Lowest Color Change Research Articles

The Effect of Different Storage Conditions on Textural, Microbiological and Color Properties of Phyllo (Yufka)

The effect of different storage conditions on textural, microbiological and color properties of phyllo was investigated. Phyllo samples were stored at room temperature (20 ⁰C) for 3, 5 and 7 days, in refrigerator (4 ⁰C) for 7, 14 and 21 days, and in deep freezer (-18 ⁰C) for 20, 40 and 60 days. It was determined that phyllo samples stored in the deep freezer exhibited higher L* color values (82.33-82.97), followed by samples stored in the refrigerator (78.53-81.75) and samples stored at room temperature (75.74-77.75), respectively. A statistically similar and lower total color change (∆E) occurred in the phyllo samples stored at room temperature and in the refrigerator than the samples stored in the deep freezer. The samples stored in the refrigerator exhibited higher hardness, chewiness and gumminess values, while the samples stored in the deep freezer exhibited lower values. Most of samples produced were similar to the control sample in terms of elasticity property. In terms of relaxation time value, the samples stored at room temperature and in the deep freezer exhibited statistically similar and lower values than the samples stored in the refrigerator. Additionally, the samples stored in the deep freezer had higher breaking force and breaking length values. The total mesophilic aerobic bacteria count of the samples varied between 3.38-12.30 log cfu/g and mold and yeast count varied between

Effect of Preheating on the Color Stability of Two Different Commercially Available Nanohybrid Dental Composites: An In Vitro Study

ABSTRACT Introduction: Color stability is one of the important criteria for the selection of composite during its service. Preheating of composite is performed to improve its handling characteristics. The present study aimed to evaluate the effect of preheating in two nanohybrid composite resins. Material and Methods: Sixty disk samples were prepared and divided into 2 main groups according to the temperature of preparation (n = 30). Both the groups were subdivided into Group 1A - Kulzer Charisma Diamond (N = 15) and Group 1B - Tetric N-Ceram (N = 15). Al: the sample discs were further immersed in testing solutions of tea, coffee, and distilled water (N = 5) for each group. Results: We observed significantly lower color change in the preheated group as compared to room temperature and also comparable color change in both the types of composites used. Conclusion: It was thus concluded that preheating composites could be effective in maintaining color stability in nanohybrid composite resins.

Effect of cigarette smoking on the optical properties of contemporary dental ceramics: an in-vitro analysis.

Cigarette smoking is the most common form of tobacco use worldwide. With the frequent introduction of new dental materials, the effect of smoking on their optical properties such as long term color stability, should to be thoroughly investigated. This in-vitro study aims to investigate the effect of smoking on the optical properties of contemporary dental ceramics used currently for restoration of teeth. Five different materials in two shades (B1 and C1) were used with 15 samples from each pressable lithium disilicate (Emax), layered lithium disilicate (Lmax), porcelain fused to metal (PFM), monolithic zirconia (MZr) and layered zirconia (LZr) were used (n=75). The samples were exposed to conventional cigarette smoke and color stability was assessed at four different time intervals i.e., baseline, 1 week, 1 month and 6 months. CIELAB color space (CIE L*a*b*) values were used to evaluate the color difference (ΔE). A one-way analysis of variance (Anova) was used for statistical analysis of ΔE. Significant P-value was kept as <0.05, followed by Tukey post-hoc test. All test materials demonstrated significant color differences (ΔE) after exposure to cigarette smoke (p<0.05). For shade B1, the highest change in shade ΔE 17.02 was exhibited by Lmax, whereas the least change in shade was exhibited by Emax followed by PFM at values of ΔE 10.11 and 11.2 respectively. For shade C1, the highest change (11.47) in shade at 6 months was demonstrated by MZr, whereas lowest values of ΔE were exhibited by Emax (7.52). Traditional smoking causes significant change in shade of dental ceramics which can affect the esthetics of the patients. All material samples tested showed the values of ΔE > 3.3 which is higher than the acceptable range. Lowest color change was observed in Emax and PFM.

