Visual and instrumental shade matching using CIELAB and CIEDE2000 color difference formulas

2016 ◽  
Vol 32 (1) ◽  
pp. 82-92 ◽  
Author(s):  
Oscar E. Pecho ◽  
Razvan Ghinea ◽  
Rodrigo Alessandretti ◽  
María M. Pérez ◽  
Alvaro Della Bona
Keyword(s):  
Color Difference ◽  
Shade Matching

The Influence of Dental Shade Guides and Experience on the Accuracy of Shade Matching

2016 ◽  
Vol 17 (1) ◽  
pp. 22-26 ◽  
Author(s):  
Mohammadreza Nakhaei ◽  
Jalil Ghanbarzadeh ◽  
Samin Alavi ◽  
Sahar Amirinejad ◽  
Hamidreza Rajatihaghi
Keyword(s):  
Calculated Data ◽  
Color Difference ◽  
Dental Students ◽  
Influential Factor ◽  
Color Measurement ◽  
Mean Values ◽  
Factors Affecting ◽  
Shade Matching ◽  
The Mean ◽  
Shade Guide

ABSTRACT Aim There is limited and inconsistent information on some factors affecting visual shade selection. The aim of this study was to evaluate the influence of shade guide type and professional experience on shade-matching results. Materials and methods Thirty Dental students (DS), 30 General dentists (GDs) and 30 Dental specialists (S) participated in this study. The participants were asked to match six target tabs using two dental shade guides: Vitapan Classical (VC) and Vitapan 3D-Master (3D). An intraoral spectrophotometer was used for color measurement of target tabs and selected tabs. The color difference (Conflict of interest: NoneE) values between the target tab and selected tab were calculated. Data were analyzed using analysis of variance (ANOVA) and paired t-test (α = 0.05). Results of the first five best matches for each target tab were expressed as ΔE1 to ΔE5. Differences in the mean values of ΔE1 to ΔE5 between VC and 3D were compared using descriptive statistics. Results There were no significant differences among the three participating groups in ΔE values when the 3D was used (p = 0.389). However, significant differences were found with VC (p < 0.001). The ΔE values achieved from the 3D were significantly lower than those from VC for DS and S (p = 0.001 and p < 0.001, respectively). For each of the first five best matches, the mean ΔE values from the 3D were smaller than the corresponding values of VC. Conclusion The type of dental shade guide affected the shadematching results. The level of experience was not found to be an influential factor in shade matching when 3D-Master shade guide was used. Clinical significance Compared with Vitapan Classical shade guide, use of the Vitapan 3D-Master shade guide improves shade-matching results. How to cite this article Nakhaei M, Ghanbarzadeh J, Amirinejad S, Alavi S, Rajatihaghi H. The Influence of Dental Shade Guides and Experience on the Accuracy of Shade Matching. J Contemp Dent Pract 2016;17(1):22-26.

scholarly journals Evaluation of patient satisfaction and the color difference between natural teeth and all-ceramic crowns fabricated from "Celtra press" treated with different surface finishing protocols. (Randomized controlled clinical trial): تقييم رضا المريض وفرق اللون بين الأسنان الطبيعية والتيجان الخزفية بالكامل المصنعة من "مطبعة سيلترا" المعالجة ببروتوكولات تشطيب الأسطح المختلفة: (تجربة سريرية معشاة ذات شواهد)

2021 ◽  
Vol 5 (3) ◽  
pp. 83-69
Author(s):  
Nourhan Sayed Saleh Ahmed, Mohamed Labib Zamzam, Maha Taymou Nourhan Sayed Saleh Ahmed, Mohamed Labib Zamzam, Maha Taymou
Keyword(s):  
Patient Satisfaction ◽  
Color Difference ◽  
Surface Finishing ◽  
Polished Surface ◽  
Full Coverage ◽  
Group I ◽  
All Ceramic ◽  
Natural Teeth ◽  
Shade Matching ◽  
Group Ii

