Machine learning models to predict submucosal invasion in early gastric cancer based on endoscopy features and standardized color metrics

Conventional endoscopy is widely used in the diagnosis of early gastric cancers (EGCs), but the graphical features were loosely defined and dependent on endoscopists' experience. We aim to establish a more accurate predictive model for infiltration depth of early gastric cancer including a standardized colorimetric system, which demonstrates promising clinical implication. A retrospective study of 718 EGC cases was performed. Clinical and pathological characteristics were included, and Commission Internationale de l'Eclariage (CIE) standard colorimetric system was used to evaluate the chromaticity of lesions. The predicting models were established in the derivation set using multivariate backward stepwise logistic regression, decision tree model, and random forest model. Logistic regression shows location, macroscopic type, length, marked margin elevation, WLI color difference and histological type are factors significantly independently associated with infiltration depth. In the decision tree model, margin elevation, lesion located in the lower 1/3 part, WLI a*color value, b*color value, and abnormal thickness in enhanced CT were selected, which achieved an AUROC of 0.810. A random forest model was established presenting the importance of each feature with an accuracy of 0.80, and an AUROC of 0.844. Quantified color metrics can improve the diagnostic precision in the invasion depth of EGC. We have developed a nomogram model using logistic regression and machine learning algorithms were also explored, which turned out to be helpful in decision-making progress.

L-Menthol for Color Difference Change Between Early Gastric Cancer and Surrounding Mucosa: A Prospective Study

BACKGROUND

L-Menthol sprayed on early gastric cancer (EGC) has been reported to improve the visibility of the lesion. However, its impact when used in combination with novel image-enhanced endoscopy has not been investigated.

AIM

This study aimed to evaluate the visual effect of spraying L-menthol on EGC under linked color imaging (LCI).

METHODS

This open-label, single-arm, prospective study investigated the color difference between EGC and the surrounding mucosa (ΔEG) before and after spraying L-menthol. The primary endpoint was the percentage of lesions with ΔEG ≥ 5 on LCI. The percentage of lesions with ΔEG  ≥ 5 on white light imaging (WLI) and blue laser imaging (BLI), ΔEG before and after spraying L-menthol, and percentage of lesions with increased ΔEG after spraying L-menthol constituted the secondary endpoints.

RESULTS

Sixty patients were included in the final analysis. 100% lesions had ΔEG ≥ 5, both before and after spraying L-menthol on LCI, with similar results observed in WLI as well as BLI. The median ΔEG on LCI, WLI, and BLI increased after spraying L-menthol (LCI: 16.9 vs. 21.5, p < 0.01; WLI: 10.4 vs. 13.4, p < 0.01; BLI; 12.1 vs. 15.7, before and after, respectively, p < 0.01); and LCI demonstrated the highest percentage of lesions with increased ΔEG (LCI, WLI, and BLI: 98.3%, 81.7%, and 76.7%, respectively, p < 0.01).

CONCLUSION

Although spraying L-menthol did not improve the visibility of EGC under LCI observation, a significant increase in ΔEG was observed in LCI (jRCTs 021200027).

Color difference for shade determination with visual and instrumental methods: a systematic review and meta-analysis

BACKGROUND

Shade determination is a critical step for the fabrication of a satisfactory restoration. Visual shade selection with conventional shade guides is subjective and influenced by variables related to light, observer, and object. Shade selection devices have been introduced to provide subjective and quantitative shade values. This systematic review and meta-analysis aimed to compare the color difference for shade selection with visual and instrumental methods.

METHODS

An initial search was conducted on databases (MEDLINE via PubMed, Scopus, and Web of Science) in addition to a manual search through references of identified articles. Studies comparing the accuracy of visual and instrumental shade selection based on ΔΕ were included in data synthesis. Mean differences (MDs) and 95% confidence intervals (CIs) were calculated to estimate the effect size for global and subgroup meta-analysis using the inverse variance weighted method and random-effects model (P ˂ 0.05). Results were presented as forest plots.