Evaluation of Color Stability of a Composite Resin Using Different Instrument Lubricants After One Month of Water Storage

Background: Clinicians use several lubricants to reduce composite sticking to instruments and facilitate composite modeling. This study evaluated the effect of instrument lubricants on the color stability of a resin composite after one month of water storage. Methods: 60 disc-shaped specimens (2×10 mm) of Tetric N-Ceram composite were prepared using four lubricants, isopropyl alcohol 70%, Adper single bond adhesive (SB), margin bond (MB) and composite wetting resin (CW) (12 samples for each group). No lubricant was used in the control group. Color measurement was done twice, 24 hours after sample preparation and after one month of water storage. Color differences were calculated, and the data were analyzed using ANOVA and Tukey’s post hoc tests. Results: The use of single bond as instrument lubricant caused the most color change (ΔE=4.26), and the control group (no lubricant) showed the least color change (ΔE=1.77). Using composite wetting resin as an instrument lubricant resulted in lower color changes than other instrument lubricants (P&lt;0.05). Conclusion: Composite Wetting Resin used as instrument lubricant had better color stability than other lubricants. Bonding agents are not recommended for composite restorations as instrument lubricants due to the higher risk of affecting color stability. Clinicians should be aware that using instrument lubricants might influence the color properties of dental composites.

Research of Optical Properties and Biocompatibility in Different Zones of Multilayered Translucent Zirconia on Hydrothermal Aging.

We assessed the changes in optical properties and biocompatibility of transition zones in multilayered translucent monolithic zirconia exposed to prolonged hydrothermal aging and compared the results to those with different yttrium oxide contents. Four types of zirconia blocks from IPS e.max ZirCAD were used: 3Y-TZP e.max ZirCAD LT (ZL), 4Y-TZP e.max ZirCAD MT (ZM), 5Y-TZP e.max ZirCAD MT Multi (ZT), and 3Y/5Y-TZP e.max ZirCAD Prime (ZP). A total of 120 specimens (15.0 mm diameter and 1.5 mm height) were fabricated and divided into three groups (n = 10). The aging process for the specimens was conducted in an autoclave set to 134 °C and 0.2 MPa, with durations of 0 h (control), 5 h (first aged), and 10 h (second aged). The optical properties and biocompatibility were analyzed, followed by a statistical analysis of the data (α = 0.05). Before and after aging, ZL and ZP exhibited the lowest color changes. ZT exhibited the highest average transmittance and translucency parameter values, while ZL had the lowest. The water contact angle test showed the highest value in ZM and lowest in ZL across all the aging stages. ZL, ZM, and ZP showed a considerable decrease in the water contact angle; however, ZT did not. A cell counting kit-8 assay showed ZL had the highest value, while ZM had the lowest. A filamentous actin test exhibited the highest value in ZL and lowest in ZM. In the vinculin analysis, ZL and ZT exhibited the lowest values, whereas ZM and ZP had the highest. 3Y/5Y-TZP exhibited a balanced performance across critical parameters, such as color stability, translucency, and biocompatibility, aligning with 3Y-TZP. While 5Y-TZP demonstrated superior translucency, it confirmed the lowest color stability, whereas 3Y-TZP achieved the highest biocompatibility. These properties provide clinicians with a reliable material option that ensures superior esthetic outcomes and long-term prognosis, ultimately contributing to improved patient satisfaction and clinical longevity.

Evaluation of Color and Translucency Changes of PEEK Material Veneered with Single-Shade Composite Resins

Aim: The aim of this study was to evaluate the color and translucency changes of single-shade composites used in veneering polyetheretherketone (PEEK) material after aging. Materials and Methods: 3 single-shade composites with different chemical structures and 1 conventional composite resin were applied on the PEEK material with a thickness of 2 mm (N=40, n=10). L, a, and b color coordinates of each specimen were measured three times with a spectrophotometer on a black, gray, and white background from the center of the specimen, and the average of these measurements was recorded. The specimens were subjected to 5000 cycles of thermal aging at 5-55°C. After aging, color measurements were repeated. Color changes (ΔE00) and translucency parameters (ΔTP00) of composite resin specimens were determined before and after aging using CIEDE 2000 color formulas. The data obtained were analyzed by one-way analysis of variance and Tukey HSD test (p&lt;0.05). Results: As a result of the study, the color change of all composite resin materials was found to be below the clinically acceptable limit (ΔE = 1.8). The lowest color change was observed in the traditional composite group, and a statistically significant difference was found between the other groups (p&lt;0.05). The translucency change of single-shade composite materials was found to be statistically lower than that of conventional composite resin (p&lt;0.05). Conclusion: This study's results show that single-shade composite resins can be used as an optical alternative to traditional composites in direct veneering of the PEEK material.

