Difference In Color Stability Research Articles

Evaluating the clinical significance of color stability in nanohybrid composite resins: a comparative study of local and international brands

Aims: The objective of this study was to evaluate the color stability of five nanohybrid composite resins, including locally produced Turkish brands and an international brand, after exposure to staining and brushing simulations over time. Methods: Five nanohybrid composite resins; Filtek Z550 (FLT), Dolgunn (DLG), RubyComp Nano (CMP), Nova Compo C (NVC), and Parion (PRN) were tested. Specimens underwent staining and brushing simulations designed to replicate clinical oral conditions. The staining process involved immersing the specimens in a coffee solution for 8 hours per day over a 10-day period to simulate short-term staining (t1), and for 12 days to simulate long-term staining equivalent to 1 year (t2). Brushing cycles were used to replicate the mechanical wear caused by daily oral hygiene practices. Color measurements were recorded at baseline (t0), after 10 days of staining (t1), and after 1 year of simulated staining and brushing (t2). Additional analyses were conducted using Energy-dispersive X-ray spectroscopy (EDX) and Scanning Electron Microscopy (SEM) to investigate structural and surface characteristics. Statistical analysis was performed using generalized linear models and two-way robust ANOVA to assess the significance of differences in color stability, with a significance level set at p

Comparison of color stability and microleakage of bioactive material and a resin infiltration material on hypomineralization in primary teeth

Aim: The current study aimed to evaluate and compare, in vitro the colour stability and microleakage of a bioactive material and a resin infiltration material on hypomineralization in primary teeth. Methods: Sixty human primary molars and incisors, which has been exfoliated or extracted were immersed in a demineralizing solution. 20 each specimen were treated by a bioactive compound (ACTIVA KIDS Bioactive-RESTORATIVE, PULPDENT, USA) (Group A), resin infiltration (Icon, DMG, Germany) (Group B) and as Control group (group C). Evaluation of colour stability and microleakage was done by using spectrophotometer analysis. The difference in color stability and microleakage of all three groups was determined by statistical analysis with a one-way ANOVA test for the proportion of the groups. p<0.05 was considered as statistically significant. Results: The bioactive compound showed statistically significant colour stability and lesser microleakage than resin infiltration material. Conclusions: Since bioactive compound exhibited better colour stability as well as showed lesser microleakage, it can be recommended for the restoration of the hypomineralized primary teeth. Keywords: Bioactive; Dental; Materials; Tooth Hypomineralization

Color Stability During Retail Display Differs Among Muscles in Pork

The objectives of this study were to determine differences in color stability among pork muscles and whether changes in color measurements for longissimus dorsi (LD) were related to changes for triceps brachii (TB) or psoas major (PM). The LD, TB, and PM from 20 pigs were aged in vacuum packages for 21 d, then fabricated into 3 chops per muscle. All chops from a single muscle were overwrapped, displayed for 5 d under constant lighting, and evaluated daily for instrumental color, myoglobin forms, and subjective visual discoloration. Chops were removed on day 1, 3, or 5 to measure oxygen consumption (OC) and metmyoglobin reducing activity (MRA). Data were analyzed using the MIXED procedure of SAS as repeated measures. Pearson correlation coefficients were determined using the CORR procedure. Over the 5-d display period, TB and PM chops had greater changes in a*, b*, chroma, 630/580 nm ratio, deoxymyoglobin, and oxymyoglobin compared to LD chops (display time×muscle interaction P≤0.01), but TB and PM did not differ from each other (P≥0.07). Conversely, LD had decreased OC and increased MRA on each display day compared to TB and PM (P<0.01). Using 20% discolored on day 5 of display as a threshold for acceptability, 85% of LD samples were considered acceptable whereas only 5% and 20% of TB and PM samples were considered acceptable, respectively. Changes in LD were correlated with TB and PM changes for redness (0.51≤r≤0.55; P≤0.02), and they trended toward a correlation with changes in TB and PM 630/580 nm ratio and hue angle (0.39≤r≤0.63). Chops from TB and PM were less color stable during display, but LD changes were not consistently correlated with changes in other muscles.

