randomized posttest only control group design. Samples for the surface roughness and color change test were divided into three groups, group 1: the acrylic resin plate was immersed in distilled water (control) for 16 sample days. Group 2: the acrylic resin plate immersed in sodium hypochlorite for 16 days, and lastly, group 3: the acrylic resin plates immersed in tobacco leaf effervescent tablets at 75% concentration for 16 days.. There were significant differences in surface roughness, namely acrylic plates immersed in Aquades, sodium hypochlorite, and 75% tobacco (Nicotiana tabacum L.) leaf extract effervescent tablets for 16 days. Acrylic plates immersed in distilled water had a significant difference in color change with acrylic plates immersed in effervescent tobacco leaves (Nicotiana tabacum L.) 75%. On the other side, there was a significant difference in discoloration between the acrylic plates immersed in sodium hypochlorite with the acrylic plate immersed in effervescent tobacco leaf (Nicotiana tabacum L.) 75%. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyze and compare the efficacy of different bleaching agents typically used for internal bleaching of endodontically treated discolored teeth. Electronic databases (PubMed, Web of Science, and Cochrane Library) were searched by 2 reviewers for clinical trials in which the color of endodontically treated discolored teeth before and after internal bleaching was examined using shade guide units (ΔSGU) or a spectrophotometer/colorimeter (ΔE). The efficacies of the bleaching agents were compared using subgroup analyses. Statistical heterogeneity was assessed with the Cochran Q test and I 2 statistic. Publication bias was evaluated using funnel plots. Eight studies were included in the systematic review, 6 of which could be included in the meta-analyses. Internal bleaching led to a significant change in tooth shade (ΔSGU: 6.27 [95% confidence interval, 5.36–7.17], ΔE: 12.83 [95% confidence interval, 9.46–16.20]). With regard to ΔSGU, the use of carbamide peroxide (35% or 37%), hydrogen peroxide (35%), and the combination of sodium perborate and hydrogen peroxide (3% or 30%) led to a better bleaching effect than sodium perborate (adjusted P value ≤.026). Regarding ΔE, there were no significant differences between carbamide peroxide (37%), hydrogen peroxide (35%), and sodium perborate mixed with hydrogen peroxide (P =.051). The risk of bias of the included studies was classified as moderate to high. Carbamide peroxide, hydrogen peroxide, and sodium perborate have a significant bleaching effect on discolored, root canal–treated teeth. For a valid assessment of shade stability and a comparison of bleaching agents and their concentrations, further studies with long-term recalls are necessary. [ABSTRACT FROM AUTHOR]

We evaluated twelve commercially available bulk-fill resin composites to determine the colorimetric changes that occurred as a result of the photo-polymerization reaction. Samples of the resin composites were prepared as disks 8 mm in diameter and 3 mm in thickness. A colorimeter was used to measure the color of samples on a black background before and after the polymerization processed had been initiated. As results, each of the photo-initiated bulk-fill resin composites tested except for Beautifil Bulk A showed a significant color difference more than that of conventional resin composites. Bulk Base Flow became darker, whereas Beautifil Bulk Flow became clearly lighter. All resin composites except for Bulk Base Flow became less yellow. Thus, Beautifil Bulk A exhibited the least color change among all the bulk-fill resin composites. However, this color change showed a marked change (NBS units) as observed by the human naked eye. [ABSTRACT FROM AUTHOR]

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To investigate the efficacy of two dental bleaching systems on stained-arrested caries lesions (s-ACLs) and assess the bleached lesions' susceptibility to re-staining. Sixty human molars with s-ACLs were selected. Baseline color was measured spectrophometrically (CIE/L*a*b*), then specimens were randomized into three groups (n=20) based on the bleaching protocol used. G1- no bleaching (negative control); G2- simulated at-home bleaching (15% carbamide peroxide,4h/dx7); G3- simulated in-office bleaching (40% hydrogen peroxide;20 minx3), after which specimens were stained (coffee and tea solution; 8h/dx5). The study outcome was color change (ΔE), measured at baseline, after bleaching and after staining. Data were analyzed using ANOVA and Dunnett T3 tests (α=0.05). G2 significantly (p<0.001) improved the color lightness (ΔE 7.6) compared to G3 and G1 (ΔE 3.7,3.2) respectively. After staining, G2 and G3 (ΔE 8,7.3) had a significant increase (p≤0.009) in stains absorption (darker) compared to G1 (ΔE 3.1). However, G3 had a significant difference (p<0.003) after bleaching and after staining compared to G1 and G2. Bleaching s-ACLs using at-home bleaching systems (15% CP) demonstrated significant color improvement compared to in-office bleaching systems (40% HP). However, both bleaching protocols resulted in a more susceptible lesion surface to re-staining. To maintain the optimum bleaching outcome of s-ACLs, clinicians should consider using remineralizing agents and instruct their patients to avoid coffee and tea consumption after the bleaching treatment. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate different aging method effects on color change of bulk-fill resin composite (BFRC) and anterior resin composite (ARC). Sixty disc-shaped samples (8-mm in diameter and 4-mm thick) were prepared (30 samples in each composite). Samples were divided into 3 groups according to different aging procedures which were thermal cycling [TC], autoclave aging [AA] and water aging [WA] (n=10). Color measurements of the samples were recorded before and after aging. Color changes were calculated using the CIEDE2000 (ΔE00) formula. Color measurements of the samples were recorded before aging. After aging, color measurements were repeated and color changes were calculated using the CIEDE2000 (ΔE00) formula. Color differences were analyzed using a two -way analysis of variance and Holm-Sidak comparison. Significant differences were observed among the composite groups and aging methods (p<0.05). All aging methods caused color change in composites. ARC showed less color change than BFRC. WA caused minimal color change and showed significantly difference than other aging methods. However no significat difference in color change were found between TC and AA. The results provide information on the color stability of composite resins ARC and BFRC after different aging methods. In terms of esthetic dentistry, ARC composites should be used in the anterior region, where there is a high risk of caries due to coloration. [ABSTRACT FROM AUTHOR]

