color

The use of tartrazine as an unauthorized synthetic color in food is a consumer health concern. In Iran, most studies have employed the Thin Layer Chromatography (TLC) to detect any fraud in food colors. Therefore, this study aimed to identify the presence of tartrazine in four types of foods commonly consumed by children in Shiraz, southern Iran using TLC and compare the results with those obtained through highperformance liquid chromatography (HPLC). One hundred and fifty food samples with yellow and orange colors, including 20 samples of freeze pop, 25 samples of ice cream, 57 samples of jelly, 48 samples of candy, were collected from the supermarkets in Shiraz, Iran. In TLC method, color extraction was performed by the white wool method. According to the findings of the TLC method, 118 samples (78.67%) contained synthetic food colors, while 32 (21.33%) food samples did not. Among the samples, 8 (5.33%) contained only tartrazine, and 14 (9.33%) had tartrazine together with other synthetic colors. The HPLC revealed that 127 samples (84.64%) contained synthetic colors, and 23 samples (15.36%) did not. Only 11 (7.33%) samples had tartrazine, while102 samples (68.00%) had tartrazine in addition to other synthetic colors. The finding of TLC and HPLC methods were differed due to the lower detection limit of the TLC method. Therefore, it is necessary to use more accurate methods such as HPLC to detect fraud in food colors.

Considering the few studies on the effect of bleaching protocols on the color properties of a newly developed monochromatic universal composite resin, the present study evaluated the effect of different bleaching protocols on the color change and translucency of Omnichroma (OMN) composite resin.

  In this laboratory study, 45 cylindrical OMN composite resin disks with a diameter of 10 mm and a thickness of 2 mm were used. The samples were randomly divided into three groups (n=15) based on the bleaching protocols: group 1: 40% hydrogen peroxide (HP) for 20 minutes, twice a day for three sessions one week apart; group 2: 20% carbamide peroxide (CP) for 8 hours a day, for 14 consecutive days; group 3: 40% HP with Nd:YAG laser (HP+Nd:YAG laser) applied on the gel for 30 seconds twice. Baseline and post-bleaching measurements of color parameters were done using a Vita Easyshade spectrophotometer. Data was analyzed using paired-samples t-test, one-way ANOVA, and post hoc Tukey tests (P<0.05).

  All the bleaching protocols significantly changed the color (P<0.001) and translucency (P<0.001) parameters. CP caused the most color changes (P<0.05) and translucency (P<0.05), which were significant, and color and translucency changes caused by HP and HP+Nd:YAG laser were not significant (P>0.05).

  Bleaching caused a noticeable change in the color and translucency of the OMN composite resin. The effect of the at-home bleaching protocol was greater than the in-office ones.

Color plays a significant role in shaping the atmosphere and experience within healthcare environments. This systematic review examines the existing literature on the effects of color in healthcare settings, aiming to provide insights into its influence on patient outcomes, staff well-being, and overall healthcare experiences. By synthesizing findings from various studies, this review identifies key themes, explores methodological approaches, and proposes a comprehensive research agenda to better understand the complex relationship between color and health outcomes. The review involved a systematic search of databases such as PubMed, Scopus, and Web of Science, as well as internet search engines including Google and Yahoo. The search focused on empirical studies, theoretical papers, and industry guidelines related to color in healthcare settings. Over 3 000 titles were screened, and relevant studies were critically evaluated for their methodological rigor and findings. A PRISMA form was used to extract the necessary information. The synthesis of existing literature highlights the importance of considering color selection, application, and environmental context in healthcare design to optimize patient care and enhance the well-being of both patients and healthcare providers. Although the existing literature underscores the importance of color in healthcare design, empirical evidence remains limited. Future research should aim to address these gaps by exploring the nuanced ways in which color influences health outcomes and by developing evidence-based guidelines for the application of color in healthcare settings.

Hybrid ceramics are gaining popularity for cosmetic dental restorations due to their advantageous mechanical properties and optimal esthetic results. However, the potential effects of bleaching on their color stability are still a subject of interest. This study aimed to assess the effect of bleaching on stained hybrid ceramics in comparison with IPS e.max.  

This in vitro study was conducted on 48 specimens fabricated from IPS e.max CAD, Vita Enamic, and Cerasmart (n=16) ceramics. The baseline color coordinates of the specimens were measured by a spectrophotometer. Eight specimens from each ceramic type underwent accelerated aging, and their color coordinates were measured again to calculate the color change (ΔE1). The remaining 8 specimens in each ceramic group were immersed in tea solution, and their ΔE was calculated (ΔE2). Subsequently, all specimens were exposed to 20% carbamide peroxide for 8 hours/day for 10 days, and ΔE3 and ΔE4 were calculated. Data were analyzed by two-way ANOVA and Tukey’s test (alpha=0.05). 

