Analysis of shade-matching ability in dental students: a comparative study under clinical and correcting light conditions.

BACKGROUND: Selecting the ideal tooth shade is essential to the success of aesthetic dental restorations. Students' cognitive abilities are involved in the multifaceted and intricate process of shade matching. Hence, the present study aimed to assess and compare the shade-matching ability of undergraduate dental students in various years of dental education under clinical and correcting light. METHODS: This comparative cross-sectional study was instigated amongst male 4th, 5th, and 6th-year students of the dental complex of King Faisal University, Kingdom of Saudi Arabia. A total of 72 male dental students assessed the shade under clinical (fluorescent light) and correcting light (handheld Dental Base Light) by using VITA Classical shade guides. Statistical analysis was done using SPSS version 23 (Armonk, NY, USA). The Chi-square test was used to evaluate the association between correct and incorrect shade matching under correcting and clinical light. RESULTS: Out of 72 male students, 22(30.6%) were from the 4th year, 26(36.1%) were from the 5th year, and 24(33.3%) were from the 6th year, with a mean age of 22.92 ± 1.01 years. The majority of the 6th-year students selected shade of anterior tooth # 11 correctly under clinical and correcting light, and 3(12.5%) students selected incorrectly under clinical and correcting light, with a statistically significant association among them (p = 0.004). As far as the shade selection of the posterior tooth is concerned, a statistically significant difference was observed under clinical light among all clinical students (p = 0.008). CONCLUSION: The clinical performance of dental students in shade matching improved with advancing years of dental education. Additionally, the shade matching ability of all groups of dental students was superior under correcting light compared to conditions under clinical light.

Influence of individual education and training on quality of color matching in dentistry.

OBJECTIVES: To evaluate the influence of the group and individual education of students on shade matching quality. Secondary study objective included a survey-assessment of quality and difficulty level of color matching. MATERIALS AND METHODS: Forty dental student participants in Integrated Academic Studies of Dentistry at the Faculty of Medicine, University of Nis (26 female, 14 male) 21-25 years old, signed consent to voluntarily participate in the research. The Ethics Committee of the Clinic of Dentistry, Faculty of Medicine, University of Nis, approved the study under number 14/11-2019-2EO. They were randomly divided into two groups (n = 20), experimental (IE, individual education) and control (GE, group education). Each group was divided into four subgroups (n = 5). The study was performed in three phases. In Phase I (I) and III (III), students matched the shade of the maxillary central left incisor (#9) using three different shade guides. Each of the students served as a "patient" for shade matching, while the other members of the subgroup, individually (VMI ) and as a team (VMT ), visually matched the tooth shade. In Phase II (between phases I and III), group IE received standard group and individual education and training, while group GE had only group education. Shade matching results in before and after education were compared with results obtained by an intraoral spectrophotometer. CIELAB (∆E*), and CIDE2000 color differences (∆E00 ) were calculated. The color differences between VMI or VMT and ES readings were graded. In addition, the students rated the level of difficulty and quality of shade matching from 1 to 5, signifying the most to least difficult, and the worst to best match, respectively. Means and standard deviations were calculated. Differences were compared using the Student t-test. RESULTS: Means (s.d.) of CIEDE2000 color differences for VMI before and after IE were 4.5 (1.5) and 3.3 (0.9), respectively. Corresponding values for group GE were 4.4 (1.4) and 4.0 (1.0), respectively. As compared with GE, group IE achieved 15% better results for the best matches and 27.5% for one of the three best matches in by-point comparison. Mean (s.d.) results for VMT in the experimental group before and after IE were 3.6 (2.4) and 2.8 (1.6), respectively. Corresponding results for the control group were 4.4 (2.1) and 3.5 (1.7), respectively. Group IE had statistically higher VMI and VMT scores than GE, while, for GE, only VMT scores were statistically higher. Group IE achieved better results in by-point comparison. After education and training, the students rated the shade matching as more precise and less difficult. Results were significantly better for Quality (IE) (sig = 0.010) and Difficulty (GE) (sig = 0.021). CONCLUSIONS: Within the limitations of the study, the experimental group achieved significantly better results in individual color matching after education and training than the control group, while both groups made progress in team color matching. Both groups rated shade matching more accurate and easier after education. CLINICAL SIGNIFICANCE: Improving the quality of shade matching is expected to enhance the esthetics of dental restorations, increase patient satisfaction, and reduce color corrections.

