Dental Shade Research Articles

MANUAL METHOD FOR GINGIVAL SHADE SELECTION- A LITERATURE REVIEW

Objective- The purpose of the article is to present a narrative review of the literature related to the different shade guides available for dental practitioners. Materials And Methods- A literature search was performed in the online databases – PubMed, Science Direct, Medline and Google Scholar with the following When fabricating a restoration, patient satisfaction with the shade match is essential. The patients level of satisfaction may not be the same as that of the dental practitioner. Esthetic expectations have dramatically increased in the last few years. Color and shade determination are generally considered difficult in dental practice. Most prostheses fail esthetically owing to improper shade selection. A good understanding of color shade guides is essential for precise shade matching, but the paucity of dental practitioners knowledge of color science because of the numerous available shade guides creates a challenge. This comprehensive review states information on shade selection, different shade guides, and shade matching devices commonly used in dental practice. Dental shade guides are a set of colour standards mimicking the colour of tissues, which dentists aim to restore – tooth structures, gingival tissues or facial structures in facial prosthodontics - skin, mucosa, eyes etc. They can be systematized based on the following principles – fabrication process, the material of manufacturing or restoration and according to the tissues, which are restored. Conclusion: To provide an esthetic restoration to the patient, the dentist must have a full understanding of the science of color and color perception. Matching the correct shade satisfies both the dentist and patient and gives a pleasing appearance to the patient.

Color reproduction trueness of 3D-printed full-color dental casts with scans derived from an intraoral scanner.

To investigate the effects of shade tab color variations (tooth-colored vs. gingiva-colored) and surface treatment (application of mineral oil) on the trueness of color reproduction from dental shade tabs to 3D-printed full-color dental casts, using digital scans obtained from an intraoral scanner. Pristine tooth-colored (with 16 shade tabs) and gingiva-colored (with five shade tabs) shade guides were digitally scanned using an intraoral scanner, and subsequently, 3D-printed replicas were created using a full-color material jetting 3D printer. Three color measurements using a contact type digital spectrophotometer were recorded, including actual shade tabs (R0), dried 3D-printed study samples (RP1 ), and study samples with mineral oil application (RP2 ), in this study to calculate color differences between the actual shade tabs and 3D-printed ones. The CIEDE2000 formula was used to calculate the color differences (color reproduction trueness) between reference shade tabs and 3D-printed full-color study samples-without and with mineral oil, ∆E00 (RP1 ), and ∆E00 (RP2 ). ∆E00 (RP1 ) and ∆E00 (RP2 ) were compared with a 50:50% accessibility threshold (AT) and a 50:50% perceptibility threshold (PT). A grading system, based on the relative ranges of AT and PT, was employed. The percentage of samples falling into each color-matching category was then recorded. The data collected were subjected to statistical analysis, utilizing a mixed model ANOVA to evaluate the effects of shade tab color and mineral oil application on color differences, α = 0.05. The application of mineral oil significantly affected the ∆E00 [F(1, 378) = 19.1, p = < 0.0001]. However, this effect was only significant for the gingiva-colored study samples; the mineral oil application significantly decreased color difference, showing ∆E00 (RP1 ) of 8.71 ± 3.78 and ∆E00 (RP2 ) of 6.55 ± 2.14 (p < 0.0001). For the tooth-colored groups, the mineral oil application did not yield any color difference, showing ∆E00 (RP1 ) of 7.05 ± 2.35 and ∆E00 (RP2 ) of 6.94 ± 2.35 (p = 0.497). In the absence of mineral oil, gingiva-colored samples revealed a significantly larger ∆E00 (RP1 ) of 8.71 ± 3.78 compared to tooth-colored samples at 7.05 ± 2.35 (p = 0.017). Conversely, mineral oil application rendered comparable ∆E00 (RP2 ) values between gingiva-colored (6.55 ± 2.14) and tooth-colored (6.94 ± 2.35) samples (p = 0.558). All 3D-printed full-color samples showed Grade 1 (extremely unacceptable mismatch) and Grade 2 (clearly unacceptable mismatch), regardless of the shades or the presence of mineral oil. Utilizing an intraoral scanner to gather digital color data, along with an MJ 3D printer, offers the potential for producing 3D-printed full-color dental casts for prosthesis characterization in the dental laboratory. While mineral oil improves the color reproduction trueness of gingiva-colored objects, all 3D-printed full-color samples exhibited unacceptable mismatches when compared to their target objects. This underscores the need for future improvement in the digital color data acquisition process and color optimization protocols in 3D printing processes.

