Dental Shade Research Articles

Preparation and Performance Evaluation of Duotone 3D-Printed Polyetheretherketone as Oral Prosthetic Materials: A Proof-of-Concept Study.

Literature has reported the successful use of 3D printed polyetheretherketone (PEEK) to fabricate human body implants and oral prostheses. However, the current 3D printed PEEK (brown color) cannot mimic the vivid color of oral tissues and thus cannot meet the esthetical need for dental application. Therefore, titanium dioxide (TiO2) and ferric oxide (Fe2O3) were incorporated into PEEK to prepare a series of tooth-color and gingival-color PEEK composites in this study. Through color measurements and mechanical tests, the color value and mechanical performance of the 3D printed PEEK composites were evaluated. In addition, duotone PEEK specimens were printed by a double nozzle with an interface between tooth-color and gingival-color parts. The mechanical performance of duotone PEEK with two different interfaces (horizontal and vertical) was investigated. With the addition of TiO2 and Fe2O3, the colors of 3D printed PEEK composites become closer to that of dental shade guides. 3D printed PEEK composites generally demonstrated superior tensile and flexural properties and hence have great potential in the dental application. In addition, duotone 3D printed PEEK with a horizontal interfacial orientation presented better mechanical performance than that with a vertical one.

CIEL*a*b* values in vita classical and vita 3d master by two dental spectrophotometers.

To compare the CIE L*a*b* values of two different dental shade guides using two shade-matching spectrophotometers. SpectroShade Micro (MHT) and Easyshade (VITA Zahnfabrik) were tested. One calibrated operator performed 30 measurements of each tab from three batches of two guides, VITA Classical (VC) and VITA 3D-Master (VM). Receiver operating characteristic (ROC) curves and intraclass coefficients (ICC) between the different batches were calculated. Results were given as mean and SD of the L*a*b* values and the respective color differences according to the CIEDE 2000 formula (ΔE00) for each of the shade tabs in the two spectrophotometers, then analyzed with independent student t test (α = .05). A total of 1,440 and 2,610 measurements for VC and VM, respectively, were performed per spectrophotometer. There were statistically significant differences between the two devices for all L*a*b* values, with the exception of: L* for 3R1.5; a* for 2R1.5, 3L1.5, 2L2.5, 3M2, 3L2.5, 4L1.5, and 4L2.5; and b* for D3, 1M2, and 3M2. When assessing the same shade guide, differences in ΔE00 were detected between devices above the acceptability threshold (ΔE00 ≥ 1.8) for all shade tabs except for VC (C1, C2, D3, A3.5, C3, and A4) and VM (4M1, 3R2.5, 4L2.5, and 4M3). The overall mean of the inter-device ΔE00 was 2.2 ± 1.0 for VC and 2.5 ± 1.0 for VM. The two dental spectrophotometers presented high ICC and ROC values, which validates their indication as auxiliary tools. However, there are discrepancies in the hues D (VC) and R (VM) with interdevice variability when evaluated for the L*a*b* component.

An analysis of an educational method to improve the shade-matching ability of dental students