Comparison between direct and indirect "digital image" dental visual shade matching considering the effect of clinical experience and gender.

INTRODUCTION: Shade matching is an essential procedure to obtain an esthetic prosthesis. The Direct Visual Shade Matching (DSM) method using shade guides is the most used method by dentists. However, The Indirect Visual Digital Shade Matching (ISM) method based on digital imaging is concerned to be reliable and useful in determining shade matching in dental practice. Several factors such as method, clinical experience, and gender can affect the success of shade matching. AIM OF THE STUDY: This study aimed to compare these two methods and evaluate the effect of experience and gender on the results. MATERIALS AND METHODS: Three volunteers' maxillary central incisor teeth were evaluated using (DSM) and (ISM) methods by 87 examiners (42 males, 45 females). These examiners were further divided into three groups based on their clinical experience: Undergraduate Preclinical Dental Students (UPDS) with 31 examiners, Undergraduate Clinical Dental Students (UCDS) with 34 examiners, and Postgraduate Dental Students from the Department of Prosthodontics (PDS) with 22 examiners. The spectrophotometer device results of three teeth were considered as a reference for shade matching. Statistical analyses of the data were performed using Kruskal-Wallis, Mann-Whitney U, and Chi-square tests. RESULTS: No significant difference was found between indirect and direct methods according to Perfect Matches (p > 0.05). However, according to Shade Matching Deviation Score (SMDS) values a statistically significant difference was found between the two methods where the best result was obtained with the ISM method (p < 0.05). There was a significant difference between the PDS group and the other two groups in terms of clinical experience (p < 0.05). There was no significant difference between gender groups (p > 0.05). CONCLUSION: Digital images, captured under standardized lighting conditions, may serve as a reliable alternative method for direct shade matching. The (ISM) method requires a camera, related accessories, and computer skills. However, as these tools are commonly available nowadays, the focus for practitioners should be on effectively learning and applying these tools to achieve the best results. While clinical experience plays a significant role in the shade matching process, gender does not appear to have a substantial influence. CLINICAL SIGNIFICANCE: This study found no significant differences between the (DSM) and (ISM) methods, leaving the clinical relevance of this method open to debate. However, the ISM method yielded superior responses. Despite requiring specialized tools, conditions, and training, the widespread use of cameras and computers in modern clinics makes the necessary equipment and software readily available. This method enhances clinician-technician communication, potentially improving prosthesis esthetics and patient satisfaction, especially for less experienced clinicians or those with color deficiencies. Further research is crucial to determine its clinical significance.

Evaluation of different color measurement methods for determining tooth color.

AIM: The purpose of this study is to develop software at a low cost that enables the detection of tooth colors by capturing photographs using various devices, and to compare its effectiveness with existing expensive methods. MATERIAL AND METHODS: A total of 60 anterior central incisor teeth from 30 individuals were included in the study. The CIELAB values (L,a,b) of each tooth were measured using a spectrophotometer, which is considered the gold standard. Subsequently, photographs of the teeth were taken using four different smartphones (iPhone- Xiaomi) and one digital camera (Canon). These images were then subjected to image processing techniques and compared with measurements obtained through computer-based analysis in order to assess the correlation. Data with three or more groups, the Kruskal-Wallis H test was utilized, and multiple comparisons were conducted using the Dunn test. A significance level of p<0.05 was considered. RESULTS: Upon examining the results of multiple comparisons, a statistically significant difference was observed (p<0.001) between the DeltaE values obtained from the camera of the iPhone and those obtained from the Canon DSLR and Xiaomi cameras. The iPhone cameras yielded result values ranging from 2.68 to 2.90 for DeltaE. CONCLUSIONS: It is reported that color determination methods based on image processing of photographs taken with iPhone mobile phones could potentially gain an advantageous position in routine clinical practice, as compared to spectrophotometry.

Color match of ultra-translucency multilayer zirconia restorations with different designs and backgrounds.