Type of ceramic, type of intervention (aging, immersion in tea solution, bleaching), and their interaction significantly affected the ΔE (P=0.0001). The maximum and minimum ΔE values were recorded for Cerasmart and IPS e.max ceramic, respectively.

Both accelerated aging and immersion in tea solution caused staining of hybrid ceramics. The minimum ΔE after bleaching occurred in aged ceramics. Bleaching of stained ceramics improved their color.

Titanium abutments are the gold standard of implant treatments. However, they may not create sufficient color matching to the natural teeth due to the gray color showing through under the ceramic crown. The present study aimed to determine the masking ability of computer‑aided design and manufacturing () bleach shade ceramics in different thicknesses on titanium abutments.

In this laboratory study, a total of 90 specimens of bleach shade ceramics Celtra Duo (CD), Vita Suprinity (VS), and zirconia Luxen were prepared in thicknesses of 1, 1.5, and 2 mm (n = 10). Background specimens of G‑aenial composite in A3 color and titanium were used. The ceramic specimens were placed on titanium and composite backgrounds and L*a*b* color parameters and color difference (ΔE) were measured with the VITA Easyshade spectrophotometer. Data were analyzed using three‑way and one‑way analysis of variance tests. Pairwise comparisons of groups were also performed with Tukey’s test. P <0.05 was considered statistically significant and ΔE <2.7 was considered clinically acceptable criteria.

The effects of thickness, ceramic type, and their interaction effects on the ΔE were statistically significant (all three: P <0.001). The difference in ΔE values of bleach shade ceramics on titanium and composite backgrounds was estimated to be statistically significant in the thicknesses of 1 mm (P = 0.01), 1.5 mm (P < 0.001), and 2 mm (P = 0.001). Zirconia had a better performance for masking ability in thicknesses of 1.5 mm (P < 0.001) and 1 mm (P = 0.01), while VS ceramic showed the best masking ability in thicknesses of 2 mm (P = 0.001). The masking ability of ceramics was improved by increasing the thickness.

Except for VS ceramic in thickness of 1 mm, the rest of the bleach shade ceramics in all three thicknesses of 1, 1.5, and 2 mm have adequate ability to mask the titanium background and their use in line with the masking ability of titanium background has brought acceptable esthetic results.

 An esthetically acceptable ceramic restoration should have optical properties like the teeth and reflect, transmit, and absorb light. The present investigation compared how hydrothermal aging affected the properties of two types of zirconia and lithium disilicate.

 Thirty rectangular samples (12×14×1 mm) were prepared and sectioned from three different ceramic blocks/blanks (n=10), then assigned into three groups according to the ceramic type: group Z: IPS e.max ZirCAD prime, gradient zirconia (3Y/5Y-TZP); group K: Katana UTML (5Y-TZP); and group E: IPS e.max CAD (lithium disilicate). Color analysis of samples was performed before and after hydrothermal aging (1, 3, and 5 hours) using a spectrophotometer. Color difference (∆E00), translucency parameter (TP00), and contrast ratio (CR) were evaluated. The microstructural analysis was performed using x-ray diffraction (XRD). Data were statistically analyzed at a significance level of P<0.05.

 A statistically significant variation was observed across means of ∆E00, TP00, and CR at different times. Group Z displayed the highest statistically significant mean ∆E00. Group E demonstrated the greatest statistically significant mean TP00. Group K exhibited the most statistically significant mean CR.

 Hydrothermal aging significantly affected the optical characteristics of lithium disilicate and zirconia ceramics. The translucency of samples increased with aging.

There is a growing demand for esthetic dental treatments with composite resins like Ceram.x SpectraTM ST® (CS) due to the importance of a beautiful smile; but color change may occur affecting the longevity and quality of composite restorations. The purpose of this study was to evaluate the color stability of a composite resin, subjected to two different polishing systems, after immersion in different coloring solutions (common beverages).

Forty specimens were fabricated from CS nanoceramic composite resin and polished with Enhance® and Astropol® finishing and polishing systems. The CIE L*a*b* color parameters were measured before and after immersing the specimens in coffee, red wine, and Coca-Cola. The chromatic difference was assessed by calculating the ∆E. Two-way ANOVA was applied to compare the ∆E values based on the type of polishing system, coloring solution, and their interaction. 