RESULTS

The authors identified 1776 articles from the initial search. Seven in vivo studies were included in the qualitative analysis of which six studies were included in the meta-analysis. For the global meta-analysis, the pooled mean (95% CI) was - 1.10 (- 1.92, - 0.27). Test for overall effect showed that instrumental methods were significantly more accurate than visual methods with significantly less ΔΕ (P = 0.009). Test for subgroup difference showed that the type of instrumental shade selection method used had a significant effect on accuracy (P ˂ 0.001). Instrumental methods including spectrophotometer, digital camera, and smartphone showed significantly better accuracy compared with visual shade selection (P ˂ 0.05). The greatest mean difference was found between the smartphone and visual method with a mean (95% CI) of - 2.98 (- 3.37, - 2.59) with P ˂ 0.001 followed by digital camera and spectrophotometer. There was no significant difference in accuracy between IOS and visual shade selection (P = 1.00).

CONCLUSIONS

Instrumental shade selection with a spectrophotometer, digital camera, and smartphone showed significantly better shade matching compared with a conventional shade guide, whereas IOS did not improve the shade matching significantly compared with shade guides.

REVIEW REGISTRATION

PROSPERO CRD42022356545.

Linked color imaging vs Lugol chromoendoscopy for esophageal squamous cell cancer and precancerous lesion screening: A noninferiority study

BACKGROUND

Lugol chromoendoscopy (LCE) has served as a standard screening technique in high-risk patients with esophageal cancer. Nevertheless, LCE is not suitable for general population screening given its side effects. Linked color imaging (LCI) is a novel image-enhanced endoscopic technique that can distinguish subtle diff-erences in mucosal color.

AIM

To compare the diagnostic performance of LCI with LCE in detecting esophageal squamous cell cancer and precancerous lesions and to evaluate whether LCE can be replaced by LCI in detecting esophageal neoplastic lesions.

METHODS

In this prospective study, we enrolled 543 patients who underwent white light imaging (WLI), LCI and LCE successively. We compared the sensitivity and specificity of LCI and LCE in the detection of esophageal neoplastic lesions. Clinicopathological features and color analysis of lesions were assessed.

RESULTS

In total, 43 patients (45 neoplastic lesions) were analyzed. Among them, 36 patients (38 neoplastic lesions) were diagnosed with LCI, and 39 patients (41 neoplastic lesions) were diagnosed with LCE. The sensitivity of LCI was similar to that of LCE (83.7% vs 90.7%, P = 0.520), whereas the specificity of LCI was greater than that of LCE (92.4% vs 87.0%, P = 0.007). The LCI procedure time in the esophageal examination was significantly shorter than that of LCE [42 (34, 50) s vs 160 (130, 189) s, P < 0.001]. The color difference between the lesion and surrounding mucosa in LCI was significantly greater than that observed with WLI. However, the color difference in LCI was similar in different pathological types of esophageal squamous cell cancer.

CONCLUSION

LCI offers greater specificity than LCE in the detection of esophageal squamous cell cancer and precancerous lesions, and LCI represents a promising screening strategy for general populations.

Linked color imaging provides enhanced visibility with a high color difference in upper gastrointestinal neoplasms

BACKGROUND AND AIM

The aim of this post-hoc analysis in a randomized, controlled, multicenter trial was to evaluate the visibility of upper gastrointestinal (UGI) neoplasms detected using linked color imaging (LCI) compared with those detected using white light imaging (WLI).

METHODS

The visibility of the detected UGI neoplasm images obtained using both WLI and LCI was subjectively reviewed, and the median color difference (ΔE) between each lesion and the surrounding mucosa according to the CIE L*a*b* color space was evaluated objectively. Multivariate logistic regression analysis was performed to identify factors associated with neoplasms that were missed under WLI and detected under LCI.

RESULTS

A total of 120 neoplasms, including 10, 32, and 78 neoplasms in the pharynx, esophagus, and stomach, respectively, were analyzed in this study. LCI enhanced the visibility 80.9% and 93.6% of neoplasms in pharynx/esophagus and stomach compared with WLI, respectively. LCI also achieved a higher ΔE of enhanced neoplasms compared with WLI in the pharynx/esophagus and stomach. The median WLI ΔE values for gastric neoplasms missed under WLI and later detected under LCI were significantly lower than those for gastric neoplasms detected under WLI (8.2 vs 9.6, respectively). Furthermore, low levels of WLI ΔE (odds ratio [OR], 7.215) and high levels of LCI ΔE (OR, 22.202) were significantly associated with gastric neoplasms missed under WLI and later detected under LCI.

CONCLUSION

Color differences were independently associated with missing gastric neoplasms under WLI, suggesting that LCI has an obvious advantage over WLI in enhancing neoplastic visibility.