In Egypt, parchment manuscripts and tanned leathers artifacts in public and private libraries, archives, museums and store houses of museums are susceptible for the growth of fungi, and this may due to the improper factors such as extreme temperature, relative humidity, high light levels and etc. this study aims to isolate and identify fungi from different locations in Egypt; and to evaluate the efficiency of Habat Albaraka (Nigella sativa L.) as a natural extract of oil fungicide used against microorganisms which isolated from historical parchment and leather samples and follows the improvements or changes of selected parchment and leather properties. As it is the first time to use it in the field of conservation of the historical manuscripts. Radial growth, change of color by spectrophotometer, mechanical properties (tensile strength and elongation) and Fourier Transform Infrared Spectroscopy (FTIR) were used for the evaluation of efficiency of Habat Albaraka used as a natural extract of oil- less toxic antifungal agent. The results showed that the most dominant fungi were Aspergillus niger and Aspergillus sulphureus. The results proved that Habat Albaraka used prevents the growth of identified fungi, but the third concentration is the best. The loss of color changes and mechanical properties decreased with increasing the concentration of fungicide used. This study confirms that the application of Habat Albaraka natural extract of oil as fungicide is necessary and useful in the preservation of parchment manuscripts and leather artifacts besides using Habat Albaraka as a natural antifungal essential oil improved the mechanical properties of the historical manuscripts. [ABSTRACT FROM AUTHOR]

The aim of this study was to clarify the temperature dependence of color, i.e. the thermochromism of restorative composite resins at typical intraoral temperatures. Five brands of restorative composite resins were used. The CIE L*a*b* color values were measured using a spectrophotometer at specimen temperatures of 4, 23, 37, 60, and 80°C. The temperature dependence of the refractive index of the materials at 4-80°C were also determined using a refractometer. The values of L* for all materials decreased, and those of a* and b* for most of the materials increased, with increasing temperature. The color difference (ΔE*) for all materials increased with increasing specimen temperatures. The refractive index of the A4 shade of the materials consistently decreased with increasing temperatures. Most of the materials exhibited perceptible thermochromism related to intraoral thermal conditions. Optical properties that change in response to temperature could help explain the thermochromism of materials. [ABSTRACT FROM AUTHOR]

Bronze was well known in ancient Egypt since the 12th dynasty (1991-1759 B.C). Bronze artifacts endure different types of corrosion due to intrinsic and extrinsic factors before and/or after extraction. This led to various deterioration aspects: corrosion products of several colors, pits, cracks, grooves and lost parts. Nanometerials and nanocomposites were widely used for the inhibition of micro - organisms, consolidation, and protection of artifacts. But very few studies were concerned with the completion of lost parts, which is considered a challenge in the conservation of cultural heritage. This research focused on finding out a suitable nanocomposite for this purpose. Three polymers: Paraloid B-66, Plexisol P-550, and thermoplastic polyurethane were evaluated through mechanical properties before and after exposure to artificial ageing (ultraviolet radiation). Nan-copper and nano-silver particles were added in three concentrations 0.25. 0.5, 1% w/v to plexisol P-550, which donate the best results to form nanocomposites. Shear strength and color change of nanocomposites were determined. Transmission electron microscope TEM was utilized for characterization of nano-particles. Whereas stereomicroscope SM, polarizing microscope PLM, scanning electron microscope SEM, attached with energy dispersive X- ray unit EDX, and portable X-ray fluorescence p-XRF spectrometer were used to diagnose deterioration phenomena, to determine microstructure and to analyse chemical composition of the studied statue's alloy. Data declared that 1% nano- copper plexisol P-550 composite was the best one for improving mechanical properties without effect on color. It was applied for the completion of lost parts in an ancient Egyptian bronze sacred Ibis bird statue, Late Period (664-332 B.C), from the Grand Egyptian museum, Giza, Egypt. [ABSTRACT FROM AUTHOR]

• 35% HP + violet LED bleached the blood-stained teeth effectively. • Ten cycles of violet LED irradiation associated with 35% HP decreased the clinical time. • 35% HP + violet LED showed the same bleaching efficacy of 35% HP used alone, even after 9 months. • Violet LED used alone was not effective to bleach blood-stained teeth. Few studies have investigated the effect of violet LED irradiation associated or not with bleaching agents on blood-stained teeth. This in vitro study aimed to evaluate the whitening efficacy and color stability of non-vital dental bleaching using 35% hydrogen peroxide (HP) photoactivated with violet LED (VL) compared to 35% HP alone and 35% HP photoactivated with blue LED (BL). Fifty bovine dental crowns were used to obtain specimens of 5 × 5 × 2 mm. After selection based on a previous colorimetric analysis, the specimens were blood-stained and randomly assigned into five groups (n = 10): control (no treatment); 35% HP, 35% HP/BL; 35% HP/VL; and VL. Three bleaching sessions were performed and the colorimetric analysis (∆E ab, ∆L, and ∆WI D) was recorded after 7 days, 30 days, and 9 months of the last bleaching session. Two-way repeated measures ANOVA followed by Bonferroni post-hoc test was used at a significance level of 5%. 35% HP, 35% HP/BL, and 35% HP/VL showed higher values of ∆E ab, ∆L, e ∆WI D (P < 0.05), without intra- and intergroup differences (P > 0.05). C and VL were similar in all the evaluation times (P > 0.05), showing lower values of ∆E ab, ∆L, and ∆WI D (P < 0.05). 35% HP/VL can be a viable alternative for dental bleaching in endodontically-treated teeth, showing bleaching efficacy similar to 35% HP solely used, even after a 9-month follow-up. VL used alone was not effective to bleach blood-stained teeth. [Display omitted] [ABSTRACT FROM AUTHOR]