Statement of problemThe predoctoral dental curriculum includes didactic lectures, demonstrations, and training on shade-matching techniques and protocols. However, a significant percentage of esthetic failures are still observed clinically. An assessment is required to determine whether reevaluation and modification of this training protocol would help future dental practitioners better perceive and communicate the dental shade. PurposeThe purpose of this study was to evaluate dental students’ knowledge of and skill in shade selection and effective prescription writing before and after educational training with 3 different shade guides. Material and methodsThirty predoctoral dental students (interns) who had completed their academic program and were undergoing clinical training were selected. After excluding color vision deficiency, the study participants were first asked to evaluate the shade of the right maxillary central incisor of 5 patient participants by using 3 different shade guides (Vitapan Classical, Vitapan 3D-MASTER, Chromascop) under standardized conditions. They were then asked to write an esthetic prescription, communicating the shade to a dental laboratory technician. A dental faculty member evaluated the baseline control shade for each participant, and a standardized prescription format was written. This was used as a reference by a dental laboratory technician to score the intern’s prescription as clear, unclear, poor, or illegible. After the assessment, focused small group learning with lectures, clinical demonstrations, and case-based discussion was provided to the interns on shade assessment over 10 to 15 days. All the interns were reassessed for their visual shade perception and prescription writing after a month’s interval. The mean percentage agreement, mean percentage shade match, and mean color difference between the shade selected and the control shade for each of the 5 participants, with all 3 shade guides, were evaluated along with the prescription scoring before and after the educational training. Statistical comparison of before and after values were made by using the paired-sample z-test for percentage agreement versus disagreement among the interns for the shade selected, paired t test for mean percentage agreement, mean percentage shade match, and mean color difference. The repeated measure ANOVA test was used for the prescription scorings (α=.05). ResultsA significant difference in prescription scoring (P<.001) was observed. A significant difference in the percentage shade match (P<.01) for all 3 shade guides and mean percentage agreement for Chromascop and Vita 3D-MASTER (P<.05) were observed. A nonsignificant mean color difference between the shade selected by the intern and the baseline shade was observed. ConclusionsA significant difference in prescription scoring was observed after training, along with a higher percentage shade match and percentage agreement. This indicated a need to reconsider the educational training provided for dental shade assessment and communication and to implement better protocols in the dental curriculum.

An evaluation of factors affecting dental shade matching in first-year dental students

Statement of problemShade selection has become more important and challenging as it becomes more emphasized in esthetic dentistry. It would be beneficial to screen dental students early in their predoctoral education for any deficiencies in color discrimination. Specific tests that reliably predict dental shade-matching ability have not been fully established. PurposeThe purpose of this study was to determine whether the Farnsworth-Munsell 100 Hue Test (FM-100), Perceptual Ability Test (PAT), ethnicity, age, sex, and time to complete the tests affect dental shade-matching ability and value discernment in first-year dental students. Secondary aims were to determine whether correlations exist between performance on the PAT and FM-100 and between FM-100 and dental shade matching. Material and methodsThe FM-100 test was administered to 98 first-year dental students in a Judge II booth (color temperature=6500 K, color rendering index=90). The Vita Toothguide 3D-Master shade guide was used in this study. For the Value Test, students arranged 3 sets of 5 masked shade tabs from lightest to darkest. In all 3 sets, the value ranged from 1 to 5. In set #1, each shade tab had the same hue and chroma. In set #2, the hues were constant, but the chroma varied. In set #3, the hue and chroma varied. For the Matching Test, students matched together 11 pairs of masked shade tabs from 2 shade guides. Ethnicity (white, African American, Hispanic, Middle Eastern, and Asian), PAT scores, age, sex, and time to complete tests were recorded. Data were analyzed by using least square means, Wilcoxon Rank Sum, Kruskal-Wallis, and Spearman correlation tests (α=.05). ResultsFM-100 total error scores (TES) ranged from 0 to 188. Forty-three students had superior color discrimination (TES 0 to16), 51 had average (TES 20 to 100), and 4 had poor color discrimination (TES>100). Ethnicity, age, and sex did not significantly affect performance on any tests. Longer completion time resulted in better performance on FM-100 (P=.002) and Matching Tests (P=.032). However, increased time resulted in fewer correct answers on the Value Test (P=.016). There was a significant effect of PAT on FM-100 results (P<.001). As PAT scores increased, TES scores decreased, indicating better color discrimination. Similarly, lower TES scores resulted in higher Matching Test results (P<.001). However, this was not observed on the Value Test (P=.302). Correlation between the PAT and FM-100 was weak (r=-0.217), as well as between the FM-100 and Matching Test (r=-0.364). ConclusionsEthnicity, age, and sex did not affect dental shade-matching ability. Participants with higher PAT scores demonstrated higher color discrimination on the FM-100 and were better at matching dental shade tabs. Time had different effects on the Matching and Value tests.