Effect of thickness on color appearance of multilayer CAD/CAM composite resin blocks

The aim of this study was to evaluate the effect of thickness on the color appearance and translucency parameter (TP) of multilayer CAD/CAM composite resin blocks. Four brands of A3-shade multilayer CAD/CAM composite resin blocks were examined (Katana Avencia, CERASMART Multi, KZR-CAD HR Block 4 E-va, and Block HC Hard AN). Six specimens of five thicknesses were prepared for each brand, yielding 120 specimens in total. CIEL*a*b* values were determined using a spectrophotometer against black and white backgrounds, and the TP was calculated. The color differences (ΔE₀₀) between layers (cervical/middle/incisal) and brands for each thickness against the black background were calculated using the CIEDE2000 system. As a result, on the black background, L* of the incisal layer was greater while a* and b* were smaller than those of the cervical layer for all brands. The ΔE₀₀ values between the cervical and middle layers (1.23-3.27) were smaller than those between the cervical and incisal layers (3.98-5.67) and those between the middle and incisal layers (3.14-5.92). TP decreased with increasing block thickness. Some TP differences between layers were significant, but they were less than 2.75. In conclusion, the color appearance of CAD/CAM blocks was significantly influenced by both the thickness and layer. L*a*b* decreased with thickness, and a negative exponential relationship between TP and thickness was observed for all layers and brands.

Optical properties evaluation of rapid sintered translucent zirconia with two dental colorimeters

Background/purpose

The efficient rapid sintering technique has employed to dental zirconia ceramics for shortening the fabrication time of zirconia restorations. The purpose was to compare the optical properties of two generations of rapid sintered translucent zirconia using two dental colorimeters.

Materials and methods

Two generations of translucent zirconia ceramics, 3 mol% yttria-tetragonal zirconia polycrystal (3Y-TZP): Copran Zr-i Ultra-T (UT) and Cercon HT (HT), and 5 mol% yttria-tetragonal zirconia polycrystal (5Y-TZP): Cercon xt (XT), of different thicknesses (0.5, 0.8, and 1.2 mm; n = 5) underwent rapid sintering (RS) or conventional sintering (CS). The CIELAB values were measured on the white and black backgrounds, respectively, by digital colorimeters, shadepilot, DeguDent (DD) and Easyshade V, Vita (Vita). Translucency parameter (TP), color difference (ΔE), surface morphology, and surface roughness were evaluated.

Results

RS resulted in reduced lightness, except in the XT group. The chromaticity increased slightly after RS. Translucency decreased with increasing material thickness. ΔE values differed between both sintering processes but were clinically acceptable (ΔE < 5). Grain size of XT decreased after RS. RS did not affect the surface roughness.

Conclusion

RS is a feasible method for shortening the manufacturing time of zirconia restorations. A significant difference in TP value was only in the XT group between both sintering methods as measured on DD. Color differences in rapid sintered translucent zirconia materials are imperceptible and acceptable. The specimen thickness affected more in the TP values of Vita than DD. DD has higher sensitivity to translucency and color compared with Vita.

[Effects of Three Illuminants on the Color of High Translucent Multilayered Zirconia]

OBJECTIVE

To evaluate the effects of three common illuminants on the color of four brands of high translucent multilayered zirconia (HTMZ) ceramics so as to provide reference for clinical practice and dental restoration fabrication, and to reduce the risks for illuminant change causing color mismatch between the natural teeth and the restorations made of HTMZ.

METHODS

Four brands of commonly used HTMZ were selected and ten cuboid samples ( n=10/group) of 12 mm×10 mm×0.8 mm were prepared for each type of HTMZ. The L*, a*, and b* values of the samples were measured under D65, A and F2, three standard illuminants. Then, the L*, a*, and b* values were statistically analyzed by using factors of the type of the illuminant and the brand of the zirconia. Color difference (ΔE) of samples of the same brand under exposure to changed illuminants was also calculated.

RESULTS

When the same samples were exposure to different illuminants, there was no significant difference in the L* value, the a* value for the different iluminants was shown to be illuminant A>illuminant F2>illuminant D65, and the b* value was shown to be illuminant F2>illuminant D65>illuminant A. The L*, a*, and b* values of samples of different brands showed statistically significant difference when they were exposed to the same illuminant ( P<0.0001). Samples of the same brand showed ΔE when they were under the three different illuninants, and all ΔE were clinically acceptable.

