scholarly journals Effects of Simulated Gastric Acid Exposure on Surface Topography, Mechanical and Optical Features of Commercial CAD/CAM Ceramic Blocks

2021 ◽  
Vol 11 (18) ◽  
pp. 8703
Author(s):  
Ioana Ligia Pîrvulescu ◽  
Daniel Pop ◽  
Elena-Alina Moacă ◽  
Ciprian-Valentin Mihali ◽  
Codruța Ille ◽  
...  
Keyword(s):  
Surface Topography ◽  
Gastric Acid ◽  
Color Change ◽  
Ceramic Materials ◽  
Acid Exposure ◽  
Severe Nausea ◽  
Sem Images ◽  
Tooth Structure ◽  
Color Changes ◽  
Ceramic Blocks

Gastric acid exposure produces tooth structure demineralization and dental ceramic degradation. The most affected patients are those who suffer from gastroesophageal reflux disease, bulimia nervosa, and pregnant women with prolonged severe nausea. In order to protect this kind of patient, the purpose of this study was to determine whether simulated gastric acid exposure leads to microstructural changes in surface topography, hardness, color changes, and translucency of some ceramic materials, which are already on the market. Forty disks (Triluxe Forte, Cerasmart, Enamic and Empress CAD) were analyzed before and after immersion in simulated gastric acid juice, in terms of microhardness, surface roughness, translucency, and surface morphology using scanning electron microscopy. Color change was assessed by using a spectrophotometer based on CIELab parameters and the results showed that, after exposure, ∆Eab remained under the threshold of acceptability and perceptibility. In terms of microhardness, Cerasmart is the only material that did not undergo changes after immersion. SEM images illustrated observable changes surface topography after acid exposure for all the tested materials. In conclusion, Triluxe Forte suffered the most important changes after simulated gastric acid juice exposure, and Cerasmart proved to be the least affected material.

scholarly journals Surface Quality Evaluation of Removable Thermoplastic Dental Appliances Related to Staining Beverages and Cleaning Agents

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1736
Author(s):  
Liliana Porojan ◽  
Roxana-Diana Vasiliu ◽  
Sorin-Daniel Porojan ◽  
Mihaela-Ionela Bîrdeanu
Keyword(s):  
Surface Topography ◽  
Surface Quality ◽  
Color Change ◽  
Water Immersion ◽  
Marked Change ◽  
Color Stability ◽  
Black Tea ◽  
Sem Images ◽  
Color Changes ◽  
Cleaning Agents

(1) Background: Thermoplastic materials are not inert and subject to changes in the oral environment, which affect their surface quality. Color stability and topographic characteristics of clear thermoplastic appliances are critical considerations. The study aimed to evaluate the optical changes and surface topography of different thermoplastic materials related to staining beverages and cleaning agents. (2) Methods: Thermoplastic polyethylene terephthalate glycol (PET-G) material specimens were selected for the study: S (Duran, Scheu-Dental GmbH, Iserlohn, Germany), D (Biolon, Dreve Dentamid GmbH, Unna, Germany), and B (Crystal, Bio Art Dental Equipment, Sao Carlos, Brazil). Four different media were involved for immersion: coffee (C) and black tea (T) at 55 °C, Coca-Cola (K) at 5 °C, and distilled water (W) at 22 °C. As for cleaning, chemical options and mechanical brushing were selected (P-powder, T-tablets, and X-brushing). Color changes, and mean surface roughness were measured at 24 h, 48 h, and after 7 days. Statistical analysis was performed. After the testing period, atomic force microscopy (AFM) analyses and SEM images were registered in order to characterize the surface topography. (3) Results: Quantitative color change evaluations revealed a slight change in color after 24 h and an extremely marked change after 48 h, respective 7 days. Mean roughness values are kept below the clinically acceptable limit of 0.20 µm for all samples. Related to mean nanoroughness values Sa, and 3D evaluations of the surface quality, Biolon samples have demonstrated the most constant behavior, while Crystal samples are visibly influenced by water immersion. Related to the cleaning method, the topography of Duran samples was influenced by mechanical brushing. (4) Conclusions: Nanoscale investigations provided high accuracy and more realistic surface quality examinations of the examined samples compared to profilometry. Both SEM and AFM should be used for a more detailed description of the surface topography.

scholarly journals Superficial Effects of Different Finishing and Polishing Systems on the Surface Roughness and Color Change of Resin-Based CAD/CAM Blocks

2021 ◽  
pp. 247-257
Author(s):  
Numan Aydın ◽  
Serpil Karaoğlanoğlu ◽  
Elif Aybala Oktay ◽  
Bilge Ersöz
Keyword(s):  
Surface Roughness ◽  
Color Change ◽  
Lower Surface ◽  
Ceramic Block ◽  
Color Changes ◽  
Surface Polishing ◽  
Cad Cam ◽  
Ceramic Blocks ◽  
One Step ◽  
Hybrid Ceramic