PURPOSE: The purpose of this in vitro study was to assess the color match of ultra-translucency multilayer zirconia restorations with different designs and backgrounds. MATERIALS AND METHODS: Thirty ultra-translucency multilayer zirconia crown specimens were made in VITA classical shade B2 for a prepared maxillary central incisor. The specimens were divided into three groups based on the restoration design: veneered zirconia with a trestle design (VZT), veneered zirconia with a dentin core design (VZD), and full-contour zirconia (FCZ). In the groups VZT and VZD, the zirconia specimens were layered with a feldspathic veneering ceramic. The specimens were seated on five different backgrounds: shade B2 composite resin, shade B2 zirconia, copper-colored metal alloy, silver-colored metal alloy, and the prepared central incisor. CIELab values of the labial middle sections of the crown specimens were measured with a spectrophotometer. Color differences between the specimens and a shade B2 VITA classical tab (as a control) were calculated from the ΔE* ab formula and compared with an acceptability threshold (ΔE* ab = 3.7) to be clinically explicated. RESULTS: Mean ΔE* ab values ranged between 1.17 and 8.48. The restoration design, the background type, and their interaction affected the ΔE* ab (p < 0.001). The mean ΔE* ab values for VZT with all backgrounds and for VZD with the silver-colored metal background were greater than the threshold (p < 0.001), whereas the mean ΔE* ab values for VZD with the other backgrounds and FCZ with all backgrounds were less than the threshold (p = 1). CONCLUSIONS: Restoration design and background type affected the color match of ultra-translucency multilayer zirconia restorations. VZT restorations on all backgrounds and VZD restorations on a silver-colored metal background showed color mismatches. However, VZD restorations on the other backgrounds and FCZ restorations on all backgrounds demonstrated color matches.

Effect of different instrumental techniques and clinical experience on shade matching.

PURPOSE: Many factors can affect the aesthetics of dental restorations, including the instrumental techniques used in shade matching, and can lead to clinical failure. The aim of this study was to investigate the effectiveness of using the cross-polarization digital photograph technique and intraoral scanners for shade matching, and also evaluate the effect of the level of clinical experience on shade matching success. MATERIALS AND METHODS: Color analysis was performed on the maxillary right central incisors of 10 subject models with Vita Easyshade. Intraoral scanning was performed 10 times on each model using TRIOS 3 and color analysis was performed from the same spot. Then cross-polarized and non-polarized photographs of the models were taken with standard settings using a gray reference card. Each shade tab of the Vita System 3D-Master scale was also photographed with two different polarization techniques. Four groups (n = 12), including prosthodontics faculty staff, postgraduate students in prosthodontics, undergraduate students, and dental technicians matched the shade tabs and the model photographs obtained with both techniques on a standardized computer screen. Finally, the color differences between the shade tabs and maxillary central incisors matched by observers from four different groups were recorded using a colorimeter, Classic Color Meter, in accordance with the CIELAB system and CIEDE2000 (ΔE00) values were calculated. The data were compared with the acceptability threshold of 1.80 for ΔE00. The data obtained from the observers were analyzed with IBM SPSS Statistics 26.0 Release Notes program. Independent Samples t-test was used to compare normally distributed data according to binary groups. The level of significance was 0.05. RESULTS: A statistically significant difference was found in the shade matching on photographs taken with different techniques in postgraduate students (p = 0.02). Also, there was a statistically significant difference in success between the groups that made shade matching based on photographs obtained with the non-polarization technique (p = 0.00). The undergraduate students achieved statistically significantly lower results than all other groups (ΔE00 = 5.57 ± 1.07). The kappa value between the intraoral scanner and spectrophotometer results was 0.10, and this value was not statistically significant (p = 0.32). CONCLUSIONS: The cross-polarization technique used especially for shade matching is not superior to the non-polarization technique. Academic and clinical experience might be correlated with shade-matching success with the non-polarization technique. The clinical acceptability threshold could not be achieved in the shade matchings made on digital photographs taken with both techniques. Shade matching performed with an intraoral scanner did not yield reliable results.

Study of attached gingiva space color according to gender and age in Caucasian population.

OBJECTIVE: To describe the color of the healthy attached gingiva adjacent to the maxillary incisors and to evaluate the effect of age and gender on CIELAB color coordinates. MATERIALS AND METHODS: The study included 216 Caucasian individuals (129 females and 87 males) divided into three age groups. A SpectroShade Micro spectrophotometer was used to register color coordinates at 2.5 mm apical of the zenith of the upper central incisors. Descriptive and inferential statistical analysis was performed. RESULTS: The minimum and maximum coordinates in which the CIELAB natural gingival space is delimited are: L* minimum 40.4 - L* maximum 61.2; a* minimum 17.0 - a* maximum 30.2; b* minimum 9.8 - and b* maximum 21.9. There are statistically significant differences between males and females for coordinates L*, a* and b* in the attached gingival area selected. Age had a significant effect on coordinate b* (p = 0.000). CONCLUSIONS: Statistically significant differences were found between the L*, a* and b* color coordinates of the attached gingiva between men and women, although the color difference is below the clinical acceptance threshold. The attached gingiva takes on a bluish color as the patients get older, which means that the b* coordinate decreases. CLINICAL SIGNIFICANCE: With a prosthodontic approach, knowledge of the CIELAB natural attached gingival coordinates based on the patient's age and gender will facilitate the clinician's work in selecting the appropriate color. The CIELAB system values found can be used as a gingival shade guide reference.

