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Background: Patients tend to favor the whitening mouthwashes as they are easily applied and affordable. This study aimed to evaluate the effect of hydrogen peroxide versus charcoal-based whitening mouthwashes on color, surface roughness, and color stability of enamel. In the current study, the whitening mouthwashes used have the ability to stop future stains due to their white seal technology., Methods: A total of 21 permanent central incisor teeth extracted for periodontal reasons were used in the present study. Teeth roots were sectioned and crowns were mounted in self-cured acrylic resin blocks. The specimens were randomly divided into three groups (n = 7) according to the tested whitening mouthwash: Control group ‟ DW" (Distilled water), ‟OW" group: Peroxide-based mouthwash (Colgate Optic White) and ‟CP" group: Charcoal-based mouthwash (Colgate ® Plax Charcoal). Regarding ‟OW" and ‟CP" groups, the specimens were immersed in 20 ml of the tested mouthwash in each corresponding group for 1 min twice daily (morning and evening) for a total of 12 uninterrupted weeks. Color change was assessed using VITA Easyshade spectrophotometer and surface roughness (Ra) was measured using a white light interferometer. The specimens were stained using black tea solution and color was measured after 24 h of immersion for assessment of color stability., Results: Color change results revealed that both whitening mouthwashes were able to restore color comparable to the control group with no significant difference between them. Regarding surface roughness, the control group showed the highest mean Ra value, followed by ‟OW" group while ‟CP" group showed the lowest mean Ra value. While color stability after staining, the control group showed a significantly higher value than the ‟CP" and ‟OW" groups., Conclusion: Hydrogen peroxide and charcoal-based whitening mouthwashes improve the color of enamel with no adverse effect on the surface roughness. Both whitening mouthwashes were beneficial to maintain the color after staining and prevent future enamel stains., (© 2024. The Author(s).)

Objective: It is aimed to evaluate the color changes of upper central incisor teeth with different root maturation levels after 15 min of dehydration and rehydration., Materials and Methods: Using the Cvek classification, 60 participants were divided into five groups. A spectrophotometer, equipped with a specially designed jig, was utilized for color measurements. Following isolation, color measurements were conducted at the dehydration process intervals of baseline, 1st, 2nd, 3rd, 5th, 7th, 10th, and 15th minutes. After mouth rinsing, measurements were repeated at the same time intervals during the rehydration process. CIEDE2000 (ΔE 00 ) values and the Whiteness Index (WI D ) were obtained to compare the color changes between the initial readings and each interval. Friedman and Repeated Measures ANOVA were applied to compare classes by time during the dehydration and rehydration periods, as well as ANOVA and Kruskal-Wallis tests to compare by classes for each time (p < 0.05)., Results: Significant differences emerged in the mean ΔE 00 values during dehydration and rehydration periods across all Cvek Classes (p < 0.05). While no statistically significant differences were observed among Classes at different minutes during the rehydration period (p > 0.05), it was particularly noted that the mean ΔE 00 values of Classes 2, 3, and 5 at the 2nd minute of dehydration were statistically significantly higher than the mean of Class 1 (p < 0.05). However, when evaluating the starting and ending measurements of both dehydration and rehydration processes, and the overall change in ΔE 00 and ΔWI D , no significant variations were detected across the Classes (p > 0.05)., Conclusions: In teeth that have just erupted and are still undergoing root development, dehydration in the initial minutes results in noticeable color changes. However, the change in ΔE 00 and ΔWI D of the teeth was found to be similar after the dehydration and rehydration processes., Clinical Significance: According to the Cvek classification, the lower color change in Class 1 teeth within the first 2 min of dehydration and the need for more than 15 min of rehydration for immature teeth with an open apex to return to their initial state after a 15-min dehydration are crucial for clinicians in terms of color assessment timing., (© 2024 The Authors. Journal of Esthetic and Restorative Dentistry published by Wiley Periodicals LLC.)

Hot air drying (HAD) is an extensive method used on oysters and it causes the most intuitive change, a color change. However, the mechanism of color change remains unclear. This study showed that oysters underwent browning during the HAD process. The colorimetric parameter L* decreased while a* and b* increased, all of which were well described by the first-order color kinetic model. Mechanistically, the HDA process induced the oxidative browning of phenols and the generation of Maillard reaction products (5-hydroxymethylfurfural and hydrophilic pyrrole). Meanwhile, the HAD process caused lipid oxidation, leading to the reduction of phosphatidylethanolamine and the generation of reactive carbonyl compounds (aldehydes and α-dicarbonyl compounds). Moreover, the accumulation of hydrophobic pyrroles, a lipid-induced Maillard-like reaction product, was observed. These results suggest that, in addition to phenolic oxidation, sugar- and amino acid-mediated non-enzymatic browning reactions, lipid-mediated Maillard-like reactions play important roles in oyster darkening during the HAD process., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Aim: This study aimed to assess the color stability of bioactive restorative materials vs nanohybrid resin composites after 3 months of immersion in three frequently consumed beverages., Materials and Methods: Thirty disk-shaped specimens of Giomer dental restorative material (Shofu, Japan) and nanohybrid resin composite (Tokuyama, Japan) were performed using a Teflon mold. Super-Snap system (Shofu, Japan) was utilized to finish and polish the specimens to be preserved for 24 hours in distilled water at 37°C. The samples had been divided into three subgroups (Coffee, tea, Pepsi) ( n = 5). The initially displayed color measurements of the samples were performed using a spectrophotometer (VITA Easyshade® V). After 7 days, 30 days, and 90 days, color measurements were repeated, and the E of each sample was estimated. E of each sample was calculated., Results: The Giomer group showed statistically significant higher E values than the nanohybrid resin composite where the p -value was ≤0.0001. Tea subgroup showed the highest statistically significant E values in both groups where the p -value was ≤ 0.0001. The highest statistically significant color change was recorded at 3 months., Conclusion: The color of bioactive restorative material is less stable if compared with nanohybrid resin composite., Clinical Significance: As tea and coffee are popular beverages, particularly in Middle Eastern nations, dentists must advise patients about the color change of resin restorations. Patients are advised to brush their teeth immediately after consuming these beverages. How to cite this article: Saber EH, Abielhassan MH, Abed YA, et al . Color Stability of Bioactive Restorative Material vs Nanohybrid Resin Composite: An In Vitro Study. J Contemp Dent Pract 2024;25(3):221-225.