The impact of the spectral composition of light on the discoloration of paint pigments has been investigated for the case of lead chromate sulfate, an unstable yellow pigment used by Vincent van Gogh and other painters. With LEDification, museum lighting is moving from using halogen to LED lamps. LED light sources have a significantly different spectral composition than halogen lamps. To understand the impact of these differences on pigment stability, the wavelength dependence of pigment discoloration was determined. Contrary to the expectation that lower wavelength photons induce more damage than higher wavelength ones, UV (394 nm), blue, and cyan light all lead to similar levels of discoloration of a pigment for the same level of radiant power. By understanding this wavelength dependence, it becomes possible to create white light LED lamps with a spectral composition tuned to minimize the degradation effect. An existing LED solution with a modified emission indeed resulted in 30% less color change in the experiment than halogen. Furthermore, a method is proposed to optimize the LED spectra by tuning to the properties of each specific artifact. Simulations show that this can reduce the damage of the light source by 45% in specific cases. [ABSTRACT FROM AUTHOR]

Wheat noodles cooked for different periods of time were stored at 5 °C, and color changes in their cross sections were quantitatively assessed by digital image analysis. The color of noodles with flattened moisture distributions whitened greatly during the early stages of chilled storage due to the retrogradation of starch, with the color change showing a significant correlation with the changes in noodle fragility. Color changes were also measured for wheat noodles and noodles containing modified starch with internal moisture distributions, and local changes within the noodles were kinetically analyzed. The addition of modified starch significantly reduced the color change in the noodle interior, where the moisture content was relatively low. Scanning calorimetric measurements indicated differences in the gelatinized state of modified starch and original wheat starch at low moisture contents, which affected the rate of color change in the interior of noodles containing modified starch. Changes in the average gray level of the cross-sectional image of wheat noodles cooked for 5 (), 13.8 (), and 20 min () during the storage at 5 °C. [ABSTRACT FROM AUTHOR]

• Violet LED increases the bleaching efficacy of 35% HP in a time-saving manner. • The pH of the bleaching gel decreased during the session. • Violet LED safely increases the temperature of 35% HP. • The renewal of the gel during the bleaching session did not influence the pH regardless of the use of violet LED. This study aimed to evaluate the bleaching efficacy, pH, and temperature of 35% hydrogen peroxide (HP) gel used alone or associated with violet LED. Sixty bovine crowns were sectioned (5 × 5 × 2mm). After staining with black tea, the specimens were randomized into four groups (n = 10) according to the bleaching protocol: HP35R: 3 × 15 min 35% HP; HP35: 1 × 45 min 35% HP; HP35VR: 3 × 8min 35% HP + Violet LED; HP35V: 1 × 24 min + Violet LED. Two bleaching sessions were performed for all the groups. Color change was evaluated before, 24h after each session, 7 days and 15 days after the last session. The variables ∆E 00 [CIEDE2000] and W ID were used for color analysis. The pH variation (initial and final) and the temperature of the gel were recorded (n = 5). ANOVA two-way for repeated measures and Bonferroni post-test was used at a significance level of 5%. HP35VR and HP35V the most noticeable color change(p < 0.05). The final values of pH were lower than the initial ones, but with no difference between the groups (p > 0.05). Groups HP35VR and HP35V showed an increase in temperature in relation to HP35R (p < 0.05). Violet LED improved the bleaching efficacy of 35% HP in a time-saving manner without negatively affecting the pH and temperature of 35% HP. The renewal of HP did not influence the outcomes. [ABSTRACT FROM AUTHOR]

The microfade tester is used to assess fading rates of fugitive colors of collection items. The paper presents the research considerations to design a simple, less expensive and portable contact microfade tester that could serve as a screening tool for conservators. Hardware design for such an instrument is presented that includes variations in light source (xenon or LED) and measuring head (ball lens or angled holder fiber), and does not need refocusing between measurements. Performance of the portable microfade tester versions was tested on lab samples and a paper based collection item and based on the ability to rank light sensitivity relative to that of ISO Blue Wool Standards 1, 2 or 3. The results are compared to the ranking obtained with the bench instrument when testing sensitivity of the same items for the same duration. All versions of the portable hardware were found suitable for use as a screening tool to discriminate light-sensitive collection items, with performance of the portable microfade testers using an LED optimized for samples more fugitive than Blue Wool Standard 3. These portable microfade testers need not replace the bench microfade tester as the presented portable microfade tester versions are only suitable to test collection items tolerating surface contact with the instrument. [ABSTRACT FROM AUTHOR]

Conservation treatments may cause alterations to the aesthetic qualities and appearance of paper materials, including their color. The scientific evaluation of color change to measure the effects of conservation treatments is therefore valuable information for the conservator weighing the advantages and disadvantages of the various treatments and approaches available. In this study, two Japanese tissue papers (Yukyu-shi and Sekishu Mare) were treated with plant dyes including black tea, henna, fresh and dried Eucalyptus cinerea leaves, as well as selected watercolors and acrylic paints. Paper specimens were subjected to both moist-heat artificial aging and accelerated photo-aging and color changes were measured using spectrophotometry and microfading tests. Color change is here defined as a change in light/dark, red/green, and yellow/blue coordinates in the International Commission on Illumination (CIE) color space of light reflected from a colored surface before and after an intervention such as accelerated aging. The findings of this study show that paper samples treated with plant dyes experienced larger and more perceptible color changes, as measured by spectrophotometry, compared to untreated controls and samples treated with watercolors and acrylic paints. Thus, plant dyes have poor color stability after moist-heat aging when compared with watercolors and acrylic paints. Nevertheless, papers treated with alizarin crimson acrylic paint, dried eucalyptus leaves, and black tea exhibited minimal color change after photo-aging. This study provides paper conservators with a better understanding of toning materials and their color stability when chosen for paper conservation treatment. [ABSTRACT FROM AUTHOR]