The accuracies of three intraoral scanners with regard to shade determination: An in vitro study.

PURPOSE: To compare the accuracies of three intraoral scanners for shade determination function in vitro, and to preliminarily investigate the shade-matching characteristics of the three intraoral scanners. MATERIALS AND METHODS: The shade of the middle third region of each shade tab on the Vita Classical A1-D4 shade guide (VC) was measured with a spectrophotometer (Vita Easyshade V, VE) and three intraoral scanners, including CEREC Omnicam (OM), 3Shape TRIOS 3 (T3), and TRIOS 4 (T4). A conversion table between VC values and CIELAB values was established from the database of VE to analyze the trueness. The reproducibility of the instruments was then compared by repeating the measurements five times. RESULTS: The mean color difference for each instrument was highest in the OM, followed by the T4, and lowest in the T3 and VE, respectively. The L* and a* value for OM, and the b* value for T4, were significantly different from those for VE (p <0.05). The reproducibility of the instrument was highest in the VE (Fleiss' kappa: 0.95), followed by the T3 (Fleiss' kappa: 0.89), T4 (Fleiss' kappa: 0.87), and OM (Fleiss' kappa: 0.78). CONCLUSIONS: Of the three intraoral scanners, the trueness was best on the T3. The reproducibility of all the instruments was excellent.

The Role of Intraoral Scanners in the Shade Matching Process: A Systematic Review.

PURPOSE: The variation in findings with regards to the accuracy and precision of intraoral scanners for shade selection are no doubt confusing for clinicians who may find it difficult to make evidence-based decisions. The aim of this systematic review is to provide a comprehensive and in-depth assessment of available studies to determine the viability of using intraoral scanners for the purpose of shade matching. The PICO-guided research question is as follows: when shade matching, are intraoral scanners as valid as visual or other digital shade measuring devices in determining tooth colors. METHODS: Electronic databases including PubMed/MEDLINE, SCOPUS, EBSCO, Cochrane, and ProQuest were systematically searched for articles published between January 1, 2011 and December 30, 2021 using the main search terms: "intraoral scanners," "scanners," "TRIOS," "CEREC," "Planmeca," "Medit," "digital dentistry" in concurrence with one of the following keywords: "EasyShade" OR "shade selection" OR "shade matching" OR "shade" OR "tooth color" OR "tooth shade" OR "digital shade matching." Bibliographies of included articles and the following journals were searched for relevant articles: Journal of Prosthetic Dentistry, Journal of Prosthodontics, Journal of Esthetic and Restorative Dentistry, Journal of Advanced Prosthodontics, and Journal of Dentistry. A total of 15 articles were included in the review. RESULTS: Intraoral scanners are highly repeatable for shade matching, and outperformed visual shade matching. Accuracy varied significantly between studies, with the majority recommending the use of visual shade matching to confirm/verify the intraoral scanner results. Setting intraoral scanners to the Vita 3D Master shade guide improved both accuracy and precision. Shade matching with intraoral scanners may be influenced by external factors such as ambient light sources and incorrect use or manipulation. CONCLUSION: Intraoral scanners set to the Vita 3D Master shade guide may be used for shade matching, but shade should be verified with visual shade matching. Further studies are required to address limitations of current studies.

Artificial intelligence systems in dental shade-matching: A systematic review.