In order to reveal the color formation mechanism of blood-red edible bird's nests (EBNs) and develop a quick and specific strategy to distinguish the artificial fake one, multiple methods of UPLC-TOF/MS, UV, NMR, FT-IR and 2D IR were used to detect the chemical markers of the reddening reaction, the results showed that the reddening substances were C 9 H 10 N 2 O 5 and C 9 H 9 NO 6 , which were verified as products of a phenol-keto tautomerism evolved from l-tyrosine. Moreover, natural and artificial red EBNs with varying degrees of chemical fumigation also can be successfully distinguished using the chemical markers, and the protein variation in SDS-PAGE gel could also support the distinction. This work established a systematic method of chemical identification for both natural and artificial blood-red EBNs, and provided a new identification strategy for food safety control that can promote the development of a healthier market of EBNs., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Aim: The aim of the present study was to determine the degree of surface staining and roughness of resin composites (RC) after finishing and polishing with different methods and immersion in three soft drinks., Methods: A microhybrid, a nanohybrid, and a hybrid composite were selected. The specimens were prepared and divided into three groups of 36 after 24 hours, and designated as either unpolished or polished using Sof-Lex discs or Enhance point. Each group was further divided into three subgroups, immersed in distilled water, coffee, or cola for 1 week (N = 12). Color change (∆E) was measured by a spectrophotometer after each treatment. The ∆E was calculated using the following formula: ∆E = ([∆L]2+[∆a]2+[∆b]2)1/2. Surface roughness (Ra) was measured after 24 hours and 1 week. To observe the Ra, a scanning electron microscope was used., Results: A moderate correlation between Ra and ∆E was determined. Only coffee caused perceptible ∆E. The effect of Ra on staining was statistically significant (P < .05), but immersion in solutions for 7 days did not increase the Ra of RC., Conclusions: The highest Ra values were obtained from hybrid RC. The Enhance point created the greatest roughness. Coffee was associated with the greatest ∆E for all materials and polishing methods., (© 2018 John Wiley & Sons Australia, Ltd.)

Purpose: To evaluate the color change caused by post-irradiation conversion (ΔE 24h and ΔE 8 days ) and artificial aging (ΔE AGING ) of resin cements light activated through ceramics of different opacities immediately and 6 minutes after manipulating the material., Materials and Methods: Resin cement disks (Allcem and LuxaCore) were light activated through ceramics (without ceramic, e.max HT, LT, and MO) immediately and 6 minutes after the manipulation (n = 10). Spectrophotometry was used to evaluate ΔE 24h and ΔE 8 days after 37˚C-dry-dark-storage for 24 hours and 8 days, and ΔE AGING after 60˚C-water-storage for 24 hours. Data were analyzed with three-way ANOVA and Tukey's HSD (α = 0.05)., Results: Regarding the post-irradiation color change, significant differences were found between the cements (p < 0.0001), light activation protocols (p = 0.037), and ceramics (p < 0.001). The immediate activation (16.2 ± 0.1) showed lower ΔE values than the delayed activation (16.5 ± 0.1). Ceramics influenced the ΔE values as follows: MO (14.0 ± 1.2) < LT (14.9 ± 1.2) ≈ HT (15.4 ± 1.2) < control (21.2 ± 1.2). Regarding ΔE AGING , significant differences were found between cements (p < 0.001), light activation (p = 0.006), and ceramics (p < 0.001). The delayed activation (8.4 ± 0.1) showed lower values than the immediate activation (8.9 ± 0.1). Ceramic spacers influenced ΔE AGING as follows: control (5.6 ± 0.2) < MO (6.6 ± 0.2) < HT (11.0 ± 0.2) ≈ LT (11.5 ± 0.2)., Conclusion: The delayed light activation resulted in increased color stability, while the ceramic interposition resulted in lower color stability., (© 2016 by the American College of Prosthodontists.)

The purpose of this study was to evaluate the color difference of nanohybrid and ormocer-based composite resins with different thicknesses when 4 different shades of resin luting cement were used. 56 disc specimens of each composite resin (Aelite aesthetic enamel, Ceram-X mono) with 0.5 and 1 mm thicknesses were fabricated. Baseline color measurements were performed using a clinical spectrophotometer. The specimens of each thicknesses of each resin were randomly divided into 4 groups according to the shades of resin luting cement (white/A1, yellow/universal/A3, transparent and white opaque) (n = 7). Mixed resin cement was applied onto the resin specimens using a Teflon mold in 0.1 mm thickness. Color measurements of cemented composite resin specimens were repeated and color difference (∆E) between baseline and after cementation measurements was calculated. ANOVA and Tukey's test were used for statistical analysis. The opaque shade had significantly increased ∆E values as compared to the other shades (p < 0.05). For all shades except white opaque in both thicknesses, ∆E values of aelite aesthetic enamel were higher as compared to Ceram-X mono. There is no significant difference between 2 thicknesses for both resins in terms of ∆E values. The shade of resin cement and the type of the resin affected the final color; however, the thickness of composite resin had no influence on the final color of restoration. Selecting the shade of resin luting cement before cementation of indirect composite laminate restoration is important to achieve final color match.

Objectives: To evaluate the effect of photoinitiators and reducing agents on cure efficiency and color stability of resin-based composites using different LED wavelengths., Methods: Model resin-based composites were associated with diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide (TPO), phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide (BAPO) or camphorquinone (CQ) associated with 2-(dimethylamino) ethyl methacrylate (DMAEMA), ethyl 4-(dimethyamino) benzoate (EDMAB) or 4-(N,N-dimethylamino) phenethyl alcohol (DMPOH). A narrow (Smartlite, Dentisply) and a broad spectrum (Bluephase G2, Ivoclar Vivadent) LEDs were used for photo-activation (20 J/cm(2)). Fourier transform infrared spectroscopy (FT-IR) was used to evaluate the cure efficiency for each composite, and CIELab parameters to evaluated color stability (ΔE00) after aging. The UV-vis absorption spectrophotometric analysis of each photoinitiator and reducing agent was determined. Data were analyzed using two-way ANOVA and Tukey's test for multiple comparisons (α=0.05)., Results: Higher cure efficiency was found for type-I photoinitiators photo-activated with a broad spectrum light, and for CQ-systems with a narrow band spectrum light, except when combined with an aliphatic amine (DMAEMA). Also, when combined with aromatic amines (EDMAB and DMPOH), similar cure efficiency with both wavelength LEDs was found. TPO had no cure efficiency when light-cured exclusively with a blue narrowband spectrum. CQ-systems presented higher color stability than type-I photoinitiators, especially when combined with DMPOH., Conclusions: After aging, CQ-based composites became more yellow and BAPO and TPO lighter and less yellow. However, CQ-systems presented higher color stability than type-I photoinitiators, as BAPO- and TPO-, despite their higher cure efficiency when photo-activated with corresponding wavelength range., Clinical Significance: Color matching is initially important, but color change over time will be one of the major reasons for replacing esthetic restorations; despite the less yellowing of these alternative photoinitiators, camphorquinone presented higher color stability., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Backgrounds: This study aimed to compare the effects of different energy drinks on the surface roughness, weight loss, and color change of various bioactive restorative materials. Methods: Charisma Diamond One, Activa™ BioActive Restorative, Activa™ Presto™ and Equia Forte HT Fil samples were prepared using plastic molds (8 × 2 mm) (n = 10/groups). After polishing, the samples were weighed, their colors were recorded using a spectrophotometer according to the CIEDE2000 system, and their surface roughness was measured using a profilometer. The samples were immersed in Powerade, Burn, Monster and distilled water for 7 days. After immersion, all the measurements were repeated. Statistical analyses were performed using the Wilcoxon signed-rank test and the Mann‒Whitney U test (p < 0.05). Results: All energy drinks roughened the surface of Equia Forte HT Fil (p < 0.05). Powerade and Monster increased the Ra of all materials after 7 days (p < 0.05). Burns affected all materials except the Activa Bioactive (p < 0.05). Significant weight loss was observed in the Equia Forte group after immersion in all the energy drinks, whereas no weight loss was observed in the other groups. According to the color measurements, ΔE00 values were greater in the Burn and Monster groups, except for the Equia Forte HT Fil group (p < 0.05). Conclusion: Energy drinks affected bioactive materials to varying degrees. The glass hybrid material was the most affected, and the bioactive restorative materials based on the resin matrix were the least. [ABSTRACT FROM AUTHOR]