Assessment of Color Parameters on Maxillary Right Central Incisors Using Spectrophotometer and RAW Mobile Photos in Different Light Conditions.

ObjectivesThe aim of the study was to compare three color parameters assessed on the maxillary right central incisors using a spectrophotometer as the gold standard, along with RAW mobile calibrated and non-calibrated photos in different light conditions.Materials and methodsA total of 30 dental students participated in the study. CIE L*a*b* values were measured in the middle third of each maxillary right central incisor spectrophotometrically and digitally on RAW mobile dental photos using different light conditions (F-frontal light; L-lateral light; D-lateral light with diffusers; P- polarizing filter on frontal light; H-hybrid filter as combination of frontal light with polarizing filter and lateral lights with diffusers) with LEDs (light emitting diode) in full power, and with gray card calibration. The obtained results were compared.ResultsMean a* and b* values on calibrated, as well as mean L* values on non-calibrated RAW mobile photos did not significantly differ in different light conditions (P>0.05). CIE L*a*b* values on non-calibrated polarizing RAW mobile photos completely matched the same values obtained using a spectrophotometer on the subject’s maxillary right central incisor (P>0.05).ConclusionsDifferent light conditions and measuring procedures affected CIE L*a*b* values on RAW mobile photos in this study. Within the limitations, non-calibrated RAW mobile photos using a lightening device with polarizing filters on frontal LED light in standardized conditions can be a useful tool for digital dental shade determination.

Accuracy and repeatability of different intraoral scanners on shade determination

AbstractObjectiveTo evaluate the accuracy and repeatability of different intraoral scanners on shade determination.Materials and methodsTen different shades of Vita Mark II blocks were used. A disc‐shape specimen (10 mm in diameter and 1 mm thick) per ceramic block was fabricated. Ten color measurements per specimen were performed by each instrument (Vita Easyshade V [control], 3shape Trios, Cerec Omnicam, Cerec Primescan) and recorded in Vita Classic color system. The number of correct shade match per instrument for each shade was recorded. Instrumental accuracy was compared using Cochran Q test and repeatability was analyzed using Cronbach's alpha.ResultsThere was a significant difference in the instrumental accuracy for shade determination (p &lt; 0.001). There was no statistical difference between the Easyshade V (78%) and the 3Shape Trios (66%) (p &gt; 0.05), with the latter being similar to the other scanners Primescan(63%) and Omnicam (57%) (p &gt; 0.05). No significant difference was found (p &gt; 0.05) when different shades were evaluated by the same instrument. Similar repeatability was found for the different devices, ranging from 44.3% for Easyshade to 51.9% for Omnicam.ConclusionThe evaluated instruments showed less than expected repeatability and accuracy on measuring different dental shades. Therefore, caution should be exercised when using instrumental shade determination, which should be accompanied by experienced human visual assessment.Clinical significanceThe outcome of this study might help clinicians evaluate the performance of intraoral scanners as a shade matching tool.

Dental Shade Matching Method Based on Hue, Saturation, Value Color Model with Machine Learning and Fuzzy Decision

Dental Shade Matching Method Based on Hue, Saturation, Value Color Model with Machine Learning and Fuzzy Decision

Is there an association between Perceptual Ability Test scores and color vision acuity?

The purpose of this study was to determine if there is an association between Perceptual Ability Test (PAT) results and color vision deficiency (CVD). Three consecutive classes of first-year dental students (n=291) voluntarily participated in the study. The Farnsworth-Munsell 100 Hue Color Vision test (FM-100) was administered to students beneath a Macbeth Judge II viewing booth that provided ideal lighting conditions to ascertain CVD. Results of FM-100 test were recorded as total error scores (TES). Color acuity was scored as superior (TES 0-16), average (TES 20-100), or poor (TES>100). Additional information of age, sex, ethnicity, and time to complete the FM-100 was obtained. Multiple linear regression was used to determine the association between PAT and CVD while adjusting for age, sex, ethnicity, and time to complete the FM-100 test. TES ranged from 0-244. There were 132 students with superior color acuity, 161 with average, and eight with poor acuity. Females performed better than males on the FM-100 test. Time to complete the FM-100 test ranged from 3:40 minutes to 25:12 minutes. There was a strong relationship between PAT scores and CVD (P=0.0003). A 1-unit increase in PAT scores was found to result in a 9% decrease in TES; indicating that students with higher PAT scores are less likely to have CVD. The PAT may be a preliminary screening instrument to identify students who may have CVD. The FM-100 test can then confirm the presence of CVD. Students with CVD may desire to improve dental shade matching skills through targeted training and education.

