Color simulation and temperature distribution characteristics of reversible color-changing composite materials for self-detection of power equipment temperature

Effects of different drinks on stainability of resin composite provisional restorative materials

Creating Chameleon-like Smart Actuators

Effect of tooth-bleaching methods on gloss and color of resin composites

An observer-free method of color classification was used to determine whether wood frogs, Rana sylvatica, exhibit sexual differences in color and color change. Males and females captured from breeding aggregations differed significantly in color: females reflected a greater amount of long-wavelength (yellow–red) light and less short-wavelength (blue–green) light than males. The color difference was not just a result of differences in the state of physiological color change at the time of capture but persisted for a month after capture. Males and females also differed in their color-change responses to black and white backgrounds: both sexes changed in brightness, but only males changed in the relative amount of light reflected at different wavelengths. Wood frog color may function in predator avoidance through crypsis. There was a good match between frogs and some of the leaves from the leaf litter surrounding the breeding ponds. Hypotheses for the development of sexual differences in wood frog color include sexual differences in availability of pigment and pigment precursors, morphological color change, and evolutionary response to different selection pressures.

Resistance to staining is desirable to maintain the esthetic appearance of a provisional material. A resin sealant may improve stain resistance. Color changes of a resin composite provisional material were measured by reflection spectrophotometry after storage in three staining solutions and water to determine stain resistance when treated with three methacrylate or urethane dimethacrylate resin surface sealants and when left untreated. Specimens of a resin composite provisional material received one of three resin sealants (Fortify Plus, Bisco, Inc., Schaumburg, IL; Jet Seal, Lang Dental Manfacturing, Wheeling, IL; Triad LC, Dentsply International, York, PA, USA) or no surface sealer and then were stored for 72 hours in one of four staining solutions (water [control], black coffee, cranberry juice, red wine). Color was measured by CIE L*a*b* on a reflection spectrophotometer (Color-Eye 7000, Macbeth Division, Kollmorgen Instruments, Newburgh, NY, USA) at baseline and after storage. Color change (deltaE*) was calculated and analyzed statistically by two-factor analysis of variance, with four solutions and four surface treatments as independent variables. deltaE* ranged from 0.7 to 1.7 in water, from 1.1 to 5.5 in cranberry juice, from 1.1 to 6.5 in black coffee, and from 1.5 to 3.9 in red wine. Statistically significant differences were observed (p < .05), with Fortify Plus showing increased staining (deltaE* > 3.3) and Jet Seal and Triad LC showing decreased staining (deltaE* < 2.0) in cranberry juice and coffee compared with staining of the unsealed specimens. Only Jet Seal provided resistance to staining in red wine. Specimens without a surface sealer had statistically higher (p < .05) and perceptible or nearly perceptible color changes in cranberry juice, black coffee, and red wine than in water. Specimens coated with Jet Seal had statistically lower (p < .05) color changes than uncoated specimens in cranberry juice, black coffee, and red wine. When coated, the color changes of the stained specimens were not perceptible. Specimens coated with Triad LC had statistically lower (p < .05) color changes than unsealed specimens in cranberry juice and black coffee. When sealed, the color changes of the specimens stained with cranberry juice and black coffee were not perceptible. Both unsealed and sealed specimens stained with red wine were nearly perceptible. Specimens coated with Fortify Plus had statistically higher (p < .05) color changes than uncoated specimens in cranberry juice and black coffee but statistically the same (p < .05) color change as uncoated specimens in red wine. These specimens had perceptible color changes in cranberry juice, black coffee, and red wine. Surface of methacrylate or dimethacrylate resins can improve resistance of a resin composite provisional material to staining caused by cranberry juice, black coffee, and red wine.