Objective: CAD/CAM blocks are widely used in dental restorations around the world. This study aimed to investigate the effects of different polishing and finishing systems on surface roughness and color change of resin-based CAD/CAM blocks. Material and Methods: In this study, material samples of 2×7×12mm were prepared. In three different experimental groups, surface polishing was carried out with one-step, two-step and multi-step polishing systems. The samples in one subgroup of each experimental group were polished with the diamond paste. Once the initial roughness and color values of the samples were measured using a profilometer and a spectrophotometer, the samples were immersed in coffee. Surface roughness and color change (∆E00) results were statistically analyzed using two-way variance analysis (ANOVA). Results: Finishing and polishing systems created significantly different levels of surface roughness on the hybrid ceramic block (Vita Enamic) but not on the composites block (Brilliant Crios, Grandio Blocs). While the two-step and multi-step finishing and polishing systems produced the lowest color change on hybrid ceramic blocks, one-step and two-step systems achieved this on composite blocks (p<0.05). In all test groups, the supplementary polishing performed after regular polishing procedures helped us reduce the surface roughness and color change on CAD/CAM blocks.  Conclusions: The findings obtained in this study suggest that one and two-step polishing systems are more suitable for resin-based composite CAD/CAM blocks; for hybrid ceramic CAD/CAM blocks, on the other hand, two and multi-step finishing and polishing systems seem to be more efficient concerning lower surface roughness and resistance to color changes.

scholarly journals Investigation of the selective color-changing mechanism of Dynastes tityus beetle (Coleoptera: Scarabaeidae)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiyu Sun ◽  
Wei Wu ◽  
Limei Tian ◽  
Wei Li ◽  
Fang Zhang ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Color Change ◽  
Incidence Angle ◽  
Ion Beam ◽  
Three Dimensional ◽  
Water Infiltration ◽  
Photonic Materials ◽  
Local Color ◽  
Water Contact ◽  
Color Changes

AbstractNot only does the Dynastes tityus beetle display a reversible color change controlled by differences in humidity, but also, the elytron scale can change color from yellow-green to deep-brown in specified shapes. The results obtained by focused ion beam-scanning electron microscopy (FIB-SEM), show that the epicuticle (EPI) is a permeable layer, and the exocuticle (EXO) is a three-dimensional photonic crystal. To investigate the mechanism of the reversible color change, experiments were conducted to determine the water contact angle, surface chemical composition, and optical reflectance, and the reflective spectrum was simulated. The water on the surface began to permeate into the elytron via the surface elemental composition and channels in the EPI. A structural unit (SU) in the EXO allows local color changes in varied shapes. The reflectance of both yellow-green and deep-brown elytra increases as the incidence angle increases from 0° to 60°. The microstructure and changes in the refractive index are the main factors that influence the process of reversible color change. According to the simulation, the lower reflectance causing the color change to deep-brown results from water infiltration, which increases light absorption. Meanwhile, the waxy layer has no effect on the reflection of light. This study lays the foundation to manufacture engineered photonic materials that undergo controllable changes in iridescent color.

scholarly journals Characterization of Food Packaging Films with Blackcurrant Fruit Waste as a Source of Antioxidant and Color Sensing Intelligent Material

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2569
Author(s):  
Mia Kurek ◽  
Nasreddine Benbettaieb ◽  
Mario Ščetar ◽  
Eliot Chaudy ◽  
Maja Repajić ◽  
...  
Keyword(s):  
Food Packaging ◽  
Water Solubility ◽  
Color Change ◽  
Chitosan Film ◽  
Water Vapor Permeability ◽  
Vapor Permeability ◽  
Color Changes ◽  
Insoluble Particles ◽  
Polymer Stability ◽  
Food Packaging Films

Chitosan and pectin films were enriched with blackcurrant pomace powder (10 and 20% (w/w)), as bio-based material, to minimize food production losses and to increase the functional properties of produced films aimed at food coatings and wrappers. Water vapor permeability of active films increased up to 25%, moisture content for 27% in pectin-based ones, but water solubility was not significantly modified. Mechanical properties (tensile strength, elongation at break and Young’s modulus) were mainly decreased due to the residual insoluble particles present in blackcurrant waste. FTIR analysis showed no significant changes between the film samples. The degradation temperatures, determined by DSC, were reduced by 18 °C for chitosan-based samples and of 32 °C lower for the pectin-based samples with blackcurrant powder, indicating a disturbance in polymer stability. The antioxidant activity of active films was increased up to 30-fold. Lightness and redness of dry films significantly changed depending on the polymer type. Significant color changes, especially in chitosan film formulations, were observed after exposure to different pH buffers. This effect is further explored in formulations that were used as color change indicators for intelligent biopackaging.