Tooth shade analysis and selection in prosthodontics: A systematic review and meta-analysis.

Aim:To evaluate the methods of the dental shade selection and provide a summary of different factors affecting the shade selection.Design and Setting:The systematic review and meta-analysis.Materials and Methods:The electronic search of the peer-review articles between 2002 and 2018 was carried out the by using the PRISMA guidelines. A total twenty-one studies related to the visual shade methods, instrumental shade methods, and the factors affecting the shade selections was evaluated. The search strategy was based on the PICOS framework.Statistical Analysis:There was statistically significant heterogeneity (Q = 1038.1518, df = 20, and P < 0.0001). The statistics of fixed-effect model reported an MD of − 0.0970 (95% CI = −0.1391, −0.0549). The random-effect model reported an MD of − 0.0862 (95% CI = −0.5866, 0.4142).Result:The review evaluated the 21 studies of tooth colour science that met with the inclusion criteria and search criteria. The meta-analysis of the 21 combined studies reported acceptable homogeneity (i2 = 98%) which indicates a statistically significant difference between the treatment and control groups.Conclusion:The VES spectrophotometer reported the highest accuracy, reliability, and repeatability in shade selection followed by photo colorimetric method. The Vita 3D master shows more consistent results in repetitive shade selection. Knowledge and training of the shade selection protocol are necessary for proper shade matching

Perception and practices with regard to tooth shade selection for composite restoration among dentists in Southwest, Nigeria

Background: The perception of tooth color is an important goal for the dentist who needs to choose the right tooth shade to create satisfactory esthetic restorations as well as for the patient who desires a better smile. The success of any tooth-colored (anterior) restoration is however directly related to the accuracy of chairside shade selection The aim of this study was to determine the knowledge and practices of dentists on shade selection in composite restorations in Southwest, Nigeria. Materials and Methods: This descriptive self-administered questionnaire-based study was conducted among 200 randomly enlisted dentists selected by multistage sampling in the Southwest of Nigeria. Chi-square statistical test was utilized for categorical variables, while the independent t-test was used to compare the mean values in subgroups. A multivariate linear regression model was used to assess the association between predictor variables and knowledge scores. The level of significance in this study was set at 0.05. Results: Majority of respondents had good knowledge (67.5%), while 60.5% of them had good practices. The highest proportion (66.5%) used only visual shade selection in natural daylight (89.0%), while only 48% determine the tooth shade at the cervical, middle, and incisal third of the tooth; 73% had never taken a color blind test. Dentists had practiced for more than 10 years and restorative dentistry consultants had significantly better knowledge about shade selection. Respondents who had poor knowledge had significantly poorer shade selection practices (P = 0.036). After controlling for confounders by multivariate logistic regression, all categories of dentists with good knowledge and consultants still had significantly better dental shade selection practices. Conclusion: Experienced dentists and restorative consultants appear to have adequate knowledge about shade selection and this had a significant impact on their practice. A need however exists to bridge the gap among other categories of dental personnel to improve the esthetic outcome of composite restorations.

Development of a novel dental shade determination application.

