Color Readouts Research Articles

Characterization of Objective Skin Color Changes during and after Breast and Chest Wall Radiotherapy and Correlation with Radiation-Induced Skin Toxicity in Breast Cancer Patients, Including Patients with Skin of Color

Radiation dermatitis (RD) is common among women undergoing breast and chest wall radiotherapy (RT); however, existing scales to assess the severity of RD are subjective and do not account for variability in skin of color (SOC). For instance, the Common Terminology Criteria for Adverse Events (CTCAE) criteria do not include hyperpigmentation in the grading scale. There is data indicating worse RD in African American and Hispanic patients; however, the rate and severity in SOC remains unknown given the lack of data using objective measures of RD. Spectrophotometry is one method to quantify the appearance of color by measuring spectral characteristics without the bias associated with subjective clinical scoring. We present a phase I prospective non-therapeutic clinical trial to objectively define SOC at baseline and evaluate spectrophotometric skin changes during and after breast or chest wall RT in parallel with physician-graded RD using CTCAE criteria. We hypothesize that there will be greater discrepancy between physician graded RD and objective measures of RD in patients with SOC in whom hyperpigmentation will be undercaptured by physician-grading. This is the first study intending to correlate SOC with objective changes after RT as a reliable indicator of RD. We offer a novel system for evaluating RD that is applicable to SOC. A total of 60 patients with localized breast cancer (stage 0-III) undergoing conventional whole breast or chest wall RT (50Gy/ 25 fx), hypofractionated whole breast RT (40.5Gy/15 fx) or ultrahypofractionated partial breast RT (6Gy x5), with or without regional nodal RT were enrolled. 3 skin color readouts using the Commission International de l'Eclairage 3D color system (l*, a*, b*) were measured within the radiation field using a spectrophotometer at baseline, once weekly during RT, 10 days post RT, 4 weeks and 12 months post RT. The spectrophotometer is a non-invasive, hand-held device that is used in the clinic room with no additional equipment or setup requirements. Data is automatically exported to a spreadsheet organized by timepoint and patient. The l* axis is a gray scale (0 = black, 100 = white) correlating with skin pigmentation and the a* axis describes red and green values correlating with erythema. The primary objective is to evaluate the changes from baseline in skin color readouts in the quadrant of tumor location during and after RT based on fractionation. The secondary objective is to evaluate changes within and across groups defined by baseline skin color. Exploratory objectives include evaluating the association of baseline color readouts and changes after RT with acute and late grade > 2 clinician-rated skin and subcutaneous tissue effects according to the CTCAE, v5.0, physician graded cosmesis and clinical interventions to treat RD, such as use of topical steroids and oral analgesics. As of January 2023, we have enrolled 100% of the planned patients. To be determined. To be determined. Clinical Study Identifier: S22-00192.

Effect of Different Denture Cleansers on Color Stability of Acrylic Resin Teeth – An In Vitro Study

Introduction: The durability of denture teeth to colour change is critical in selecting denture teeth, especially in terms of aesthetic demands and patient expectations. It is critical that the artificial teeth color remains constant over time when exposed to various cleaning solutions. The objective of the study is to assess the influence of three different commercially available denture cleansers on the color of acrylic resin teeth using the digital photography method and the Commission Internationale de l’Eclairage (CIE) L*a*b* standard. Methodology: Sixty acrylic maxillary central incisor teeth were divided to three groups of 20 samples each. The samples were left immersed in three different denture cleansers (DENSIVE, SECURE and CLINSODENT) for one month, simulating one month of usage by the patient. Digital photography was used to obtain baseline and final color readouts of the teeth on the basis of CIE L*a*b* standard, using image analysis software (Adobe Photoshop Inc System) and the color alteration (ΔE) of the samples was computed. Results: Maximum color change was found in teeth treated with DENSIVE denture cleanser, followed by CLINSODENT and SECURE, respectively. And this was found to be statistically significant (p-value ≥ 0.05). Conclusion: It is possible to deduce that the color stability of acrylic resin teeth is influenced by the use of denture cleansing solutions, and a marked color change was noted with the digital photography method.