Investigation of the oxidative self- polymerization of dopamine under alkaline conditions on wool fabrics

Most studies about polydopamine in the textile field have been related to cotton fibers. There are not many studies about the use of polydopamine on wool fibers. A limited number of studies have focused on the coloring of wool, whereas wool is the fiber with the highest variety of intermolecular attraction forces among all natural and man-made fibers. Polydopamine contains high amounts of catechol and amine functional groups due to its structure. In this study, different from the literature, oxidative self-polymerization of dopamine was achieved on wool fabric for different periods of time, and the coated fabrics were examined with characterization tests and spectrophotometrically. In this study, lower values were obtained than lightness (L*) values reported for other fibers in previous studies, and it was concluded that the wool-PDA interaction is superior to other fibers. Scanning electron microscopy and energy-dispersive X-ray spectroscopy results showed that the polymerization and nano-coating formed successfully and continued to remain on the surface after washing. The lowest lightness value was obtained in the 32 h coating. However, the lowest color change after washing was in the 16 h coating (0.44%). This result showed that the coating was completed within 16–32 hours and there was only accumulation on the surface in the later times.

Effect of immune-boosting beverage, energy beverage, hydrogen peroxide superior, polishing methods and fine-grained dental prophylaxis paste on color of CAD-CAM restorative materials

BackgroundThe effect of an immune-boosting beverage (SAM) containing Sambucus Nigra, an energy beverage (ENE), an in-office bleaching (BLE) agent with 25% hydrogen peroxide superior, glazing (GLA) or polishing (POL) methods, and professional dental prophylaxis (PDP) on the color of CAD-CAM restorative materials is unknown.MethodsIn total 210 specimens were prepared, consisting of CAD-CAM feldspathic (FC), zirconia-reinforced lithium disilicate ceramic (ZLS) and hybrid ceramic (HC). The ceramic specimens were divided according to the polishing methods of glazing (GLA) and mechanical polishing (POL). All materials were divided into two groups: with and without BLE. A 25% hydrogen peroxide superior (HPS) gel was used for BLE. After the baseline (BAS) measurement, the specimens were immersed in 3 different beverages (distilled water (DIS), SAM, ENE). After 28 days, a fine-grained (RDA 7) prophylaxis paste was applied. Statistical analysis of ∆E00 color difference values was performed by 3-way ANOVA and Bonferroni test (α = 0.05).ResultsThe effect of all other actions except material-BLE-beverage on color for BAS-Day 28 was statistically different (p < 0.05). The effect of material, material-BLE, beverage on color for Day 28-PDP was statistically different (p < 0.05). After 28 days, the lowest color change was found in FC-GLA and HC immersed in DIS (p = 0.0001) and the highest in FC-POL immersed in ENE (p = 0.0002). PDP was efficient in color recovery in HC immersed to DIS, ENE and SAM (p = 0.0010). For FC, HC and ZLS, BLE caused a higher color change (p < 0.0001). Regardless of the material, the highest color change for BLE-beverage was found in BLE-treated specimens immersed in ENE (p = 0.0496) and the lowest color change was found in non-BLE-treated specimens immersed in SAM (p = 0.0074).ConclusionsIn materials pre-exposed to 25% HPS, the effect of PDP on color recovery was lower than in unexposed materials. After 28 days, mechanical polishing produced higher color change in FC than glazing, however, in ZLS effects of glazing and mechanical polishing on color were similar. For material/polishing method, HC was the most effective. ENE caused higher color change than DIS and SAM. PDP was more effective than ENE in restoring color to DIS- and SAM-immersed specimens.

Evaluation of color Stability of Different Restorative Materials Used in Pediatric Dentistry

Background: The aim of this study was to evaluate the color changes of restorative materials (Filtek z550, EverX Posterior, Dyract XP, EQUIA Forte Fill), which are frequently used in pediatric dentistry, after aging with beverages (cola, cherry juice) that children and adolescents frequently consume in their daily life. Methods: Four different restorative materials; nanohybrid composite (Filtek Z550), glass fiber reinforced bulk fill composite (EverX Posterior), polyacid modified composite resin (Dyract XP) and glass hybrid glass ionomer cement (EQUIA Forte Fill) were used. A total of 120 samples were prepared for each material using plexiglass molds with a thickness of 2 mm and a diameter of 10 mm. A total of 30 samples from each group were divided into 3 group (n=10) to be immersed in cola, cherry juice and distilled water. After the initial color measurements, the samples were stored in beverages for 7th and 14th days. Color change values (ΔE) were calculated after 7th and 14th days. Results: When the ΔE values of materials were examined, it was observed that EQUIA Forte Fill group had the highest color change and Filtek z550 group had the lowest color change. Conclusion: The glass hybrid GIC showed the most distinct color change in all time periods and beverages. ΔE values in cola and cherry juice of all resin-based restorative materials tested were less than or equal to 3.3. Therefore, color changes were clinically acceptable as they were not visually perceptible Key words: Bulk-Fill Composite Resin, Color Stability, Glass Hybrid Glass Ionomer Cement