Determining the shade of dental materials is a challenging requirement for the restorative dentist. Improper shade selection is the second cause for laboratory remakes, resulting in inefficiency and additional cost, and unnecessary stress for the clinician and patient. The process of shade selection is somewhat subjective, with no consensus on the protocol. This research investigation aimed to develop a novel software application to provide an accurate, objective, and systematic approach to shade determination for teeth, soft tissues, and dental materials. An IOS software application was developed, termed Smile Shade, to facilitate a simple approach for dental shade determination. Smile Shade functions on a high-dynamic-range microcolor sensor with automatic temperature control and inter-device repeatability of <1.0 ∆E. The determination of shade is completed through the evaluation of color based on CMYK, RGB, and LAB, which are different techniques of storing colors. Further research is underway to compare this novel application to the traditional shade tab approach commonly practiced at most dental schools.

Repeatability of the human eye compared to an intraoral scanner in dental shade matching

ObjectiveThe purpose of this investigation was to compare the repeatability of an intraoral scanner (3Shape TRIOS) with the traditional visual method for dental shade matching in patients and to assess the influence of ambient lighting and the observer's sex and experience on visual shade matching. An additional aim was to determine the color dimension for which repeatability is greater with both the visual method and intraoral scanner. MethodsThirty observers (15 men and 15 women), grouped by professional experience, selected the shade of the right maxillary central incisor in 10 patients on three different occasions under different ambient lighting conditions (twice under studio clinic lighting and once under natural light). The same procedure was repeated using an intraoral scanner. All shades were selected based on the VITA Toothguide 3D-MASTER. The repeatability of each observer and the intraoral scanner were recorded for each color dimension (hue, chroma, and value). ResultsThe TRIOS intraoral scanner obtained a mean repeatability of 86.66% in dental shade matching compared to 75.22% achieved by the visual method. Ambient lighting had a direct effect on the repeatability of the shade selection for the visual method, whereas the observer's sex and clinical experience did not. For the visual method, the repeatability in dental shade matching depended on the dimension studied, with the best results in value, followed by hue and chroma; however, such dependence was not detected for the intraoral scanner. ConclusionsThe TRIOS intraoral scanner ensured better repeatability than the visual method in dental shade matching.

Demonstration of SiO2/SiC based protective coating for dental ceramic prostheses.

SiO2/SiC coatings were deposited onto ceramics disks using plasma enhanced chemical vapor deposition. The effects of deposition pressure and gas-flow ratio on the refractive index, extinction coefficient, and SiC composition were studied. For the highest studied SiH4 to CH4 gas-flow ratio of 1.5, the refractive index increased by 17% from 2.53 (at the wavelength of 845 nm) to 2.96 (at the wavelength of 400 nm). For the lowest studied SiH4 to CH4 gas-flow ratio of 0.5, the refractive index only increased by 4% from 2.11 (at the wavelength of 845 nm) to 2.20 (at the wavelength of 400 nm). At higher deposition pressures, the variation in refractive index of the SiC coatings was significantly lower showing a slight increase from 1.93 (at a wavelength of 845 nm) to 1.96 at a wavelength of 400 nm. Except for the case of a low SiH4 to CH4 gas-flow ratio of 0.5, for light with wavelengths ≤ 650 nm, the extinction coefficient of the SiC coatings increased significantly. Light with a wavelength > 650 nm had an extinction coefficient near 0 in all cases. After annealing the sample at 400°C for 4 hours, hydrogen-related bonds broke and the stress of the film was reduced from -245 to -71 MPa. By utilizing different thicknesses of SiC, the full standard dental shade guide was matched with the ΔE of each coated disk being less than 3.3 compared to the shade guide.

An efficient image processing methodology based on fuzzy decision for dental shade matching

An efficient image processing methodology based on fuzzy decision for dental shade matching

Two years survivability of VITA 3D master shade matching guides after disinfection with isopropyl alcohol: An in vitro study.