Background: To evaluate the effect of the low-viscosity Icon resin infiltrate application on the color change of white spot enamel lesions (WSLs) over 3-, 6-, and 12-m follow-up periods. Methods: Ninety-six teeth diagnosis with WSLs using the ICDAS scoring system in 49 participants were assessed for their color change using the Icon resin infiltration technique. The Icon kit was applied to WSLs as instructed by the manufacturer. Icon-Etch (15% hydrofluoric acid) was applied to the lesions for 2 min, and then, it was rinsed off with copious amount of water for 30 s. Then, Icon-Dry (99% ethanol) was applied to the etched lesions for 30-s followed by the application of the Icon resin infiltrate that was light cured for 40 s. Color change assessment was performed using Vita Easyshade V spectrophotometer at baseline and immediately after Icon resin infiltration, then at 3-, 6-, and 12-m follow-up periods. Analysis of the data was performed using the test of repeated measure ANOVA and the paired sample t test. Results: There was a statistically significant difference in ∆E between the different follow-up periods at immediate, 3-m, 6-m, and 12-m. The highest mean value was found in the immediate follow-up period, while the lowest mean value was found in 12-m follow-up period. Conclusions: Low-viscosity Icon resin infiltration has the ability for immediate diffusion into the WSLs giving an immediate improvement in the esthetic outcome of the WSLs. However, its long-term outcomes might not be consistent for the color change of the WSLs. [ABSTRACT FROM AUTHOR]

Purpose: The aim of the current study was to evaluate the effect of simulated gastric acid on the color and translucency of different indirect restorative materials. Materials and methods: A total of 36 disc-shaped samples were cut by using an isomet saw and divided into four equal groups (n = 9) according to the material type: Group Z: translucent zirconia (Ceramill® Zolid ht.+ preshade, Amann Girrbach, Koblach, Austria); Group E: lithium disilicate (IPS e.max CAD, Ivoclar Vivadent AG, Schaan, Liechtenstein); Group C: resin nanoceramic (Cerasmart, GC, Tokyo, Japan); Group P: polyether ether ketone (PEEK) (Bettin Zirconia Dentale Italy) veneered with indirect high impact polymer composite (HIPC) (breCAM HIPC, Bredent GmbH & Co. KG, Germany). The samples were immersed in simulated gastric acid (HCl, pH 1.2) for 96 hours at 37 °C in an incubator. The color change (ΔE00) and translucency (RTP00) were measured every 9.6 hours (one-year clinical simulation) of immersion in simulated gastric acid. Results: For color change (∆E00) and translucency (RTP00) among the tested materials, there was a highly statistically significant difference (P < 0.001) after every year of follow-up. The color change in both Z and G groups was the lowest after 1 year of acid immersion, followed by that in group H, and the highest change in color was recorded in group P. Conclusion: High translucent zirconia is recommended in patients who are concerned about esthetic, especially with acidic oral environment. [ABSTRACT FROM AUTHOR]

In the context of optimizing dental care for patients who are elderly, the purpose of this in vitro study was to evaluate the surface gloss (with a micro-area gloss meter) of, surface roughness (with a compact surface roughness measuring instrument) of, and color change (with a dental colorimeter) in two commercially available injectable resin-based composites (Estelite Universal Flow (EUF) and Beautifil Flow Plus F00 (BFP)) as well as two glass–ionomer cements (GC Fuji II LC CAPSULE (FLC) and GC Fuji IX GP EXTRA CAPSULE (FGP)), before and after dental prophylaxis. After 24 h, the surfaces of each specimen were polished at 2500 rpm with a prophy brush (Mersage Brush, Shofu) and one-step prophylaxis paste (Prophy Paste Pro, Directa): under 100 or 300 gf load, and for 10 or 30 s, 4× cycles of cleaning. After mechanical cleaning, conditions were found for a significant reduction in the gloss level (EUF, BFP, or FLC; p < 0.05) and a significant increase in surface roughness (BFP; 300 gf load, 10 s × four cycles of cleaning). Overall, the longer time or higher prophylaxis load tended to decrease the surface gloss. However, the observed change in surface roughness varied between the restorative materials. There was no color change post-prophylaxis. [ABSTRACT FROM AUTHOR]

This study investigated the relationship between the green/brown colors and Yb/Y-co-doped ternary eutectic reactions. A color difference was initially observed at 1600 °C. The green color indicates a relatively highly porous area compared to the brown color, and it was confirmed that the green color was spherical in all samples. This difference in color was analyzed through photoluminescence (PL), and it was confirmed that the reduction of Yb2+ increased at temperatures higher than 1550 °C owing to the reducing atmosphere generated by the carbon ambient. The reaction sequence of the phase formation of SiAlON exhibited a difference resulting from the reduction in Yb ions, and the sequence of phase formation improved with an increase in the content of Y substituted for Yb. [ABSTRACT FROM AUTHOR]

Background: Due to the close proximity to the oral cavity, shade guides are prone to contamination with saliva. Hence, disinfection of shade guides is important to prevent cross infection in clinics. This study has compared and evaluated the color change in VITA shade guide and the WALDENT shade guide after disinfecting with 70% isopropyl alcohol. Objectives: The objective of this study was to compare and evaluate the amount of color change in the VITA shade guide and WALDENT shade guide after disinfecting them with 70% isopropyl alcohol for the simulated time of 6 months and 1 year. Materials and Methods: Four commonly used shade tabs, namely A2, A3.5, B2, and C1 of two shade guides – VITA Classical Shade Guide and Waldent shade guides – were chosen for this study. VITA Easyshade spectrophotometer measured the shade, and the values were recorded in the International Commission on Illumination L*a*b* Scale. Baseline values of 8 shade tabs were obtained followed by surface disinfection using 70% isopropyl alcohol using gauze. The testing process was done to simulate a 6-month period and 1-year period. Results: Unpaired t-test was used for statistical analysis. It was found that shade tabs underwent significant changes in short period of time. Conclusion: Within the limitations of this study, it was found that shade guides undergo significant changes in color when disinfected with 70% isopropyl alcohol during a simulated period of 6 months. Clinical Significance: If shade guides are not periodically evaluated using a control (preferably unused) shade guide, they may have a profound impact on resulting restoration. [ABSTRACT FROM AUTHOR]

