Color Change Values Research Articles

The Effect of Beverages and Polishing on Color Change of Different Temporary Prosthetic Materials: In Vitro Study

Objective: The aim of this study was to evaluate the effect of five different beverages and polishing on the color change of two different temporary prosthetic materials manufactured with different methods.
 Method: 160 (10x2 mm) disc-shaped samples were fabricated using direct (Acrytemp)(n=80) and indirect (Imident) (n=80) temporary prosthetic materials. Samples prepared using molds were divided into four groups as polished (direct/indirect material) and unpolished (direct/indirect material) (n=40 each). After initial measurement of L,a,b values using a spectrophotometer, the samples in each group were immersed in five different beverages (distilled water (DW), coffee (CF), cola (CC), sour cherry juice (CJ), red wine (RW) (n=8) and stored for 7 days. Then, the spectrophotometric measurements of the samples were repeated and the color change (ΔE00) values were calculated. Data were analyzed using a three-way-ANOVA followed by post hoc Tukey HSD test (p=0.05).
 Results: Greater color change was observed in the direct temporary material (p

Color stability of nano resin-modified glass Ionomer restorative cement after acidic and basic medications challenge

Background: Color stability of glass ionomers (GIs) could be affected by many factors such as pH and consumption of liquid medications like antibiotics. Most common antibiotics used during childhood are amoxicillin suspension (AM.S) and azithromycin suspension (AZ.S) which have acidic and basic pH respectively. Aim: to evaluate and compare the effect of AM.S and AZ.S on color stability of nano resin-modified GI. Methods: Thirty disc of nano resin-modified glass ionomer (2mm height x 4mm diameter) were divided into three groups (n=10 for each) and independently exposed to AM.S, AZ.S, and artificial saliva (A.S.). Color stability was evaluated in triplicate by VITA Easyshade® before and after three immersion protocols, repeated over a three-week duration with two-days intervals. In each protocol, samples were exposed for two minutes, three times daily for AM.S, once daily for AZ.S, and A.S. full day. GI discs rinsed off after each immersion and kept in artificial saliva until next immersion period. Results: One way ANOVA test and Post-hoc analysis of the changes in color space compartments of nano-resin modified GI samples demonstrated just a significant change (p˂0.05) in yellow-blue axis (Δb*) value after immersion in AM.S in comparison with A.S. Total Color change values (ΔE) of nano resin-modified glass ionomer samples also illustrated a significant effect (p˂0.05) between AM.S and A.S. only. The highest (ΔE) value was recorded for samples immersed in AM.S (ΔE =12.5) followed by AZ.S (ΔE=6.5) while the lowest was recorded for A.S. (ΔE=1.1). Conclusion: AM.S (the acidic medication) exhibited a higher staining effect to nano-resin modified GI samples when compared with AZ.S (the basic medication). Several factors such as low pH, more exposure time and coloring material of the immersion media added critical roles in coloring instability.

Comparison of Enamel Discoloration using Flash-Free and Conventional Adhesive Brackets with Different Finishing Protocols.

The aim of this study was to compare the effects of flash-free and conventional adhesive brackets and different finishing techniques on enamel discoloration. Forty human premolar teeth were utilized and randomly divided into four groups based on the type of brackets and finishing technique: (1) Gemini® brackets were used for orthodontic bonding. After debanding, adhesive remnants were cleaned using a 12-blade tungsten carbide bur. (2) Gemini® suspenders were used for orthodontic bonding. After debanding the brackets, adhesive remnants were cleaned using12-blade APC™ Flash-Free brackets were used for orthodontic bonding. After debanding, adhesive remnants were cleaned a 12-blade tungsten carbide bur and polished with Sof-Lex disks. (4) APC™ Flash-Free brackets were used for orthodontic bonding. After debanding, the adhesive remnants were cleaned using a 12-blade tungsten carbide bur. A Vita Easyshade spectrophotometer was used to measure the color change values of the 40 teeth. The color change of the enamel surface in the Flash Free bracket group was significantly less than that in the conventional groups (p=0.003 p˂0.05). The mean ΔE values obtained from the Sof-Lex groups were lower than those obtained from the groups without Sof-Lex, but these results were not statistically significant (p=0.280 p>0.05). It is recommended to use Flash-Free brackets and polish with Sof-Lex disk following the clean-up procedures to minimize the possibility of discoloration of the teeth during orthodontic treatment.