Influence of Hydrogen Peroxide Bleaching Gels on Color, Opacity, and Fluorescence of Composite Resins

2012 ◽  
Vol 37 (5) ◽  
pp. 526-531 ◽  
Author(s):  
CRG Torres ◽  
CF Ribeiro ◽  
E Bresciani ◽  
AB Borges
Keyword(s):  
Hydrogen Peroxide ◽  
Composite Resin ◽  
Color Change ◽  
Composite Resins ◽  
Control Group ◽  
Peroxide Bleaching ◽  
Color Changes ◽  
Tukey Test ◽  
Bleaching Gels ◽  
Bleaching Treatment

SUMMARY The aim of the present study was to evaluate the effect of 20% and 35% hydrogen peroxide bleaching gels on the color, opacity, and fluorescence of composite resins. Seven composite resin brands were tested and 30 specimens, 3-mm in diameter and 2-mm thick, of each material were fabricated, for a total of 210 specimens. The specimens of each tested material were divided into three subgroups (n=10) according to the bleaching therapy tested: 20% hydrogen peroxide gel, 35% hydroxide peroxide gel, and the control group. The baseline color, opacity, and fluorescence were assessed by spectrophotometry. Four 30-minute bleaching gel applications, two hours in total, were performed. The control group did not receive bleaching treatment and was stored in deionized water. Final assessments were performed, and data were analyzed by two-way analysis of variance and Tukey tests (p&lt;0.05). Color changes were significant for different tested bleaching therapies (p&lt;0.0001), with the greatest color change observed for 35% hydrogen peroxide gel. No difference in opacity was detected for all analyzed parameters. Fluorescence changes were influenced by composite resin brand (p&lt;0.0001) and bleaching therapy (p=0.0016) used. No significant differences in fluorescence between different bleaching gel concentrations were detected by Tukey test. The greatest fluorescence alteration was detected on the brand Z350. It was concluded that 35% hydrogen peroxide bleaching gel generated the greatest color change among all evaluated materials. No statistical opacity changes were detected for all tested variables, and significant fluorescence changes were dependent on the material and bleaching therapy, regardless of the gel concentration.

Comparison of the color and weight change in Paulownia tomentosa and Pinus koraiensis wood heat-treated in hot oil and hot air

BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 5574-5585
Author(s):  
Intan Fajar Suri ◽  
Jong Ho Kim ◽  
Byantara Darsan Purusatama ◽  
Go Un Yang ◽  
Denni Prasetia ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Color Change ◽  
Treated Wood ◽  
Pinus Koraiensis ◽  
Weight Changes ◽  
Paulownia Tomentosa ◽  
Wood Color ◽  
Color Changes ◽  
Hot Air ◽  
Heat Treated

Color changes were tested and compared for heat-treated Paulownia tomentosa and Pinus koraiensis wood treated with hot oil or hot air for further utilization of these species. Hot oil and hot air treatments were conducted at 180, 200, and 220 °C for 1, 2, and 3 h. Heat-treated wood color changes were determined using the CIE-Lab color system. Weight changes of the wood before and after heat treatment were also determined. The weight of the oil heat-treated wood increased considerably but it decreased in air heat-treated wood. The oil heat-treated samples showed a greater decrease in lightness (L*) than air heat-treated samples. A significant change in L* was observed in Paulownia tomentosa. The red/green chromaticity (a*) of both wood samples increased at 180 and 200 °C and slightly decreased at 220 °C. The yellow/blue chromaticity (b*) in both wood samples increased at 180 °C, but it rapidly decreased with increasing treatment durations at 200 and 220 °C. The overall color change (ΔE*) in both heat treatments increased with increasing temperature, being higher in Paulownia tomentosa than in Pinus koraiensis. In conclusion, oil heat treatment reduced treatment duration and was a more effective method than air heat treatment in improving wood color.

Quantifying Coronal Permanent Tooth Discoloration Caused by Different Pulpotomy Materials

2021 ◽  
Vol 45 (5) ◽  
pp. 306-311
Author(s):  
Hanaa Azem ◽  
Sigalit Blumer ◽  
Benjamin Peretz ◽  
Sohad Haj-Yahya ◽  
Shlomo Elbahary
Keyword(s):  
Color Space ◽  
Mineral Trioxide Aggregate ◽  
Permanent Tooth ◽  
Control Group ◽  
Major Drawback ◽  
Tooth Structure ◽  
Color Changes ◽  
Base Materials ◽  
Tooth Discoloration ◽  
Over Time