Discoloration of Bulk-Fill Versus Conventional Composites: A Spectrophotometric Evaluation

Purpose: The purpose of this study was to evaluate the discoloration of a dual-cure bulk-fill (DCBF) and light-cure bulk-fill (LCBF) composites relative to conventional composites (CC) after water and coffee immersion. Methods: One-hundred disc-shaped specimens (8mm in diameter × 4mm thickness) were prepared using five commercially available composites (n=10); two LCBF (XB-X-trafil Voco, FB-FiltekTM Bulk Fill), one DCBF (FU-Fill-upTM Coltene), and two CC (CE-Clearfil Majesty ES2, EQ-Estelite ΣQuick). Initial and final color readouts were measured with a spectrophotometer (Easyshade,Vita) according to the CIELAB color system. Statistical analyses were performed using 2-way ANOVA with Bonferroni adjustment to evaluate ∆E, ∆L, ∆a, and ∆b parameters (p<0.05). Results: Significant interactions were noted among the material types and immersion solutions for all evaluated parameters (p=0.00). ∆E values were observed in the order of FU>FB≥XB>EQ≥CE in water immersion groups and XB>FB>EQ≥FU≥CE in coffee immersion groups. Conclusion: Within the limitations of this study, DCBF composite is more susceptible to intrinsic discoloration compared to LCBF and CC. However, DCBF exhibited lower extrinsic discoloration than LCBF and comparable with CC after coffee immersion. Depending on their chemical and structural compositions, composites will exhibit color change, which compromises the esthetic performance of composite restorations.

Colorimetric Polymerase Chain Reaction Enabled by a Fast Light-Activated Substrate Chromogenic Detection Platform

Miniaturization of nucleic acid tests (NATs) into portable, inexpensive detection platforms may aid disease diagnosis in point-of-care (POC) settings. Colorimetric signals are ideal readouts for portable NATs, and it remains of high demand to develop color readouts that are simple, quantitative, and versatile. Thus motivated, we report a fast light-activated substrate chromogenic polymerase chain reaction (FLASH PCR) that uses DNA intercalating dyes (DIDs) to enable colorimetric nucleic acid detection and quantification. The FLASH system is established on our finding that DID-DNA intercalation can promote the rapid photooxidation of chromogenic substrates through light-induced production of singlet oxygen. Using this principle, we have successfully converted DID-based fluorescent PCR assays into colorimetric FLASH PCR. To demonstrate the practical applicability of FLASH PCR to POC diagnosis, we also fabricated two readout platforms, including a portable electronic FLASH reader and a paper-based FLASH strip. Using the FLASH reader, we were able to detect as low as 60 copies of DNA standards, a limit of detection (LOD) comparable with commercial quantitative PCR. The FLASH strip further enables the reader-free detection of PCR amplicons by converting the colorimetric signal into the visual measurement of distance as a readout. Finally, the practical applicability of the FLASH PCR was demonstrated by the detection and/or quantification of nucleic acid markers in diverse clinical and biological samples.

Simply converting color signal readout into thermal signal readout for breaking the color resolution limitation of colorimetric sensor

Traditional colorimetric sensors often suffer from the low color resolution and the not well-defined boundary between the yes and no answers, especially for distinguishing the similar color readouts with the naked eye. Herein, a simple strategy is communicated for greenly converting colorimetric sensor into a photothermal sensor, which is based on the simple color-to-thermal (temperature) signal readout conversion. The colorimetric system based on simply mixing commercially available chemicals of 3,3,5,5-tetramethylbenzidine (TMB) and silver ions (Ag+), provides a straightforward blue color readout owing to the generation of oxidized TMB (TMBox). In the presence of the target alkaline phosphatase (ALP), ascorbic acid phosphate (AAP) in the system could be hydrolyzed into ascorbic acid (AA), subsequently reducing the blue colored TMBox into colorless TMB. The blue-to-colorless change-based colorimetric system also exhibits the highly sensitive near-infrared (NIR) laser-driven photothermal response, allowing the successful thermometer-detectable signal-based assay for point-of-care testing (POCT) of ALP levels just using a common thermometer. This study not only demonstrated a regulatory strategy to convert color-based signal readout into thermal (temperature)-based signal readout, but also established a facile method to design affordable thermometric sensors for POCT and instrument-free bioanalysis, especially in low-resource settings.