Objectives: To conduct a scoping review on color stability of bulk‐fill compared to conventional resin‐based composites exposed to colored beverages. Materials and Methods: In vitro studies, investigating bulk‐fill resin‐based composites color stability submitted to artificial staining by colored beverages were included. Studies investigating color change induced by smoke and whitening treatments as well as papers not written in English language were excluded. A systematic search, following the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses extension for Scoping Reviews (PRISMA‐ScR) was performed on four databases (Embase, Medline, Scopus, Web of Science) for articles published until October 01st 2022. The study selection was then performed by two authors who screened the abstracts independently and followed the JBI approach. Results: Of 717 screened abstracts, 59 were selected for full‐text analysis. Finally, 19 studies were included in this review. They investigated 19 different bulk‐fill composites and different artificial‐staining‐by‐liquids‐protocols including coffee, red wine, tea, coke, and others. Seven papers reported higher color change in the investigated bulk fill materials than in conventional resin‐based composites, while nine studies reported the opposite. SonicFill showed the highest color stability for most of the papers. Conclusions: The available evidence suggests that bulk‐fill materials show variability in color stability. This behavior can be attributed to the heterogeneity of composition and staining procedures in the selected studies. Clinical Significance: Clinicians should keep in mind that bulk‐fill materials may change color when exposed to colorant drinks or food. [ABSTRACT FROM AUTHOR]

The feasibility of using microwaves to quickly stimulate automatic color change in 3D-printed food containing curcumin or anthocyanins was studied. Firstly, with a dual-nozzle 3D printer, stacked structures included mashed potatoes (MPs, upper part, containing anthocyanins) and lemon juice–starch gel (LJSG, lower part) were 3D-printed and post-treated using a microwave. The results indicated that the viscosity and gel strength (indicated by the elastic modulus (G′) and complex modulus (G*)) of LJSG were improved with the increase in starch concentration, while water mobility was reduced. During microwave post-treatment, the color change speed was negatively correlated with the gel strength but positively correlated with the diffusion of H+ and anthocyanin concentration. Secondly, nested structures were 3D-printed using MPs containing curcumin emulsion and baking soda (NaHCO3). During microwave post-treatment, the curcumin emulsion structure was destroyed, and NaHCO3 was decomposed, along with an increase in alkalinity; thus, the automatic color change was achieved with the automated presentation of hidden information. This study suggests that 4D printing could enable the creation of colorful and attractive food structures using a household microwave oven, leading to more imaginative solutions regarding personalized foods, which may be particularly important to people with poor appetites. [ABSTRACT FROM AUTHOR]

The study's main objective was to evaluate as well as compare the impact of diode laser 940 nm and conventional in-office bleaching technique on the color change of different composite resin restorations. A total of ninety composite resin discs (CRDs) were made from Filtek™ Bulk Fill, nanohybrid composite resin Filtek™ Z550 XT Universal Restorative, and flowable composite resin restoration Filtek™ Z350xt Flowable Composite. Group A: (30) CRD for Filtek™ Bulk Fill, group B: (30) CRD for Filtek™ Z550 XT Universal Restorative, and group C: (30) CRD for Filtek™ Z350xt Flowable Composite. A1, B1, and C1: (10 CRD in each group): Control group without bleaching. A2, B2, and C2: 10 CRD in each group bleached with Laser White20 without laser activation. A3, B3, and C3: 10 CRD in each group bleached with Laser White20 and activated by diode laser 940 nm. The color was evaluated using a dental spectrophotometer. One-way ANOVA was utilized for the comparison of the color stability of the CRD. P = 0.05 is regarded as statically significant. Both conventional and diode laser in-office vital tooth bleaching protocols affected the color stability of composite resin restorations. The result demonstrated that bleaching without laser activation produced color change (mean [8.30], standard deviation [SD] (1.95) P [= 0.001]), whereas the bleaching and activation by diode laser produced color change (mean [8.11], SD [1.99], P [= 0.001]). Both types of bleaching protocol affected composite resin restorations' color stability. In all tested materials, color changes after the bleaching protocol were clinically perceptible. The restorations following the bleaching procedure are required to be replaced by clinicians. [ABSTRACT FROM AUTHOR]

Background: To evaluate the effect of different experimental staining procedures on color stability and translucency of a nano-hybrid resin-based composite (RBC). Methods: Forty-eight cylindrical-shaped specimens (10 × 2 mm) were prepared with a nano-hybrid RBC (Clearfil Majesty ES-2) and randomly divided in four groups according to the experimental staining procedure: G1) static immersion in a staining solution (coffee) (44 ± 1 °C); G2) staining cycling between coffee (44 ± 1°C) and distilled water (37 ± 1°C) with an experimental staining machine based on Arduino, an Open Source hardware development platform; G3) staining cycles as in G2 + brushing with a low abrasive toothpaste (Relative Dentin Abrasion RDA = 30) (Elmex Sensitive Professional); G4) staining cycles as in G3, with brushing performed with a very strong abrasive toothpaste (RDA = 90) (Lacult Active). Color parameters were recorded at the baseline (T0) after staining procedures (T1) and repolishing (T2) using a spectrophotometer. Color change (∆E00) and translucency (TP, CR) were evaluated. Data were statistically analyzed (p < 0.05). Results: For ∆E00 after staining, Group 1 showed the highest color change and Group 3 the lowest. All groups were significantly different (p < 0.001) except for Group 2 vs. Group 4; after repolishing, Group 1 was significantly higher than Group 3 (p < 0.001), Group 2 (p < 0.001), and Group 4 (p = 0.003); Group 2 was higher than Group 3 (p < 0.001). For TP variable, after staining procedures, Group 2 was significantly higher than all other groups (p < 0.001), and Group 1 was significantly higher than Group 3 (p < 0.001) and Group 4 (p = 0.007). After repolishing, Group 4 was significantly lower than Group 3 (p = 0.008) and Group 2 (p = 0.027). Repolishing procedure significantly reduced color parameters. Conclusions: The investigated staining procedure induced significant differences in color stability and translucency. The use of a very strong abrasive toothpaste (RDA = 90) induced higher color change than a low abrasive one (RDA = 30). Repolishing procedures are able to partially reduce color change induced by artificial staining procedures. [ABSTRACT FROM AUTHOR]