Astropol® resulted in better color stability and smoother surfaces than Enhance®. Wine and coffee significantly changed the color stability of tested composite resin (P<0.05), while Coca-Cola did not affect the color stability (P>0.05).

The choice of dental finishing and polishing system affects the color stability of CS composite resin following exposure to commonly consumed drinks.

This study assessed the effect of thickness of high-translucent (HT) and super-translucent (ST) monolithic zirconia on its color, translucency, and marginal and internal adaptation.

Monolithic zirconia restorations were fabricated from HT and ST zirconia blanks (n=30) with 0.5-, 1- and 1.5-mm thicknesses (n=10). The color and translucency parameter (TP) was measured by a spectrophotometer, and marginal gap (MG), internal gap (IG), and occlusal gap (OG) were measured by the replica technique.

Zirconia type had no significant effect on TP (P=0.362) but the effect of thickness was significant (P<0.001); 1.5-mm thickness yielded the lowest and 0.5-mm thickness yielded the highest TP. Zirconia type (P<0.001) and thickness (P=0.001) had significant effects on color difference (ΔE); ST yielded significantly higher ΔE, and 0.5-mm thickness resulted in significantly lower ΔE than 1-mm (P=0.047) and 1.5-mm (P<0.001). The MG of both HT and ST increased with thickness (P<0.05). The IG of 0.5 mm-thick restorations was significantly higher than 1 mm (P=0.005) and 1.5 mm (P=0.003). In ST restorations, the difference in IG was not significant among different thicknesses (P>0.05). OG was the highest in 0.5 mm thickness. In ST restorations, minimum OG was found in 1 mm thickness. Zirconia type had no significant effect on adaptation (P>0.05).

Zirconia type had no significant effect on TP or adaptation. Increasing the thickness decreased TP. ΔE was lower in lower thicknesses, and ST zirconia yielded higher ΔE. Thickness had a direct correlation with MG and an inverse correlation with IG and OG.

 This study assessed the effect of repeated preheating of three types of composite resins and a giomer on their color stability.

 In this in vitro study, 128 composite resin and giomer specimens with a 10-mm diameter and a 2-mm height were evaluated in eight groups (n=16) of Heliomolar microfilled, Brilliant Enamel microhybrid, and Tetric N-Ceram nanohybrid composite resins, and Beautifil II giomer used at room temperature and also after preheating of the tube in a water bath at 55‒60 °C for 40 times. After preparing the specimens, their color parameters were measured by a spectrophotometer. The specimens were immersed in a tea solution for 3 hours/day for 40 days and underwent spectrophotometric color assessment again. The color change (∆E) was calculated and analyzed by two-way ANOVA (α=0.05).

 The effects of composite resin type (P<0.001) and preheating (P<0.001) and their interaction effect (P<0.001) were significant on ∆E. Immersion in a tea solution caused a significantly greater color change in giomer (P<0.05). The ∆E of the microfilled composite resin was significantly higher than that of nanohybrid (P=0.003) and microhybrid composite resin (P=0.004).

 Repeated preheating of giomer, microhybrid, and nanohybrid composite resin specimens to 55‒60 °C for 40 times adversely affected their color stability in the tea solution. The color change was significantly greater for giomer.

This study aimed to assess the effects of chlorhexidine (CHX) and Listerine mouthwashes on color stability of glazed bilayer zirconia and IPs e.max ceramics.

This in vitro experimental study was conducted on 36 glazed bilayer zirconia and IPS e.max ceramic specimens. The baseline CIE L*a*b* color parameters of specimens were measured by a spectrophotometer. The bilayer zirconia and IPS e.max ceramic specimens were then randomly assigned to two subgroups for immersion in 10 mL of 0.2% CHX (n=9) and 10 mL of Listerine (n=9). The specimens were immersed in the respective solutions for 2 minutes daily for 7 days. Next, their color parameters were spectrophotometrically measured again. The color change (∆E) of ceramics in the three groups was calculated and compared by the Kruskal-Wallis test and two-way ANOVA (alpha=0.05).   

The L*, a*, and b* color parameters of glazed bilayer zirconia and IPs e.max ceramic specimens were not significantly different at baseline (P=0.8) or after the intervention (P=0.6). The ∆E of the subgroups was not significantly different either (P>0.05).