Introduction: Bioceramic materials, gray and white mineral trioxide aggregate (GMTA, WMTA), have been shown to have high rates of success in various endodontic applications. A major drawback is their tendency to discolor teeth compared to Biodentine (BD), that has been claimed not to discolor teeth. The aim of this study was to compare tooth discoloration after applying different pulpotomy base materials (BD, GMTA and WMTA). Study design: Forty human incisors teeth were used in this study. Coronal access was achieved by a Tungsten Carbide drill, and the pulp chambers were accessed and chemo-mechanically debrided. Each material was placed in the pulp chamber, up to the cervical sectioning level. All specimens were incubated at 37°C and 100% humidity for three months and have been evaluated before the study and weekly. Color was assessed according to the CIE L*a*b* color space system. Results: ΔE of all experimental groups (GMTA, WMTA and BD) were significantly different from the control group at all time points (P&lt;0.05). Color changes in the GMTA and WMTA groups, had no statistically significant differences, but showed higher discoloration compared to BD group in the cervical part of the crown, since week 1 (P&lt;0.05). WMTA group showed significant discoloration in the cervical part as of week 1 (P&lt;0.05), and gradually increased over time (Figure 2). BD group showed no significantly discoloration over time. GMTA group showed the significant discoloration at week 1 and week 14 (P&lt;0.05). Conclusions: both GMTA and WMTA pulpotomy materials may discolor tooth structure over time in an extracted permanent anterior tooth model. When choosing bioceramic pulpotomy material, BD may be preferable in esthetic area.

scholarly journals Analysis of the Influence of Food Colorings in Esthetic Orthodontic Elastomeric Ligatures

2016 ◽  
Vol 10 (1) ◽  
pp. 516-521 ◽  
Author(s):  
Vanessa Dias da Silva ◽  
Eduardo Martinelli S de Lima ◽  
Caroline Dias ◽  
Leandro Berni Osório
Keyword(s):  
Color Change ◽  
Black Tea ◽  
Control Group ◽  
Distilled Water ◽  
Water Control ◽  
Color Changes ◽  
Influence Of Food

Proposition: The purpose of this study was to evaluate in vitro the color changes of esthetic orthodontic elastomeric ligatures of different shades when exposed to four food colorings commonly found in the diet of patients. Materials and Methods: The sample consisted of esthetic orthodontic elastomeric ligatures in the colors pearl, pearl blue, pearl white and colorless, which were immersed for 72 hours in five different solutions: distilled water (control group), coffee, tea, Coca-Cola ® and wine. The color changes of the esthetic orthodontic elastomeric ligatures were measured with the aid of a spectrophotometer, at T1 - as provided by the manufacturer; and T2 - after colorings process. Results: The results indicated that the esthetic orthodontic elastomeric ligatures of all initial hues are susceptible to pigmentation. Among the evaluated colors, all changed the finished look and the color of the samples tested. In ascending order, the color of the samples was as follows: distilled water, Coca-Cola®, black tea, wine and coffee. Conclusion: The substances that have a greater potential for pigmentation in esthetic orthodontic elastomeric ligatures were black tea, wine and coffee, respectively. All shades of esthetic orthodontic elastomeric ligatures are susceptible to color change.

scholarly journals Fusarium graminearum Colors and Deoxynivalenol Synthesis at Different Water Activity

Foods ◽  
2018 ◽  
Vol 8 (1) ◽  
pp. 7 ◽  
Author(s):  
Edgar Cambaza ◽  
Shigenobu Koseki ◽  
Shuso Kawamura
Keyword(s):  
Fusarium Graminearum ◽  
Color Change ◽  
High Growth ◽  
Cereal Crops ◽  
Color Analysis ◽  
Surface Color ◽  
Color Changes ◽  
White Mycelium ◽  
Imagej Software ◽  
Inverse Proportionality

Deoxynivalenol (DON) is a well-known mycotoxin, responsible for outbreaks of gastrointestinal disorders in Japan. Fusarium graminearum, a parasite of cereal crops, produces this toxin and this is one of the reasons why it is important to understand its metabolism. It is possible to predict the mold’s color change and the quantity of DON synthesized throughout its lifecycle. Furthermore, aw has been found to affect the amount of DON. This study aimed to analyze the potential of F. graminearum surface color as a predictor of DON concentration at aw = 0.94, 0.97, and 0.99. Thus, 36 specimens were incubated at 25 °C, 12 at each aw. After 4, 8, 12, and 16 days, three specimens from each aw were collected for color analysis and DON quantification. For color analysis, photos were taken and red, green and blue (RGB) channels were measured on ImageJ software. DON was quantified through liquid chromatography (HPLC). Color changes were only observed at aw = 0.99 because at lower aw the molds presented high growth of white mycelium. Yet, DON increased in all cases. It was only possible to relate the colors with DON concentration at aw = 0.99, where they presented inverse proportionality.

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