A sequence-specific plasmonic loop-mediated isothermal amplification assay with orthogonal color readouts enabled by CRISPR Cas12a

Herein, we introduce a sequence-specific plasmonic loop-mediated isothermal amplification (LAMP) assay with dual, complementary color readouts enabled by CRISPR Cas12a. Using this assay, any double-stranded LAMP amplicon containing a 5'-TTN PAM sequence can be recognized by Cas12a through a specific CRISPR RNA. The signal transduction is achieved using two orthogonal plasmonic systems mediated by Cas12a.

Color evaluation of a resin cement light polymerized by different light sources and submitted to potentially staining beverages

Abstract Introduction The color stability of resin cements, whether dual-pre-cured or photopolymerizable, as well as the color of the dental substrate, are fundamental for the aesthetic success of ceramic restorations, since the ceramic presents a high level of translucency due to its small thickness. Objective The aim of this in vitro study was to evaluate the color of a resin cement light polymerized by different light sources and immersed in potentially staining beverages. Material and method Were made 42 specimens of resin cement Variolink-Esthetic (2×6mm) (n=7), being half polymerized with LED light (F1) and half with Halogen light (F2). The specimens were stored in artificial saliva at 37 °C±1 °C. After 24 hours, they were polished with abrasive discs, and divided for the purpose of being submitted to the different solutions for 2 minutes per day, for 28 days, as follows: S1 – Coca-Cola; S2 – Red Wine; and S3 – Distilled Water (Control). Five color readouts were taken: T0 – initial; T1 – 7 days; T2 – 14 days; T3 – 21 days; and T4 – 28 days; with a spectrophotometer (Model SP62S). The color change data (ΔE*) were submitted to statistical analysis, ANOVA and Tukey (p≤0.05). Result Analyzing the factor solution, S2 (5.89 (±0.02)), produced a higher ΔE* value than S1 (3.79 (±0.02)) and (S1), a higher value than S3 (1.41 (±0.02)). Analyzing the factor light source, F2 (4.05 (±0.12)), produced a higher ΔE* value than F1 (3.33 (±0.12)). When analyzing the factor time, ΔE* values were found to increase gradually over the course of time: T1(2.36 (±0.08)); T2(3.27 (±0.08)); T3(4.06 (±0.08)); and T4(5.09 (±0.08)). Conclusion It was concluded that red wine produced a greater color change; Halogen light promoted highest degree of pigmentation; and the longer the time of immersion, the greater the color change of the material.

Randomized clinical study of alterations in the color and surface roughness of dental enamel brushed with whitening toothpaste.

This clinical study evaluated the influence of whitening toothpaste on color and surface roughness of dental enamel. Initially, the abrasiveness of the toothpastes used (Sorriso Dentes Brancos [SDB]; Colgate Luminous White and Close up White Now) was tested on 30 (n = 10) plexiglass acrylic plates that were submitted to mechanical tooth brushing totalizing 29,200 cycles. Subsequently, 30 participants were selected, and received a toothbrush and nonwhitening toothpaste (SDB). The participants used these products for 7 days and initial color readouts (Spectrophotometer) and surface roughness of one maxillary central incisors was performed after this period of time. For surface roughness readouts, one replica of the maxillary central incisor was obtained by a polyvinyl siloxane impression material (Express) and polyurethane resin. After baseline measurements, participants were separated into three groups (n = 10), according to the toothpaste used. The participants returned after 7, 30, and 90 days when new color readouts and surface roughness were recorded. The measured values were statistically analyzed (2-way-ANOVA, repeated measures, Tukey, P < .05). Whitening toothpastes did not promote significant (P > .05) color alteration and nor increased the surface roughness of the dental enamel in brushing time of the study. The abrasiveness of whitening toothpaste and the brushing trial period did not affect the surface roughness of dental enamel. However, color changes observed on enamel were above the perceptibility and acceptability thresholds reported in the literature. The over-the-counter toothpastes tested had an effect on dental enamel color above the perceptibility and acceptability thresholds but did not change the surface roughness of the teeth.