CONCLUSION

The types of illuminant used, to a certain degree, affected the hue and chroma of HTMZ. There were colorimetric differences between restorations made of different brands of HTMZ ceramics of the same color. The types of illuminants most common to the daily life of patients and the color characteristics of materials of different brands should be taken into consideration to facilitate the selection of restoration materials and dental restoration fabrication, and to reduce the risks for color mismatch between the restorations and the adjacent teeth caused by the change of illuminants.

Effectiveness of L-Menthol Spray Application on Lesions for the Endoscopic Clarification of Early Gastric Cancer: Evaluation by the Color Difference

INTRODUCTION

Although L-menthol spray application on lesions has been shown to be effective for the endoscopic clarification of early gastric cancer (EGC), the currently available data are all based on subjective evaluations.

OBJECTIVES

This study was aimed to objectively evaluate the effectiveness of L-menthol spray for the endoscopic classification of EGC.

METHODS

Patients with EGC treated by endoscopic submucosal dissection were included. Images taken by white light imaging (WLI) and narrow band imaging (NBI) before and after spraying L-menthol directly on a lesion were saved. The primary endpoint was a change in the color difference between the EGC lesion and surrounding mucosa (ΔExy) before and after L-menthol spray application. The secondary endpoints were patient factors related to the change in ΔExy after L-menthol spray application and the pathological findings.

RESULTS

Fifty cases of EGC were included in the analysis. The median ΔExy was significantly larger after L-menthol spray application than before, as assessed by either WLI (p <0.001) or NBI (p < 0.001). An increased ΔExy after L-menthol spray application was noted in 76 and 92% of patients by WLI and NBI, respectively. The percentage of patients with a ΔExy ≥5 (a level distinguishable by human eyes) was significantly larger after L-menthol spray application either by WLI (p <0.001) or NBI (p < 0.001). Pathologically, mucosal vasodilatation and stromal edema were noted after L-menthol spray application in the evaluated 2 cases.

CONCLUSIONS

These results objectively demonstrate that L-menthol provides benefits in the endoscopic clarification of EGC.

Widely targeted metabolomics analysis of white peony teas with different storage time and association with sensory attributes

The sensory features of white peony teas (WPTs) significantly change with storage age; however, their comprehensive associations with composition are still unclear. This study aimed to clarify the sensory quality-related chemical changes in WPTs during storage. Liquid chromatography-tandem mass spectrometry based on widely targeted metabolomics analysis was performed on WPTs of 1-13 years storage ages. Weighted gene co-expression network analysis (WGCNA) was used to correlate metabolites with sensory traits including color difference values and taste attributes. 323 sensory trait-related metabolites were obtained from six key modules via WGCNA, verified by multiple factor analysis. The decline and transformation of abundant flavonoids, tannins and amino acids were related to the reduced astringency, umami and increased browning of tea infusions. In contrast, the total contents of phenolic acids and organic acids increased with storage. This study provides a high-throughput method for the association of chemical compounds with various sensory traits of foods.

Gender-Dependent Quality of Shade Matching of Dental Professionals and Students

Objectives

The purpose of this study was to evaluate shade matching ability of dental professionals and students using the VITA 3D-Master shade guide.

Materials and methods

A hundred and twenty participants have been assigned to one of four groups as follows: specialists in prosthodontics (SPs), residents in prosthodontics (RPs), dental technicians (DTs) and dental students (DSs). The Toothguide Training Box (TTB) was used to test the participants' shade-matching ability based on using 3 exercises and a final test. The mistakes were recorded during the exercises and mistake ratios (MR) were calculated. Time, scores, and color difference values (ΔE) were recorded and calculated. The one-way ANOVA was used to analyze the differences, and multiple regression analyses were used to evaluate the relationship in mean MRs, time, score and ΔE values between the groups.

Results

Male participants needed significantly greater amount of time than females to complete the final test (P<0.05). Male SPs achieved a significantly lower percentage of mistake ratios in second exercise than RPs (P<0.05), needed significantly less time than DSs to complete the final test and achieved significantly higher scores than RPs (P<0.05). Female SPs assessed the highest and DSs and RPs the lowest color differences (P<0.05). The results obtained from the exercises and final tests highly affected the amount of estimated color difference in both male and female groups (by 78% and 76%, respectively).