Effect of denture cleansers on color stability and surface properties of denture base material containing titanium dioxide nanoparticles.

To investigate the effect of different denture cleansers on color stability, surface roughness, and hardness of polymethylmethacrylate (PMMA) infused with titanium dioxide nanoparticles (TiO2 NPs) at concentrations of 1% and 2% by weight on each. In this in vitro study, 90 disc-shaped specimens (10×10×2mm) were divided into 3 main groups: the non-containing nanoparticle group (0wt% concentration), 1wt% concentration, and 2wt% concentration TiO2 NPs groups. Each group was further assorted into 3 subgroups (n = 10): immersed in distilled water, oxygenating tablet (Corega), and 0.5% sodium hypochlorite. Color change, surface roughness, and hardness values were assessed after 90 and 180 days of storage. Color changes (∆E) were measured with a spectrophotometer (VITA, Easy Shade V, Germany) and assessed using the CIE L*a*b* colorimetric system and the American National Bureau of Standards (NBS = 0.92×∆E). The surface roughness and surface hardness values were measured using a profilometer device and Vickers hardness tester, respectively. First, ANOVA-repeated measurements were performed, followed by the Tukey test. The significance level in this study was considered 0.05. At all concentrations, there were significant differences in the mean color changes of samples immersed in cleansers compared to distilled water (p < 0.01). Moreover, hypochlorite caused a significant increase compared to Corega at 0wt% concentration after 90 days and at 1wt% concentration after 90 and 180 days. Evaluations also showed that the mean NBS values in all cleanser groups were in the range of appreciable change, except the water group. In addition, only hypochlorite changed the color higher than the clinically acceptable range (∆E >3.7). The mean roughness of samples immersed in hypochlorite at 0wt% concentration was significantly higher than the samples containing TiO2 NPs (p = 0.006). No significant difference was observed in surface roughness of samples containing different concentrations of TiO2 NPs immersed in different cleansers; however, hypochlorite increased the surface roughness of samples without TiO2 NPs compared to samples containing TiO2 NPs after 180 days. The immersion time in cleansers had a significant influence on the surface roughness and hardness while having no effect on the color. In general, the cleansers had a significant effect on color change in all groups compared to distilled water. The adverse effect of hypochlorite was more than Corega. The cleansers in the samples containing TiO2 NPs did not make a significant difference in surface roughness in comparison with the distilled water groups. Surface hardness of the samples was not affected in a steady pattern by the cleansers.

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.

Effect of different pre-treatments on rehydration kinetics of solar and hot-air dried Fuji apple slices

The present study demonstrates the effect of direct solar drying (DSD) and hot air drying (HAD) on the quality attributes of Fuji apple slices. DSD samples took a longer time (150–180 min) to dry and simultaneously reached higher equilibrium moisture content at the end of rehydration than HAD samples. DSD samples have higher rehydration ability, dry matter holding capacity, and water absorption capacity than HAD samples. Among several empirical models, the Weibull model is the best fit with higher R2 (0.9977), lower root mean square (0.0029), and chi-square error (0.0031) for describing the rehydration kinetics. Rehydrated HAD samples showed better color characteristics than DSD in terms of overall color change, chroma, and hue angle values. Whereas the hardness and chewiness of rehydrated DSD samples were better than HAD samples because of higher dry matter holding capacity in DSD. Apart from color retention, the DSD samples showed better rehydration capacity and a good texture upon rehydration than HAD slices.