All studies agree that glazing can produce a smooth porcelain surface, but although the glaze is an important factor in esthetics, with respect to light reflection, it can frequently change the color value of the restorations, reflecting more light than the natural teeth, thus creating an artificial effect on these restorations. A number of more recent studies have suggested that a polished surface may be as acceptable as a glazed surface. Many ceramists prefer polishing instead of glazing to control the surface luster. Other studies have reported no significant differences between polished and glazed surfaces.Since studies addressing the effect of surface finishing protocols on the color of ZLS ceramics are rare, thus our study is important to investigate this issue. Methodology: 20 teeth esthetic zone requiring full - coverage crown -with their contralateral are sound and not severely discolored - were prepared to receive an all -ceramic crown. The crowns are divided into two groups: Group I: Teeth received crowns fabricated from glazed Celtra Press ceramic Group II: Teeth received crowns fabricated from polished Celtra Press. The color difference ΔE was measured using an intraoral spectrophotometer and evaluated for each group. Shade matching to the contralateral tooth was evaluated by 2 experienced prosthodontists according (USPHS) criteria. Patient satisfaction of the two groups assessed using the (VAS) scale which is Binary and documented in the chart. Results: Patient satisfaction was graded according to the (VAS) scale. There was no statistically significant difference between (Group I) and (Group II). The color change was recorded according to the (ΔE), the polished Celtra Press group recorded statistically non-significant higher color changes than the glazed Celtra Press group. shade matching was graded according to USPHS, where in Glazed Celtra Press group most of the patients stated Alpha score (80%) while minority showed Bravo score (20%). In the Polished Celtra Press group, all of the patients informed Bravo score100%. Conclusion: Within the limitations of this clinical study: Glazed and polished Celtra Press full coverage restorations revealed excellent patient satisfaction. Glazed celtra restorations have a clinically more acceptable shade matching.    

scholarly journals Does Gender Influence Color Matching Quality?

2016 ◽  
Vol 20 (2) ◽  
pp. 89-93 ◽  
Author(s):  
Ivan Ristic ◽  
Rade D Paravina
Keyword(s):  
Color Difference ◽  
Dental Students ◽  
Color Matching ◽  
Gender Influence ◽  
Shade Matching ◽  
Standard Deviations ◽  
Normal Males ◽  
Student’S T ◽  
Result Analysis ◽  
Match Score

Summary Objectives: To compare shade matching skills of color normal males and females.Material and Methods: A total of 174 dental students of both genders (117 females and 57 males, 20 to 25 years old), with no experience in color matching in dentistry, participated in the study. All recruited students passed the Ishihara color vision test for color deficiency, and matched the colors of eight shade tabs using VITA Linearguide 3D-Master shade guide. Standardized lighting conditions were provided using Rite-Lite (Addent Danbury, CT, USA) hand-held shade matching unit. Color differences between the task tabs and selected tabs were calculated using two CIE color difference formulae and students results were evaluated from 10 (for the best match score) to 1 for the 10th best match score. Means and standard deviations were determined. Student’s t-test was used for result analysis (p = .05).Results: The mean shade matching scores and standard deviations for male and female students were 5.86 (SD 1.38) and 6.10 (SD 1.36), respectively (p = .266). No statistically significant differences in overall and individual target tab scores by gender were recorded.Conclusion: Within the limitation of this study, it was concluded that gender did not influence color matching quality

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

2020 ◽  
Vol 54 (4) ◽  
pp. 363-370
Author(s):  
Žarko Udiljak ◽  
Hrvoje Pezo ◽  
Robert Ćelić
Keyword(s):  
Color Difference ◽  
Dental Students ◽  
Lower Percentage ◽  
Final Test ◽  
Color Differences ◽  
Shade Matching ◽  
The One ◽  
The Relationship ◽  
Dental Professionals

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.

Modification of optical properties of PC-PBT/Cr2O3 and PC-PBT/CdS nanocomposites by gamma irradiation

2020 ◽  
Vol 92 (2) ◽  
pp. 20402
Author(s):  
Kaoutar Benthami ◽  
Mai ME. Barakat ◽  
Samir A. Nouh
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Band Gap ◽  
Color Difference ◽  
Band Gap Energy ◽  
Polybutylene Terephthalate ◽  
Γ Irradiation ◽  
Gap Energy ◽  
Vis Spectroscopy ◽  
Oxygen Atoms

