A yellowness index for use in dentistry.

OBJECTIVES: To develop an equation that predicts the perceptual yellowness of teeth. METHODS: A large set of new psychophysical yellowness data were generated from an experiment where 500 participants each ranked a set of 58 shade guide samples. Two existing equations (WIO and b*) and one new equation (YIO) were evaluated by comparing their values for the 58 shade guide tabs with the psychophysical data. Coefficient of determination (r2), '% wrong decisions', and STRESS were used as measures of performance. The YIO equation was optimized using these data to maximize the r2 value. A validation set of psychophysical data was prepared in an experiment where 40 participants each ranked 5 sets of 9 samples that were viewed on an emissive display. The candidate equations were evaluated using these data and the r2, %WD, and STRESS metrics. RESULTS: All three metrics YIO, WIO and b* were strongly correlated with perceptual yellowness. YIO and WIO both showed stronger correlation than b*. CONCLUSIONS: A new yellowness equation YIO has been developed to correlate with tooth yellowness. It is suggested that tooth yellowness and whiteness are highly related concepts.

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.

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

PURPOSE: 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. MATERIALS AND METHODS: 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). RESULTS: 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. CONCLUSIONS: Females and individuals who performed better on the Farnsworth-Munsell 100 Hue Test have improved dental shade-matching ability.

Influence of light source, polarization, education, and training on shade matching quality.

STATEMENT OF PROBLEM: Many factors influence the quality of shade selection, and isolating how significantly each of these factors influences results is difficult. PURPOSE: The purpose of this in vitro study was to compare results of shade matching using handheld lights with or without a polarizing filter with results obtained using a professional viewing booth and to analyze the influence of education and training on shade selection outcome. MATERIAL AND METHODS: A total of 96 third-year dental students (evaluators) were randomly separated into 4 groups. Each group was assigned 1 of 2 handheld shade-matching devices (lights) with or without a polarizing filter. Each group performed a shade matching exercise using the handheld light or a professional viewing booth. The exercise consisted of matching shade tabs placed in a typodont to a commercial shade guide. Each group repeated this procedure 4 times over a 9-week period. A lecture on shade matching was presented at the fifth week of the study, between "before" and "after" shade matching procedures. RESULTS: Shade matching scores with handheld lights (7.8) were higher than scores of shade matching with the viewing booth (7.2). The mean scores for before (7.2) and after (7.8) shade matching (with education and training in between) were significantly different. The combined effect of light and education and training improved the shade matching score by 1.2, from 6.8 in the before sessions using the viewing booth to 8.0 in the after sessions using handheld lights. A 21% increase in the number of evaluators who selected 1 of 4 best matches was recorded, 10% for handheld lights versus viewing booth after education and training versus before sessions and 11% between after sessions using handheld lights versus before sessions using viewing booth. CONCLUSIONS: Within the limits of the study, the shade matching scores with handheld lights were significantly better than the results obtained using a viewing booth (P<.01). Using a handheld light with or without a polarizing filter did not influence shade matching results. Mean shade matching scores were significantly better after education and training (P<.01). Light combined with education and training resulted in the greatest increase in shade matching quality.

Development of a customized whiteness index for dentistry based on CIELAB color space.

OBJECTIVES: To develop a customized CIELAB-based whiteness index for dentistry that accurately correlates to perception of tooth whiteness. METHODS: Four psychophysical experiments (PE1-4) were conducted by three panels of observers (OP1-3) under diffuse/0° observation/measuring conditions and under typical clinical viewing conditions. Nine whiteness indices (WI, Z%, WIC, WIO, W31, W64, W, WLAB, W*), two yellowness indices (YID1925, YIE313) and tint of white in the CIELAB color system (T) were compared with regard to their ability to measure the perceived whiteness of human teeth. Determination coefficient (R(2)) and '% wrong decision' (%WD) method were used as direct measures of the quality of the indices for whiteness perception in dentistry. RESULTS: CIELAB-based whiteness index (WID=0.511L* -2.324a* -1.100b*) was developed through optimization from the data obtained in PE1. The proposed WID performed better than all the CIELAB and CIE1931 XYZ-based indices under laboratory and clinical conditions (only WIO was comparable to WID in PE2 and PE4). CONCLUSION: The validation experiments under laboratory and typical clinical conditions revealed that the proposed index WID outperformed previous indices, being the only CIELAB-based index developed for evaluation of whiteness in dentistry.

Lighting conditions used during visual shade matching in private dental offices.