Objective: To evaluate the color stability of Tetric® N-Ceram Bulk Fill composite restorative material after immersion in three different (energy drink, protein supplement solution, and combination of energy drink and protein supplement solution) drinks. Materials and Methods: Composite resin disks, 2 mm in depth and 5 mm in diameter, were prepared from the Tetric® N-Ceram Bulk Fill composite restorative material. Specimens were tested after immersion and aging in energy drink (Red Bull) alone, protein supplement solution alone, and in combination with energy drink and protein supplement. Deionized water was used as a control group. Specimens were stored at room temperature of ±23°C for a period of one week in each drink. Color was assessed in the CIELAB using Color Eye 7000A Spectrophotometer. Color differences in different group specimens were measured. Mean values were statistically analyzed using one-way analysis of variance (ANOVA). Further Tukey’s multiple comparison tests were applied to know the differences between the group of specimens. A p value of p &lt; 0.05 was set as significance level. Results: N-Ceram Bulk Fill composite showed Δ L, Δ a, Δ b, and Δ E mean and standard deviation values when immersed in deionized water (–2.6 ± 3.24, 0.16 ± 0.19, 0.32 ± 1.26, and 3.51 ± 2.47), energy drink (–4.19 ± 4.24, 0.21 ± 0.21, 1.57 ± 1.32, and 5.40 ± 3.11), protein supplement (62.71 ± 12.48, –2.63 ± 0.7, 7.7 ± 5.67, and 63.45 ± 12.56), combined energy drink and protein supplement (68.52 ± 13.43, –4.06 ± 1.73, 10.94 ± 5.31, and 69.71 ± 13.42), respectively. All the color coordinates (Δ L, Δ a, and Δ b) showed statistically significant difference, p &lt; 0.001. The color change of N-Ceram Bulk Fill composite specimens Δ E occurred by immersion in energy drink, protein supplement solution, and combined solution of energy drink and protein supplement after seven days was found to be statistically significant p &lt; 0.001. Conclusion: The study’s finding suggests that the energy drink (Red Bull), protein supplement (ISOPURE), and combined immersion in energy drink and protein supplements caused perceptible and clinically unacceptable color change in the Tetric® N-Ceram Bulk Fill composite material. This color change was remarkably high with a combined immersion in energy drink and protein supplement solution.

To evaluate changes in tooth color for 2 age cohorts (younger cohort, YC: 1950-1952; older cohort, OC: 1930-1932) over a mean observation period of 8 years. Sixty-one participants with 106 upper central incisors were subjected to baseline and follow-up examinations (YC: n = 46/OC: n = 15). International Commission on Illumination color coordinates of 1 or 2 unrestored test teeth for each participant were recorded by use of a spectrophotometer (VITA Easyshade 1) during both measurement times. Changes of color coordinates during the study period were evaluated by use of generalized linear mixed models with the variable "participant" as random effect. ΔEab and E2000 color differences were calculated between baseline and follow-up. Significant changes in color coordinates were observed, with the exception of lightness in OC. The direction of the changes depended on the cohort. A decrease of lightness (value) was observed in YC (ΔL = 4.0; P < .001) whereas in OC chroma increased (ΔC = -3.3; P < .001). For both groups, a significant shift to more reddish tooth colors was observed. In almost all cases, color differences between baseline and follow-up exceeded the 50:50 acceptability thresholds for color differences (ΔE = 2.7) in both YC (≈90%) and OC (≈80%). For both quinquagenarians and septuagenarians, clinically relevant changes in tooth color were observed after a decade; these could affect the long-term success of prosthetic restorations in terms of a satisfactory color match between natural teeth and dental prostheses. In contrast with the findings of cross-sectional studies, the changes were partially age-group-specific. Tooth color can change over a decade. When fixed dental prostheses are planned, one should consider that changes of tooth color could lead to mismatch between a restoration and adjacent teeth during the period in clinical service.

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.