Evaluation of color stability of bulk-fill restorative materials with different properties

Aims: The present study aims to evaluate the color stability of bulk-fill restorative materials with different properties over different time periods when immersed in a coffee solution.&#x0D; Methods: According to the selected restorative materials, the study groups were formed as follows: CNT/light (Alkasite, Cention N, Ivoclar Vivadent, light cure mode), CNT/self (Alkasite, Cention N, self cure mode) EQF (Glass hybrid restorative, Equia Forte HT, GC Corporation), AU (Single-shade bulk fill, Aura Bulk Fill, SDI), Z550 (Filtek Z550, 3M) (control group). A total of 50 samples (n=10) were prepared using standard molds (2mmx10mm). After finishing and polishing procedures, all samples were kept in distilled water at 37°C for 24 hours. The first color measurement (L*a*b ) was performed with Vita Easy Shade V (VITA Zahnfabrik). Samples were added to the coffee solution. Color was measured at times simulating 7 days, 1 month, 6 months and 1 year of clinical service. Color changes (ΔE1, ΔE2, ΔE3 and ΔE4) were calculated according to the CIE L*a*b system. Normality of the data was examined by D'Agostino &amp; Pearson omnibus normality test. One-way ANOVA analysis and Tukey test were performed. Statistical significance level was set at p 0.05 and statistical analysis software (GraphPad Prism 6.0, GraphPad Software, USA) was used for the analysis.&#x0D; Results: According to ΔE1 results; clinically unacceptable color change (ΔE&gt;3.3) values were observed in CNT/light and CNT/self groups. The color change values of EQF, Z550 and AU groups were statistically similar (p&gt;0.05). According to ΔE2 results; an unacceptable color change (ΔE&gt;3.3) was observed in all groups except EQF. According to ΔE3 results; an unacceptable color change (ΔE&gt;3.3) was observed in all groups. According to ΔE4 results; an unacceptable color change (ΔE&gt;3.3) was observed in all groups. The color change values of EQF, Z550 and AU groups were statistically similar (p&gt;0.05). CNT/light group showed the highest color change in all time periods, followed by CNT/self group.&#x0D; Conclusion: The color stability of single-shade bulk fill material and glass hybrid restorative materials is similar to the control group. The color stability of alkasite material needs to be improved.

Colorimetry-based and smartphone-assisted machine-learning model for quantification of urinary albumin

The presence of albumin in the urine is indicative of kidney damage and can occur due to several underlying conditions, such as diabetes. The concentration of albumin in urine is used for the diagnosis and staging of chronic kidney disease (CKD). In clinical samples, the detection of albumin at lower concentrations is crucial for the early diagnosis and monitoring of CKD. Current urine analyzers precisely quantify albumin but are expensive and difficult to use in point-of-care (PoC) settings. Here, we demonstrate the quantification of albumin concentration in a urine sample using colorimetry. This model presents an accessory-free urine analyzer that uses a smartphone and customized machine-learning algorithms. Here, a urine sample is introduced onto a chemically impregnated dipstick that exhibits a change in color with the amount of albumin. Images of the urine dipsticks are captured using a smartphone camera under different illumination/experimental conditions and are processed to extract changes in the color values arising due to changes in the concentration of urinary albumin. Albumin concentrations are estimated from changes in color values. We used customized machine-learning algorithms to classify albumin concentrations and mitigate the effect of ambient light conditions. The k-nearest neighbor algorithm yielded an average classification accuracy of 96% with a detection limit of 4 mg l−1. The proposed scheme can be extensively used to monitor albumin concentration in PoC settings.

Polycaprolactone/Anthocyanin-Based Electrospun Volatile Amines Gas Indicator with Improved Visibility by Varying Bi-Solvent Ratio: A Case of Intelligent Packaging of Mackerel.

Electrospun nanofibers have been applied as a new technology for gas indicators in food intelligent packaging. A poly(ε-caprolactone) (PCL)/red cabbage anthocyanin (RCA)-based nanofiber volatile amines gas indicator was developed by applying a bi-solvent of acetic acid (AA) and formic acid (FA) in electrospinning. The visibility of color change was improved from pink to blue, compared to blue to yellow-green, when using a single solvent of AA. The solutes of PCL (12.5, 15, 17.5, and 20%) and RCA (10, 20, 30, and 40%) and the solvents of AA/FA (9:1, 7:3, 5:5, 3:7, and 1:9) were applied in electrospinning under the condition of 12.5 cm, 1.0 mL/h, and 20 kV. The optimal microstructure with the thinnest fiber diameter and constant arrangement without forming NF beads appeared under the 7:3 FA/AA, 15% PCL, and 20% RCA condition. The indicator changed from pink to blue with the values of total color change (ΔE) of 10, 14, and 18 when exposed to the saturated gas of ammonia solutions of 8, 80, and 800 mM, respectively. The indicator was stable and unchanged in color for 28 days when exposed to light at room temperature. In the application to mackerel packaging, the built-in indicator changed from pink to purple regardless of storage temperature when the spoilage point was reached.