Effect of Reduced-Step Polishing Systems on Color Stability of Nanocomposites Submitted to Thermocycling Staining with Common Beverages - An In Vitro Study.

Long-term color stability of composite resins is one of the most important factors influencing the clinical longevity of aesthetic restorations. This study evaluated the effect of novel reduced steps and gold standard multiple steps polishing systems of two composite resins; a nano-filled (Filtek Z350XT) versus a supra-nanofill (Palfique LX5) on their color stability after submitting to thermocycling with common beverages. Sixty disc-shaped specimens were fabricated from both composite resins ( n = 30). From each material, ten specimens acted as the control group (Mylar strip), ten specimens were polished with Sof-Lex Diamond spirals, and ten were polished with Super-Snap X-Treme discs. All the specimens were thermocycled with staining solutions. Color was measured by a spectrophotometer before and after thermocycling and color difference (ΔE*) was calculated. One-way analysis of variance followed by Tukey's post-hoc test and independent t -test ( α = 0.05) were used. A significantly highest color change was recorded for both control subgroups ( P < 0.05), and the Sof-Lex Diamond spiral showed significantly the lowest color change ( P < 0.05). Both the control and Sof-Lex Diamond spiral subgroups of Palfique LX5 produced significantly lower color change compared with subgroups of Filtek Z350 ( P < 0.05). Sof-Lex Diamond spiral polishing system provided the least color difference for both composites, while there was no significant difference between the materials when the Super-Snap X-Treme polishing system was used.

In-vivo evaluation of the effects of short-term dehydration and rehydration on the color differences of immature permanent incisor teeth.

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. 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 (ΔE00) values and the Whiteness Index (WID) 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). Significant differences emerged in the mean ΔE00 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 ΔE00 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 ΔE00 and ΔWID, no significant variations were detected across the Classes (p > 0.05). 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 ΔE00 and ΔWID of the teeth was found to be similar after the dehydration and rehydration processes. 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.

Impact of combining dental composite brushes with modeling resins on the color stability and topographic features of composites.

This study explores the effect of using dental brushes with or without metacrylate-based modeling resins on long-term color stability and surface topographies of resin-based composites. This study examined the effects of two variables: (1) the type of brush used (Art brush, Micro-brush, or Mylar strip) and (2) the application of a modeling resin (applied or not applied). The specimens were artificially aged through 10,000 cycles of thermocycling and subsequently immersed in coffee for 30 days. Measurements of color and surface roughness were taken at baseline and after the aging, using a non-contact profilometer for surface roughness and a spectrophotometer for color. Data were analyzed using paired t-tests and one-way ANOVA. Resin-based composites smoothed with dental brushes or micro brushes without modeling resins exhibited lower color change (ΔE) than other groups. Paired t-tests revealed significant differences in average surface roughness (Ra) and valley depth (Rv) for each surfacing technique before and after aging (p ⩽ 0.01). The root means square average of the profile heights (Rq) significantly increased in the control and micro-brush groups (p ⩽ 0.01). In conclusion, the use of brushes in resin-based composites placement does not increase the susceptibility to staining. Instead, the inclusion of resin modeling contributes to discoloration over time.

Influence of different finishing, aging with coffee, and repolishing protocols on the properties of nanoparticle composite resins.