Sociodemographic factors associated with knowledge and attitudes of Peruvian dental interns about dental shade selection

BackgroundThe dentist should have a thorough knowledge of the science, protocols and procedures for dental shade selection in order to mimic dental tissue with restorative materials, respecting the individual needs and attitudes of each patient and providing them with a pleasant and esthetically acceptable appearance. The present study evaluated the knowledge and attitudes of dental interns from two Peruvian universities about dental shade selection and its relationship with sociodemographic factors.MethodsThe present cross-sectional and analytical study was carried out on Peruvian dental interns from the Universidad Nacional Federico Villarreal and the Universidad Privada de San Juan Bautista during May to June 2022. Two validated questionnaires on knowledge and attitudes about dental shade selection were used. A Poisson regression model with robust variance using the adjusted prevalence ratio (APR) was used to assess the influence of the variables: age group, sex, place of origin and type of university, considering a significance level of p<0.05.ResultsThe results showed that 40.8% (95% CI: 34.0% - 47.6%) of the interns presented unfavorable attitudes while 90.1% (95% CI: 86.0% - 94.2%) presented insufficient knowledge. It was also found that dental interns under 29 years of age were 32% less likely to have unfavorable attitudes (APR = 0.68, 95% CI 0.48 - 0.96) and 11% more likely to have insufficient knowledge (APR = 1.11, 95% CI 1.01 - 1.24) about tooth shade selection compared to dental interns aged 29 years and older. Finally, women were 55% more likely to have unfavorable attitudes about tooth shade selection compared to men (APR = 1.55; 95% CI: 1.08 - 2.22).ConclusionThe majority of dental interns presented insufficient knowledge and less than half had unfavorable attitudes about dental shade selection. In addition, being a student under 29 years of age was a risk factor for presenting insufficient knowledge and at the same time constituted a protective factor for presenting unfavorable attitudes. Likewise, being a female student was a risk factor for presenting unfavorable attitudes about dental shade selection.

Three-dimensional representation of the Vita Toothguide 3D-Master: An in vivo clinical study.

The Vita Toothguide 3D-Master (Vita Zahnfabrik) is considered the dental shade guide in which the three dimensions of color - lightness, hue, and chroma - are most well-ordered in the CIELAB color space. No research has yet explored how well the Vita Toothguide 3D-Master is ordered in the 3D color space by recording color coordinates in vivo. To evaluate the spatial color distribution of the Vita Toothguide 3D-Master's lightness, chroma, and hue groups and its 26 physical shade tabs. The dental color (L*, C*, h°, a*, and b* color coordinates) of a healthy maxillary central incisor was recorded for 1361 participants (aged between 18 and 89 years) using a Vita Easyshade Compact spectrophotometer (Vita Zahnfabrik). The R 2.7.2. statistics program was used to create the visual representations. The five lightness levels are those that are best distributed in the color space, in relation to the L* coordinates, followed by the chroma group and, finally, the hue group. The 5M1, 5M2, and 5M3 physical shade tabs are situated at a greater distance apart from the other tabs in the color space. The Vita Toothguide 3D-Master's 26 physical shade tabs are satisfactorily distributed in three-dimensional space, although strict mathematical criteria are not followed. The natural dental shades that fall lower on the lightness scale are the most poorly represented by the physical shade tabs. Darker teeth are poorly represented by the Vita Toothguide 3D-Master's physical shade tabs. The spatial distribution of dental shade guides needs to be improved to ensure they provide homogeneous coverage of the entire chromatic spectrum corresponding to natural teeth. This would help reduce the errors inherent to the subjective visual color selection process.