Evaluation of the color stability of different temporary restorative materials

This study aimed to evaluate the color stability of different temporary restorative materials in contact with staining solutions, as well as to verify which one presents the highest resistance to staining. In this laboratory study, five types of temporary restorative materials were evaluated: self-curing acrylic resin, bis-acrylic resin, light-curing acrylic resin, CAD/CAM machinable, and 3D printed resin. Thirty samples of each material were produced in a circular mold measuring 10 mm diameter and 2 mm thickness. The materials were divided into subgroups (n=10) and immersed in solutions: Coffee, Coca-cola®, and distilled water (control). Color measurements were carried out at baseline, 1, 7, and 14 days using a digital spectrophotometer and the color parameters were calculated according to the CIEDE00 system. The color change data were subjected to two-way ANOVA (temporary material vs time) and post-hoc Tukey test (α = 0.05). The materials showed a color change only comparing baseline vs. one day, according to acceptability standard ΔE00 > 1.8. Thus, we concluded that there was a difference in color stability already on the first day of immersion. In addition, the coffee solution showed the highest color variation when compared to the other solutions. Clinical applicability: Temporary restorations are widely used in prosthetic treatments and can remain in the mouth for a considerable period. They are responsible for aesthetic and function maintenance along the rehabilitation process. In addition, they provide data for the definitive prosthesis and should assure comfort and confidence to the patient. Thus, it is necessary that these materials are resistant and present such color stability that does not compromise the aesthetics during the treatment phase.

Effect of Different Artificial Staining Procedures on the Color Stability and Translucency of a Nano-Hybrid Resin-Based Composite.

To evaluate the effect of different experimental staining procedures on color stability and translucency of a nano-hybrid resin-based composite (RBC). 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). 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. 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.

Effects of Accelerated Aging on Color Stability and Surface Roughness of a Biomimetic Composite: An In Vitro Study.

The aim of this in vitro study is to compare the color stability and surface roughness of conventional and self-blending resin composites before and after staining and aging. Three conventional composites (Filtek Z350, IPS Empress Direct, and Estalite Palfique LX5) and one self-blending (Omnichroma) resin composite were used in this study. Sixty discs were prepared and polymerized in a metal mold (n = 15 per group). Samples were then finished and polished by Layan discs. Color testing and roughness testing were measured as a baseline (T0) by a spectrophotometer and profilometry. Samples were then stained with tea for 24 h, water aged for 30 days, and then a second reading (T1) was performed. Finishing and polishing were performed again, and a third reading (T2) was collected. All groups showed significant decrease in all color parameters (L*, a*, and b*); however, after polishing, all groups showed color enhancements matching pre-experiment baseline colors in all color parameters (L*, a*, and b*), except for Estelite Palfique LX5, which showed a significant difference in L relative to the baseline. Furthermore, Estalite Palfique LX5 showed increased roughness after staining compared to the baseline, unlike other groups. No significant differences in color stability were found between self-blending composites and other composite materials. Accelerated aging and staining had minimal effects on the surface roughness of self-blending composite.

Metabolomics of Meat Color: Practical Implications

Objective: Meat is biochemically active. Various pre-and post-harvest processes affect meat quality. Metabolomics is a valuable tool to elucidate metabolite changes in meat. The overall goal of this mini-review was to provide an overview of various techniques, data analysis, and application of metabolomics in meat color research. Results: Both targeted and non-targeted approaches are used to determine metabolite profiles in meat. Researchers use gas-, liquid-chromatography, and nuclear magnetic resonance platforms to separate molecules. Metabolomics is used to characterize muscle-specific differences in color stability, meat tenderness, the impact of aging on meat color, and to determine metabolite profile differences between normal-pH and dark-cutting beef. Color stable muscles have more glycolytic metabolites than color labile muscles. Conclusion: The use of metabolomics has greatly enhanced our understanding of metabolites' role in meat quality. There is a need for multiple databases to obtain comprehensive metabolite libraries specific to food. Metabolomics in combination with wet-laboratory techniques can provide novel insights on the relationship between postmortem metabolism and meat color.