Considering the variability of finishing protocols for composite resins, the literature does not offer a consensus about the influence of these approaches to obtain a final polishing and whether the physical properties of these composite resins change at different analysis times. Therefore, the study analyzed the microhardness, roughness, color stability, and gloss of a nanocomposite resin with different finishing, aging with coffee, and repolishing protocols. Nanocomposite resin samples were divided into three finishing protocol groups: Diamond burs (F and FF), multi-fluted tungsten carbide burs (18 and 30 flutes), and coarse and medium abrasive discs (Soflex-3M). All protocols used spiral rubber tips (F and FF) for polishing. Knoop microhardness (KHN), roughness (Ra), color changes (ΔE00 and YI), and gloss (GU) were analyzed. Scanning electron microscopy provided images of resins and finishing and polishing instruments. Resin KHN (p<0.001) decreased, and Ra (p<0.001), ΔE00 (p<0.001), and YI (p<0.001) increased after aging with coffee, regardless of finishing protocol. Abrasive discs showed lower color changes, YI, and Ra and higher GU. Repolishing restored KHN and Ra but not ΔE00 (p>0.05) and YI (p>0.05). Abrasive disc finishing reduced roughness and yellowness and increased nanocomposite resin gloss after aging with coffee. Key words:Color, Composite resins, Dental materials, Staining, Surface properties.

Influence of Ceramic Material Type and Cement Shade on the Translucency of Lithium Disilicate Ceramic Veneers.

Aims: Careful selection of materials and resin cement shade can minimize color changes in laminate veneers. This study aimed to evaluate the influence of two ceramic material types, lithium disilicate glass-ceramic material (Ivoclar, Schaan/Liechtenstein; IPS e.max), computer aided design (CAD) and IPS e.max Press, and four different resin cement shades on color changes in lithium disilicate ceramic laminate veneers. Methods: Forty extracted human maxillary first premolars were prepared to receive a laminate veneer. Optical scanning and digital designing were used to prepare 20 IPS e.max CAD and 20 IPS e.max Press veneer samples. These samples were divided into four groups based on resin cement shade and material: Group CAD A1 : (IPS e.max CAD with A1 cement shade), Group CAD T : (IPS e.max CAD with translucent cement shade), Group CAD M : (IPS e.max CAD with milky bright cement shade), Group CAD B1 : (IPS e.max CAD with B1 cement shade) and the same divisions for IPS e.max Press. Before cementation, color measurements were obtained using precision colorimeter NR110. After cementation, the ∆E (color change) value was recorded and tabulated. One-way analysis of variance (ANOVA) and Duncan's post hoc test were used to evaluate the influence of ceramic material types and cement shade on ∆E. Results: There were significant differences between the IPS e.max CAD and e.max Press veneers for the four tested cement shades. The highest color change was observed in press M veneers (8.84 ± 0.63931) while the lowest color change was observed in CAD M veneers (0.5 ± 0.16371). There were significant differences in color change based on cement shade, with B1 showing the greatest change (8.84 ± 0.47440 for Press veneers and 2.3 ± 0.11992 for CAD veneers). Conclusions: Different shades of resin cements and different manufacturing techniques produce different levels of color changes therefore careful selection of materials and cement shade can minimize color changes in laminate veneers.

Impact of adding 3% titanium oxide nanoparticles in different denture base materials on some of the biological, physical, and mechanical properties properties: In-vitro study

Background/aim Acrylic resin denture base material with all its varieties and curing techniques enormously influence their physical, biological, and mechanical properties. This study designed to evaluate and compare the impact of acrylic resin reinforcement with titanium oxide nanoparticles (TiO2NP) on physical, biological, and mechanical criteria of two dissimilar denture base materials. Materials and methods This study was constructed on 120 specimens of 2 different types of acrylic resin denture base materials. The specimens were divided equally into 2 groups (60 each), group I (heat cured acrylic resin) and group II (microwave cured acrylic resin). Each group was additionally divided into two subgroups (each 30). Subgroup A as control, while subgroup B was modified with 3% TiO2NP. Biological evaluation was performed on Enterococcus faecalis by using antimicrobial assay by agar diffusion test color stability via employing spectrophotometer, and the Modulus of elasticity through universal testing machine. Results Regarding the results of biological assessment, groups IA and IIA (control groups) revealed no inhibitory zone, while groups modified with 3% TiO2NP group IIB demonstrated significantly higher (P &lt; 0.05) inhibitory zone when compared with group IB. Concerning color stability, Regarding color stability, Group IA and IIA (control groups) demonstrated the highest color changes, while Group IB and IIB(modified groups) demonstrated the lowest color changes. In modulus of elasticity, groups IB and IIB were significantly higher (P&lt;0.05) than groups IIA and IIB. Conclusion Adding 3% TiO2NP to heat and microwave cured resins induced antibacterial characteristics against E. faecalis. Besides improvement of the evaluated mechanical (modulus of elasticity) and color stability properties.