PURPOSE: Uses for artificial intelligence (AI) are being explored in contemporary dentistry, but artificial intelligence in dental shade-matching has not been systematically reviewed and evaluated. The purpose of this systematic review was to evaluate the accuracy of artificial intelligence in predicting dental shades in restorative dentistry. METHODS: A systematic electronic search was performed with the databases MEDLINE (PubMed), Scopus, Cochrane Library, and Google Scholar. A manual search was also conducted. All titles and abstracts were subject to the inclusion criteria of observational, interventional studies, and studies published in the English language. Narrative reviews, systematic reviews, case reports, case series, letters to the editor, commentaries, studies that were not AI-based, studies that were not related to dentistry, and studies that were related to other disciplines in dentistry, other than restorative dentistry (prosthodontics and endodontics) were excluded. Two investigators independently evaluated the quality assessment of the studies by applying the Joanna Briggs Institute Critical Appraisal Checklist for Quasi-Experimental Studies (non-randomized experimental studies). A third investigator was consulted to resolve the lack of consensus. RESULTS: Fifty-three articles were initially found from all the searches combined from articles published from 2008 till March 2023. A total of 15 articles met the inclusion criteria and were included in the systematic review. AI algorithms for shade-matching include fuzzy logic, a genetic algorithm with back-propagation neural network, back-propagation neural networks, convolutional neural networks, artificial neural networks, support vector machine algorithms, K-nearest neighbor with decision tree and random forest, deep learning for detection of dental prostheses based on object-detection applications, You Only Look Once-YOLO. Moment invariant was used for feature extraction.  XG (Xtreme Gradient) Boost was used in one study as a gradient-boosting machine learning algorithm. The highest accuracy in the prediction of dental shades was the decision tree regression model for leucite-based dental ceramics of 99.7% followed by the fuzzy decision of 99.62%, and support vector machine using cross-validation of 97%. CONCLUSIONS: Lighting conditions, shade-matching devices and color space models, and the type of AI algorithm influence the accuracy of the prediction of dental shades. Knowledge-based systems and neural networks have shown better accuracy in predicting dental shades.

Shade matching and blending capabilities of a new single-shade composite: an in vivo study.

Demand for direct esthetic restorations is high, but shade matching can be challenging. Some manufacturers claim that a single product is able to match all colors of the human dentition, eliminating shade matching challenges. This in vivo study, which followed the International Commission on Illumination's (CIE) CIEDE2000 color difference standard (ΔE00), aimed to quantify the shade matching and blending capabilities of a single-shade composite (Omnichroma PLT) used as a direct veneer. A color difference of ΔE00 ≤ 1.8 was set as the acceptability threshold. Ten participants with an unrestored and noncarious maxillary left central incisor were enrolled in the study. Direct spectrophotometric measurements (CIE L*a*b*) were made on the tooth and then on composite cured on the tooth. Consistency in measurements and composite resin placement were attained through the use of a specially designed jig. A digital photograph was then taken with the composite in place, and colorimetric software was used to obtain the L*a*b* values at the most incisal and cervical edges of the restoration. These values were compared to those of the natural tooth structure immediately adjacent to the composite resin. The ΔE00 scores were calculated to determine the composite's ability to match the tooth shade beneath it (ΔEm) and to blend with the incisal (ΔEi) and cervical (ΔEc) tooth shades. Mean scores for ΔEm, ΔEi, and ΔEc were calculated, and an independent t test (α = 0.05) was used to compare means for ΔEi and ΔEc. The mean (SD) ΔE00 values were 6.16 (2.38), 3.90 (2.47), and 6.84 (1.80) for ΔEm, ΔEi, and ΔEc, respectively. A statistically significant difference (P = 0.008) was observed between ΔEi and ΔEc. As a direct veneer, the tested composite did not meet the acceptability threshold for any ΔE00 measurement; however, it was better at matching the incisal third of the tooth than it was the other thirds. More in vivo studies are needed to verify and expand on these results.

Visual and instrumental coverage error of two dental shade guides: an in vivo study.

OBJECTIVES: This study aims to evaluate in vivo the color agreement between natural teeth and dental shade guides by means of visual and instrumental coverage error ([Formula: see text]) index. MATERIALS AND METHODS: The color of the middle third of 735 incisors was visually determined by two evaluators using the Vita Classical (VC) and Vita 3D Master (V3DM) shade guides. The color match between the natural tooth and the shade tab was rated as poor (P), good (G), or optimum (O) by each observer. CIE color coordinates of the target teeth and shade tabs of VC and V3DM were instrumentally measured using a clinical spectrophotometer. Visual ([Formula: see text]) and instrumental ([Formula: see text]) coverage error indexes were computed using CIELAB and CIEDE2000 metrics for both shade guides. For [Formula: see text] calculation, only the concordant inter-observer determination on tooth shade rated as O-O or O-G was used. The results were evaluated using perceptibility (PT, [Formula: see text]= 1.2, [Formula: see text]= 0.8) and acceptability (AT, [Formula: see text]= 2.7, [Formula: see text]= 1.8) color thresholds for dentistry. RESULTS: VC and V3DM exhibited [Formula: see text] (2.5, 3.2, and 3.2, 2.7 CIELAB units; 1.9, 2.3, and 2.8, 2.4 CIEDE2000 units, respectively, for O-O and O-G match) and [Formula: see text] (4.7, 4.8, and 4.1, 4.6 CIELAB units; 3.3, 3.4, and 3.4, 3.6 CIEDE2000 units, respectively, for O-O and O-G match) values greater than 50:50% AT for both color difference formulas. [Formula: see text] contributes more than 50% (53.2-82.4% range) to the [Formula: see text] value. This contribution depends on the shade guide used and the quality of the visual rating. CONCLUSIONS: The evaluated shade guides exhibited visual coverage errors above acceptability thresholds, largely due to the contribution of the instrumental coverage error to the visual coverage error. CLINICAL RELEVANCE: It necessary to further improve commercially available dental shade guides to facilitate achievement of satisfactory esthetics results in clinical practice.