Effect of finishing protocols and staining solutions on color stability of dental resin composites.

ObjectiveThe objective of this study was to evaluate the effect of finishing protocol and exposure to staining solutions on color stability of dental resin composites.Materials and MethodsA nanofill and microhybrid composite, three finishing protocols (mylar, Soflex disc, and white polishing stone) and four staining solutions (tea, red wine, khat extract—two concentrations, control—distilled water) were evaluated. A digital spectrophotometer was used for color change (ΔE) measurements employing the CIE‐Lab‐color system. Paired/independent‐sample t test and two‐way analysis of variance (ANOVA) followed by Tukey's honestly significant difference posthoc test were used for inferential statistics at α = .05.Results Soflex finish was associated with least staining and comparable color stability for the two materials in tea and red wine. In Khat 2, microhybrid composite had statistically significant better color stability than nanofill for Soflex finish (14 days t = 3.270, p = .011). For microhybrid composite, mylar resulted in highest mean ΔE, whereas Soflex recorded the least in all staining solutions. For nanofill composite, white stone resulted in highest mean ΔE, whereas Soflex demonstrated the least mean ΔE in all staining solutions, except red wine where mylar demonstrated the least mean ΔE. For mylar finish, nanofill demonstrated statistically significant better color stability than microhybrid in both red wine (14 days t = 4.902, p = .001) and Khat 1 (14 days t = 3.252, p = .012). For stone finish, microhybrid demonstrated statistically significant better color stability than nanofill in all staining solutions (14 days t ≥ 4.785, p ≤ .001). Two‐way ANOVA showed a statistically significant difference in mean ΔE between and within specimens (F = 42.658, p < .001). All staining solutions caused clinically unacceptable discoloration for mylar and white stone finish. For Soflex finish, red wine produced clinically unacceptable color difference beyond 48 h.ConclusionThere was a difference in color stability of resin composites depending on filler type, further influenced by finishing protocol. Soflex disc finish results in better color stability than mylar and white stone in both microhybrid and nanofill composites.Clinical significanceEsthetic dental restorations such as resin composites are routine in contemporary restorative practice. Color stability of composites may be influenced by surface finish, dependent on the filler type, and consumption of chromogenic substances such as khat. To prolong their service, selection of suitable finishing protocols is an important consideration.

Effects of 3 different light-curing units on the physico-mechanical properties of bleach-shade resin composites.

ObjectivesThis study investigated the microhardness, flexural strength, and color stability of bleach-shade resin composites cured with 3 different light-curing units.Materials and MethodsIn this in vitro experimental study, 270 samples were fabricated of bleach and A2 shades of 3 commercial resin composites (Point 4, G-aenial Anterior, and Estelite Sigma Quick). Samples (n = 5 for each trial) were cured with Bluephase N, Woodpecker LED.D, and Optilux 501 units and underwent Vickers microhardness and flexural strength tests. The samples were tested after 24 hours of storage in distilled water. Color was assessed using a spectrophotometer immediately after preparation and 24 hours after curing. Data were analyzed using 3-way analysis of variance and the Tukey test (p ≤ 0.001).ResultsSamples cured with Optilux exhibited the highest and those cured with LED.D exhibited the lowest microhardness (p = 0.023). The bleach shade of Point 4 composite cured with Optilux displayed the highest flexural strength, while the same composite and shade cured with Sigma Quick exhibited the lowest (p ≤ 0.001). The color change after 24 hours was greatest for the bleach shade of G-aenial cured with Bluephase N and least for the A2 shade of Sigma Quick cured with Optilux (p ≤ 0.001).ConclusionsLight curing with polywave light-emitting diode (LED) yielded results between or statistically similar to those of quartz-tungsten-halogen and monowave LED in the microhardness and flexural strength of both A2 and bleach shades of resin composites. However, the brands of light-curing devices showed significant differences in color stability.