Digital Shade Matching in Dentistry: A Systematic Review.

The pursuit of aesthetic excellence in dentistry, shaped by societal trends and digital advancements, highlights the critical role of precise shade matching in restorative procedures. Although conventional methods are prevalent, challenges such as shade guide variability and subjective interpretation necessitate a re-evaluation in the face of emerging non-proximity digital instruments. This systematic review employs PRISMA protocols and keyword-based search strategies spanning the Scopus®, PubMed.gov, and Web of ScienceTM databases, with the last updated search carried out in October 2023. The study aimed to synthesise literature that identified digital non-proximity recording instruments and associated colour spaces in dentistry and compare the clinical outcomes of digital systems with spectrophotometers and conventional visual methods. Utilising predefined criteria and resolving disagreements between two reviewers through Cohen's kappa calculator, the review assessed 85 articles, with 33 included in a PICO model for clinical comparisons. The results reveal that 42% of studies employed the CIELAB colour space. Despite the challenges in study quality, non-proximity digital instruments demonstrated more consistent clinical outcomes than visual methods, akin to spectrophotometers, emphasising their efficacy in controlled conditions. The review underscores the evolving landscape of dental shade matching, recognising technological advancements and advocating for methodological rigor in dental research.

Comparison of the colour accuracy of a single-lens reflex camera and a smartphone camera in a clinical context

ObjectivesThis study aimed to investigate the colour accuracy of digital photographs captured by a single-lens reflex (SLR) camera and a smartphone camera in a clinical setting. MethodsDentate subjects were recruited, and their maxillary anterior teeth were photographed along with a colour target and a dental shade guide. There were eight groups: Group 1: SLR camera with a 100 mm macro-lens and a ring-flash (SLRC); Group 2: SLRC with a polarizer; Group 3: SLRC with white-balance calibration; Group 4: SLRC with a polarizer and white-balance calibration. Groups 5 to 8 were similar to Groups 1 to 4, except a smartphone camera and an external light source (SC) were used. The CIE LAB coordinates of the colour target, shade guide, and centre of the maxillary right central incisor (tooth 11) in the digital photographs were retrieved. The colour difference ΔE=[(ΔL*)2+(Δa*)2+(Δb*)2]1/2 to the reference colour coordinates or the reading of the dental spectrophotometer was calculated. The results were analysed by the Kruskal-Wallis test at α=0.05 with Bonferroni correction. ResultsThirty-nine subjects were photographed. SLRC with a polarizer showed the largest ΔE in this study (P<0.001). When capturing tooth 11, SLRC with calibrated white-balance resulted in the smallest ΔE in this study (P<0.001), and the use of a polarizer and/or calibrated white-balance did not result in a smaller ΔE than that of SC alone (P>0.001). ConclusionCalibration for white-balance is recommended for the SLRC. The use of a polarizer does not show an improvement in colour accuracy. SC alone may be sufficient for intraoral photography. Clinical significanceWhen capturing intraoral photography using a single-lens reflex camera, it is recommended to calibrate the white-balance. The use of a polarizer does not significantly improve colour accuracy. However, a smartphone camera with an external light source can serve as a viable alternative.

In pursuit of gold standard shade guide method, a comparative in-vivo study between manual and digital shade guides

The available shade guide system in dentistry includes Manual and Digital. Although there is lot of research going on better system to choose dental shade but still there are many factors including source of light illuminating the tooth, the characteristics of tooth and the observer viewing the tooth which needs to study further. In this study, a comparative analysis is made between the Manual and Digital shade guide systems.: The objective of the study is to record the manual (subjective method) and a digital shade (Objective method) of 500 subjects by two observers (Prosthodontist 1 {P1} and Prosthodontist 2 {P2}). : 500 patients having a complete set of anterior teeth with sound maxillary central incisors were selected for the study. Manual shade selection (Vita 3D Master) of 50% of subjects is made by P1. Then P2 does shade selection of the same subjects by digital method (Vita Easy Shade Advance) and records the deviation of values including ∆E, ∆L, ∆C, and ∆h by digital shade guide from the manual shade as recorded by P1 using verification mode of Digital shade guide. Recording of shades and deviation values is done for the remaining 50 % of patients by role reversal between P1 and P2.: The kappa correlation values for Hue value and chroma when P1 records manually and P2 documents shade by digital shade guide include 0.26, 0.42, and 0.13 indicating fair, moderate, and slight to no agreement respectively. The kappa correlation values for Hue value and chroma when P2 records manually and P1 records shade by digital shade guide include -0.08, 0.51 and 0.12 indicating no agreement, moderate and slight to no agreement respectively.It is advisable to use technology to overcome the errors of subjectivity. Due to edge loss with a spectrophotometer, especially in the incisal and cervical region, a combination of digital and manual systems always comes in handy when deciding on a particular shade or shade map.