Design and Implementation of a PV-Integrated Solar Dryer Based on Internet of Things and Date Fruit Quality Monitoring and Control

In Egypt, the climate has a direct impact on the dried date fruit production. The traditional drying method or open sun drying (OSD) leads to pollution of the final product caused by sand-laden winds, rain, or animals and harmful insects, etc. This study is aimed at designing, implementing, and experimentally validating a solar dryer based on IoT technology and integrated with a PV system in Aswan, Egypt. The purpose of the dryer is to monitor and control the quality of the three most popular date fruit varieties and determine the most effective drying method, with an algorithm that operates the system automatically for optimal performance and high-quality products. The automatic solar dryer (ASD) significantly affects the final moisture content and color characteristics and reaches the equilibrium moisture content (EMC) at a faster rate for dried date samples compared to the OSD. The drying rate of ASD was 29.03% (Sakkoti), 31.04% (Malkabi), and 25.49% (Gondaila) higher than OSD. Also, the dried date fruit samples reached EMC on the ASD after 8 days for both Malkabi and Gondaila and 9 days for Sakkoti, while it took 14 to 15 days on OSD. The maximum open circuit voltage V oc , short circuit current I sc , and output power P output were 41.70 V, 8.84 A, and 365.09 W, respectively. All values of total color change ( Δ E ∗ ) after open-air drying of dry date varieties were higher than solar drying for both drying systems. This study can be then more helpful for producers of dried foods.

FARKLI CAM İYONOMER SİMANLARIN RENK STABİLİTELERİ VE MİKROSERTLİKLERİ

Objective&#x0D; Glass ionomers are preferred in many different&#x0D; treatment procedures in dentistry due to their positive&#x0D; features. The aim of this study is to evaluate the&#x0D; color difference and microhardness values of various&#x0D; glass ionomer cement after storing them in different&#x0D; solutions.&#x0D; Material and Method&#x0D; A total of 120 samples were prepared, including 40 of&#x0D; each of the Equia Forte, AHfil Silver, and Ionofil glass&#x0D; ionomers. Each glass ionomer sample was stored in&#x0D; distilled water, cola, tea, and coffee solutions. Color&#x0D; and microhardness measurements of the specimens&#x0D; were performed before and after a week before it was&#x0D; immersed in solutions. The color measurements of the&#x0D; samples were evaluated with a spectrophotometer and&#x0D; microhardness values were evaluated with Vickers&#x0D; microhardness device. For color analysis, color&#x0D; changes (ΔE) were calculated by obtaining the values&#x0D; of L*, a*, and b* of the samples before and after a week&#x0D; after being immersed in solutions. The data obtained&#x0D; were evaluated by variance analysis (ANOVA) and&#x0D; Tukey’s test.&#x0D; Results&#x0D; Except for specimens stored in cola for AHfil Silver,&#x0D; microhardness values were increased for all materials&#x0D; immersed in test solutions. The highest color change&#x0D; was obtained in coffee for Equia Forte, in the samples&#x0D; immersed in cola for AHfil Silver and Ionophil (p

Effect of Different Mouthwashes on Stain Susceptibility of Resin Composite in Contact with Beverages.

Objectives: This study aimed to investigate the effect of common mouthwashes on the color change of a nanohybrid composite and its further stain susceptibility to Coke and coffee. Materials and Methods: One hundred and fifty composite discs were prepared and initial color values were measured using a spectrophotometer. The specimens were grouped based on the 24h exposure to common mouthwashes including Listerine, chlorhexidine, two types of fluoride mouthwashes (alcohol free and alcohol containing) as well as distilled water as control (N=30). The color change (ΔE1) values were calculated to show the amount of color change caused by mouthwashes. Subsequently, the specimens in each group were subdivided and immersed in the secondary colorant solution (coffee, Coke and, distilled water) for seven days. The total color change (ΔE total) values were obtained to show the stain susceptibility. Statistical analysis was conducted using ANOVA and Tukey's post hoc test. A P-value less than 0.05 was considered statistically significant. Results: The calculated ΔE1 of resin composite was significantly higher for all mouthwash groups than that of the control group; however, all were in the clinically acceptable range. Exposure to Listerine and distilled water caused more staining effects compared to other mouthwashes after immersion in secondary colorant solutions. Regardless of primary mouthwash type, coffee and distilled water caused the highest and the least total discolorations, respectively (P<0.001). Conclusion: All mouthwashes caused a clinically acceptable color change in resin composite; however, further stain susceptibility depended on the mouthwashes but was not higher than distilled water.