Background:Dental shade guides are used before restorative and prosthodontic procedures for the evaluation of tooth color. The spectral coverage of the specific shaded guide and a clinician's experience in shade matching are the two most important factors for a clinically viable shade match of the restoration to the given tooth. Repeated disinfection of the shade guide with disinfectant lead to a clinically significant difference of the shade to be matched, finally resulting in a clinically unacceptable prosthesis. The purpose of this study is to evaluate the effects of disinfection on various shade tabs of VITA 3D Master Shade guide after being subjected to 2 years of simulated disinfection with 70% isopropyl alcohol.Methodology:Two sets of VITA 3-D Master Shade Guides were used. One set of each shade guide was assessed after simulated use and surface disinfection with 70% isopropyl alcohol (test group), while the other full set was subjected to cleansing with distilled water (control group). Spectrophotometer was used to measure each of the shade tabs. Readings were recorded at regular intervals of 120, 240, 360, 480, 600, 720, 840, and 960 disinfection cycles. The ΔE values obtained were used to examine the color difference.Results:There was a significant difference in terms of ΔE between the shade tabs of control and test groups of VITA 3D Master shade guides after 960 cycles of disinfection. The change in mean ΔE was more in the test specimens in the shade tabs of VITA 3D Master Shade Guide tabs than the control specimens. These results are of statistical significance, but they might not be of any clinical significance.Conclusion:There was a statistically significant but clinically nonsignificant color change in the shade tabs of VITA 3D Master shade guides after 2 years of simulated use and disinfection with 70% isopropyl alcohol.

A comparison between visual, intraoral scanner, and spectrophotometer shade matching: A clinical study

Statement of problemVisual shade matching is subjective and a cause of concern for clinicians. Different measurement devices have been developed to assist in tooth color selection and to achieve better esthetic results. However, consensus is lacking as to which method of tooth shade selection provides more predictable results. PurposeThe purpose of this clinical study was to compare the reliability of different visual and instrumental methods for dental shade matching. Material and methodsVisual shade matching was performed by 3 experienced clinicians using 2 different shade guides (VITA Classical A1-D4 and VITA Toothguide 3D-MASTER with 29 tabs; VITA Zahnfabrik) with and without the aid of a light-correcting device (Smile Lite; Smile Line). An intraoral scanner (TRIOS; 3Shape A/S) and a spectrophotometer (VITA Easyshade Advance 4.0; VITA Zahnfabrik) were also used for color shade matching. The instrumental methods were repeated 3 times to determine repeatability. Shade-matching sessions for each method were performed under controlled lighting on the middle third of the maxillary right central incisor of 28 participants. The Fleiss' kappa statistical test was used to assess the reliability of each method. The weighted kappa statistical test was used to assess the agreement between the shades matched by different methods (α=.05). ResultsInstrumental methods were more accurate than visual methods. The best performance was found for the intraoral scanner configured for the 3D-MASTER scale (Fleiss' kappa value of .874) and for the spectrophotometer configured for the VITA Classical scale (Fleiss' kappa value of .805). The best visual shade-matching method was the VITA Classical scale associated with the light-correcting device (Fleiss' kappa value of .322). The Classical scale without the light-correcting device showed the poorest reliability (Fleiss' kappa value of .177) (P<.05). ConclusionsInstrumental methods for color shade matching were more reliable than the visual methods tested.

Evaluation of small‐group education on the shade determination ability of preclinical dental students—A controlled clinical trial

To evaluate the effect of small-group education including practical training on dental students' shade determination performance compared with a control group. Sixty-three non-colour-blind preclinical students were asked to participate and belonged to an intervention (n=31) and a control (n=32) group, respectively. All students received a lecture on dental shade determination. The members of the intervention group were educated and practically trained in small groups in addition. Ten volunteers, each with unrestored upper right middle and lateral incisors, were recruited. The students of both the intervention and control groups were then asked to determine the colour of the volunteers' test teeth using the 3D-Master shade guide (Vita Zahnfabrik, Bad Säckingen, Germany) under artificial daylight illumination. For analytical purposes, the CIE L*a*b* coordinates were obtained using a spectrophotometer. Colour differences, ΔE, between all shade tabs selected by the students and the natural teeth were calculated. ΔE observed in the intervention and control groups were compared using t tests. In addition, a multi-level regression model was adjusted for age and gender. Mean (SD) ΔE between the shade tabs selected by the students and the natural teeth in the intervention and control groups were 3.8 (2.1) and 4.3 (2.3), respectively (P<.001). The effect of group membership was reproduced in multivariate analysis whereas age and gender did not reach statistical significance. With more intensive education and practical training the ability to perform clinical shade determinations improved for students without previous clinical experience. The results obtained support the idea of implementing thematic small-group education in the dental curriculum.