This in vitro study aimed to investigate the effect of quercetin pretreatment on the bond strength of bleached dentin. Human dentin blocks (2 × 2 × 1 mm) were prepared and randomly divided into 5 groups (n = 16): deionized water pretreatment + no bleaching treatment (DNB); deionized water pretreatment + bleaching treatment (DYB); 75 μg/mL quercetin pretreatment + bleaching (Q75B); 150 μg/mL quercetin pretreatment + bleaching (Q150B); and 300 μg/mL quercetin pretreatment + bleaching (Q300B). The surfaces of superficial dentin (bonding surfaces) were treated with the respective solutions for 2 min, and then the surfaces opposite to the bonding surfaces (near pulp, bleaching surfaces) were subjected to bleaching treatment with 40% hydrogen peroxide (Ultradent, USA) for two 15-min sessions (groups DYB, Q75B, Q150B, and Q300B). After the bleaching procedure, the bonding surfaces were bonded with resin cements (Panavia V5, Kuraray, Japan). The bonded specimens were then divided into 2 subgroups (n = 8): the aging group (subgroup T), which was subjected to 10,000 thermocycles, and the nonaging group (subgroup N), which was not subjected to thermocycling. The microshear bond strength (μSBS) was obtained using a universal testing machine (AGS-X, Shimadzu, Tokyo, Japan). Additional dentin blocks (5 × 5 × 1 mm) were prepared and treated the same as the groups DYB, Q75B, Q150B, and Q300B (n = 8) to evaluate the color change, defined as groups CC DYB , CC Q75B , CC Q150B , and CC Q300B , respectively. Color evaluation was performed using a spectrophotometer (Vita Easyshade Advance 4.0, Vident, USA) to obtain a baseline and again at the end of the bleaching treatment. The data were analyzed via two-way analysis of variance (ANOVA) and Tukey's post-hoc test (α = 0.05). For the immediate bond strength, the specimens in the groups Q75B, Q150B, and Q300B showed significantly higher μSBS values than those in the group DYB (all P < 0.05). No significant differences in the μSBS values were found among the groups Q75B, Q150B, Q300B, and DNB, respectively (all P > 0.05). For the aged bond strength, both the groups Q150B and Q300B exhibited significantly higher μSBS values than groups DYB and DNB (all P < 0.05), whereas no significance differences were found between groups Q150B and Q300B (P = 1.00) or between the groups DYB and DNB (P = 1.00). No significant differences were observed in the △E values among all the groups tested (P = 0.80). Therefore, the application of quercetin for 2 min prior to the bleaching procedure preserved the immediate bond strength and improved the aged bond strength of bleached dentin while maintaining the effectiveness of bleaching. [ABSTRACT FROM AUTHOR]

Bleaching protocols using low concentration hydrogen peroxide (HP) photoactivated with LED sources have been widely discussed. Herein, we evaluated the whitening efficacy of 15% HP photoactivated with blue or violet LED compared to 35% HP. Thirty bovine crowns were sectioned into 5 × 5 × 2 mm specimens. After staining in black tea, the specimens were randomized into three groups (n = 10): 35% HP, 15% HP + blue LED and 15% HP + violet LED. Two bleaching sessions were performed and the color assessment (∆L*, ∆a*, ∆b*, ∆E ab [CIELab], ∆E 00 [CIEDE2000] and WI D) was performed before, 24h after each session, 7 days and 1 month after the last session. Data were evaluated by two-way repeated measures ANOVA and Bonferroni post-test at a significance level of 5%. All groups showed effective and similar results over 1 month of follow-up (p > 0.05), with only intragroup differences among the time intervals (p < 0.05). The use of 15% HP photoactivated with blue or violet LED showed similar whitening efficacy compared to 35% HP. Thus, the association of low concentration bleaching gels with blue or violet LED sources can provide successful and less-aggressive treatment in terms of color change. [ABSTRACT FROM AUTHOR]

To improve the mechanical strength of denture base resin, several types of noble metal cluster were introduced into PMMA, and the mechanical properties and color changes were evaluated. Complex salts of gold, silver, platinum, and palladium were used as the raw materials of noble metal clusters, and after adding each cluster to MMA, polymerization and thermal treatment were performed to produce PMMA-noble metal cluster complexes. Bending deflection, bending strength, and Vickers hardness were measured, and the formation conditions of metal clusters were investigated using EPMA, SEM, and TEM. Furthermore, color changes between before and after metal cluster creation were measured. The bending deflection increased with the addition of silver and platinum, and decreased with the addition of palladium. The bending strength was lowest with the addition of gold, highest with the addition of palladium. Vickers hardness increased with the addition of palladium. Color differences increased with increasing thermal treatment temperature. [ABSTRACT FROM AUTHOR]

• 35% HP and 6% HP + violet LED showed the best bleaching efficacy. • The use of violet LED alone promoted slight color change. • No enamel microhardness changes were observed. • 35% HP and 6% HP + violet LED changed the enamel roughness. Background : This study evaluated the color change, enamel surface roughness and microhardness after different tooth bleaching protocols, using hydrogen peroxide (HP) and/or violet LED. Methods : Forty bovine specimens (7 × 7 × 2 mm) were randomly distributed into 4 groups: 35% HP, 6% HP, 6% HP + violet LED and violet LED alone. First, the specimens were stained with black tea and then submitted to two bleaching sessions of 30 min with an interval of 7 days. Color change (∆L*, ∆a*, ∆b* and ∆E 00) after 24 h of each session and 1 week after the last session was evaluated. Enamel roughness and microhardness were evaluated immediately before the sessions, 24 h and 1 week after the last session. Data were evaluated by ANOVA for repeated measures and Bonferroni post-test or Kruskall-Wallis and Dunn tests (α = 0.05). Representative specimens from each group were analyzed by scanning electron microscopy. Results : 6% HP + violet LED and 35% HP showed the highest color change, while violet LED alone had the lowest results. Enamel roughness analyses showed that 6% HP + violet LED and 35% HP showed changes after two bleaching sessions. No differences were observed regarding enamel microhardness. Conclusions : The use of 6% HP + violet LED showed enhanced bleaching efficacy compared to 35% HP. However, violet LED used alone exhibited the lowest color change. 6% HP + violet LED and 35% HP promoted changes on enamel roughness, while no microhardness changes was observed for any group. [ABSTRACT FROM AUTHOR]