Evaluation of accuracy and characteristics of tooth-color matching by intraoral scanners based on Munsell color system: an in vivo study.

To compare the accuracy of visual and instrumental methods for tooth-color matching based on three attributes in the Munsell color system and to investigate the characteristics of intraoral scanners for tooth-color matching. Shades of the cervical, middle, and incisal third region of 130 maxillary anterior teeth were matched visually by an experienced prosthodontist (EP) using Vita classical A1-D4 (VC) and Vita System 3D-Master (V3D) shade guides, and digitally by a spectrophotometer (Vita Easyshade V, VE) and two intraoral scanners (3Shape TRIOS 3, T3; TRIOS 4, T4). VE was used as a reference. The reproducibility of the three test groups was examined by repeating the measurements in triplicate. The overall trueness of the three test groups (from high to low) was T3 > EP > T4 for VC values (p < 0.01), and T3, EP > T4 (p < 0.01) for V3D. The trueness of T3 in incisal regions was lower than cervical and middle regions. When hue or lightness was correct, the mismatched chroma in test groups was smaller than VE (p < 0.01). The repeatability of EP was the poorest (p < 0.01). The color-matching trueness of T3 was higher than EP and T4. The reproducibility of intraoral scanners was better than visual methodology.

Effect of assessor's sex on visual color matching in dentistry: A systematic review of the literature.

OBJECTIVES: To evaluate systematically the influence of sex of dental professionals on their capability for visual color matching. MATERIALS AND METHODS: The protocol was registered on PROSPERO (CRD42020205393). PICOS question was develop based on the population, intervention, comparison, outcomes, and study design (PICOS). Eligibility criteria included cross section studies, randomized clinical trials and cohort studies that compared the effect of sex on the visual color matching process. Five electronic databases (Pubmed, Cochrane, EMBASE, Medline, and SCOPUS) and additional literature were screened independently by two researchers in July 2020. Clinical studies evaluating visual color matching skills of dental professionals were included. Studies that did not compare the difference between sexes were excluded. Duplicate articles were removed, titles and abstracts were screened, and studies were selected according to the inclusion criteria. Data were collected and reported in accordance with PRISMA guidelines. Risk of bias was assessed using Joanna Briggs Institute Critical Appraisal Tools. RESULTS: A total of 1192 articles were screened from which 132 full text articles were analyzed and 37 finally included in the systematic review. Most of the studies evaluated the color matching abilities of dental students in vitro with shade tabs or extracted teeth. Out of the 37 articles included, 25 reported no significant difference in shade matching abilities between the sexes. Of the 12 studies that found a significant difference, 11 reported that females had better scores in shade matching exercises. For all studies a low risk of bias was revealed for most of the domains. CONCLUSIONS: While the non-homogeneity of the settings and methods in the included studies make it impossible to construct aggregate statistic, this systematic review suggests that the sex is unlikely to be a critical factor influencing color matching abilities. CLINICAL SIGNIFICANCE: This study suggest that sex of dental professionals does not play a critical factor in matching satisfactory color of future dental restoration with surrounding teeth.

Comparison of visual shade matching and photographic shade analysis.