Effectiveness of changing the color of darker teeth is potentiated by association with violet LED light

BackgroundThe effectiveness of in-office bleaching protocols performed with violet LED light either combined with a bleaching agent containing 37% carbamide peroxide, or not, was determined by comparing teeth with different degrees of darkening. MethodologyEighty bovine incisors were separated into groups of “light” teeth (luminosity greater than or equal to B3) and “dark” teeth (less than or equal to A3.5) to receive the protocols: HP - 35% hydrogen peroxide (Whiteness HP), CP - 37% carbamide peroxide (Whiteness SuperEndo), LED - violet LED light (Bright Max Whitening), CPLED - CP associated with the LED. For color analysis the CIEL*a*b* e WID, ΔEab, ΔE00 e ΔWID parameters were used. Data were analyzed using Mann-Whitney, Kruskal-Wallis, Dunn, Friedman or Nemenyi tests (α = 5%). ResultsHP and CP resulted in similar color change values (ΔEab, ΔE00 e ΔWID) for light and dark teeth (p > 0.05). Dark teeth showed better bleaching effectiveness (ΔEab, ΔE00 e ΔWID) than light teeth when CPLED was used (p < 0.05). LED showed color change that were below the limits of acceptability and perceptibility for ΔWID. Conclusionlight teeth are effectively bleached with the use of HP or CP, whereas dark teeth respond better to treatment with the CPLED protocol. Violet LED used alone did not show a satisfactory result.

Assessment of Photocatalytic Nano-TiO2 Mortars’ Behavior When Exposed to Simulated Indoor Conditions of Glazed Buildings

The application of nano-TiO2 as a photocatalytic agent in buildings’ internal surfaces has recently attracted attention to mitigate microorganism growth, soiling, and contamination in indoor environments. This work aimed at comparing the Rhodamine B (RhB) dye degradation efficiency of three different mortar compositions subjected to simulated internal radiation, in which nano-TiO2 (10 wt% of binder mass) was dispersed by ultrasonic and mechanical methods. Mortar specimens were produced with white Portland cement, hydrated lime, sand, and water in different volume proportions of 1:1:6 (cement:lime:sand), 1:3 (cement:sand), and 1:4 (cement:sand). The first stage of the research evaluated samples exposed to the natural outdoor environment and proved the efficiency of specimens’ photoactivity when covered by a glass layer. The second and principal phase of the study simulated indoor conditions in glazed buildings through artificial weathering in which the composition of 1:1:6 was mechanically dispersed and exhibited the highest global color change (ΔE) values for RhB staining. The main finding of the study was that the mortars exposed to simulated indoor conditions presented high ΔE grades, classified as easily perceived by the human eye. This demonstrates the photocatalytic efficiency in an internal building environment that receives radiation through a glass surface.

EFFECTS OF DIFFERENT CLIMATE TYPES ON COLOR CHANGE OF WOOD MATERIAL USED OUTDOOR

Field tests are important for evaluating how wood performs in real-world conditions and making informed choices for material selection. These tests help assess wood's durability, strength, decay processes, and resistance against harmful organisms. Furthermore, it helps users make more informed decisions about the color of wood and understand the importance of color changes depending on the place and time of use. Because weather conditions are asignificant factor that influences the color of wood. Wood that is exposed to prolonged sunlight, moisture, and rain may experience fading, darkening, or staining in its color. In this study, heartwood, sapwood, and CCB impregnated sapwood samples of Scotchpine, spruce, beech and alder were exposed to the soil contact (hazard class 4) according to EN252 for 3years in Trabzon, Muğla, Çanakkale, and Elazığ provinces of Turkey with completely different climatic conditions from each other. Color parameters and color change values were evaluatedusing L*, a*, b*and ∆E* of the samples collected from test sites. The most significant color change was observed at Scotchpine in Çanakkale province. Greater color changes were observed in theheartwood of coniferous species.Impregnated samples showed the least color change.