Both glazed bilayer zirconia and IPs e.max ceramics showed clinically acceptable color stability (∆E<3.3) following immersion in CHX and Listerine mouthwashes.

The aim of the present study is to investigate physicochemical attribute, antioxidant function, antimicrobial activity and sensory feature in Lepidium latifolium L. (L. latifolium) extract on fish burgers during the shelf life. Initially, L. latifolium was extracted using soxhlet (LES), ultrasound (LEU) and supercritical water (LEW). The major components were assessed using high performance liquid chromatography, where sinigrin and glucosinolates constituents were identified. The results illustrated that satisfactory values were obtained for these values in the treated sample by LEU. In next step, 0.2 % of each extract was added to fish burgers. The control and treated samples were tested to determine pH level, cooking yield, color features, thiobarbituric acid (TBAR), peroxide value (PV), microbial population, sensory evaluation and scanning electron microscope (SEM). The lowest TBAR and PV levels were found to be 0.38 and 0.40 (mg malonaldehyde) as well as 4.22 and 4.28 (meqO2/kg) for treated fish burgers by LEU and LEW respectively (p < 0.05). The most sensory desirability was observed for treated sample by LEU, which also exhibited the uniform structure in SEM images as compared to others. In conclusion, fish burgers obtained by LEU and LEW can be considered as optimal samples to preserve burgers.

This study aimed to investigate the aesthetic aspect of screw-retained restorations by examining three different types of filling materials used for the access cavity, highlighting the significance of aesthetics in implant restorations.

In this laboratory investigation, simulation samples of screw-retained restorations were filled with flowable composite resin (group F), opaque and flowable composite resin (group O) and porcelain plug (group P) at baseline (T0). The samples were subjected to thermocycling twice (T1 and T3), undergoing 1000 cycles in coffee, orange juice, and distilled water, followed by washing performed after each thermocycling (T2 and T4). Colorimetric analysis and surface roughness measurements were conducted, and the data were statistically analyzed using. two-way analysis of variance (ANOVA), Tukey post hoc, two-way analysis of covariance (ANCOVA), and paired-t test. P<0.05 was considered significant.

The type of filling material had a significant effect on the color difference observed between the restoration and filling materials (P<0.05). Notably, samples from group P exhibited a more pronounced color difference at T4, despite showing a lower color difference at T0, when compared to group O.

The use of porcelain plugs did not provide a notable advantage over the combination of flowable and opaque composite resins, particularly given the difficulties in fabricating and positioning porcelain plugs within the access cavity. Therefore, it is recommended to utilize flowable composite resins in conjunction with an opaque composite resin layer beneath, to effectively conceal any dark shades from the underlying metal

This study examined the impact of a blue covarine whitening mouthwash on enhancing the color of stained composite resin specimens and teeth.

This in vitro study involved a total of 72 specimens including 36 human incisors and 36 disks prepared from a resin composite. The specimens in each group were randomly distributed to three subgroups (n=12) according to the applied mouthwash: Listerine, iWhite and a control group. Control specimens were maintained in distilled water throughout the study. The remaining specimens were immersed in a coffee solution for two weeks, then treated with either Listerine (containing hydrogen peroxide) or iWhite (containing blue covarine) mouthwashes. The immersion lasted for four minutes daily over 56 days. Color assessment was performed by a spectrophotometer at baseline (T1), post-staining (T2), and post-mouthwash immersion (T3) and color change (ΔE) between stages was calculated.

Significant discoloration was observed after immersion in coffee solution in the experimental groups as compared to the control (P<0.05). The color change between baseline (T1) and after immersion in mouthwashes (T3) was not significantly different between the two experimental groups on tooth samples (P=0.12). However, ΔE (T1-T3) was significantly lower in iWhite (ΔE=2.27) than the Listerine mouthwash (ΔE=4.99) on composite specimens (P<0.001).

Both hydrogen peroxide- and blue covarine-containing mouthwashes showed comparable effects in restoring tooth discolorations, although the color changes were detectable after treatment (ΔE > 3.3). The mouthwash containing blue covarine (iWhite) restored the original color of composite resin specimens more successfully than the mouthwash containing hydrogen peroxide (Listerine).

Similarity in the appearance of a monolithic restoration with the adjacent teeth is necessary. This study aims to influence the foundation material type and ceramic thickness on the final color of zirconia‑reinforced lithium silicate (ZLS) ceramic.