EFFECT OF DIFFERENT DRINKS ON STAINABILITY OF ACRYLIC DENTURE TEETH

Acrylic denture teeth may experience colour change after some time in service. The aim of this study was to evaluate the discolouration of the acrylic denture teeth when immersed in tea and cola solutions. These solutions were chosen as they are the daily drink by most Malaysians despite of the age based on surveys in Malaysia. 45 first maxillary anterior acrylic denture teeth were divided into three groups (n=15): control (distilled water), tea and cola solutions. The colour changes were recorded after Day 1, Day 7, Day 15 and Day 30 using Coral dental shade guide and visible spectrometer. The visible spectrometry analysis showed that there is a relatively distinctive feature between reflectance from samples immersed in tea and cola. There is strong indication of colour changes for the samples immersed in tea compared to cola, particularly for wavelength between 400-500 nm after 30 days. The result shows that acrylic teeth became slightly darker when immersed in the tea solution for 15 days and 30 days. Average discolouration of the acrylic teeth on day 15 was 1.1333 (SD 0.3519) and day 30 was 1.4467 (SD 0.5164). On the contrary, teeth immersed in cola did change colour but became slightly brighter. The colour change is insignificant, indicating the stable properties of acrylic denture teeth colour and they were not influenced by extrinsic factors. The discolouration of acrylic resin denture teeth was time dependent and increased proportionally with the immersion period.

Influence of image file and white balance on photographic color assessment

Statement of problemHow the color parameters obtained from digital photographs may be influenced by illumination, file format, and subject color is unclear. PurposeThe purpose of this in vitro study was to evaluate color differences (ΔE00) and CIELab color coordinates among different types of file formats of dental shade tab images with and without white balance. Material and methodsDifferent shade tab colors (n=10) were photographed with a digital camera under standard conditions. The photographs were stored in RAW, JPEG, and TIFF file formats and evaluated with and without white balance (WB) adjustment by using an image software program and a gray reference card with known color coordinates. CIEDE2000 color differences between each image file format and the control group (RAW WB) were calculated, and interpreted by the visual perceptibility (PT00=0.8) and acceptability (AT00=1.8) thresholds. The ΔE00 color shift was defined according to CIEDE2000 lightness, chroma, and hue and interpreted by the following respective visual acceptability thresholds: 2.92, 2.52, and 1.90. The differences among the color coordinates were analyzed by Kruskal-Wallis and Bonferroni post hoc tests (α=.05). ResultsThe color coordinates presented statistically significant differences between the file formats and control group (P<.001). Excellent matches (ΔE00 ≤0.8) were observed on TIFF and JPEG saved from RAW-WB. Images without WB presented unacceptable mismatches (ΔE00 >5.4). ΔE00 color shift of images without WB were predominantly influenced by ΔH00, while JPEG, WB, and TIFF WB were mostly influenced by ΔC00. ConclusionsOnly compressed JPEG or TIFF files of dental shade tabs derived from original RAW WB photographs were able to achieve color differences within the limits of the 50:50% perceptibility threshold, providing excellent color matches with the RAW WB files.