Comparative evaluation of greenhouse gas emissions and specific energy consumption of different drying techniques in pear slices

AbstractIn recent years, global warming, climate change, and carbon emissions have emerged due to the uncontrolled use of fossil fuels and the lack of widespread use of renewable energy sources on a global scale. This research investigated specific energy consumption (SEC) and greenhouse gases (GHG) emissions (carbon dioxide [CO2] and nitrogen oxides [NOX]) during the drying of pear samples by five different types of dryers, namely, convective (CV), infrared (IR), microwave (MW), combined IR/CV, and MW/CV. Moreover, the quality properties of dried pears, such as shrinkage, rehydration (RR), and color change were determined. The results showed that the highest shrinkage (72.53%) and color change (ΔE = 33.41) values were obtained in CV drying at 50 °C and thickness of 2 mm and IR dryer 1000 W and thickness of 6 mm, respectively. The greatest rehydration rate (4.25) was also determined in MW/CV drying at 450 W and an air temperature of 60 °C. The lowest SEC was observed for the MW/CV dryer with a power of 630 W and air temperature 70 °C (20.25 MJ/kg), while the highest SEC (267.61 MJ/kg) was obtained in the CV drying (50 °C, sample thickness of 6 mm). The highest CO2 and NOX emissions (GT-GO power plant) were 280.45 and 1.55 kg/kg water in the CV dryer at 50 °C and a thickness of 6 mm. In conclusion, the increases in IR and MW power and temperatures led to reduced CO2 and NOX emissions, while the increases in sample thickness led to increase CO2 and NOX emissions.

Hybrid light applied with 37% carbamide peroxide bleaching agent with or without titanium dioxide potentializes color change effectiveness

BackgroundThe effectiveness of dental color change was assessed by incorporating titanium dioxide (TiO2) into 37% carbamide peroxide bleaching agent associated with hybrid light. MethodologyFifty bovine incisors were selected to receive the bleaching treatment, and separated into five groups (n = 10): 35% hydrogen peroxide (HP) (Whiteness HP, FGM/HP); 37% carbamide peroxide (CP) (Whiteness SuperEndo, FGM/CP); CP + hybrid light (HL) (CP HL); CP + 1% TiO2 (CP TiO2); CP TiO2 + hybrid light (CP TiO2 HL). The bleaching gels were applied to the dental surface for 30 min. Hybrid light (Whitening Plus, DMC/infrared laser diodes + blue LEDs +violet LEDs) was applied with 1 min of active light, alternating with 1 min of pause. A spectrophotometer (VITA Easyshade® Advance, Vita) was used to determine the color of the dental elements at baseline and time points after the 1st, 2nd and 3rd bleaching sessions. Color change effectiveness was evaluated using Vita Classical, CIEL*a*b*, WID and ΔEab, ΔE00 and ΔWID parameters. ResultsGeneralized mixed linear models for repeated measures (α = 5%) showed significant decrease in Vita Classical scores and a* and b* values, as well as an increase in L* and ∆WID values for all the groups. Higher color change values for ΔEab were observed for CP HL and CP TiO2 HL, while those of ΔE00 and ΔWID were higher for CP TiO2 HL at the end of the bleaching treatment. ConclusionHybrid light applied with TiO2 incorporated into CP potentiated the effectiveness of the color change in the tooth structure.

Effect of aging and fiber-reinforcement on color stability, translucency, and microhardness of single-shade resin composites versus multi-shade resin composite.