Color stability of dental restorative materials submitted to cold temperatures for forensic purposes

In the post-mortem examination of the dental arches of accident victims in cold locations, dental restorative materials can be found. Cold temperatures can be capable of causing color changes of aesthetic materials, such as composite resin (CR) and glass ionomer cement (GIC). The aim of this study was to evaluate the effect of the cold action on the color stability of CR and GIC restorations, in order to discriminate them and enable the adequate comparison between antemortem and post-mortem data. Sixty bovine teeth (30 CR and 30 GIC) were prepared (6 × 6 × 2 mm) and separated into groups (n = 10). The color readouts were taken by a portable spectrophotometer, before and after of cold action (2.5 °C, −20 °C, −80 °C) inside of freezers. There were color alterations in the coordinates (ΔE, ΔL∗, Δa∗ e Δb∗) for both materials. The authors concluded that cold was capable of producing changes in color in the two esthetic materials, with similar intensities between the two, at all the temperatures studied, when analyzed at 7 days. After being submitted to cold for 30 days, the changes were more significant for CR, allowing it to be differentiated from GIC after 30 days, at all the temperatures tested. Therefore, the test proposed in the study was shown to be practical, feasible and capable of helping Forensic Odontology with the identification of victims.

Color Stability of Dental Restorative Materials Submitted to Heat Sources, for Forensic Purposes.

During postmortem examination of the dental arches of carbonized victims, dental restorative materials may be found. The aim of this study was to evaluate the effect of heat source action on the color stability of composite resin (CR) and glass ionomer cement (GIC) restorations, to discriminate between them and compare with antemortem dental data. Sixty bovine teeth (30 CR and 30 GIC) were prepared (6 × 6 × 2 mm) and separated into groups (n = 10). The color readouts were taken by spectrophotometer, before and after heat action (100°C, 200°C, 300°C), in an oven for 15 min. There were color alterations for all coordinates (ΔE, ΔL*, Δa* eΔb*) for both materials. GIC presented greater change. The authors concluded that it is possible to distinguish between the materials by the color changes analyzed by instrumental method, helping victim identification.

Influence of Different Types of Resin Luting Agents on Color Stability of Ceramic Laminate Veneers Subjected to Accelerated Artificial Aging.

The aim of this study was to evaluate the influence of accelerated aging (AAA) on the color stability of resin cements for bonding ceramic laminate veneers of different thicknesses. The occlusal surfaces of 80 healthy human molars were flattened. Ceramic laminate veneers (IPS e-max Ceram) of two thicknesses (0.5 and 1.0 mm) were bonded with three types of luting agents: light-cured, conventional dual and self-adhesive dual cement. Teeth without restorations and cement samples (0.5 mm) were used as control. After initial color evaluations, the samples were subjected to AAA for 580 h. After this, new color readouts were made, and the color stability (ΔE) and luminosity (ΔL) data were analyzed. The greatest color changes (p<0.05) occurred when 0.5 mm veneers were fixed with light-cured cement and the lowest when 1.0 mm veneers were fixed with conventional dual cement. There was no influence of the restoration thickness when the self-adhesive dual cement was used. When veneers were compared with the control groups, it was verified that the cement samples presented the greatest alterations (p<0.05) in comparison with both substrates and restored teeth. Therefore, it was concluded that the thickness of the restoration influences color and luminosity changes for conventional dual and light-cured cements. The changes in self-adhesive cement do not depend on restoration thickness.

Color stability and surface roughness of artificial teeth brushed with an experimental Ricinus communis toothpaste