OBJECTIVE: To compare the performance of a standardized photographic shade analysis (PSA) and visual shade matching (VSM) using two color difference formulas. MATERIALS AND METHODS: Fifty observers (35 undergraduate and 15 graduate students) evaluated the color of two upper left central incisors (LT-light tooth, and DT-dark tooth). VSM was performed using the VITA 3D Master (3D) shade guide in a controlled clinical environment. For PSA, a cross-polarized filter and a gray card (Whibal) were used to standardize the photographs taken (target teeth and shade tabs from 3D). From the pictures obtained, the CIELAB coordinates, and color differences ( Δ E ab * and ΔE00 ) were obtained. The shade tabs selected by two experienced researchers were conducted as part of the pilot study, and finally used as a standard for the analysis. Data were analyzed using descriptive statistics and the chi-square test (p ≤ 0.05). RESULTS: Shade tabs selections of VSM and PSA agreed only for LT. The best "Match" selected by the researchers agreed with data from PSA using ΔE00 . PSA using ΔE00 showed higher total percentages of "Match" and higher percentage of agreement among observers. A relationship was found for LT performing the PSA (p < 0.05). CONCLUSIONS: The performance of the PSA was better than the VSM, but only when the CIEDE2000 color difference formula was used. Therefore, the color difference formulas influenced on the performance of PSA. Finally, the PSA improved the precision of the VSM. CLINICAL SIGNIFICANCE: To use a standardized PSA to improve the VSM and shade communication in clinical esthetic dentistry.

Evaluation of shade correspondence between current monolithic CAD/CAM blocks and target shade tab by considering the influence of cement shade and restorative material thickness.

It was aimed to evaluate shade matching between novel CAD/CAM blocks and the A2 target shade tab by considering the influence of cement shade and restorative material thickness on the chromatic background. A total number of 120 rectangular-shaped specimens were subtracted from four different prefabricated CAD/CAM blocks [Vita Enamic (VE), Lava Ultimate (LU), GC Cerasmart (GC), and Vita Mark II (VMII)]. These specimens had thicknesses of 0.5 mm and 1.0 mm. Three different shades (A2, opaque, and translucent) of dual-polymerized resin cement were chosen. The dentin shade (A3.5) restorative composite foundation was incrementally fabricated in a silicon mold. For control group, the A2 shade tab of the Vitapan classical shade guide was used. Different restorative material-cement-foundation assemblies were generated with optic gel. Color readings were performed by using a clinical spectrophotometer, and CIEDE2000 (ΔE00) formula was used to assess color differences. Data were statistically analyzed (α = 0.05). With increasing thickness, color difference values decreased. Higher mean ΔE00 units were observed in all restorative material sub-groups for 0.5 mm thickness. In TR shade, no statistically significant difference was detected among the mean ΔE00 values of 0.5 mm-thick restorative materials. Color differences in groups 1.0 mm-opaque-LU and 1.0 mm-opaque-GC indicated perceptible but clinically acceptable values (0.8˂ΔE00 ≤ 1.8). The highest and lowest ΔE00 units were observed in the 0.5 mm-A2-VE group (ΔE00 = 7.07) and 1 mm-opaque-GC group (ΔE00 = 1.46), respectively. Luting cement shade, restorative material type, and thickness significantly influenced the resultant color of restoration. Opaque cement on dentin foundation exhibited lower color differences.

Objective shade matching, communication, and reproduction by combining dental photography and numeric shade quantification.

OBJECTIVE: The subject of this case report is the application of a newly developed workflow for objective shade communication sans visual shade assessment or the use of shade guides. CLINICAL CONSIDERATIONS: Clinical complications stemming from issues relating to esthetic integration can present a burden on the restorative team, often resulting in strenuous relationships among its members. The faithful imitation of the optical appearance of dental hard tissues with direct- and indirect restorations has been at the center of interest in a great number of publications from the realm of esthetic dentistry over the past 40 years. The present report describes a new approach to objective shade communication, by transcending the role of dental photography from its purely descriptive purpose to the level of quantification, thus abandoning the use of the established shading regimes and replacing them with a patient personal shade recipe based on the CIELAB color space instead. CONCLUSIONS: Objective shade communication is possible with the eLAB system by combining numeric shade quantification with dental photography. CLINICAL SIGNIFICANCE: The eLAB system presents a viable alternative to the traditional approach to shade communication and shade matching in dentistry.

Visual and digital tooth shade selection methods, related effective factors and conditions, and their accuracy and precision: A literature review.