The effect of thermocyclic aging on color stability of high translucency monolithic lithium disilicate and zirconia ceramics luted with different resin cements: an in vitro study

BackgroundHigh-translucency monolithic zirconia were developed to combine the esthetics of all ceramic restorations with the strength properties of zirconia. The purpose of this study was to compare the color stability of high-translucency monolithic zirconia ceramics with lithium disilicate luted using light-cure versus dual-cure resin cements following thermocyclic aging.MethodsForty specimens, each composed of 10 × 10 × 1 mm ceramic slice luted to dentin surface of an extracted tooth, were prepared and assigned into four groups (n = 10) as follows; LiDi/LC: lithium disilicate luted by light-cure resin cement; LiDi/DC: lithium disilicate luted by dual-cure resin cement; Zr/LC: zirconia luted by light-cure resin cement; and Zr/DC: zirconia luted by dual-cure resin cement. Color analysis of the specimens was performed before and after 3000 thermal cycles by means of spectrophotometry. The CIE L*a*b* values of the specimens were measured, and data were analyzed statistically at a significance value of p < 0.05.ResultsThermocycling resulted in a significant change in color coordinates of specimens with an overall ΔE = 3.59 ± 1.60, but there was no statistically significant difference in the color change value among all tested groups (P = 0.756).ConclusionsAt 1 mm restoration thickness, the color stability of high-translucency monolithic lithium disilicate and zirconia ceramics were not significantly different irrespective of the cement type used.Clinical implication Understanding the difference in color stability of dental ceramics may help in determining long-term esthetic result.

Multifactorial analysis of optical properties, sorption, and solubility of sculptable universal composites for enamel layering upon staining in colored beverages.

To analyze the effects of factors 'composite,' 'medium,' and 'time' on color, translucency, and sorption/solubility of sculptable universal composites for enamel layering upon immersion in colored beverages. Disk-shaped specimens, 10 mm in diameter and 2 mm thick (n=5/group), of ultrafine, hybrid composite Essentia (GC), microhybrid Gaenial Anterior (GC), nanofilled Filtek Ultimate Enamel and Body ( 3M ESPE) were immersed in red wine, coffee, or distilled water for 15 days. CIELab color coordinates were measured and CIEDE2000 (∆E00 ) and Translucency Parameter differences (∆TP00 ) were calculated. Sorption and solubility were determined according to ISO 4049:2009. Data were analyzed using the analyses of variance and Tukey's post-hoc test (α=0.05). Essentia and Gaenial exhibited the lowest and the highest staining-dependent color differences, with mean ∆E00 range of 1.7-6.1 and 5.1-11.3, respectively (p < 0.05). ∆TP00 was more pronounced in wine than in coffee (p < 0.05). Sorption and solubility varied between 9.8 and 15.3μg/mm3 and -1.6 and -5.4μg/mm3 , respectively, with positive correlation between ∆TP00 and sorption (p=0.005). Total color and translucency differences of sculptable composites for enamel layering were material-, time- and medium-dependent. Translucency differences positively correlated with sorption. Overall, the ultrafine, hybrid composite exhibited the best results in terms of color stability, sorption and solubility. Clinicians should be aware of differences in color stability of sculptable composites for enamel layering as these are directly exposed to discoloration in the oral environment and are directly related to patients' long-term satisfaction and restoration longevity. Ultrafine, hybrid composite may be preferred due to better color stability, lower sorption and solubility compared to nanofilled and microhybrid composites evaluated in this study.