Blue (0.44 µm) and red (1.7 µm) diode laser activated bleaching—dental shade changes determination

Tooth whitening or bleaching is one of the most common dental procedures that optimize the white color of the teeth and minimize the simultaneous damage to the tooth structure. Light can speed up the whitening process with halogen lamps, light-emitting diodes, plasma arc lamps, and lasers. Our results show that combinations of a teeth whitening agent with laser light irradiation with a 0.44 µm blue laser diode or a 1.7 µm near-IR laser diode accelerate the whitening process not only during tooth irradiation but also within two weeks after the procedure.

Spectrophotometers, Shade Guides, and Color Perception and its Relation to Digital Shade Matching in Restorative Dentistry

Achieving an aesthetically pleasing appearance in dental restorations is a complex task that depends on the accurate selection of tooth shade. The shade of a tooth is influenced by both intrinsic factors, such as light scattering within enamel and dentin, and extrinsic factors, such as the absorption of staining substances. As patient awareness and expectations regarding aesthetically attractive dental restorations have grown, so too has the pressure on dentists to deliver more naturally appearing results. Conventional approaches have often shifted towards artistic interpretation, but advances in materials and technology have prompted a shift towards more scientifically rigorous methods. Despite the availability of advanced devices for shade matching, their adoption remains low. Studies suggest that electronic tools can measure up to 100,000 dental shades, far surpassing the human eye's ability to detect only 1% of dental color variations. This paper calls for more research to examine the accuracy of various shade-selection techniques in meeting the rising aesthetic expectations in modern dentistry.

Comparison between Visual shade selection and Instrumental Shade Determination using Intra Oral Scanner and Digital Spectrophotometer

Background: Improper shade selection is one of the most common causes behind restorations’ remake and patient dissatisfaction. Multiple protocols and devices have been proposed to address the limitations of visual shade selection. Objective: To compare the accuracy of dental shade matching gathered visually with both VITA Classical (VC) and VITA 3D-Master (V3D) shade guides with those obtained instrumentally with both 3Shape Trios 3 and VITA Easyshade® Advance 4.0. Materials and Methods: For visual shade selection (VSS), one- hundred participants from King AbdulAziz University, Faculty of Dentistry participated in the study and asked to select the shade of six masked shade tabs from both VC [A1, A2, B1] and V3D [1M1, 2M3, 3R1.]. Later, Instrumental shade determination (ISD) was completed by one experienced participant for six cycles using: VEasy and Trios 3. Results: Significant difference was found between VSS and ISD. The results suggested that although participants significantly preferred VC over V3D in terms of VSS, this did not improve the shade selection performance. Besides, in ISD, no significant difference was reported between VEsay and Trios 3. There was no statistical significance difference between neither Trios 3 when combined with VC and V3D nor between VEasy when combined with VC and V3D. VEasy showed the best shade selection performance when combined with V3D, although the difference was non-significant. Conclusion: The result of the present study supports the promising use of the intra oral scanner 3Shape Trios 3 and dental spectrophotometer VITA Easyshade® Advance 4.0. Combination with a visual selection method may result in more accurate and reliable results.

Effectiveness of calibrated digital photography technique in dental shade analyses applications

Objectives: Although spectrophotometers are commonly used in shade analysis in dentistry; digital cameras, photographic lighting systems, computer programs and photographs have also become the part of this field. The aim of this study was to compare the success of spectrophotometer and calibrated digital photography on shade selection. Materials and Methods: 3D-Master toothguide (VITA) with 29 tabs was used for the analyses. L, a, b values were determined by a spectrophotometer (Minolta CM-2300D, Konica) and these values were matched with digital photographic measurements. Photographs were transferred to an image analyzing software (Adobe Photoshop CC). Results: There were significant differences between L* values of the spectrophotometric analyses and digital measurements in 3 different regions of the tab (p&amp;lt;0.05). For the evaluation of ΔE values, Post hoc Bonferroni analysis which was performed between the 3 regions of shade tabs revealed significant difference between the middle (21.92 ± 2.31), incisal (13.67 ± 1.69) and cervical (19.57 ± 2.47) region of the tabs (p&amp;lt;0.05). Conclusion: Spectrophotometer was found to be a more accurate shade determination technique compared to calibrated digital photography.