Nanocomposite (NCP) films of polycarbonate-polybutylene terephthalate (PC-PBT) blend as a host material to Cr2O3 and CdS nanoparticles (NPs) were fabricated by both thermolysis and casting techniques. Samples from the PC-PBT/Cr2O3 and PC-PBT/CdS NCPs were irradiated using different doses (20–110 kGy) of γ radiation. The induced modifications in the optical properties of the γ irradiated NCPs have been studied as a function of γ dose using UV Vis spectroscopy and CIE color difference method. Optical dielectric loss and Tauc's model were used to estimate the optical band gaps of the NCP films and to identify the types of electronic transition. The value of optical band gap energy of PC-PBT/Cr2O3 NCP was reduced from 3.23 to 3.06 upon γ irradiation up to 110 kGy, while it decreased from 4.26 to 4.14 eV for PC-PBT/CdS NCP, indicating the growth of disordered phase in both NCPs. This was accompanied by a rise in the refractive index for both the PC-PBT/Cr2O3 and PC-PBT/CdS NCP films, leading to an enhancement in their isotropic nature. The Cr2O3 NPs were found to be more effective in changing the band gap energy and refractive index due to the presence of excess oxygen atoms that help with the oxygen atoms of the carbonyl group in increasing the chance of covalent bonds formation between the NPs and the PC-PBT blend. Moreover, the color intensity, ΔE has been computed; results show that both the two synthesized NCPs have a response to color alteration by γ irradiation, but the PC-PBT/Cr2O3 has a more response since the values of ΔE achieved a significant color difference >5 which is an acceptable match in commercial reproduction on printing presses. According to the resulting enhancement in the optical characteristics of the developed NCPs, they can be a suitable candidate as activate materials in optoelectronic devices, or shielding sheets for solar cells.

Exploring the Facial Color Representative Regions Using the Humanae Images

2020 ◽  
Author(s):  
Yuchun Yan ◽  
Hayan Choi ◽  
Hyeon-Jeong Suk
Keyword(s):  
Image Analysis ◽  
Future Study ◽  
Skin Color ◽  
Color Difference ◽  
Facial Skin ◽  
Female Images ◽  
Gender And Race ◽  
Facial Landmarks

It is difficult to describe facial skin color through a solid color as it varies from region to region. In this article, the authors utilized image analysis to identify the facial color representative region. A total of 1052 female images from Humanae project were selected as a solid color was generated for each image as their representative skin colors by the photographer. Using the open CV-based libraries, such as EOS of Surrey Face Models and DeepFace, 3448 facial landmarks together with gender and race information were detected. For an illustrative and intuitive analysis, they then re-defined 27 visually important sub-regions to cluster the landmarks. The 27 sub-region colors for each image were finally derived and recorded in L ∗ , a ∗ , and b ∗ . By estimating the color difference among representative color and 27 sub-regions, we discovered that sub-regions of below lips (low Labial) and central cheeks (upper Buccal) were the most representative regions across four major ethnicity groups. In future study, the methodology is expected to be applied for more image sources.

A new color difference formula in RGBcolor space

2009 ◽  
Vol 29 (2) ◽  
pp. 465-467
Author(s):  
Zhen-ya YANG ◽  
Yong WANG ◽  
Zhen-dong YANG ◽  
Cheng-dao WANG
Keyword(s):  
Color Difference ◽  
Difference Formula

scholarly journals A Study of Automatic Judgment of Food Color and Cooking Conditions with Artificial Intelligence Technology

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1128
Author(s):  
Chern-Sheng Lin ◽  
Yu-Ching Pan ◽  
Yu-Xin Kuo ◽  
Ching-Kun Chen ◽  
Chuen-Lin Tien
Keyword(s):  
Artificial Intelligence ◽  
Image Processing ◽  
Color Space ◽  
Color Difference ◽  
Color Space Conversion ◽  
Before And After ◽  
Artificial Intelligence Technology ◽  
Artificial Intelligence Algorithm ◽  
Time Image ◽  
Cooking Conditions

In this study, the machine vision and artificial intelligence algorithms were used to rapidly check the degree of cooking of foods and avoid the over-cooking of foods. Using a smart induction cooker for heating, the image processing program automatically recognizes the color of the food before and after cooking. The new cooking parameters were used to identify the cooking conditions of the food when it is undercooked, cooked, and overcooked. In the research, the camera was used in combination with the software for development, and the real-time image processing technology was used to obtain the information of the color of the food, and through calculation parameters, the cooking status of the food was monitored. In the second year, using the color space conversion, a novel algorithm, and artificial intelligence, the foreground segmentation was used to separate the vegetables from the background, and the cooking ripeness, cooking unevenness, oil glossiness, and sauce absorption were calculated. The image color difference and the distribution were used to judge the cooking conditions of the food, so that the cooking system can identify whether or not to adopt partial tumbling, or to end a cooking operation. A novel artificial intelligence algorithm is used in the relative field, and the error rate can be reduced to 3%. This work will significantly help researchers working in the advanced cooking devices.

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