Influence of Light-Curing Units on Color Stability of Composite Resins After Aging

Background and AimOne of the most important problems with composite restorations is the loss of consistency between the composite and tooth color. The present study aimed to compare the color stability of two types of nanohybrid composites cured with different light-curing devices after aging.Materials and MethodsIn this study, the color stability of 40 disc-shaped specimens (10 mm in diameter and 2 mm in height) from two types of enamel and dentin nanohybrid composites (IPS Empress Direct, Ivoclar Vivadent) was investigated. A group of 10 samples of each composite was cured by light-emitting diode (LED) Bluephase device (Ivoclar, Vivadent) at 1200 mW/cm2 for 20 seconds, and another group of 10 specimens was cured by a quartz-tungsten-halogen (QTH) device (Coltolux 2.5, Colten, USA) at 600 mW/cm2 for 40 seconds. The initial color of the samples was determined by the Konica Minolta spectrophotometer (CS2000, USA), and then, the composite samples were subjected to an accelerated artificial aging (AAA) process in the QUV/SPRAY device. Then, the color of the samples was reassessed. Two-way analysis of variance (ANOVA) was used to compare the color changes in the study groups at a significance level of P=0.05.ResultsThe specimens cured by the LED device showed significantly lower color change compared to QTH (P=0.047). However, there was no significant difference in color stability between enamel and dentin composites cured by a fixed apparatus (P=0.474).ConclusionThe curing of nanohybrid composites with LED devices causes lower color change compared to QTH.

Color Stability in Temporization

Abstract Introduction Provisional restoration refers to a prosthesis which is designed to enhance the esthetic value, or function for a short time, following which it is replaced by using a fixed prosthesis. Color stability is very important factor to be kept in mind during selection of provisional materials in aesthetically important areas. Although there are various studies which look into the issue of stability of color of provisional restorations, the results are contradictory and confusing. This study was planned to compare the color stability of commonly used provisional restorative materials after exposing them to various kinds of discolorants. Materials and Methods This work evaluated the effect of five common beverages, including tea, on color changes of different provisional materials: 1) Polymethyl methacrylates (DPI); 2) Bisacryl composite (ProtempTM II–3M ESPE); 3) Light polymerized composite (Revotek LC–GC). Color measurement of all specimens was compared with the original values of each specimen prior to immersion. Results Within the limitations of this study, it was concluded that:a) There is no difference in color stability of provisional materials.b) Only food dye produced a clinically appreciable color change, whereas color change by cola and coffee cannot be appreciated by humans and that of tea can be appreciated only by trained eyes.

Investigation of muscle-specific beef color stability at different ultimate pHs.

ObjectiveThis study was aimed to investigate the muscle-specific beef color stability at normal and high ultimate pHs.MethodsThe impact of muscle (Longissimus lumborum [LL] vs psoas major [PM]) and pH (normal ultimate pH [Np] vs high pH dark cutting beef [Hp]) on color stability, indicated by basic color traits, metmyoglobin reducing activity (MRA) and oxygen consumption (OC), as well as the lipid oxidation, were determined over 7 days of display at 4°C.ResultsHp-LL had the highest pH (6.92), followed by Hp-PM (6.01), Np-PM (5.76), and Np-LL (5.52). Hp-LL had increased (p<0.05) a*, chroma and % oxymyoglobin during display. Hp-LL also had the highest metmyoglobin (MMb) reducing activity and OC among all the samples, thus, the greatest color stability, although very dark throughout storage, with lowest values for lightness (L*) and yellowness (b*). Np-LL also exhibited relatively high color stability, as a result of its lower % MMb and OC and higher MRA than psoas muscle samples. The 0.2 unit difference of the pH between Hp and Np psoas muscle, resulted in the difference of the color intensity, not the color stability. Interestingly, high pH psoas muscle (Hp-PM) did not have better color stability than Np-PM, and in fact had lower color stability than even Np-LL. The similar level of OC and lipid oxidation cannot explain the difference in color stability between Hp-PM and Np-LL.ConclusionThe Hp does not always show better color stability compared with Np beef, which depends on the muscle type. The balance of MRA and OC is important to keep the color in great intensity and stability in the meantime.

Is It Necessary to Photoactivate the Adhesive System Inside Ceramic Laminate Veneers in a Luting Procedure?