An Overview of Shade Selection in Clinical Dentistry

The selection of an accurate tooth shade has always been a challenging task for dental practitioners in restoring the natural appearance of teeth. Various factors can influence shade selection, such as different lighting conditions, clearness and opaqueness of teeth, eye fatigue, aging and color vision problems. It is imperative to have a sound knowledge about the concept of shades and its selection protocol for obtaining good esthetics outcomes. To attain the best esthetics, four elementary contributing factors are essential: exact position, shape, surface texture and shade. The current analysis focuses on several features of shade, sensitivity of shades, optical properties of the teeth, visual and innovative instrumental techniques for shade selection, protocols for shade selection and factors affecting dental shade selection.

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

ObjectivesThis study aims to evaluate in vivo the color agreement between natural teeth and dental shade guides by means of visual and instrumental coverage error (mathrm{CE}) index.Materials and methodsThe 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 ({mathrm{CE}}_{mathrm{V}}) and instrumental ({mathrm{CE}}_{mathrm{I}}) coverage error indexes were computed using CIELAB and CIEDE2000 metrics for both shade guides. For {mathrm{CE}}_{mathrm{V}} 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, {mathrm{Delta E}}_{mathrm{ab}}^{*}= 1.2, {mathrm{Delta E}}_{00}= 0.8) and acceptability (AT, {mathrm{Delta E}}_{mathrm{ab}}^{*}= 2.7, {mathrm{Delta E}}_{00}= 1.8) color thresholds for dentistry.ResultsVC and V3DM exhibited {mathrm{CE}}_{mathrm{I}} (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 {mathrm{CE}}_{mathrm{V}} (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. {mathrm{CE}}_{mathrm{I}} contributes more than 50% (53.2–82.4% range) to the {mathrm{CE}}_{mathrm{V}} value. This contribution depends on the shade guide used and the quality of the visual rating.ConclusionsThe 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 relevanceIt necessary to further improve commercially available dental shade guides to facilitate achievement of satisfactory esthetics results in clinical practice.

Repeatability of dental shade by digital spectrophotometry in current, former, and never smokers

Cigarette smoking contributes to poor oral health and dental discoloration. Therefore, stopping smoking may translate into measurable amelioration of dental shade indices. We compared dental shade parameters by digital spectrophotometry among current, former, and never smokers and verified their repeatability at 7 and 30 days. Dental shade parameters (CIE L*a*b* and corresponding whiteness index for dentistry-WID) were measured in current, former, and never smokers with a digital spectrophotometer (Vita Easyshade V) on three separate study visits: at baseline (day 0), at day 7, and day 30. Dental shade parameters were analyzed in 18 current, 18 former, and 20 never smokers. The repeatability of shade parameters was consistent in current, former, and never smokers. L*, a*, b*, and WID show significant short and long-term repeatability (p < 0.0001, by regression analyses). The mean (± SD) WID score of 13.42 (± 4.9) in current smokers was significantly lower compared to the WID score of 20.38 (± 5.3) in never smokers (p = 0.001). No significant differences were observed between current and former smokers and between former smokers and former smokers. Dental shade measurements by digital spectrophotometry were highly reproducible and showed that teeth whiteness of current smokers is substantially inferior compared to never smokers. Objective discrimination of dental shade can be a valuable regulatory science endpoint for investigating oral hygiene and dental aesthetics of consumer care products, smoking cessation medications, and tar-free tobacco products (e-cigarettes, heated tobacco products, oral nicotine products) for cigarette substitution.Clinical trial registration: the study was not registered in ClinicalTrials.gov considering that it is a pilot study, parts of a larger project with ID: NCT04649645

Accuracy and repeatability of different intraoral instruments on shade determination compared to visual shade selection.