OBJECTIVE: Despite developments of dental shade selection methods, shade selection is still a challenge affecting esthetic outcomes. The purpose of this review was to discuss visual and digital shade taking methods, related effective factors and conditions, and their accuracy and precision to find out the most accurate, precise shade selection method available in dentistry. OVERVIEW: The key terms of accuracy, background, ceramic, color, colorimeter, color analysis, color science, color measurement, color measuring instrument, color matching, composite resin, dental/tooth shade guide, digital camera, esthetics, imaging, imaging application/program/ software, intraoral scanner, light source, photography, precision, shade, shade matching/ determination/prediction/reproduction/selection, shade taking device, spectrophotometer, spectrophotometry, tooth color measurement, tooth color/shade, and visual perception were used separately and jointly to detect related English-language articles published between January 1, 1985, and January 1, 2021. Electronic/non-electronic searches of Google Scholar/PubMed/Scopus/Web of Science were accomplished. Consequently, 249 articles were considered. Accordingly, the digital methods show higher accuracy and precision compared to the visual methods while requiring to be enhanced regarding accuracy to achieve ideal shade taking results. CONCLUSIONS: Dental spectrophotometers provide the highest overall accuracy and precision among different shade selection methods while needing clinical setting to control related effective factors/conditions and technological improvement to perform optimally. CLINICAL SIGNIFICANCE: Different factors can affect the accuracy and precision of tooth shade selection methods and devices. The understanding of these effective factors may lead to a standard shade taking protocol using accurate, precise methods and devices.

Evaluation of shade matching of a novel supra-nano filled esthetic resin composite employing structural color using simplified simulated clinical cavities.

OBJECTIVE: To evaluate the shade matching ability of a novel supra-nano filled esthetic resin composite employing structural color technology using simplified simulated clinical cavities. Filler morphology and light transmittance characteristics were also evaluated. MATERIALS AND METHODS: One-hundred and twenty frames of resin composite were built in A1, A2, A3, and A4 shades to simulate Class I cavities (diameter = 4 mm, height = 2 mm). For each shaded frame, cavities were filled with three different types of filler containing resin composites (n = 10): supra-nano filled (SN filled) resin composite, microhybrid filled (MH filled) resin composite, and clustered-nano filled (CN filled) resin composite. Color parameters were calculated using CIELAB (△Eab ) and CIEDE2000 (△E00 ). Data were analyzed using one-way analysis of variance (ANOVA), followed by Duncan's test (α = .05). Filler morphology and light transmittance characteristics were measured to explore the role of structural color on shade matching. RESULTS: △Eab and △E00 of SN filled resin composite were significantly lower in A2, A3, and A4 shades (P < .05). CONCLUSIONS: The SN filled resin composite showed better shade matching with A2, A3, and A4 shades of resin composite frames compared to MH filled resin composite, and CN filled resin composite. CLINICAL SIGNIFICANCE: Universal-shade resin composites, which were expected to match nearly all shades, simplify the restorative procedure. Resin composite, which contained spherical supra-nano filler particles, could contribute most to its shade matching by stimulating structural color. Structural color technology may provide additional benefits for shade matching of resin composites.

Evaluating the relationship between tooth color and enamel thickness, using twin flash photography, cross-polarization photography, and spectrophotometer.

OBJECTIVES: To understand (a) the effects of labial enamel on tooth color (b) relationship of color data taken by nonpolarized (NP), cross-polarization photography (CP), and spectrophotometry (SP). MATERIALS AND METHODS: Fifty extracted human maxillary incisors were coated with resin on their palatal surfaces. Their color was measured with NP, CP, and SP and their dimensions were scanned by an intraoral scanner. The labial enamel was removed using a modified selective enamel demineralization technique. Tooth dimensions and color were recorded again. The differences in the labial enamel thickness (ΔT) and color (∆E*00 and ∆L*, ∆a*, ∆b*) were statistically analyzed with the Pearson correlation coefficient and simple linear regression. RESULTS: In CP and SP methods, ΔT and ∆E*00 were weakly to moderately positively correlated (r = .38 and .27). In NP, CP, and SP methods, ∆T and ∆b* are weakly positively correlated (r = .27, .27 and .29). The color data of three measuring methods were highly positively correlated (r > .8). A linear relationship between ∆E*00 and ∆T were found (CP and SP groups). CONCLUSIONS: (a) Thicker labial enamel has a greater impact on tooth color. (b) Reducing labial enamel thickness shifts the tooth color toward yellow. (c) Tooth color measured from the three methods were highly correlated. CLINICAL SIGNIFICANCE: Knowing the relationship between enamel thickness and tooth color, a clinician can better predict the stump shade before tooth preparation. Due to the highly correlated measuring outcomes, it is reasonable to combine these three methods during shade matching.