To investigate the need for photoactivation of the adhesive system inside ceramic laminates before the luting procedure and to evaluate the color stability, nanohardness, and elastic modulus of the adhesive interface activated with singlewave and polywave light-curing units. A total of 44 lithium disilicate ceramic veneers (7.0 mm × 8.0 mm × 0.6 mm) were fabricated, bonded to enamel, and sorted into four experimental groups (n = 11 each) according to the type of light-curing unit (Radii-Cal [singlewave] or Valo [polywave]) and mode of adhesive system activation (with or without previous photoactivation). Two luting agents were used: the Tetric N-Bond adhesive system and Variolink Veneer resin cement. A visible ultraviolet spectrophotometer was used to evaluate the color stability before and after UVB artificial accelerated aging for 252, 504, and 756 hours (n = 8 samples from each group). A nanohardness tester under a load of 1,000 μN was used to evaluate the nanohardness and elastic modulus (n = 3 samples from each group). Data regarding the color stability and the mechanical properties (nanohardness and elastic modulus) were subjected to analysis of variance and Tukey protected least significant difference test (α = .05). Prior activation of the adhesive system, the distinct light-curing units, and different aging periods exerted no significant difference on the color stability or mechanical properties of the resin cement (P > .05), except for in the group activated with Radii-Cal after 756 hours, in which the nonprevious activation showed lower color alteration compared to the previous photoactivation (P = .0285). Without prior activation of the adhesive with Valo, the polywave unit promoted higher nanohardness and elastic modulus values in the adhesive system (P < .05). In general, singlewave and polywave light-curing units promoted no difference in color stability or the mechanical properties of the adhesive interface. The prior curing of an adhesive system inside ceramic laminate is not necessary.

Effect of previous photoactivation of the adhesive system on the color stability and mechanical properties of resin components in ceramic laminate veneer luting

Statement of problemThe color stability and mechanical properties of luting agents influence the esthetics and longevity of ceramic restorations. However, studies evaluating the color changes and mechanical properties of luting agents under ceramic laminates activated by using different methods are lacking. PurposeThe purpose of this in vitro study was to evaluate the effects of different modes of photoactivation on the nanohardness and elastic modulus of resin cements and dental adhesives and on the color stability of ceramic laminate veneers. Material and methodsForty-four lithium disilicate blocks (7×8×0.6 mm) were cemented onto bovine enamel and divided into 4 groups according to the polymerization light (Radii-Cal or Valo) used and the mode of activation of the dental adhesive (no previous photoactivation or previous photoactivation). Single Bond Universal dental adhesive and RelyX Veneer resin cement were used in all experimental groups. Color stability was measured using a UV-2450 ultraviolet-visible spectrophotometer before and after ultraviolet-B artificial accelerated aging (n=8). The nanohardness and the elastic modulus of the adhesive and resin cement were measured using a nanohardness tester (n=3). The color stability and mechanical properties were measured and analyzed using ANOVA and the Tukey least significant difference test (α=.05). ResultsNo difference in color stability or mechanical properties of the resin cement among the polymerization lights was detected (P>.05). Specimens that underwent previous photoactivation of the adhesive using the Valo polywave unit exhibited higher elastic modulus values than those that did not undergo previous photoactivation (P<.001). ConclusionsThe Valo polywave polymerization light improved mechanical properties and color stability more than the Radii-Cal unit. Previous activation of the dental adhesive in the dental enamel with the Valo polywave polymerization light yielded more satisfactory results.

Muscle-Specific Mitochondrial Functionality and Its Influence on Fresh Beef Color Stability.

During retail display tenderloin steaks packaged in PVC overwrap discolor quicker than strip loin steaks. This research determines the basis for muscle-specific differences in color stability. The results indicate that mitochondria present in tenderloin lose its functionality faster than strip loin mitochondria. Developing strategies to minimize muscle-specific differences in mitochondrial changes can increase color stability and value of fresh beef.