Saffron floral bio‐residues (SFB) are a valuable natural source of antioxidants and dyes that can contribute to the development of new food products and cosmetic products. Color change was usually observed during SFB storage, which may result in quality degradation of SFB or even cause potential hazard to human health. In order to clarify the mechanism of color change of SFB sample, the chemical differences among SFB samples stored under different conditions were analyzed using ultra‐performance liquid chromatography coupled with quadrupole time‐of‐flight mass spectrometry and chemometrics methods, from which differential flavonols and anthocyanins were screened and their kinetic variations during sample storage summarized. In addition, the color change of the SFB sample was digitalized using an electronic eye (E‐eye), which was found to be related to the content of delphinidin‐3,5‐di‐O‐glucoside (DDG). Moreover, the degradation kinetic parameters of DDG under different storage conditions were studied. In conclusion, the variation of kaempferol‐, isorhamnetin‐, and quercetin‐type flavonol, and delphinidin‐ and petunidin‐type anthocyanin resulted in the color change of SFB sample, and anthocyanin was found more unstable than flavonol. Practical Application: Saffron floral bio‐residues (SFB) are popular natural sources of antioxidants and colorants that can be used in food and cosmetic products. Color change usually occurs during SFB storage period. Clarifying the mechanism of the color change of SFB will help us to ensure the quality of SFB. [ABSTRACT FROM AUTHOR]

Color of dried edible material is one of the most essential considerations for consumers when making product purchases. The similarity between the color of the dried product and the color of the fresh product increases their marketability. The primary objective of drying operations is to dry products with minimal energy consumption, to prevent the growth of microorganisms, preserve their flavor and nutritional value, to make the moisture content suitable for storage, and to ensure that the color change after drying closely resembles that of the fresh product. This study seeks to dry Oyster mushrooms (Pleurotus spp.) at different drying power levels (90 W, 180 W, 360 W, and 600 W) using the microwave drying method of thin slices and to determine the color changes of the dried mushrooms. As a result of the trials carried out in the laboratory, it was discovered that the increase in drying power caused the samples to dry faster. At the end of the drying period, the colors of the mushrooms became darker than the initial levels. The highest change in brightness was recorded during the drying process at a power of 90 W. In the investigation, it was determined that the drying time was longer and the color change of the dried product was greater when the power was 90 W. Based on this, it can be stated that the color changes of the product will exhibit less deformation if the desired humidity level is obtained quickly during the drying process using the thin slice microwave drying method. However, this should just be viewed as a suggestion for minimizing color change. Numerous criteria, including color change, drying duration, nutrient content, and shelf life, should be assessed concurrently while determining the drying process. [ABSTRACT FROM AUTHOR]

The spatial characteristics of discontinuity traces play an important role in evaluations of the quality of rock masses. Most researchers have extracted discontinuity traces through the gray attributes of two-dimensional (2D) photo images or the geometric attributes of three-dimensional (3D) point clouds, while few researchers have paid attention to other important attributes of the original 3D point clouds, that is, the color attributes. By analyzing the color changes in a 3D point cloud, discontinuity traces in the smooth areas of a rock surface can be extracted, which cannot be obtained from the geometric attributes of the 3D point cloud. At the same time, a necessary filtering step has been designed to identify redundant shadow traces caused by sunlight on the rocks' surface, and a multiscale spatial local binary pattern (MS-LBP) algorithm was proposed to eliminate the influence of shadows. Next, the geometric attributes of the 3D point cloud were fused to extract the potential discontinuity trace points on the rocks' surface. For cases in which the potential discontinuity trace points are too scattered, a local line normalization thinning algorithm was proposed to refine the potential discontinuity trace points. Finally, an algorithm for establishing a two-way connection between a local vector buffer algorithm and a connectivity judgment algorithm was used to connect the discontinuity trace points to obtain the discontinuity traces of the rock mass's surface. In addition, three datasets were used to compare the results extracted by existing methods. The results showed that the proposed method can extract the discontinuity traces of rock masses with higher accuracy, thereby providing data support for evaluations of the quality of rock masses and stability analyses. [ABSTRACT FROM AUTHOR]

This study evaluated the efficacy of different cleaning methods with respect to changes in the color and light transmittance of both rough and smooth thermoformed, copolyester retainer specimens, after staining in different solutions. Four hundred copolyester sheets (Essix ACE) specimens were fabricated over molds with different surface textures, smooth and rough. The specimens were stained in four different solutions (n = 100 per solution) over 28 days; then, each of the four groups of 100 stained specimens was sub-divided into five groups of 20 specimens and subjected to a different destaining solution. The specimens were sub-divided with half subjected to an additional ultrasonic cleaning procedure. Light transmittance and color changes were analyzed using a spectrometer/integrating sphere assembly and a spectrophotometer. Mean difference comparisons were performed using appropriate statistical tests at p = 0.05. All five destaining solutions proved to be effective at removing coffee and tea stains. The surface roughness of the retainer material plays a significant role in the ability of cleaning solutions to remove stains, demonstrating a greater effect on cleaning rough specimens with respect to improvements in light transmittance and greater changes in color. Additionally, an ultrasonic cleaning unit generally enhanced the ability of all five solutions to clean the tea-stained specimens. However, the enhancements were only significant for light transmittance. [ABSTRACT FROM AUTHOR]

In this study far infrared vacuum drying kinetics and change of color quality parameters of apple slices were analyzed. The experimental data set of drying kinetics was obtained on the experimental set-up designed to imitate an industrial far infrared vacuum dryer. For approximation of the experimental data with regard to the moisture ratio four well known thin-layers drying models from scientific and engineering literature and new developed model of Mitrevski et al., were used. The performed statistical analyzes show that the model of Mitrevski et al., has the best statistical performance than well-known thin-layer drying models. The estimated values of moisture diffusivity of apple obtained from this study are within the range from 2.80·10-11 to 1.70·10-10 m²2/s. A negative effect on the total color change of far infrared vacuum dried apple slices was observed with increasing of temperature of infrared heaters and vacuum pressure. [ABSTRACT FROM AUTHOR]

Purpose: To systematically review past studies to determine the effect of various solutions on the color of denture teeth, thus answering the question in regards to which type of denture teeth has the best optical properties after exposure to various solutions. The method of measuring the color of artificial teeth was also evaluated as a secondary outcome. Materials and Methods: A search of studies that quantitatively investigated the influence of immersion solutions on the color change of denture teeth was conducted. Ovid MEDLINE, PubMed and Scopus databases were searched from 1997 to April 2021. The Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines were used during article selection. Data regarding the effect of immersion solutions, accelerated aging and surface treatments on color change were gathered. Methodologies used to assess optical properties were also summarized and compared. The modified CONSORT checklist was used to determine the risk of bias of past studied included in this review. Results: One hundred thirty‐three studies were identified after removing duplicates. Forty‐one studies were selected for full‐text analysis, and 35 remaining papers met the inclusion criteria and were therefore included in this systematic review. Thirty‐two in vitro studies and 3 in vivo studies were included in the review. All studies reported that immersion in various solutions has a significant influence on the change in color and optical properties of denture teeth. However, the discoloration of denture teeth is still clinically acceptable in most studies. Exposure to various solutions also affected the translucency parameter of denture teeth. Most studies also investigated the surface roughness and hardness along with the optical properties, and reported that immersion cycles did not cause changes in surface roughness of denture teeth, while hardness was affected. The optical properties of PMMA denture teeth have been studied extensively, whereas that of CAD/CAM and 3D printed denture teeth is limited. Conclusions: Color stability of CAD/CAM milled denture teeth is comparable to conventional PMMA denture teeth. There are contradictory findings in terms of color stability of 3D printed denture teeth as compared to conventional PMMA denture teeth. Staining by coffee is worst among the common beverages and solutions investigated. Denture teeth can show color changes after immersion in staining beverages as early as one week. The degree of discoloration of denture teeth after immersion is time dependent, with the larger extent in the initial phase. [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]