In this experimental study, the A2 translucent blocks of ZLS were sectioned into rectangular specimens with thicknesses 1, 1.5, and 2 mm (n = 15). Substructure materials include resin composite (B1, D2, A2, A3, and C3), nickel chrome alloy, amalgam, and white and black substrate. Substructure material of resin composite with A2 color was proposed as the control group. The value of the color difference (ΔE00) is calculated by the CIEDE2000 formula. Data analysis was accomplished by two‑factor repeated measures ANOVA and one‑sample t‑test (α =0.05).

The mean value of maximum ΔE00 with a black substrate (12.13 ± 0.17) at 1 mm ceramic thickness and the mean value of minimum ΔE00 with B1 resin composite foundation material (0.02 ± 0.17) at 2 mm ceramic thickness are visible. The significant effect of the foundation restoration type, thickness, and interaction between them is visible on ΔE00 (P < 0.001).

Different thickness is required to meet ideal esthetic outcomes with different substrates. Under the conditions of this investigation, zirconia‑reinforced lithium silicate over black, white, nickel–chromium, and amalgam did not meet acceptable outcomes.

This study aims to investigate the color stability of feldspathic porcelains with different concentrations of silver nanoparticles (AgNPs).

In this experimental study, feldspathic porcelain disks with AgNPs of 0 parts per million (ppm), 250 ppm, and 500 ppm were used (sample size = 180). These ceramic discs were subjected to thermocycling in tea, orange juice, and artificial saliva. The optical parameters of disks were measured before and after being immersed in the solutions. Then, the color change (ΔE 00) of the samples was measured by using the CIEDE 2000 formula. The data were analyzed by one‑way analysis of variance (ANOVA) and Tukey’s post hoc test. The level of significance was determined to be 0.05.

The results of the ANOVA test show that there was a significant difference in ΔE 00 (P ≤ 0.05). The maximum ΔE 00 was visible in the samples with AgNPs 0 ppm that were exposed to orange juice, and the minimum ΔE 00 was related to the disks with AgNPs 500 ppm in artificial saliva.

Based on the results of this study, adding AgNPs to feldspathic porcelain increases the color stability of the ceramic discs.

Visual and advanced instrumental methods are the most common tools for shade selection. The instrumental methods are considered reliable and provide quantifiable values, but the high cost puts them out of the reach of most dentists. Light‑correcting devices provide an economical alternative for clinical shade selection. The aim of this study was to assess the reliability of the light‑correcting device in clinical shade selection.

The in vivo experimental prospective study sample included 60 volunteers aged 18–25 years, with no severe enamel pigmentation or anomaly in anterior maxillary teeth. Two observers performed visual shade matching of the maxillary right central incisor without a light‑correcting device and later with a light‑correcting device at the same time of the day at an interval of 1 week. The shades were confirmed with the control value obtained by using a spectrophotometer. Each observer was blinded to the shade color selected by the other examiner. The data collected were subjected to the statistical analysis. The shade measured with the light‑correcting device and without its use was compared with the control shade obtained by the spectrophotometer. The value closer to the control shade value was considered accurate, and the method used for shade matching would be considered reliable. The Fleiss kappa statistical test was used to assess the reliability of each method. P ≤ 0.05 was considered statistically significant.

Using a light‑correcting device significantly increased the reliability of the visual shade selection method. When compared to the shades recorded by the spectrophotometer (control), the use of a light‑correcting device as an aid in visual shade selection showed more accurate and reliable results as compared to the visual shade selection without a light‑correcting device (P < 0.05).

Light‑correcting devices can assist in reliable shade selection and allow better communication with the dental laboratory technician to provide predictable esthetic results.

This study aimed to investigate the effects of zinc oxide nanoparticle shape on the optical characteristics of tapioca starch films and the microbial growth kinetics of Escherichia coli. For this purpose, nanorods, nano-spheres, and nanoparticles of ZnO at 0.5, 1.0, and 2.0% levels were incorporated into the tapioca starch film solution by solvent casting method. The results showed that tapioca starch-based films were colorless, and by adding different morphology of ZnO nanoparticles and increasing nanoparticles concentrations, the lightness and transparency of the films decreased, and a*, b* and ΔE increased significantly (p<0.05). The bionanocomposite films containing nano-ZnO represented antibacterial activity against E. coli. Their action was directly related to their concentration. With increasing the nano-ZnO concentration, the antibacterial activity increased, and the microbial growth kinetics tended downward. The morphology of nano-ZnO had a remarkable effect on their antibacterial activity, so the highest activity was related to ZnO nano-spheres.