Intramuscular Variations in Color and Sarcoplasmic Proteome of Beef Semimembranosus during Postmortem Aging

Beef semimembranosus exhibits intramuscular difference in color stability, and the inside region (ISM) of the muscle is color-labile, whereas the outside region (OSM) is color-stable. Variations in sarcoplasmic proteins are known to contribute to this intramuscular color difference. Sarcoplasmic proteome and beef color are affected by postmortem aging. The objective of the present study was to examine the effect of aging on intramuscular color variations and the sarcoplasmic proteome of beef semimembranosus. Semimembranosus muscles obtained from 8 beef carcasses (n = 8) were subjected to aging at 2°C for 0, 7, 14, and 21 d. On each aging day, the muscles were fabricated into ISM and OSM steaks and allotted to refrigerated storage (2°C) under aerobic packaging. Instrumental color and metmyoglobin reducing activity were evaluated on d 0, 3, and 6 of storage. Samples frozen on d 0 and d 21 of aging were utilized for sarcoplasmic proteome analysis. Color attributes of both ISM and OSM steaks were influenced by aging, with steaks aged for 21 d having the lowest (P &lt; 0.05) color stability. The ISM steaks had greater (P &lt; 0.05) lightness than OSM counterparts, and the difference in lightness was not negated by aging. The ISM and OSM had similar (P &gt; 0.05) redness on d 0 of storage, whereas ISM had lower (P &lt; 0.05) redness compared to OSM on d 3 and d 6 of storage. Several proteins associated with glycolysis and energy metabolism were of greater abundance (P &lt; 0.05) in OSM than in ISM after 21-d aging. Furthermore, the influence of 21-d aging on sarcoplasmic proteome was observed at a greater extent in OSM than in ISM, indicating that the effect of aging on sarcoplasmic proteome of beef semimembranosus was influenced by the location within the muscle.

Color stability of heat polymerized polymethyl methacrylate resin denture base after addition of high molecular nano chitosan

Background: The addition of other ingredients to maintain color stability of heat polymerized polymethylmethacrylate is being developed. One of them is by adding high molecular nano chitosan. Purpose: This study aimed to determine the color stability of heat polymerized polymethyl methacrylate denture base resin after an addition of high molecular nano chitosan. Method: 30 sample pieces of acrylic plate (40x10x2 mm) were divied into 6 groups: control group and groups with the addition of chitosan nano gel percentages of 0.25, 0.50, 0.75, 1.0 and 1.50%. 2 ml chitosan nano gel was added into the mixture of acrylic resin with 23 g : 10 ml (P : L). After the mixture was inserted into a mold and then pressed and cured at 74oC for 120 minutes and then 100o C for 60 minutes. Acrylic plates were then released from the mold and finished. Color stability of acrylic resin were measured using UV-Vis Spectrophotometer and analyzed with a one way Anova. Result: The results showed significant differences in color stability after the addition of high molecular nano chitosan. The best color stability found in 1.0% the addition of chitosan nano gel group, the value was 0.07589 cm-1. Conclusion: The chitosan nano gel can be used to maintain color stability of heat polymerized polymethyl methacrylate denture base resin.

Influence of Exposure Time to Coffee on Color Stability of Selected Composite Resin Veneers

Objectives: The aim of the study is to evaluate the effect of the time and instant coffee solution on the color stability of three types of composite resin based veneer systems. Materials and Methods: 24 composite resin veneer samples were selected and divided into three groups: two groups of prefabricated veneers (Edelweiss, Ultradent Inc™ (EDL) and Componeer, Coltène/Whaledent AGTM (CMP)) and one group of laboratory made (Nexco, Ivoclar Vivadent (NEX)) veneer system were tested (n=8). Specimens were prepared and stored in staining solution (instant coffee) and assessed color changes with Minolta spectrophotometer every three days for a period of 27 days, after which color differences (ΔE*) were calculated. Data collection and analysis was done using one-way ANOVA and Student’s t-test (α=0.05). Results: One-way ANOVA revealed a significant difference in color stability between the two veneer systems. NEX group veneer system exhibited the highest color stability (ΔE*= 0.73 ± 0.5) as compared to prefabricated veneer groups (EDL 10.07 ± 5.15, CMP 7.41 ± 4.64) with p value &lt;0.05. Conclusion: The color stability (ΔE*) of the laboratory made veneer system is significantly higher than the prefabricated veneer systems and more clinically accepted.