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Animal coloration has multiple functions including thermoregulation, camouflage, and social signaling, and the requirements of each function may sometimes conflict. Many terrestrial ectotherms accommodate the multiple functions of color through color change. However, the relative importance of these functions and how color-changing species accommodate them when they do conflict are poorly understood because we lack data on color change in the wild. Here, we show that the color of individual radio-tracked bearded dragon lizards, Pogona vitticeps, correlates strongly with background color and less strongly, but significantly, with temperature. We found no evidence that individuals simultaneously optimize camouflage and thermoregulation by choosing light backgrounds when hot or dark backgrounds when cold. In laboratory experiments, lizards showed both UV-visible (300-700 nm) and near-infrared (700-2,100 nm) reflectance changes in response to different background and temperature treatments, consistent with camouflage and thermoregulatory functions, respectively, but with no interaction between the two. Overall, our results suggest that wild bearded dragons change color to improve both thermoregulation and camouflage but predominantly adjust for camouflage, suggesting that compromising camouflage may entail a greater potential immediate survival cost.

The aim of this research was to assess the color differences (∆E00), Vickers microhardness, whiteness index, and surface roughness values of different durations of bleaching the enamel. One hundred and eight teeth were utilized for color evaluation, roughness, and microhardness (n = 36). Teeth were assigned to three groups (n = 12) based on the durations of the bleaching application. Bleaching agent was applied for 20 minutes in group 1, 40 minutes in group 2, and 60 minutes in group 3. The color was measured with a Vita Easyshade Advance 4.0 spectrophotometer before applying the bleach, and 24 hours, 7, and 14 days after bleaching application. The CIEDE2000 and whiteness index for dentistry values were calculated. The microhardness and surface roughness values were obtained before application and 7 and 14 days after application. Data were analyzed using two‐way ANOVA and post‐hoc LSD tests Group 3 had the largest color and whiteness changes. The whiteness index for dentistry values were statistically significantly increased, considering baseline measurements within all groups (P <.05). For the Vickers micohardness values, in group 3, a statistically significant difference was observed among baseline, and 7 days after application (P <.05). However, the surface roughness values showed no significant difference in any measurement (P >.05). According to this research in all groups, effective whitening was accomplished. Based on the results evaluated for whiteness, color alteration, microhardness, and roughness, the optimal bleaching duration of application was in 40 minutes. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effect of thickness, cement shade, and coffee thermocycling (CTC) on the optical properties of zirconia reinforced lithium silicate (ZLS) paired with different shades of a resin cement. Materials and Methods: Thirty ZLS specimens were prepared in two different thicknesses (0.8 and 1.5 mm) and three different resin cement shades (Tr, A2, and A3) were applied (n = 5). Color determinations were done before and after 5000 CTC by using a noncontact spectroradiometer. Color change due to CTC and relative translucency parameter (RTP) before and after CTC were calculated by using CIEDE2000. Data were analyzed using ANOVA and Bonferroni‐corrected t‐tests(α = 0.05). Results: Material thickness and resin cement shade (P < 0.001) affected baseline color. Material thickness affected color difference (P = 0.025). Thickness, resin cement shade, and CTC (P ≤ 0.0001) affected RTP. The difference between the color changes of the 0.8‐ and 1.5‐mm specimens combined with A2 shade cement after CTC was significant (P = 0.01). RTPs of all pairs decreased after CTC (P < 0.001). Conclusions: Cement shade and material thickness affected the baseline color. The thickness of ZLS affected the color change after CTC only with A2 resin cement and the color change was less when the ZLS was thicker. CTC reduced the translucency of all pairs. Clinical Significance: Clinicians and patients should be aware of a potential color change after long‐term coffee consumption when zirconia reinforced lithium silicate is used particularly for laminate veneers with A2 shade of the tested resin cement. [ABSTRACT FROM AUTHOR]

Cylindrical specimens obtained from the monzogranite host rock of the National Radioactive Waste Repository of Hungary were tested at room temperature and 250 °C, 500 °C, and 750 °C of heat treatment. Reflectance spectra (color), bulk density, Duroskop surface hardness, and ultrasound-wave velocity values were measures before and after thermal stress. According to CIE L*a*b* colorimetric characteristics, the specimens' color became brighter and yellower after the heat treatment. At 750 °C, a significant volume increase was recorded linked to the formation of macro-cracks, and it also led to the drop in bulk density. Smaller temperature treatment (250 °C) caused a minor decrease in density (−1.3%), which is higher than the reduction of density at 500 °C (−0.8%). Duroskop surface strength showed a slight decrease until 500 °C, and then a drastic decline at 750 °C. P- and S-wave velocity values tend to decrease uniformly and significantly from room temperature to 750 °C. P-wave velocity and Duroskop values have a high exponential correlation at elevated temperatures. Physical alterations originated from the differential thermal-induced expansion of minerals, the formation of micro-cracks. Mineralogical changes at higher temperatures also contribute to the volume change and the loss in strength. [ABSTRACT FROM AUTHOR]

Objective: To analyze the impact of the color of a resin composite cement (RCC) on the optical properties of different computer‐aided design and computer‐aided manufacturing (CAD/CAM) ceramics. Materials and methods: Specimens (N = 220, thickness: 0.9 ± 0.03 mm) were fabricated from: leucite (Initial LRF Block/IPS Empress CAD), lithium disilicate (Amber Mill/IPS e.max CAD), lithium metasilicate (Celtra Duo), and lithium alumina silicate ceramic (n!ce) in translucency levels HT and LT. All specimens were bonded with an RCC (Light+/Warm+). Color was analyzed (spectrophotometer) initially as well as after bonding of RCC with CAD/CAM ceramics using CIELab and CIEDE2000. Kolmogorov–Smirnov test, one‐way ANOVA and t test served for analyzing (α = 0.05). Results: Highest impact on ΔE presented the choice of ceramic (ηp2 = 0.155/p < 0.001), followed by translucency level (HT/LT; ηp2 = 0.050/p = 0.001) as well as interaction between ceramic and translucency level (ηp2 = 0.175/p < 0.001). ΔE00 was mainly influenced by the choice of ceramic (ηp2 = 0.490/p < 0.001), the shade of resin composite (ηp2 = 0.031/p = 0.012) as well as the interaction between ceramic and resin composite (ηp2 = 0.258/p < 0.001). Conclusions: RCC shades presented differential impacts on color change of CAD/CAM ceramics. Clinical significance: Knowledge of the impact of available RCC shades on different CAD/CAM ceramics is crucial for an esthetic outcome and proper selection of ceramic restorations. [ABSTRACT FROM AUTHOR]