To evaluate the accuracy and repeatability of intraoral instruments used for shade determination compared to visual shade selection (VSS). A total of 20 subjects and 10 observers, balanced by gender, participated in the study. Observers performed VSS of the upper right central incisor from each subject. Instrumental shade determination of the same teeth was performed using a spectrophotometer (Easyshade V) and intraoral scanners (CEREC Omnicam, Primescan, Trios 3 and Trios 4). Vita Classical shade nomenclature was used to record the shade designation for all instruments and VSS. The accuracy of the instruments was determined by comparing the instrument readings with the most frequent visual shade selected. The percentage of accuracy was obtained by comparing the number of agreements with the number of comparisons. The percentage of repeatability was obtained by comparing the number of repeated shades with the number of shade measurements in each group. Accuracy was compared using Cochran Q test followed by pairwise comparisons using multiple McNemar's tests with Bonferroni correction. Repeatability of the instruments was evaluated using Cronbach's alpha. Omnicam showed a significant lower accuracy than the other instruments (p <0.05). No statistical difference on repeatability was found among the different instruments (p >0.05). It was not found any statistical differences for VSS accuracy among the observers (p =0.437) and between genders (p =0.867). Instrumental repeatability (≥75%) and similar accuracy between the best performed instruments (69%-77.5%) and the observers performance (65%-90%) supports the use of high-performance instruments for dental shade determination. Most instruments (Easyshade V, Primescan, Trios 3, and Trios 4) showed similar accuracy performance to observers in the VSS.

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

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. 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. 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. 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.

Assessment of coverage error for two common commercial dental shade guides using a spectrophotometric method

AbstractThe purpose of this study was to assess the coverage error and the coverage error percentage for two common commercial dental shade guides named VITA classical A1‐D4 shade guide and VITA Toothguide 3D‐MASTER. Totally, 197 dental students with intact maxillary anterior teeth were randomly selected to participate in the study. CIELAB values of the teeth were measured with a spectrophotometer. The teeth matched shades were selected by using the spectrophotometer. ∆E00 and ∆E*ab color differences between the matched shades and the teeth shades were calculated. The mean ∆E00 and ∆E*ab values represented the coverage errors for the shade guides. The coverage error values were compared with the thresholds for perceptibility and acceptability using 1‐sample t test (α = 0.05). To calculate the coverage error percentages for the shade guides, a color matching error for the shade guides was considered when the color difference value was greater than the thresholds. For VITA classical shade guide, the coverage error was 3.0 ± 1.2 (∆E00) and 3.3 ± 1.3(∆E*ab) while the coverage error percentages ranged between 63.6% and 99.4%. For VITA 3D‐MASTER guide, the coverage error was 2.5 ± 1.3 (∆E00) and 2.9 ± 1.5 (∆E*ab) while the coverage error percentages ranged between 44.5% and 96.9%. Overall, the teeth were more reddish than their matched shades of the shade guides. Using these shade guides may cause inaccurate shade determination in the population studied due to their high coverage error and coverage error percentage values.

Can identical dental shade guides be used interchangeably?

To determine if identical dental shade guides can be used interchangeably considering their precision. Twenty Vita classical (VC) and Vita 3D-Master (VM) shade guides were subjected to spectrophotometric measurements and their CIELab values were measured in three shade tab regions: incisal, middle, and cervical and also in total. The mean L*, a*, and b* values for analogous shade tabs were calculated to identify CIELab values for typical shades. ∆E00 color differences between a typical shade and its analogous shade tabs were measured. ∆E00 values were compared with perceptibility (∆E00 = 0.8) and acceptability (∆E00 = 1.8) thresholds using one-sample t test (α= 0.05). An error was considered when the ∆E00 value was greater than the threshold. Subsequently, the shade guides' precision scores were calculated. Mean ∆E00 values ranged between 0.3 and 0.5 for VC tabs and between 0.3 and 0.6 for VM tabs. Precision scores for both shade guides ranged from 83.3% to 100%, considering the perceptibility threshold. Regarding the acceptability threshold, precision scores for VC ranged from 93.3% to 100%, while the precision scores for VM were 100%. Owing to high precision of VC and VM, identical dental shade guides can be used interchangeably. Using identical dental shade guides interchangeably may affect the color results of restorative treatments. This study identified high levels of precision for identical shade tabs of Vita classical and Vita 3D-Master across different batches. Thus, similar dental shade guides can be used interchangeably.