Aim: To evaluate, in vitro, the effect of brushing with a Ricinus communis-based experimental toothpaste on color stability and surface roughness of artificial teeth. Methods: Ninety artificial teeth (maxillary central incisors) in different shades, light and dark (NatusDent Triple Pressing, Dentbras) were used. Initial color (Spectrophotometer Easyshade, VITA) and surface roughness (Rugosimeter Surfcorder SE 1700, Kosakalab) readouts were performed. After baseline measurements, samples were assigned to 10 groups (n=9) according to the artificial tooth shade and type of toothpaste used during the mechanical brushing test (Pepsodent, MAVTEC): Sorriso Dentes Brancos - SDB, Colgate Luminous White - CLW (Colgate-Palmolive), Close up White Now - CWN (Unilever), Trihydral - THL (Perland Pharmacos) and Ricinus communis - RCE (Experimental). After 29,200 cycles of brushing, corresponding to 2 years of brushing by a healthy individual, new color and roughness readouts of the specimens were performed. Data (before and after the tests) were statistically analyzed (2-way repeated measures ANOVA, Tukey, p 0.05) for any tested toothpaste regardless of tooth shade. Conclusions: The experimental Ricinus communis toothpaste did not cause color and surface roughness alteration in the artificial teeth, and it may be considered a suitable option for denture cleaning.

Effect of Brushing Time and Dentifrice Abrasiveness on Color Change and Surface Roughness of Resin Composites.

Dentifrice abrasiveness and brushing time may increase color change (∆E) and surface roughness (∆Ra) of resin composites. This study aimed to evaluate the effect of mechanical brushing time of dentifrices with different abrasiveness on ∆E and ∆Ra of nanofilled (Z350, 3M ESPE) and nanohybrid (Tetric N-Ceram, Ivoclar Vivadent) resin composites. Sixteen specimens (12 mm diameter x 2 mm thick) were fabricated using a white Teflon matrix of each resin composite and a ceramic (IPS e.max Ceram, Ivoclar Vivadent), used as control. After initial color readouts on white backgrounds (Spectrophotometer PCB 6807, Byk Gardner), with D65 standard illuminant, and surface roughness (Rugosimeter Surfcorder SE 1700, Kosalab) with cut-off=0.8 mm and speed=0.25 mm/s, specimens were assigned (n=8) according to the abrasiveness of the dentifrices: RDA* 68 (Colgate) and RDA* 180 (Colgate Total Plus Whitening). Specimens were submitted to mechanical brushing (58,400 cycles) and after every 14,600 cycles (1 year of brushing by a healthy individual), new color and surface roughness readouts were taken. Color stability was calculated by CIEDE2000. Data were analyzed by 3-way repeated measures ANOVA and Bonferroni test (p<0.05), and demonstrated that the dentifrice abrasiveness (p=0.02) and brushing time (p<0.0001) affected the ∆E of nanofilled resin composite. There was no difference on surface roughness of materials (p=0.6752) or brushing time (p=0.7997). In conclusion, the longer the brushing time and dentifrice abrasiveness, the greater the color change of the nanofilled resin composite. The surface roughness was not influenced by dentifrice abrasiveness.

Color stability of experimental composites containing different photoinitiators

ObjectivesTo evaluate the color stability (ΔE) of experimental composites containing different photoinitiators when submitted to accelerated artificial ageing (AAA). Material and methodsThirty test specimens were made in a Teflon matrix (8mm×2mm), using an experimental composite (n=10) with the same monomer composition and particle size, but varying photoinitiator used: Group CQ (0.4% Camphorquinone), Group PPD (0.4% 1-Phenyl-1,2 Propanodione) and Group CQ+PPD (0.2% CQ+0.2% PPD). The samples were light activated (QTH – Ultralux – Dabi Atlante – 40s) and polished before performing the initial color readouts (EasyShade – Vita). Next, they were submitted to AAA for 300h, after which final color readouts were made. ResultsThe results (1-way ANOVA – Tukey – p<0.05) demonstrated that all the groups presented color alteration above the clinically acceptable level (ΔE≥3.3), however, with no statistically significant difference among them (p>0.05). Analysis of Δb demonstrated increase in the values of this coordinate, indicating yellowing in all groups. ConclusionsIt was concluded that the type of photoinitiator, which presented a tendency towards yellowing, did not interfere in the color stability of composites submitted to AAA. Clinical significanceAlternative photoinitiators have been extensively studied since Camphorquinone presents a yellowish color, which compromises the aesthetic performance of composites, especially the lighter-shade ones.