Purpose: To investigate and compare the translucency and color stability of a newly introduced polymer‐infiltrated ceramic network (PICN) material (Crystal Ultra) to those of clinically well‐established restorative materials. Materials and Methods: A total of 80 specimens measuring (12 × 14 × 1 mm ± 0.05 mm) were prepared from five CAD/CAM (IPS e.max (IPS), Lava Ultimate (LU), Cerasmart (CS), Vita Enamic (VE), Crystal Ultra (CU)) high translucency (HT) blocks in A2 or equivalent shades. Specimens were randomly allocated into two groups (A and B) (n = 8), and were subjected to 5,000 thermal‐cycles (TC). This was followed by one‐week immersion of group A specimens in coffee (staining) solution and group B specimens in distilled water. Following immersion, the specimens from both groups were further subjected to 5,000 TC. A spectrophotometer was used to measure the translucency parameter (TP) and color change (ΔE00) of the samples using CIELAB color coordinates at baseline, after 5,000 TC, following immersion, and after further 5,000 TC. Color stability was evaluated using the CIEDE2000 formula. Data were analyzed by non‐parametric tests (α = 0.05). Results: The TP values of the CAD/CAM materials ranged from 18.0‐22.0. Following the initial TC, the changes in TP values were significant for VE (p = 0.012). Coffee immersion and further TC significantly impacted the TP values of PICN (VE and CU) materials compared to glass‐ ceramics (IPS), and resin nanoceramic (CS and LU) materials (p = 0.012). The comparison between CAD/CAM materials at different intervals showed a significant difference in the TP values (p < 0.01). The materials showed perceptible color changes following the initial TC except for PICN materials which demonstrated acceptable color changes. The major color difference was noticed for the resin nanoceramic specimens immersed in coffee; LU and CS showed higher color changes (ΔE00 = 2.45 and 2.09, respectively) than VE and CU (ΔE00 < 1.8). Conclusions: The translucency of the newly introduced Crystal Ultra PICN material was low compared to the resin nanoceramics and lithium disilicate glass‐ceramic. The Crystal Ultra material exhibited better color stability compared to resin nanoceramics, but higher color change when compared with Vita Enamic PICN and lithium disilicate glass‐ceramic CAD/CAM materials. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effects of staining and bleaching on color change of two different Nano-Hybrid resin composite materials. Materials and Method: In total, 48 samples were fabricated (24 samples from each Nanotype). Samples of each composite group were sub-divided into three sub-groups (n=8). Samples of Stain sub-groups immersed in coffee solution for 48 hours at 37°C; in Stain Bleach sub-groups, samples were stored in coffee solution for 48 hours at 37°C then bleached with 30%H2O2; in Bleach sub-groups, samples were bleached with 30% H2O2. After that, color measurements were recorded again for each sub-group. Results: After staining and bleaching, all sub-groups of both tested materials demonstrated clinically acceptable color change (ΔE<3.3) with significant differences (P<0.05). Conclusion: Color change of the two tested materials do not affected by staining and bleaching. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effect of the accelerated aging process on the color stability of feldspathic ceramic treated with dual ion exchange, overglaze, polishing, and autoglaze surface treatments. Method and Materials: A total of 40 disks (15 mm in diameter and 2 mm thick) of feldspathic ceramic were made in an A2 shade according to the manufacturer's recommendations. The samples were randomly divided into 4 groups: dual ion exchange, overglaze, polishing, and autoglaze. The samples were subjected to conditions in an accelerated aging machine for 150 and 300 hours. Differences in color before and after accelerated aging were calculated using spectrophotometric analyses. Overall color difference (ΔE) was determined using the CIE L*a*b* system for measuring small color differences. Scanning electron microscopy was used to evaluate the surface texture of samples. Color difference data were evaluated statistically by Kruskal-Wallis and Mann-Whitney U tests, with a significance level of .05. Results: After 150 and 300 hours of accelerated aging, color changes of the 4 surface treatment groups ranged between 0.35 and 1.31ΔE units. All ΔE values were below a quantitative level that would be considered clinically acceptable. Autoglazed samples were the most color stable, followed by ion exchanged, overglazed, and polished test samples. Conclusions: All groups demonstrated color stability below a quantitative level that would be considered clinically acceptable, but long-term clinical studies are necessary to verify these findings. [ABSTRACT FROM AUTHOR]

[Display omitted] • FDRCJ-loaded WPI/GA was used as a smart material to realize 4D color changes. • The morphology and thermal stability of WPI/FDRCJ/GA mixture were examined. • The WPI/FDRCJ/GA microparticles were more thermally stable than pure materials. • Microparticles had no significant effect on viscosity or printing accuracy of samples. • Microparticles addition changed the printed samples' color after microwave heating. This study aimed to explore the feasibility of utilizing microparticle mixture (MCPs) comprised of whey protein isolate (WPI), gum Arabic (GA), and freeze-dried red cabbage juice (FDRCJ) as a smart material to realize a rapid color change of 3D printed apple/potato starch gel in response to microwave heating stimulation. The particle size, morphology and thermal stability of WPI/FDRCJ/GA microparticles were examined. Then, the rheology, texture properties and printability of Apple/potato starch gel affected by different concentrations of WPI/FDRCJ/GA microparticles (0, 15, 30, 45, 60% (w/w)) were studied. Results showed that the WPI/FDRCJ/GA microparticles were more thermally stable than pure materials, indicating that the heat-sensitive anthocyanin and other compounds present in FDRCJ were effectively protected by the wall materials (WPI/GA). Moreover, the addition of various microparticle concentrations decreased the samples' mechanical properties but had no significant influence on their loss modulus, viscosity, or printing accuracy. As the microwave heating time increased, the lightness (L*) and yellowness (b*) of microparticle-added samples decreased while the redness (a*) significantly increased (p < 0.05), resulting in a gradual color change from yellow/brown to red. These findings could be useful to produce novel colorful and appealing 4D healthy food products that stimulate consumer appetite. [ABSTRACT FROM AUTHOR]