Conclusions

Within the population tested, gender of the participants showed a significant impact on quality of shade matching of dental professionals and students.

Infrared drying effects on the quality of eggplant slices and process optimization using response surface methodology

The aim of this work was to study the effect of thickness of samples, air velocity and infrared power on the drying kinetics and quality attributes of blanched eggplant slices during infrared drying. The drying experiments were made by Response Surface Methodology (RSM) based on a Box-Behnken design (BBD). Experiments were conducted at a thickness of 3, 5, and 7 mm, air velocity of 0.5, 1.25, and 2 m/s, as well as at infrared power 1000, 1500, and 2000 W. The drying time was affected by operating parameters. The drying processes increased total phenolic content and potassium content, significantly. The total color difference (ΔE) was in the range of 10.22-25.14. In the end, this process was optimized for reaching the best experimental condition.

Linked color imaging improves visibility of reflux esophagitis

Background

With more prevalent gastroesophageal reflux disease comes increased cases of Barrett's esophagus and esophageal adenocarcinoma. Image-enhanced endoscopy using linked-color imaging (LCI) differentiates between mucosal colors. We compared LCI, white light imaging (WLI), and blue LASER imaging (BLI) in diagnosing reflux esophagitis (RE).

Methods

Consecutive RE patients (modified Los Angeles [LA] classification system) who underwent esophagogastroduodenoscopy using WLI, LCI, and BLI between April 2017 and March 2019 were selected retrospectively. Ten endoscopists compared WLI with LCI or BLI using 142 images from 142 patients. Visibility changes were scored by endoscopists as follows: 5, improved; 4, somewhat improved; 3, equivalent; 2, somewhat decreased; and 1, decreased. For total scores, 40 points was considered improved visibility, 21–39 points was comparable to white light, and < 20 points equaled decreased visibility. Inter- and intra-rater reliabilities (Intra-class Correlation Coefficient [ICC]) were also evaluated. Images showing color differences (ΔE*) and L* a* b* color values in RE and adjacent esophageal mucosae were assessed using CIELAB, a color space system.

Results

The mean age of patients was 67.1 years (range: 27–89; 63 males, 79 females). RE LA grades observed included 52 M, 52 A, 24 B, 11 C, and 3 D. Compared with WLI, all RE cases showed improved visibility: 28.2% (40/142), LA grade M: 19.2% (10/52), LA grade A: 34.6% (18/52), LA grade B: 37.5% (9/24), LA grade C: 27.3% (3/11), and LA grade D: 0% (0/3) in LCI, and for all RE cases: 0% in BLI. LCI was not associated with decreased visibility. The LCI inter-rater reliability was “moderate” for LA grade M and “substantial” for erosive RE. The LCI intra-rater reliability was “moderate–substantial” for trainees and experts. Color differences were WLI: 12.3, LCI: 22.7 in LA grade M; and WLI: 18.2, LCI: 31.9 in erosive RE (P < 0.001 for WLI vs. LCI).

Conclusion

LCI versus WLI and BLI led to improved visibility for RE after subjective and objective evaluations. Visibility and the ICC for minimal change esophagitis were lower than for erosive RE for LCI. With LCI, RE images contrasting better with the surrounding esophageal mucosa were more clearly viewed.

The Color Difference between Differentiated Early Gastric Cancer and Suspicious Mucosal Areas on Linked Color Imaging

BACKGROUND

Image enhanced endoscopy (IEE) contributes to the early detection of gastrointestinal cancer. IEE enhances the color between a lesion and the background mucosa. Linked color imaging (LCI), a novel form of IEE, is a unique system for enhancing color and some studies have demonstrated the efficacy of LCI in the diagnosis of early gastric cancer (EGC) based on the color difference between cancer and the background mucosa. However, the effect may increase the area in which cancer is suspected and lead to an increase in false-positive results.

SUMMARY

We conducted a retrospective study of linked color images of differentiated EGC and suspicious mucosal areas to compare the colors between each lesion. Images of 38 EGCs and 23 suspicious areas were analyzed. The mean color values of EGC were as follows; L*(lightness), 61.7; a*(green to red), 41.2; and b*(blue to yellow), 27.1. Those of suspicious mucosal areas were as follows; L*, 56.1; a*, 44.2; and b*, 21.3. EGC had significantly higher L*, b* values and lower a* values in comparison to suspicious mucosal areas. EGC and suspicious mucosal areas had significantly higher a* values in comparison to the background mucosa. Key Messages: EGC had higher b* values in comparison to suspicious mucosal areas, and was not only reddish but also mixed with yellow, with an orange-like color.