Staining susceptibility of new calcium aluminate cement (EndoBinder) in teeth: a 1‐year in vitro study

To evaluate the staining susceptibility of new calcium aluminate cement (EndoBinder, EB) in teeth, with or without radiopacifying agent, in comparison with mineral trioxide aggregate (MTA). Forty bovine incisors were used. After biomechanical preparation and filling, 2 mm of their fillings were removed for cervical plug fabrication (n = 10): EB without radiopacifier; EndoBinder + Bismuth Oxide (EBBO); Gray mineral trioxide aggregate (GMTA) and White mineral trioxide aggregate (WMTA). After teeth restoration, initial color readout was taken (Easyshade - CIE Lab) on the vestibular face. The teeth were stored in artificial saliva at 37°C for 1 year, and after time intervals of 30, 180, and 360 days, new color readouts were taken to determine color alteration (ΔE) in comparison with the initial readout (baseline). The results (2-way anova repeated measures, Bonferroni - P < 0.05) demonstrated that after 360 days, all groups presented ΔE above the clinically accepted limit (ΔE ≥ 3.3), however, without significant difference among them (P > 0.05). All groups presented decrease in ΔL values over the course of time, and the greatest variation occurred for WMTA, with significant difference in comparison with EB and EBBO (P < 0.05). Some negative features of MTA, such as the high incidence of dental structures staining justify the development of new materials. GMTA, WMTA, and EB with and without radiopacifying agent displayed color alteration (ΔE) after 360 days; however, the luminosity change (ΔL) was lower in EB in comparison with GMTA and WMTA.

Color stability of modern composites subjected to different periods of accelerated artificial aging

The aim of this study was to evaluate the color stability of composites subjected to different periods of accelerated artificial aging (AAA). A polytetrafluorethylene matrix (10 x 2 mm) was used to fabricate 24 test specimens of three different composites (n=8): Tetric Ceram (Ivoclar/Vivadent); Filtek P90 and Z250 (3M ESPE), shade A3. After light activation for 20 s (FlashLite 1401), polishing and initial color readout (Spectrophotometer PCB 687; BYK Gardner), the test specimens were subjected to AAA (C-UV; Comexim), in 8-h cycles: 4 h exposure to UV-B rays at 50°C and 4 h condensation at 50°C. At the end of each cycle, color readouts were taken and the test ended when the mean value of ΔE attained a level ≥3.30. Tetric Ceram presented alteration in ΔE equal to 3.33 in the first aging cycle. For Filtek P90 and Z250, two (ΔE=3.60) and four (ΔE=3.42) AAA cycles were necessary. After each cycle, there was a reduction of luminosity in all the samples (ΔL). It was concluded that a short period of AAA was sufficient to promote clinically unacceptable color alteration in composites, and that this alteration was material-dependent.

A 1536 Colorimetric SPAP Reporter Assay: Comparison with 96- and 384-Well Formats

We report the successful miniaturization of a functional cell-based reporter gene assay. Utilizing interleukin-1beta (IL-1/β)-induced secreted placental alkaline phosphatase (SPAP)-catalyzed colorimetric readout, we reduced the assay volume to 10 μl using a Greiner 1536-well microplate. Our experiences of assay development, liquid handling (using a Hydra® 96; Robbins Scientific, Sunnyvale, CA), and detection (using the SpectraImage and SpectraFluor-Plus plate readers, Tecan Austria GmbH, Grodig, Austria) in 1536 wells are discussed. The effect of a set of 1,280 compounds in this SPAP reporter assay were compared between 96-, 384-, and 1536-well formats and were shown to be very similar. We conclude that cell-based reporter gene assays using SPAP-catalyzed color readouts are sensitive and highly reproducible in 1536-well plates and should be considered as a cost-effective alternative to luciferase reporters for miniaturized assay formats. Finally, we review the prospects for the implementation of routine HTS in 1536-well plates based around the instrumentation investigated.

An Analysis of Digitally Processed Color Readouts from Scintillation Cameras and Scanners

The application of nuclear engineering discussed in this paper relates to digital processing of images formed by the detection of gamma radiation retained in various organs in the body after the injection of radio-pharmaceuticals. These images are presented in a color photograph display to aid diagnosis and minimize system artifacts.