Objective: The color of all‐ceramic restorations is one of the main criteria to achieve esthetical success. Many factors such as ceramic thickness, condensation techniques, firing temperature, and numbers can affect the final color of restoration. The purpose of this study was to investigate the color changes in alumina‐based ceramic system according to ceramic shade and thickness during the multiple firings. Materials and Methods: Sixty disc‐shaped specimens with two different veneering porcelain shades (A1 or A3), and with three different ceramic thicknesses (0.5, 1, or 1.5 mm), were fabricated from an alumina‐based ceramic system. Multiple firings (3, 5, 7, or 9 firings) were performed, and color changes (ΔE00) were determined using a spectrophotometer. Repeated‐measures ANOVA were used to analyze the data. The Duncan test was used for multiple comparisons (α =.05). Results: The L*a*b* values of the specimens were affected by the number of firings (3, 5, 7, or 9), veneering ceramic shades (A1 or A3) and veneering ceramic thicknesses (0.5, 1, or 1.5 mm). Significant interactions were present between the number of firings, veneering ceramic shade, and veneering ceramic thickness for L* (p < .001), a* (p < .001), and b* (p < .001) values. Conclusions: No statistically significant color change was observed between 3rd and 9th firings. Clinical Significance: Veneering ceramic shade, veneering ceramic thickness, and number of firings should be carefully considered to obtain an acceptable color match of the definitive restorations. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the ability of a novel silica (SiO2)‐based nanocoating approach to extend the superficial integrity of current composites. Cylindrical discs (7 × 2 mm) were produced from nanohybrid and nanofilled composites. Specimens in control groups were not coated, but SiO2 nanocoating was performed on specimens in experimental groups (n = 8). Specimens were stored for 24 h in distilled water at 37°C (baseline) and then artificially aged for 15, 90, or 180 d in a low‐pH staining solution. Surface roughness (Ra) was measured using a profilometer, and a goniometer was used to determine surface free energy (SFE). Color change was evaluated by a reflectance spectrophotometer, applying the color distance metric, ΔE00, according to the Commission Internationale de l'Eclairage (CIE) L*a*b* coordinates. Data were subjected to repeated‐measures anova and the Tukey post‐hoc test. Composites presented visually perceptible color changes (ΔE00 > 0.81) as early as 15 d of aging, with significantly higher ΔE00 values recorded over time. Nanocoating with SiO2 significantly reduced the SFE of composites at all storage times, and significantly lower Ra values were identified after aging. Nanohybrid and nanofilled composites were susceptible to substantial hydrolytic superficial degradation and staining, which was dramatically attenuated by the proposed SiO2 nanocoating approach. Nanocoating effectively lowered the SFE of composites, thus minimizing water–composite interactions, which contributed to reduced superficial deterioration and lower stain susceptibility over time. [ABSTRACT FROM AUTHOR]

Background and AIM: The gradual color change of the tooth shade guide is due to the use of an autoclave is one of the clinical problems for correct color reproduction. The purpose of this research was study the effect of autoclave on dental shade guide. Materials and methods: This experimental experiment was experimental and done on 20 dental paints guide (vitaA3). Subsequently, they were divided into 2 groups color guide by randomly. First, all specimens were washed Before placing in the autoclave Distilled for 3 minutes and they were dry with a tissue and they went on to the autoclave, of course The first group is at 121 °C for 40 minutes and the second group was kept at 134 °C for 10 minutes. These specimens were placed in an autoclave with 180 cycles and3 times a day, 5 days a week (equivalent to 3 months). At each stage set the Spectrophotometer color Indicators (abl) and E Guide the color of the teeth. Statistical analysis was performed in SPSS software and in the way of Mann-Whitney. Results: Mean in the group with a temperature of 121 degrees was 3.79 ± 0.63 and in the group with a temperature of 134 degrees, it was 3.55 ± 1.04 which are not significant. According to the statistical test, there is a difference (P <0.3). About b and c index, difference were minor and no significant difference was observed in the case of other measured indicators, L, a, H in the two groups.(P<0.2). The color change was more than 3.3 for both method and not acceptable related to clinical subjects. (3.55 and 3.79) Conclusion: In this study, it was observed that sterilization process by autoclave, can lead to change the color properties of the classic VITA color guide. [ABSTRACT FROM AUTHOR]

The aim of the research was to establish whether addition on fragranced microcapsules influences on color values and perceptive properties of prints. For this purpose, three types of printing inks were used on two sets of the paper substrate. Color properties were measured by standard methods while perceptive properties were determined by subjective method. Research has shown that microcapsules cause small color differences while perceptive analyses gave very interesting results.

Background and Aims: Fracture and color change are among the most common causes of clinical failure of resin composite restorations. Therefore, this study aimed to examine the fracture toughness and color changes of 3 Nano-hybrid resin composites in dry and wet conditions. Materials and Methods: Three resin composites were studied. A total of 36 rectangular specimens were prepared for each material, randomly divided into 2 groups, and stored at 37°C dry or soaked in distilled water. In each group, the specimens were subdivided into three groups (n=6) and stored for 1, 7, and 60 days. After each time interval, the specimens were tested for the fracture toughness and loaded at a cross-head speed of 0.5mm/min using a universal testing machine. The baseline and final color measurement was recorded for each specimen using a spectrophotometer. The collected data was analyzed using ANOVA and Kruskal-Wallis tests. Results: After 60 days, the mean value of fracture toughness was lower in the wet condition compared to that of dry condition. However, it was not significantly different except for aura Bulkfil (P=0.001). Color change was significantly different for Tetric Evoceram and aura with a greater value in the wet condition compared to that of dry (P=0.004). The greatest color stability was found for aura and the least for Tetric Evoceram. Conclusion: In this study, most of the materials stored in a dry condition showed a greater fracture toughness and color change. [ABSTRACT FROM AUTHOR]

Introduction: Color changes that occur after the light-activation of resin composites should be understood. Objective: To evaluated the influence of light-curing devices on the color of resin composites immediately after light-activation and after one-week, at 37ºC, into water storage. Material and methods: Three A2-shade composites (Z100, Z250, and Z350), and four light-curing devices (three halogens and one LED) were evaluated. Seventy-five cylindrical specimens were light-activated for 20s. CIE-Lab color was analyzed using a spectrophotometer. Color changes between uncured and immediately light-activated materials (ΔE1), and between immediately light-activated and one-week-37°Cwater-stored materials (ΔE2) were obtained. Data were evaluated by two-way Anova, followed by Tukey test (α = 0.05). Results: For ΔE1, composites (p = 0.0008), lights (p = 0.015), and the interaction (p = 0.017) were significant. Z100 showed the smallest value (3.08 ± 1.73). The halogen 210 mW/cm² device showed the smallest ΔE1 (3.09 ± 1.25), while the LED 200mW/cm² showed the highest value (4.94 ± 2.37). For ΔE2, composites (p = 0.00016), lights (p < 0.0001), and the interaction effect (p = 0.0002) were significant. Z350 showed the smallest value (2.24 ± 1.17). The halogen 400mW/cm² device showed the smallest ΔE2 (2.15 ± 2.15), while the halogen device 525mW/cm² showed the highest value (4.45 ± 2.15). Conclusion: The color of resin composites change significantly from the uncured to the cured and water-aged phases. [ABSTRACT FROM AUTHOR]

This article presents the authors' first attempt to improve quality of edible bird's nest through continuous and intermittent low-temperature drying (25 and 40°C) with infrared and ultraviolet C (UVC) treatments. The attributes of quality were compared in regard to quality of hot-air-dried samples at 70-90°C. Experimental results showed that a significant improvement in the quality of edible bird's nest in terms of minimizing color changes and rehydration capacity using intermittent low-temperature drying with infrared and UVC drying profile. However, it was also found that any drying method has less significant effect on the nitrite content of edible bird's nest. [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]

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]