How to objectively determine the color of beer?

Beer color is an important sensory attribute, the first one that the consumer observes. There are two standard methods accepted for determining the color of these products, one related to the European Brewery Convention (EBC) and the other is the Standard Reference Method (SRM). Both methods are based on absorbance, but in case of the more and more popular fruit beers these methods give false result since these products appear in varied colors and have different spectra than regular beers. In this study 39 different types of beers were investigated, including fruit beers and beer based mixed drinks to compare their color in CIE 1976 L*a*b* color space, absorption-based colors and transmission spectra. ΔE*_ab values of products with less than 5% EBC difference ranged from 4.5 to 17.4. There were magnitude differences in the transmission spectra of these products, fruit beers showed different tendencies due to the added fruit or fruit juice. The highest ΔE*_ab value belonged to two traditional Weissbiers. Absorption-based methods are not able in many cases to differentiate between products which have nearly the same EBC or SRM color but visually are different. A multi-wavelength method would be reasonable to be developed for more objective and accurate beer color determination.

Linked color imaging can enhance recognition of early gastric cancer by high color contrast to surrounding gastric intestinal metaplasia

BACKGROUND

Linked color imaging (LCI) increases the visibility of early gastric cancers, which may be associated with characteristic findings including background purple mucosae. These lesions are found in areas of chronic gastritis and surrounding mucosa. The aim of this study is to objectively characterize these lesions by color differences and color component values using LCI.

METHODS

Fifty-two patients with early gastric cancer were enrolled. Color differences were calculated prospectively in malignant lesions and adjacent mucosa and compared with histological findings in resected specimens. Color component values of L*, a*, and b* were compared between purple and non-purple mucosae in areas of chronic gastritis. Based on histological findings, the accuracy of identifying gastric intestinal metaplasia was calculated.

RESULTS

Cancers and surrounding mucosa in 74% of lesions had similar colors using white light imaging (WLI), whereas purple mucosa surrounded part or all of cancers appearing orange-red, orange or orange-white using LCI. Greater color differences were seen using LCI compared to WLI, including flat-type cancers, leading to higher contrast. The surrounding purple mucosa corresponded histologically to intestinal metaplasia, facilitating the identification of malignant lesions. Forty lesions (83%) with purple mucosa and eight lesions (17%) with non-purple mucosa in areas of chronic gastritis were diagnosed as intestinal metaplasia by biopsy (83% accuracy). Color component values of purple mucosa differ significantly from those of non-purple mucosae.

CONCLUSIONS

LCI images have higher color contrast between early gastric cancers and surrounding mucosa compared to WLI. A characteristic purple color around gastric cancers using LCI represents intestinal metaplasia.

[Optical properties of computer aided design and computer aided manufactured materials for veneer restorations]

Objective: To investigate the translucency parameters (TP) and the color parameters of computer-aided design and computer-aided manufacturing (CAD/CAM) materials for veneer restorations in order to guide clinical practice. Methods: Eleven groups of CAD/CAM materials (A2 shade) were included in this study: IPS e.max CAD HT/LT, IPS Empress CAD HT/LT, Lava(TM) Ultimate HT/LT, VITA SUPRINITY HT/T, VITA ENAMIC HT/T, VITABLOCS Mark Ⅱ, and were named as Group A, B, C, D, E, F, G, H, I, J, K. Each material was designed and milled to disk-shaped specimens (10.0 mm×8.0 mm×0.7 mm) (n=6). The specimens were polished with silicon carbide paper and the thickness of specimens were adjusted into (0.60±0.03) mm. The color parameters of specimens were individually measured with the colorimeter against black and white ceramic tiles background to obtain the TP values. The color parameters of the specimens against the composite resin background were also measured and the color differences (ΔE values) between specimens and the A2 shade tab were calculated. Results: One-way ANOVA showed that the translucency parameters of the 11 groups of materials were statistically significant (F=253.69, P<0.05). The ΔE values of CAD/CAM material groups ranged from 1.78 to 4.12 (ΔE values<5.5). Conclusions: The microstructure of CAD/CAM materials and the types of material translucency influence the optical properties. The CAD/CAM materials in this experiment have achieved color matching with the A2 shade tab.