Objectives: The purpose of this study was to determine the effect of resin infiltration technique on color and surface hardness of white spot lesion (WSL) with various degrees of demineralization. Materials and Methods: Ten human upper premolars were cut and divided into quarters with a window on the enamel surface. Each specimens were separated into four groups (n = 10) and immersed in demineralization solution to create WSL: control, no treatment (baseline); 12 h, 12 hr demineralization; 24 h, 24 hr demineralization; 48 h, 48 hr demineralization. Resin infiltration was performed to the specimens using Icon (DMG). color parameters of the enamel-dentin complex were determined using a spectroradiometer at baseline, after caries formation and after resin infiltration. Surface hardness was measured by Vickers Micro Hardness Tester (Shimadzu, HMV-2). The differences in color and hardness among the groups were analyzed with ANOVA followed by Tukey test. Results: Resin infiltration induced color changes and increased the hardness of demineralized enamel. After resin infiltration, there was no difference in color change () or microhardness among the groups (p

Analysis of color differences in stained contemporary esthetic dental materials

(1) Background: This study aimed to determine the effect of repeated pre-polymerization heating on the color and translucency of a one-shaded resin-based composite and to evaluate whether the heating cycles affect its color stability. (2) Methods: Fifty-six samples of 1-mm thickness were fabricated from Omnichroma (OM) after applying different heating cycles (for one, five, and ten times at 45 °C) before polymerization (n = 14/group) and afterwards were stained with a yellow dye solution. CIE L*, a*, b*, C*, h° coordinates were recorded, and color differences, whiteness, and translucency were calculated, before and after staining. (3) Results: Heating cycles significantly influenced the color coordinates, WID00, and TP00 of OM being higher after one heating cycle and decreasing as the number of heating cycles increased. The color coordinates, WID, and TP00 after staining significantly differed for each group. The color and whiteness differences calculated after staining exceeded the acceptability thresholds for all groups. The color and whiteness variations after staining were clinically unacceptable. (4) Conclusions: Repeated pre-polymerization heating induces a clinically acceptable color and translucency change to OM. Although the color changes resulting after staining are clinically unacceptable, increasing the number of heating cycles up to ten times slightly reduces the color differences.

Background. Acid etching and bonding is a routine process in orthodontic treatment. The present study aimed to evaluate enamel discoloration after using different types of acid etching and adhesive agents. Methods. A total of 105 extracted human premolars were divided into six groups regarding the type of acid etching agent: solution and gel of 37% phosphoric acid, and type of self-cured adhesive agent: Unite (3M, fluoride-free), Resilience (Ortho Technology), and Rely-a-Bond (Reliance, fluoride-releasing adhesive), with each group containing 15 specimens. All the selected teeth were subjected to a staining process, and color parameters were determined using a spectrophotometer. Results. The type of phosphoric acid (solution or gel) had no significant effect on the color change of enamel (P >0.05). Resilience significantly changed the enamel color compared to the Unite and Rely-a-Bond (P <0.001). There was no significant difference in color change between the Unite and Rely-a-Bond adhesives (P =0.67). The difference in color change between all the three time intervals (T0-T1, T1-T2, and T0-T2) was significant (P <0.001). Conclusion. In this study, the type of phosphoric acid (solution or gel) did not result in any significant difference in enamel color. Also, considering the lack of the effect of the orthodontic adhesive type in terms of fluoride release or no fluoride release, it can be concluded that this is most affected by the commercial brand of adhesives.