The purpose of this study was to evaluate the effect of aging and fiber-reinforcement on the color stability, translucency, and microhardness of single-shade resin composites versus multi-shade resin composite. Four resin composites (Filtek Z250, Omnichroma, Vittra APS Unique, Zenchroma) were tested. Three subgroups of specimens were prepared for each of the composites: control, polyethylene fiber-reinforcement, and glass fiber-reinforcement- groups (n = 10/per group). The samples were subjected to aging for 10,000 thermal cycles. Color differences (ΔE00 ) were calculated after aging. Relative translucency parameter (RTP00 ) and microhardness values were calculated before and after aging. A two-way analysis of variance and the generalized linear model was used (p < 0.05). The lowest and highest ΔE00 values were found for Filtek Z250 (0.6 ± 0.2) and Omnichroma resin composites (1.6 ± 0.4), respectively. The ΔE00 value of the polyethylene fiber-reinforcement group (1.2 ± 0.6) was significantly higher than the ΔE00 value of the glass fiber-reinforcement group (1.0 ± 0.4, p < 0.001). The RTP00 value of the glass fiber-reinforcement group (1.92 ± 0.78) was significantly higher than the RTP00 value of the polyethylene fiber-reinforcement group (1.72 ± 0.77, p < 0.001). The highest microhardness values were found in glass fiber-reinforcement group (76.48 ± 17.07, p < 0.001). Single-shade resin composites were more translucent, had higher color change, and lower hardness than multi-shade resin composite. For relative translucency and microhardness, statistical significance was found in the material and fiber type interaction. The glass fiber-reinforcement provided higher translucency, lower color change and higher microhardness values than polyethylene fiber-reinforcement group after aging. Thermocycling had a significant impact on the color stability, translucency parameter, and microhardness of the tested resin composite materials. Single-shade resin composite materials have greater color-changing potential. The glass fiber-reinforcement optimize resin material mechanical properties and color stability more than polyethylene fiber-reinforcement.

The effect of varnish type, glue amount, and density on the surface properties of low density particleboards produced from waste wood bark

Particleboards, which are widely used in various fields, are commonly coated with solid and liquid surface coating materials to achieve better physical, mechanical, and aesthetic results. This study produced low-density particleboards from waste wood bark using different adhesive mixtures and densities. These particleboards were then coated with three types of varnish: water-based (Aq), polyurethane-based (Pu), and oil/wax-based (Ow). The color, gloss, and surface roughness values of the coated boards were determined to investigate the effect of varnish type, total adhesive usage, and density on these properties. In the board groups produced with the same glue ratio and density, the roughness values obtained with Ow varnish application were mostly higher compared to Aq and Pu. In the Ow varnish type, the roughness (Rmax) decreased linearly with increasing total adhesive amount in particleboards produced at low density (320 kg/m3). The highest color change (ΔE*) values for all variations were obtained in the Ow varnish type, while the highest gloss values were achieved at 85° and in the B2 (4%-420 kg/m3) board group. It was concluded that higher density should be preferred for smoother and glossier surfaces, which are important in terms of surface properties and aesthetics. Overall, these findings highlight the preference for higher density to achieve smoother and glossier surfaces in areas where surface properties and aesthetics are significant.

DIFFERENCES OF BIOACTIVE COMPOSITE RESIN COLOR ON IMMERSION IN ALCOHOL AND NON-ALCOHOL MOUTHWASH

Background: Composite resin is the most used material for caries restoration and highly chosen by dental patients regarding it’s high aesthetic value. People often use mouthwash to maintain dental and oral hygiene, both those containing alcohol and non-alcohol. According to several studies, the alcohol in mouthwash will cause a decrease in the physical properties of the composite resin, such as surface roughness, compressive strength, hardness, and also the aesthetic value of the composite resin. Objective: To determine the difference of bioactive composite resin color on immersion in alcohol and non alcohol mouthwash. Methods: Experimental laboratory with a pre-test and post-test with control group design using 27 samples of composite resin with a diameter of 15 mm and 1 mm. The samples were divided into 3 groups, namely the immersion group in alcoholic mouthwash, non-alcohol, and aquades. Each group consisted of 9 samples to be measured the value of color change before and after immersion for 12 hours. Results: The results of the One Way ANOVA statistical test showed that there was an effect of soaking mouthwash on the color of the bioactive composite resin. The Post Hoc LSD test showed between the alcohol and non-alcohol mouthwash group, as well as alcohol and distilled water group had a significant difference, but not in the non-alcohol mouthwash and distilled water group. Conclusion: The immersion in both alcohol and non- alcohol mouthwash are significantly affecting the color changing in bioactive composite resin. The value of color changing between mouthwash goups are significantly different. Keywords: Bioactive composite resin, discoloration, liquid absorption, mouthwash.