Enerji İçeceği ve %35 Hidrojen Peroksitin Güncel Restorasyon Malzemelerinin Renk Değişimleri ve Mikrosertlikleri Üzerindeki Etkisinin Değerlendirilmesi

Objective: This study aimed to determine the effect of 35% hydrogen peroxide and carbonated energy drinks on microhardness and discoloration of CAD/CAM hybrid blocks and existing composite resins.&#x0D; Materials and Methods: Fifteen disc (4x10 mm) samples were produced from each material (Tetric-N-Ceram=TNC, Estelite Sigma Quick=ESQ, Shofu HC=SH and Vita Enamic=VE). Five samples from each group were randomly assigned according to the application procedure (soaking in an aerated energy drink, 37 °C distilled water, and exposure to 35% hydrogen peroxide bleach gel). The color change and microhardness of the samples were measured before and after the treatments. Data were analyzed with Mann-Whitney-U, the Wilcoxon rank-sum test, a one-way ANOVA, and a post hoc test (p&gt;0.05).&#x0D; Results: No change in microhardness was observed in all groups. The highest color change was found in the ESQ group exposed to hydrogen peroxide, while the lowest color change was found in the VE group. Energy drink and hydrogen peroxide do not affect the microhardness of test materials, but may cause discoloration.

Chitosan vs chitin: Comparative study of functional pH bioindicators synthesized from natural red dyes and biopolymers as potential packaging additives

In this study, we compare pH-sensitive bioindicators fabricated via the facile one-pot reaction of biopolymers (chitosan or chitin) and natural red dyes (carminic acid and purpurin). The relationship between the biocomponents and the structure, stability, and pH-sensing activity of the resulting materials is also investigated. XPS, FT-IR, SEM and pH assessments confirmed the presence of interactions between the biopolymers and the natural dyes, leading to the formation new functional smart colorants. The type of biopolymer determined the stability of the materials, and the incorporation of natural dyes significantly increased their chemical and thermal stability. All the colorimetric indicators were highly sensitive to HCl and NH3 vapors, changing color after just a few minutes. Their application as new biocolorants for ethylene-norbornene copolymer (EN) resulted in composites with attractive color performance and good photostability. This was evidenced by the lower color changes and carbonyl index increment of the samples containing the new color systems after 50 h, 100 h, and 200 h of UV irradiation compared to pure natural dyes. For the real-time analysis of the application of colorimetric pH indicators, the colored EN composites were applied to colorimetric monitor the freshness of shrimps at room temperature. The findings indicated that the designed biopolymer-dye materials could be used simultaneously as colorants, pH indicators, and additives for polymers, providing protection against unfavorable aging conditions. Importantly, the new colorants also exhibited lower tendency to leach from the polymer matrix compared to natural dyes. This could elegantly overcome the strong migration problems associated with natural dyes and enable widespread application of the new biocolorants in packaging systems.

Is the whitening effect of charcoal-based dentifrices related to their abrasive potential or the ability of charcoal to adsorb dyes?

ObjectivesTo evaluate if tooth color alteration of activated charcoal-based dentifrices may be attributed to the dye adsorption potential of charcoal (chemical action - C - slurry only) or to the association of dye adsorption with abrasion (chemo-mechanical action - CM- slurry/toothbrushing). Potential adverse effects in surface roughness, gloss, and wear were also assessed. MethodsBovine enamel/dentin specimens were randomly allocated into the groups according to treatments and test model (n = 15): deionized water (negative control- NC); Colgate Maximum Anticaries Protection (conventional toothpaste- positive control- PC); Colgate Luminous White Activated Charcoal (LW); Oral-B 3D White Therapy Charcoal (WT); Curaprox Black is White (BW); Dermavita Whitemax (Activated charcoal powder- WP). Specimens were exposed to the C or CM models, in 28-day staining-treatment cycling. Color change (ΔE00), whiteness index (ΔWID), percentage of alteration of surface roughness (%Raalt), and gloss (%GUalt) were calculated. Additional specimens (n = 9) were indented with a Knoop diamond and subjected to 100,000 abrasion cycles. Enamel wear was determined by calculating the decrease in indentations geometry. Data were analyzed by ANOVA/Tukey tests (α = 0.05). ResultsThe CM-model produced lower color change (staining) than C (p = 0.0001). PC, LW, WT, BW, and WP showed similar color results for both models, differing from NC (p < 0.05).%Ra and%GU did not differ among the C-model groups (p > 0.05) and WP exhibited the highest variation (%Ra and%GU) under CM-model. Enamel wear values were lowest in the NC and PC groups, intermediate for LW, WT, BW, and highest for the WP (p < 0.05). ConclusionActivated charcoal-based dentifrices have a similar ability to minimize tooth staining as the conventional toothpaste, with increased enamel wear potential in the long term (after 100,000 cycles). The activated charcoal powder damaged the enamel surface, showing a higher deleterious effect on enamel roughness, gloss, and wear. Clinical significanceDentifrices containing activated charcoal do not provide superior results to minimize tooth staining compared to conventional toothpaste. Charcoal powder should be used with caution because it promotes higher superficial alterations on the enamel surface.