Dental Shade Matching and Value Discernment Abilities of First-Year Dental Students.

To determine if Farnsworth-Munsell 100 Hue Test, Perceptual Ability Test, gender, age, ethnicity, and time predict dental shade matching and value discernment in first-year dental students. Farnsworth-Munsell 100 Hue Test was administered to 95 first-year-dental students beneath a Judge II booth (color temperature of 6500°K, and color rendering index of 90). Students also arranged 16 masked shade tabs from a Vita Classic shade guide by value (lightest to darkest) and matched together 16 pairs of masked shade tabs from two Vita Classic shade guides. Ethnicity, age, Perceptual Ability Test scores, gender, and time to complete the tests were recorded. Associations and correlations were investigated using chi-square, Tukey-Kramer HSD, standard least square, and multilinear regression (p < 0.05). Total error scores on the Farnsworth-Munsell 100 Hue Test ranged from 0 to 144. Forty-eight students exhibited superior color acuity, 45 average, and two poor. The mean number of correct answers for matching shade tabs together was 11.6, and 6.1 for arranging the shade tabs by value. Females performed statistically better than males on the Farnsworth-Munsell 100 Hue Test and shade tab matching. Better color discrimination identified by lower total error scores on the Farnsworth-Munsell 100 Hue Test was directly correlated to greater ability to match shade tabs together. Perceptual Ability Test scores had slight significance. As the scores increased there was slightly better performance on the Farnsworth-Munsell 100 Hue Test. Older participants performed better than younger subjects on the value test. No other correlations were significant for any of the tests. Females and individuals who performed better on the Farnsworth-Munsell 100 Hue Test have improved dental shade-matching ability.

Dental Shade Guide Variability for Hues B, C, and D Using Cross-Polarized Photography

This study evaluated the color variability of hues B, C, and D between the VITA Classical shade guide (Vita Zahnfabrik) and four other VITA-coded ceramic shade guides using a digital camera (Canon EOS 60D) and computer software (Adobe Photoshop CC). A cross-polarizing filter was used to standardize external light sources influencing color match. A total of 275 pictures were taken, 5 per shade tab, for 11 shades (B1, B2, B3, B4, C1, C2, C3, C4, D2, D3, and D4), from the following shade guides: VITA Classical (control); IPS e.max Ceram (Ivoclar Vivadent); IPS d.SIGN (Ivoclar Vivadent); Initial ZI (GC); and Creation CC (Creation Willi Geller). Pictures were evaluated using Adobe Photoshop CC for standardization of hue, chroma, and value between shade tabs. The VITA-coded shade guides evaluated here showed an overall unmatched shade in all their tabs when compared to the control, suggesting that shade selection should be made with the corresponding manufacturer guide of the ceramic intended for the final restoration.

Performance analysis of color matching technique for teeth classification based on color histogram

Objective: Color matching technique is one of the requirement in clinical dentistry. Using dental shade selection can help the dentist to determine the suitable color for the patients during fabrication of prosthesis. However the lack of dentists’ knowledge in color science due to many kinds of shade guide becomes a problem in the field of dentistry. So color matching technique by using digital images are feasible solution when suitable color features have been properly manipulated.Material and Methods: Separating the color features of digital images into RGB and HSV feature spaces are the first step of this system. Due to many features in this step, it requires some classifier algorithm according to the shade type of teeth. In this paper, we proposed color teeth classification for dental shade selection using DT, NN, and K-nearest neighbors algorithm based on color histogram feature spaces.Results: The result showed that on using the KNN algorithm it achieved 96.67% in learning process and 90% in testing process which had error level (0.183).Conclusion: It proves that our proposed system have high similarity in color matching according to the learning and testing process.