The fiber mouthfeel of fish muscle is a highly sought-after goal for surimi gel products. The primary aim of research and development has been to quickly and accurately evaluate fiber degree for fish muscle. Therefore, based on the ResNet model, edge feature attentional mechanism was introduced to obtain the edge feature attention net (EFANet) to evaluate fiber degree for fish muscle. The EFANet was trained and tested on a dataset, which was made by collecting microscopic pictures of fish samples with different degrees of breakage. Compared with the three classic convolutional neural network (CNN) models, the EFANet emphasizes the learning of fiber texture information for fish muscle, reduces the effect of image color change, and significantly improves the detection accuracy. The average accuracy and specificity of the EFANet-50 on the testing dataset were 96.22% and 97.92%, respectively, which proved that it can effectively predict the fiber degree of fish muscle. [Display omitted] • EFANet was created for evaluating the fiber degree of fish muscle. • The attentional mechanism of edge feature was introduced in the EFANet. • EFANet emphasizes the learning of fiber texture information for fish muscle. • EFANet reduces the effect of image color change on the model. • The average accuracy and specificity of 96.22% and 97.92% were achieved. [ABSTRACT FROM AUTHOR]

Polyurethane display excellent mechanical and chemical properties. In this work polyurethane containing diacetylene unit was synthesized by two step polymerization with methylene diphenyl diisocyanate (MDI), diol from the mixture of PET glycolysed products and hexadiyne-1,6-diol as chain extender with a molar ratio of NCO:OH (1:1). The reaction was carried out at 80 ̊C for 2 hrs. The obtained polyurethane was characterized using Fourier transform infrared spectroscopy (FTIR), 1H NMR spectroscopy for it functionalities. The thermal behavior of polyurethane was investigated using differential scanning calorimetry (DSC). The result shows that polyurethane containing diacetylene unit could be crosslink by thermal that cause the polyurethane undergoes a color change under thermal treatment and hence heated environment. [ABSTRACT FROM AUTHOR]

Copyright of Wood Industry / Drvna Industrija is the property of Drvna Industrija and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Vlakna a Textil is the property of Vyskumny Ustav Chemickych Vlaken and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: Objective: To investigate the association of the failure of porcelain laminate veneers with factors related to the patient, material, and operator. Methods: This clinical survey involved 29 patients (19 women and 10 men) and their dentists, including undergraduate and postgraduate dental students and dental interns. Two questionnaires were distributed to collect information from participants. All patients were clinically examined. Criteria for failure of the porcelain laminate veneers included color change, cracking, fracture, and/or debonding. Results: A total of 205 porcelain laminate veneers were evaluated. All of the restorations were fabricated from IPS e.max Press and cemented with Variolink Veneer (Ivoclar Vivadent, Schaan, Principality of Liechtenstein) or RelyX veneer cement (3M ESPE, St. Paul, MN, USA). The preparations were generally located in enamel (58.6%), and most veneers had an overlapped design (89.7%). Ten patients (34.48%) showed veneer failure, most often in terms of color change (60%). Overall, 82.8% of patients were satisfied with their restorations. Conclusion: Insufficient clinical skills or operator experience resulted in restoration failure in one-third of patients. [Copyright &y& Elsevier]

The purpose of this study was to evaluate how the temperature affects the stability of polymerized additional photoinitiator-containing composite resins. Five resm products were light-cured using a quartz-tungsten-halogen, and single and dual emission peaks light-emitting diodes. The degree of conversion (DC) and water sorption, solubility, and color change of the specimens were evaluated after immersion in the solutions of different temperatures (4, 37, and 60°C) for 14 days. On the top surface, the light-curing units had no significant influence on DC of the tested specimens. On the bottom surface, the influence was inconsistent. As the solution temperature increased, water sorption also consistently increased in all specimens, whereas solubility changed inconsistently. Water sorption and solubility had a high linear correlation only at low temperature solution. Color change of the specimens was similar, mostly slight, and statistically inconsistent regardless of solution temperature. The restored composite resins are needed to avoid contact with hot solutions for durable dental restoration. [ABSTRACT FROM AUTHOR]

In the wearing of fabrics by abrasion, the relation between the rate of their color change to reach the worn level criterion, ΔE*ab=1.5, and their properties has been investigated. 22 different kinds of cotton plain-woven fabrics and one kind of linen fabric were supplied to prepare the fabric samples with 6 different degree of abrasion. It has been found that the rate of the increase by abrasion in the color difference of the abraded sample from the non-abraded, the rate of wearing, is related to the lightness of the fabrics and to the stiffness in their warp direction. Through the multiple regression analysis of the wearing rate for the 8 factors, stiffness (warp, weft), yarn density (warp, weft), thickness, yarn fineness (average), twist level (average), and lightness L*, it has been clarified that the rate is smaller for the larger lightness, and is greater for the larger warp stiffness, giving a proper regression formula. [ABSTRACT FROM AUTHOR]