Utility of linked color imaging for endoscopic diagnosis of early gastric cancer

BACKGROUND

Linked color imaging (LCI) is a method of endoscopic imaging that emphasizes slight differences in red mucosal color.

AIM

To evaluate LCI in diagnostic endoscopy of early gastric cancer and to compare LCI and pathological findings.

METHODS

Endoscopic images were obtained for 39 patients (43 lesions) with early gastric cancer. Three endoscopists evaluated lesion recognition with white light imaging (WLI) and LCI. Color values in Commission Internationale de l'Eclairage (CIE) 1976 L*a*b* color space were used to calculate the color difference (ΔE) between cancer lesions and non-cancer areas. After endoscopic submucosal dissection, blood vessel density in the surface layer of the gastric epithelium was evaluated pathologically. The identical region of interest was selected for analyses of endoscopic images (WLI and LCI) and pathological analyses.

RESULTS

LCI was superior for lesion recognition (P < 0.0001), and ΔE between cancer and non-cancer areas was significantly greater with LCI than WLI (29.4 vs 18.6, P < 0.0001). Blood vessel density was significantly higher in cancer lesions (5.96% vs 4.15%, P = 0.0004). An a* cut-off of ≥ 24 in CIE 1976 L*a*b* color space identified a cancer lesion using LCI with sensitivity of 76.7%, specificity of 93.0%, and accuracy of 84.9%.

CONCLUSION

LCI is more effective for recognition of early gastric cancer compared to WLI as a result of improved visualization of changes in redness. Surface blood vessel density was significantly higher in cancer lesions, and this result is consistent with LCI image analysis.

The influence of different shades and brands of resin-based luting agents on the final color of leucite-reinforced veneering ceramic

Objectives

This study aimed to evaluate the influence of different shades and brands of resin-based luting agents on the final color of a leucite-reinforced veneering ceramic.

Methods

This in-vitro study was done on 36 ceramic discs (IPS Empress I, 11 × 0.5 mm, A2 shade) and 36 cement disks (11 × 0.2 mm) made of Panavia SA Cement Plus (Kuraray Medical Inc.) and Choice2 (Bisco Inc., Schumburg) brands in translucent, universal A2, and opaque shades (n = 6 per each color in each resin cement brand). Color parameters (CIEL^*a^*b^*) of ceramic specimens were calculated without and with each brand/shade of resin-based luting agents by using a spectrophotometer, and put into CIELab formula. The color differences (ΔE) between the two sets of measurements were calculated and analyzed with two-way ANOVA and Tukey’s post hoc test (α = 0.05).

Results

Both the resin-based luting agent shade (P < 0.001) and brand (P = 0.023) significantly affected the color differences. ΔE values were significantly different between Panavia-opaque and Choice2-opaque (P < 0.001). No significant difference existed between ΔE of the two brands in A2 (P = 0.178) and translucent shades (P = 0.079). The ΔE values of Panavia-A2 was significantly different from the translucent and opaque shades of the same brand. Moreover, the ΔE of Choice2-translucent shade was significantly lower than that of A2 and opaque shades. The ΔE values were higher than the clinically-acceptable threshold in all groups (ΔE > 3.7) except for Choice2-translucent (ΔE = 3.37).

Conclusions

The final color of leucite-reinforced veneering ceramic can be affected by the same shades of resin-based luting agents from different brands and different shades of resin-based luting agents from the same brand.

Color stability of different composite resins after polishing

The goals of the present study were to evaluate, in vitro, the staining of different composite resins submitted to different common beverages, and to compare the staining effect of each of these solutions. A total of 288 specimens were randomly divided into six groups and immersed for 4 weeks in five staining solutions represented by red wine, orange juice, coke, tea and coffee or in artificial saliva as a control group. When analyzed over a black background, mean ΔE00 values varied from 0.8 for Venus Diamond, Saremco Microhybrid and ELS in saliva and Estelite Posterior in coke to 37.6 for Filtek Supreme in red wine. When analyzed over a white background, mean ΔE00 values varied from 0.5 for Saremco Microhybrid in saliva to 51.1 for Filtek Supreme in red wine. All materials showed significant changes in color after 4 weeks of immersion in staining solutions. Significant differences were found between the tested composite resins and also between the staining solutions.