Effects of ZnO/trimethylsilyl cellulose nano-composite coating on anti-UV and anti-fungal properties of papers

Trimethylsilyl cellulose (TMSC) was employed as the coating matrix for the application of zinc oxide nanoparticles (ZnO) onto paper surfaces and the protections of ZnO/TMSC coating against UV-induced damages and fungal spoilage were evaluated. Filter papers were immersed in 2% w/v TMSC solution loaded with ZnO and air-dried. Three ZnO/TMSC suspensions were prepared with 0.1, 0.5, and 1% w/v ZnO NPs. The presences of ZnO/TMSC protective layers were confirmed with ATR-IR spectroscopy. The coated papers exhibited high surface hydrophobicities. After the coated papers were subject to 365-nm UV irradiation at 400 W for 3 h, the contact angles dramatically dropped. The trimethylsilyl (TMS) groups exposed on the surface formed a moisture barrier and were partially removed on UV exposure. ATR-IR revealed that more TMS groups were removed in the protective layer with no ZnO. UV-irradiated papers turned yellow and papers protected with 1% ZnO/TMSC exhibited significantly lower color changes than that of the uncoated one. Compared to the TMSC-coated paper, the addition of ZnO resulted in a significant reduction in tensile strength at maximum. However, after UV irradiation, significant increases in both the strain at break and strength at maximum were only observed in 1% ZnO/TMSC-protected papers. Regarding their anti-fungal properties, the 1% ZnO/TMSC films were effective in growth inhibitions of Aspergillus sp. and Penicillium sp. on the nonirradiated papers. Despite being hydrophilic after UV-irradiation, growths of the molds were severely suppressed on the UV-irradiated paper.

Effect of Material Thickness and Coffee Thermocycling on the Color Stability and Translucency of Additively and Subtractively Manufactured Resin-Based Materials for Definitive Restorations.

To evaluate the effect of material thickness and coffee thermocycling on the optical properties of definitive resin-based materials created via additive manufacturing (AM) and subtractive manufacturing (SM). Specimens were prepared in three thicknesses (1, 1.5, and 2 mm) from three AM (3D-CB, 3D-TH, and 3D-CT) and two SM (G-CAM and VE) resin-based materials (n = 15 per material and thickness combination). Color coordinates of each specimen were measured after polishing and after 10,000 cycles of coffee thermocycling. Color differences (ΔE00s) and relative translucency parameter (RTP) values were calculated. After logarithmic transformation, ΔE00 values were analyzed with two-way ANOVA, while RTP values were analyzed with generalized linear model test (α = .05). 3D-TH had the highest pooled ΔE00 and G-CAM had the lowest (P ≤ .004). 3D-CB had higher pooled ΔE00 than VE and 3D-CT (P ≤ .002). For the SM group, the 1.5-mm and 2-mm 3DCT specimens and 1-mm 3D-TH specimens had lower ΔE00 than 1.5-mm and 2-mm 3D-TH specimens (P ≤ .036). Most of the AM specimens and 1-mm VE specimens had higher ΔE00 than 2-mm G-CAM specimens (P ≤ .029). Further, most AM specimens had higher ΔE00 than 1.5-mm G-CAM specimens (P ≤ .006). RTP values increased in order of 3D-CT, G-CAM, VE, 3D-CB, and 3D-TH specimens (P < .001). Increased thickness and coffee thermocycling mostly reduced RTP (P < .001). 3D-TH typically had higher color change values than SM specimens, while G-CAM typically had lower color change values than AM specimens. Only the 1.5-mm and 2-mm 3D-TH specimens had unacceptable color changes. Thickness and coffee thermocycling mostly reduced the translucency.