This study sought to evaluate the effects of different staining solutions on the colour stability of nanocomposites compared with micro hybrid resin and to evaluate the degree of conversion of these two materials. Two different shades of two different composites were cured in polytetraflouroethylene disk rings. Coffee, tea and cola drinks were used as staining solutions, and distilled water was used as a control. Data were statistically analysed using a paired T-test with a significance. level of 5%. Nano composite showed the highest degree of conversion (DC) values based on calculation of the bonded and free carbonyl peak intensities in the spectrum. The colour analysis showed that nanohybrid had the highest ΔE values when exposed to coffee solutions; they showed less color stability despite having a higher degree of conversion. Nano resin composite showed significantly higher discoloration than microhybrid composite. [ABSTRACT FROM AUTHOR]

This study evaluated the influence of beverages and brushing on the surface roughness(SR) and color change(ΔE) of a composite resin. For this, 120-disks(10 mmx2 mm) of composite resin(Filtek-Z250) were prepared and polished. Initials SR(Ra-μm) and color(CIELab-system) were measured with rugosimeter and spectrophotometer; specimens were divided into four groups(red wine, soft drink, sugar cane spirit, or artificial saliva=control) and three subgroups (without brushing; brushed with Colgate or with Close-Up). Specimens were immersed in the beverage 5x/day, for 5', over 30 day, being two subgroups brushed(120 strokes/day). Color was measured at 15th day, 30th day and after repolishment; SR at 30th day. ΔE-values were statistically different after immersion in the beverages(p<0.05). Red wine promoted the highest alteration, followed by soft drink=sugar cane spirit and finally saliva. At 30th day, specimens exhibited ΔE higher than 15th day; after repolishing, ΔE was similar to 15th day. Beverages and brushing negatively influenced the SR. Therefore, ΔE and SR can be influenced by beverages and brushing. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: The purpose of this research was to evaluate the color change of five aesthetic dental materials, before and after immersion in distilled water and blue food color solution for 7 and 21days, and to study the effect of finishing the surfaces on any color change. Methods: Disc shaped samples of five types of light curing composite (A2) (n =10 samples/composite) were prepared and all samples were light-cured with a Plasma Arc light cure unit for ten seconds. One side of each sample disc was finished and polished with a Super-Snap system all samples. After 24h, color measurements of each sample were conducted using a digital spectrophotometer. Five sample discs from each composite group were immersed in 30ml of food color solution for 7 and 21days, while the remaining five sample discs were immersed in 30ml of distilled water as a control. Color measurements were repeated for all samples at 7 and 21days after immersion. The color changes were statistically analyzed using t-tests within the same group. A result was considered statistically significant at α =0.05. Results: The color differences (ΔE) ranged from 0.4 to 4.66 and statistically significant differences on the finished and unfinished surfaces were observed after immersion in the food color solution for 7days. No significant differences were found in any group after immersion in the food color solution for 21days. The Tetric EvoCeram and Arabesk groups showed less color differences after 7 and 21days than other composites. Conclusion: Finished composite surfaces showed less coloration than unfinished surfaces after 7days, but all surfaces (finished and unfinished) were highly colored for all composite types after 21days. [Copyright &y& Elsevier]

A wide-ranging sample set consisting of dry pigments, dyed textiles, organic and aniline-based dyes, gouaches and watercolors, fluorescent inks, and natural history specimens was exposed to light in air (20.9% oxygen) and near-anoxic environments. After a light dosage of approximately 17.5 Mlux-hours under controlled temperature and humidity conditions, 113 of 125 samples (90% of the sample set) were shown to exhibit less color change in a low-oxygen environment compared with its behavior in air. Thirty-nine percent of this subset displayed color change in anoxia that was between two and four times lower than that observed in air, whereas 47% showed color change in anoxia reduced by a factor of four or more. In contrast, six samples exhibited greater color change in anoxia than in air - these samples included Prussian blue watercolor (three samples), Antwerp blue watercolor, Verdigris dry pigment, and Fluorescent Yellow Winsor & Newton Gouache. Although the results from this small sample subset may cause concern when considering the use of anoxia in the conservation of cultural heritage, particularly for colorant systems whose behavior in anoxia has not yet been identified, this study demonstrates the overwhelming benefits of anoxic light exposure for the vast majority of samples investigated here. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: Recent studies have reported the color change and formation of precipitates containing para-chloroaniline (PCA) after a reaction of sodium hypochlorite (NaOCl) and chlorhexidine (CHX). Alexidine (ALX), a biguanide disinfectant similar to CHX, has greater affinity for bacterial virulence factors than CHX. This study determined by electrospray ionization mass spectrometry (ESI-MS) and scanning electron microscopy (SEM) whether the chemical interaction between ALX and NaOCl results in PCA or precipitates. Methods: ESI-MS was performed on 4 different concentrations of ALX (1%, 0.5%, 0.25%, and 0.125%) with 4% NaOCl to detect the presence of PCA. As control groups, 1% ALX, 0.5% PCA, and a mixture of 2% CHX and 4% NaOCl were analyzed. The formation of precipitates on the dentinal surfaces of premolar root canals treated with the solutions of ALX and NaOCl (AN) or CHX and NaOCl (CN) was observed by SEM and the color change in the reaction solutions was also analyzed. Results: ESI-MS showed that the peak (mass/charge ratio = 128.026) in the PCA spectrum was not detected in any of the 4 AN solutions, whereas the peak was found in the CN solution. SEM revealed precipitates covering dentinal surfaces in the CN solution. The AN solutions produced no precipitate. The AN solutions changed in color from light yellow to transparent with decreasing ALX concentration, whereas peach-brown discoloration was observed in the CN solution. Conclusions: The interaction of ALX and NaOCl did not produce PCA or precipitates, and the color of the reacted solution changed transparent with decreasing ALX concentration. [Copyright &y& Elsevier]