Linked color imaging improves the visibility of various featured colorectal polyps in an endoscopist's visibility and color difference value

PURPOSE

Linked color imaging (LCI) by laser endoscopy is a novel narrow band light observation. In this study, we analyzed the efficacy of LCI for improving the various featured colorectal polyp's visibility utilizing a subjective endoscopist's visibility scoring and objective color difference (CD) value.

METHODS

We retrospectively reviewed two pictures both with white light (WL) and LCI for 54 consecutive neoplastic polyps 2-20 mm in size. All pictures were evaluated by four endoscopists according to a published polyp visibility score from four (excellent visibility) to one (poor visibility). Additionally, we calculated CD value between each polyp and surrounding mucosa in LCI and WL using an original software.

RESULTS

The mean polyp visibility scores of LCI (3.11 ± 1.05) were significantly higher than those of WL (2.50 ± 1.09, P < 0.001). The ratio of an endoscopist's poor visibility (polyp visibility scores 1 and 2) was significantly lower in LCI (27.9%) than WL (55.6%, P < 0.001). With respect to the CD analysis, the CD value of LCI was significantly higher than that of WL (33.3 ± 13.9 vs. 20.7 ± 13.6, P < 0.001). In a subgroup analysis, the polyp visibility scores and CD values of LCI about 24 diminutive polyps (≤5 mm) were higher than those of WL (3.29 ± 0.99 vs. 2.12 ± 0.99, P < 0.001; 31.6 ± 12.8 vs. 14.7 ± 7.6, P < 0.001). Additionally, the polyp visibility scores and CD values of LCI for polyps with any location, size, histology, and morphology were significantly higher than those of WL.

CONCLUSIONS

LCI improved the various featured polyp's visibility compared to WL in both polyp visibility scores and CD value.

Narrow-band imaging can increase the visibility of fibrin caps after bleeding of esophageal varices: a case with extensive esophageal candidiasis

A 58-year-old man with hepatitis B cirrhosis noticed black stools and underwent an endoscopy at a community hospital. The presence of esophageal varices (EVs) was confirmed, but the bleeding point was not found. He was referred to our institution and underwent a second endoscopy. Extensive white patches of esophageal candidiasis were visible on endoscopy by white-light imaging (WLI), but it was difficult to find the fibrin cap of the EVs. This was easier under narrow-band imaging (NBI), however, as the color turned red from absorption by hemoglobin adhered to it. We retrospectively measured the color differences (CD) between the fibrin cap and the surrounding mucosa 10 times using the CIE (L*a*b*) color space method. The median value of CD increased after NBI (13.9 → 43.0, p < 0.001), with increased visibility. However, the median CD between the white patch and surrounding mucosa decreased after NBI (44.8 → 30.3, p < 0.001). The fibrin cap was paler than the white patch of candidiasis, but the increased visibility of the fibrin cap by NBI enabled it to be found more easily. This is the first report of a case in which NBI was helpful in locating a fibrin cap of EVs.

The effect of ceramic thickness and resin cement shades on the color matching of ceramic veneers in discolored teeth

The objective of this study was to analyze the effects of ceramic material thickness and resin cement shade on the color matching of ceramic veneers at the gray tooth structures. Seventy-two artificial maxillary right central incisor teeth (C2 shade) were prepared according to veneer tooth preparation in practice. Ceramic materials (LT, A2 shade, IPS e.max Press) were selected to fabricate the 0.50- and 0.75-mm thick veneers at the body region. The ceramic veneer specimens were bonded to the artificial teeth by the 6 shades of resin cements (Variolink Veneer: shades of HV+3, LV-2, LV-3; and RelyX^TM Veneer: shades of WO, TR, A3). A clinical spectrophotometer (Crystaleye, Olympus) was used to measure the color parameters. The color differences (ΔE values) of ceramic veneers and A2 shade tab (Vitapan Classical, Vita) and C* _ab values were calculated. The results of three-way ANOVA indicated that the ΔE values of ceramic veneer and A2 shade tab were significantly different in the thickness of ceramic materials, shades of resin cements, and measuring regions (p < 0.001). There were significant differences in 0.50-mm-thick ceramic veneers that exhibited higher ΔE values compared with veneers that were 0.75-mm thick. Tukey's HSD test showed that the average ΔE values in body region were significantly smaller than that in cervical and incisal regions. The color matching of ceramic veneers was significantly influenced not only by the ceramic thickness and the resin cement shades but also the tooth regions.