&lt;p&gt;At TAGA 2007 conference in Pittsburgh I presented a paper about color-differencing equations and the human eye. The color test was done with inexperienced observers. One of the main results was that the DE2000 equations correspond quite well with the perceived color differences, followed closely the DECMC2:1 equation.&lt;/p&gt; &lt;p&gt;A very similar test was carried out with experienced color observers at the IPA technical conference in Chicago in June 2008 and local print professionals. Besides having to judge a solid color chip, they were also asked to rank visual differences in four test images.&lt;/p&gt; &lt;p&gt;As an addition to the test carried out in 2007, the DIN99 equation was also tested to see if it relates better to the perceived color differences. Interestingly the DE2000 equation related the best with how the observers perceived the color differences of the solid color patches.&lt;/p&gt; &lt;p&gt;The results from the test carried out in 2007 were revisited to see how well they relate to the DIN99 equation. The DIN99 color differencing equation did not correlate better with the data gathered from inexperienced observers.&lt;/p&gt; &lt;p&gt;Experienced observers were also asked to rank color differences of solid color patches. The perceived differences related well with the numerical differences given by the DE2000 equation. Based on the experiments carried out in 2007 and 2008 it can be said that the DE2000 equation should be used more widely in industry since it relates well with the way experienced and inexperienced observers perceive color differences.&lt;/p&gt; &lt;p&gt;Another question is how do any of the modern color-differencing equations relate to differences present between two similar images displayed on a computer screen? Due to the large number of new soft proofing systems being introduced into the graphic arts industry, the test images were shown on a color-calibrated display.&lt;/p&gt; &lt;p&gt;Four ISO SCID images were chosen and modified in regards to lightness, chroma and hue. The images that were chosen varied in chroma from very colorful to mostly neutral colors. In the neutral colors all observers identified differences quite easily, but in the other images many observers had difficulties identifying slight changes in regards to changes in lightness, but could readily identify differences in chroma and hue. The observers more readily reported chroma and hue differences than differences in lightness. The most sensitive image for small color changes contained large neutral gray areas, as was to be expected.&lt;/p&gt; &lt;p&gt;Threshold values in relation to differences in Lightness, Chroma and Hue will be presented and also which of the newer colour differencing equations relates better to the perceived color differences.&lt;/p&gt;

&lt;p&gt;At TAGA 2007 conference in Pittsburgh I presented a paper about color-differencing equations and the human eye. The color test was done with inexperienced observers. One of the main results was that the DE2000 equations correspond quite well with the perceived color differences, followed closely the DECMC2:1 equation.&lt;/p&gt; &lt;p&gt;A very similar test was carried out with experienced color observers at the IPA technical conference in Chicago in June 2008 and local print professionals. Besides having to judge a solid color chip, they were also asked to rank visual differences in four test images.&lt;/p&gt; &lt;p&gt;As an addition to the test carried out in 2007, the DIN99 equation was also tested to see if it relates better to the perceived color differences. Interestingly the DE2000 equation related the best with how the observers perceived the color differences of the solid color patches.&lt;/p&gt; &lt;p&gt;The results from the test carried out in 2007 were revisited to see how well they relate to the DIN99 equation. The DIN99 color differencing equation did not correlate better with the data gathered from inexperienced observers.&lt;/p&gt; &lt;p&gt;Experienced observers were also asked to rank color differences of solid color patches. The perceived differences related well with the numerical differences given by the DE2000 equation. Based on the experiments carried out in 2007 and 2008 it can be said that the DE2000 equation should be used more widely in industry since it relates well with the way experienced and inexperienced observers perceive color differences.&lt;/p&gt; &lt;p&gt;Another question is how do any of the modern color-differencing equations relate to differences present between two similar images displayed on a computer screen? Due to the large number of new soft proofing systems being introduced into the graphic arts industry, the test images were shown on a color-calibrated display.&lt;/p&gt; &lt;p&gt;Four ISO SCID images were chosen and modified in regards to lightness, chroma and hue. The images that were chosen varied in chroma from very colorful to mostly neutral colors. In the neutral colors all observers identified differences quite easily, but in the other images many observers had difficulties identifying slight changes in regards to changes in lightness, but could readily identify differences in chroma and hue. The observers more readily reported chroma and hue differences than differences in lightness. The most sensitive image for small color changes contained large neutral gray areas, as was to be expected.&lt;/p&gt; &lt;p&gt;Threshold values in relation to differences in Lightness, Chroma and Hue will be presented and also which of the newer colour differencing equations relates better to the perceived color differences.&lt;/p&gt;

Effects of various finishing procedures on the staining of provisional restorative materials