Abstract: This in vitro study was designed to quantitatively evaluate and compare color changes in different types of direct resin-based composites including a silorane-based low-shrink resin composite, after bleaching with 10% carbamide peroxide. Fifty disc-shaped specimens (10/material) from five resin-based composites (Z250, Z350, Valux Plus, P90, and Dyract Extra) were fabricated in a cylindrical rubber mold (10mm diameter×2mm depth) according to the respective manufacturers’ instruction. A spectrophotometer (Color Eye 7000A) against a white background using CIE (L∗a∗b∗) relative to a standard illuminate D65 was used to measure the color of specimens before bleaching procedure as baseline records and after bleaching procedure using (Opalescence PF-10% carbamide peroxide) 8-h daily for 14 consecutive days. The magnitude of color difference (between baseline and after bleaching measurements) is represented by ΔE. Data were subjected to a one-way ANOVA and Bonferroni multiple comparison test at 95% confidence level. The mean color change values (ΔE) were less than 1 and visually non-perceptible to the naked eye for silorane-based low-shrink composite (P90) as well as the other resin-based composites used in this study (nanofilled Z350, hybrid Valux Plus, and microhybrid Z250). Whereas, the mean color change value (ΔE) was higher than 1 and noticeable to the naked eye for polyacid-modified resin-based composite (Dyract Extra), yet considered clinically not significant. [Copyright &y& Elsevier]

The present study sought to evaluate the effect of resin shades on the degree of the polymerization. To this end, response variables affected by the degree of polymerization were examined in this study - namely, microhardness, polymerization shrinkage, and color change. Two commercial composite resins of four different shades were employed in this study: shades A3, A3.5, B3, and C3 of Z250 (Z2) and shades A3, A3.5, B3, and B4 of Solitaire 2 (S2). After light curing, the reflectance/absorbance, microhardness, polymerization shrinkage, and color change of the specimens were measured. On reflectance and absorbance, Z2 and S2 showed similar distribution curves regardless of the resin shade, with shade A3.5 of Z2 and shade A3 of S2 exhibiting the lowestIhighest distributions. Similarly for attenuation coefficient and microhardness, the lowest/highest values were exhibited by shade A3.5 of Z2 and shade A3 of S2. On polymerization shrinkage, no statistically significant differences were observed among the different shades of Z2. Similarly for color change, Z2 specimens exhibited only a slight (ΔE*=0.5-0.9) color change after immersion in distilled water for 10 days, except for shades A3 and A3.5. Taken together, results of the present study suggested that the degree of polymerization of the tested composite resins was minimally affected by resin shade. [ABSTRACT FROM AUTHOR]

• 6% HP and 6% HP + LED/laser present good whitening effects. • 6% HP + LED/laser showed greater whitening efficacy than 6% HP. • LED/laser photoactivation is an option for low concentration HP agents. • No enamel microhardness changes were observed in intra and intergroup evaluation. • Minerals presented in the bleaching gels does not interfere the color change. : The association of low concentration hydrogen peroxide (HP) and a light source has been widely used to achieve efficient bleaching. We investigated the colorimetric and microstructural changes of bovine enamel bleached with 6% HP associated or not with a hybrid light source system of violet light and laser (LED/laser). : Twenty bovine crowns were used to obtain specimens of 7 × 7 × 2 mm. Then, they were randomized in two groups (n=10): 6% HP and 6% HP + LED/laser. After staining with dark tea solution, three bleaching sessions were performed. Colorimetric evaluation (∆L*, ∆a*, ∆b*, ∆E 00 [CIEDE2000] and WI D) after 24 hours of each session and 7 days after the final bleaching session was performed. Enamel Vickers microhardness at baseline, 24 hours and 7 days after the last bleaching session were also evaluated. Two-way repeated measures ANOVA and Bonferroni post-test was used at a significance level of 5%. : 6% HP and 6% + HP LED/laser showed satisfactory bleaching results. The group photoactivated showed higher WI D values (p<0.05). Differences between groups were observed for ∆E 00 , ∆L* and ∆a* (p<0.05), except for ∆b* (p>0.05). Intra-group differences were also found (p<0.05). Regarding microhardness, no inter or intra-group differences were observed (p>0.05). : The photoactivation with LED/laser enhanced the whitening efficacy of 6% HP compared to the group without photoactivation. Thus, the LED/laser activation appears to be a good option when using low concentration HP-based agents. In addition, both bleaching protocols did not cause changes on enamel microhardness. [ABSTRACT FROM AUTHOR]

The objective of the study was to develop pH indicator membranes from polymeric nanofibers with phycocyanin and to evaluate the irreversibility of the system. The polymeric solutions were prepared with 13% (w/v) polycaprolactone (PCL) and 6% (w/v) poly (ethylene oxide) (PEO), with varying phycocyanin concentrations of 0.5, 1 and 2% (w/v) phycocyanin with chloroform and distilled water (8:2) as the solvent. The electrospinning technique was used to form polymeric nanofibers. PCL/PEO nanofibers developed with 2% (w/v) of phycocyanin presented a smaller average diameter (875 nm) when compared to the membranes produced with 0.5 and 1% (w/v) of the pigment. Through the thermal analysis, events associated with the elimination of volatiles, free water, and bound water were observed. The phycocyanin encapsulation efficiency in PCL/PEO nanofibers with 0.5, 1, and 2% (w/v) phycocyanin was 97.7, 97.8, and 91.7%, respectively. The nanofibers with the addition of 1 and 2% (w/v) of microalgal pigment showed slightly hydrophobic characteristics (contact angle>90.0°). The nanofibers of 13% PCL and 6% PEO with 2% (w/v) phycocyanin when tested in pH buffers ranging from 3 to 4 and 5–6 showed color variation values ≥ 8.5. Thus, PCL/PEO nanofibers containing 2% (w/v) phycocyanin become a promising alternative as indicators in packaging to monitor the viability of food. • Nanofibers loaded with phycocyanin showed ΔE≥ 8.5 in the pH ranges of 3–4 and 5–6. • Phycocyanin-containing nanofibers have the potential to monitor food viability. • The color irreversibility of phycocyanin is a relevant characteristic for food monitoring. [ABSTRACT FROM AUTHOR]

This study assessed the effect of acetic NaF solutions on stainless steel orthodontic brackets. Acetic acid was added to a 0.1% NaF solution to make two solutions, one with pH 3.5 and the other with pH 6. For the two different stainless steel brackets (Tomy, Dentaurum) used in this study, they had a similar elemental composition-except with Mo (molybdenum) in the Tomy bracket. The brackets were then immersed in the prepared test solutions for three days and their responses evaluated. In terms of hydrofluoric acid (HF) concentration, the 0.1%/ pH 3.5 solution showed a high HF concentration at 227 ppm, while that of 0.1%/ pH 6 solution was very low at 7 ppm. In terms of color change and element release, only the Dentaurum brackets in 0.1%/ pH 3.5 solution showed an appreciable color change (ΔE*=4.0) and released a great amount of elements (Fe, Cr, Ni, Mn) after three days. Otherwise, regardless of pH value and product, only minor color change (ΔE*<1.0) and negligible element release occurred. In terms of surface modification, no visible changes in surface morphology were observed in any product after immersion in test solutions. [ABSTRACT FROM AUTHOR]

The article presents a study which investigates the color stability of composite resins for a facing crown cured with high output photo-curing unit. It notes the comparison of the four brands of composite resins for a facing crown polymerlized with Hyper LII, after four weeks of immersion in coffee. The study found out that composite resins for a facing crown cured with a high output photo-curing unit has changed its color.

The article presents the research that investigates the response of larval salamander, Ambystoma barbouri and Ambystoma texanum, to ultraviolet radation (UVR) and risk of predation in the U.S. The topics discussed include the effectiveness of microhabitat use, color change and adaptations on coping and avoiding UVR, the evolutionary history and difference of UVR exposure of the two species of salamander, and the sublethal UVR levels.

The article focuses on the study concerning on the artificial resin teeth and its effect from electrolyzed water. The study involves immersion of poly sulfone resin artificial teeth, acrylic resin and hard resin in electrolyzed water. It shows that the electrolyzed water has no effect to artificial resin teeth.

The article focuses on the study concerning denture base resin and its effect from electrolyzed water. It examines the effect of electrolyzed water on dental engineering plastics, dental base resin and relining materials, since electrolyzed water has been widely used for cleaning of the denture. The study shows that electrolyzed water has a little effect on the cleaning of the denture.

• There was a colorimetric change in the teeth evaluated in the study, regardless of the group analyzed after 180 days of whitening. • Quality of life improved for all patients in all groups. • Only patients treated with hydrogen peroxide within the first 24 h in the first 3 whitening sessions reported postoperative dental sensitivity. • Only in hydrogen peroxide group in 33% of patients in the first 3 whitening sessions was it necessary to take pain medication. • Although the violet LED alone did not cause sensitivity and did improve the patients' quality of life, it was not able to whiten teeth to the same degree (WID) as it was when associated with the CP 35% gel or when compared to the gold standard, HP 35%. When using the CieLAB system, there was improvement for ΔL, Δa and Δb, in hydrogen peroxide group, and for carbamide peroxide + LED only for ΔL and Δb after 180 days of bleaching. Background: Although there is little evidence showing the effectiveness of violet LED on in-office tooth whitening, there are some studies which have reported satisfactory results. This double-blind randomized controlled clinical trial aimed to evaluate the effect of a violet light emission diode (LED) (405 nm) system, used in-office, on tooth whitening, sensitivity, use of medication after whitening and quality of life. Methods: Eight patients were randomized into 4 groups (n = 20): G1 - violet LED, G2 - 35% carbamide peroxide (CP) and violet LED, G3 only CP 35% and G4 35% hydrogen peroxide (HP). The color was measured using a spectrophotometer at the following times: baseline, 15 and 180days. The colorimetric changes were analyzed using measurements from the CieLab System ΔE (ΔL, Δa and Δb) and the WID (Whiteness Index for Dentistry) for the 4 groups. Tooth sensitivity was recorded via a visual analog scale (VAS). Additionally, the Psychosocial Impact of Dental. Aesthetics Questionnaire (PIDAQ) was used to evaluate quality of life. Results: For the analysis of ΔL, G4 and G2 presented more brightness than G1 and G3 (p <0.05), implying that G2 is at least as good as G4 (p >0.05). For measure of Δa, G4 presented better results, standing out from the other groups. (p <0.05). For Δb, both G4 and G2 showed a greater tendency for blue color than groups G1 and G3 (p <0.05). When analyzing ∆E at the 180-day follow up, G4 produced the highest ∆E, while G3 showed the lowest ∆E. The other 2 whitening groups produced intermediate ∆E values. For ∆W, G1 and G3 significantly differed from G2 and G3. When analyzing the 180-day follow up, G2 produced the highest ∆W, while G3 showed the lowest ∆W. The other two whitening treatments produced intermediate ∆W values. As for sensitivity, only G4 patients showed dental sensitivity within 24 h of the bleaching, with pain ceasing after 48 h. For G4, 33% of the patients needed to take analgesics within the first 24 h after the first 3 whitening sessions. For PIDAQ, there was no overall decrease in score over time for any of the groups and there was no difference between them (p >0.05). Conclusion: Our results showed that violet LED was not able to whiten teeth at the same intensity, when used alone, as it was when associated with 35% CP, contrary to our initial hypothesis. However, given that pain was not consistently reported in G2, one could suggest that treatment with LED + 35% CP is quite similar to that of 35% HP when used for tooth whitening, but with better pain outcomes. All treatments suggested an improvement in quality of life.Clinical Trial Registry: This trial is registered at ClinicalTrials.gov; the registration number is NCT03192852 https://clinicaltrials.gov/ct2/show/NCT03192852 [ABSTRACT FROM AUTHOR]