STATEMENT OF PROBLEM: To our knowledge, no data are available on the actual lighting that is used for visual shade matching in private dental offices. PURPOSE: The purpose of this study was to determine the shade matching practices and interest in continuing education in dental practices and to determine the quantity and quality of the ambient lighting used during visual shade matching in a sample cohort of dentists in private practices. MATERIAL AND METHODS: Thirty-two private practices were enrolled, and each completed a 1-page survey on the clinic's shade matching practices. A spectrophotometer was used to measure the ambient lighting in each practice, collecting data on color temperature (Kelvin), color rendering index (CRI), and light intensity (foot candles/fc). A 2-sided nonparametric sign test was used to compare the true median color temperature with the standard (5500°K). A 1-sided t test was used to compare the CRI with the standard (CRI >90) (α=.05 for all statistical analyses). RESULTS: All dental practitioners surveyed used mainly visual shade matching in their practices. Of those, 87.5% showed interest in attending continuing education on this topic, with 56.3% preferring a clinical demonstration course. The mean color temperature was 4152.9°K and was significantly different from the standard 5500°K (P<.001). The 1-sided t test indicated that the mean CRI was less than 90 (P=1). The 95% confidence interval for the intensity was 80.7 to 111.6 fc. CONCLUSIONS: The ambient light in the majority of the 32 dental private practices measured was not ideal for visual shade matching.

Shade selection of primary maxillary anterior teeth in children using Vitapan classical shade guide.

AIM: The purpose of this study was to determine the closest matching shade for primary maxillary anterior teeth from the most widely used Vitapan classical shade guide available for permanent teeth. MATERIALS AND METHODS: A total of 313 children aged between 3 and 5 years were evaluated. Vitapan classical shade guide was used to determine the shade of six primary maxillary anterior teeth. Scores obtained were noted down in a scoring sheet and values were tabulated. Data collected were tabulated and statistically analyzed using Pearson Chi-square test. RESULTS: A1 was found to be the closest matching shade for primary maxillary anterior teeth. D3 was found to be the least prevalent shade for primary maxillary anterior teeth. There was no statistical significant difference in the shades among teeth of same quadrant (p > 0.05) and also between teeth of right and left quadrants (p > 0.05), respectively. CONCLUSION: A1 shade of Vitapan classical shade guide is the most prevalent shade for primary maxillary anterior teeth and can be satisfactorily reproduced to all primary maxillary anterior teeth in general.

Color difference threshold determination for acrylic denture base resins.

This study aimed to set evaluation indicators, i.e., perceptibility and acceptability color difference thresholds, of color stability for acrylic denture base resins for a spectrophotometric assessing method, which offered an alternative to the visual method described in ISO 20795-1:2013. A total of 291 disk specimens 50±1 mm in diameter and 0.5±0.1 mm thick were prepared (ISO 20795-1:2013) and processed through radiation tests in an accelerated aging chamber (ISO 7491:2000) for increasing times of 0 to 42 hours. Color alterations were measured with a spectrophotometer and evaluated using the CIE L*a*b* colorimetric system. Color differences were calculated through the CIEDE2000 color difference formula. Thirty-two dental professionals without color vision deficiencies completed perceptibility and acceptability assessments under controlled conditions in vitro. An S-curve fitting procedure was used to analyze the 50:50% perceptibility and acceptability thresholds. Furthermore, perceptibility and acceptability against the differences of the three color attributes, lightness, chroma, and hue, were also investigated. According to the S-curve fitting procedure, the 50:50% perceptibility threshold was 1.71ΔE00 (r(2)=0.88) and the 50:50% acceptability threshold was 4.00 ΔE00 (r(2)=0.89). Within the limitations of this study, 1.71/4.00 ΔE00 could be used as perceptibility/acceptability thresholds for acrylic denture base resins.

A clinical study relating CIELCH coordinates to the color dimensions of the 3D-Master System in a Spanish population.

STATEMENT OF PROBLEM: The 3D-Master System comprises 26 physical shade tabs and intermediate shades. Determining the relationship among all the groups of lightness, chroma, and hue of the 3D-Master System (Vita Zahnfabrik) and the L*, C*, and h* coordinates is important, because according to the manufacturer, 2 Toothguide 3D-Master shades need to be mixed in a 50:50 ratio to create an intermediate shade. PURPOSE: The purpose of the study was to relate the lightness, chroma, and hue groups of the 3D-Master System with the polar coordinates of the CIELAB chromatic space, L*, C*, and h*, and to quantify the shades tabs and intermediate shades of the 3D-Master System according to color coordinates. MATERIAL AND METHODS: The middle third of the facial surface of a natural maxillary central incisor was measured with an Easyshade Compact spectrophotometer (Vita Zahnfabrik) in 1361 Spanish participants aged between 16 and 89 years. Natural tooth color was recorded in the 3D-Master nomenclature and in the CIE L*, C*, and h* coordinates system. The program used for the present descriptive statistical analysis of the results was SAS 9.1.3. RESULTS: In the L* variable, the minimum was found at 47.0 and the maximum at 91.3. In the C* variable, the minimum was found at 5.9 and the maximum at 49.8, while for h*, the minimum was 67.5 degrees and the maximum 112.0 degrees. CONCLUSIONS: Despite the limitations of this study, the 3D-Master System was found to be arranged according to L*, C*, and h* coordinates in groups of lightness, chroma, and hue. The corresponding groups of lightness, chroma, and hue can be estimated on the basis of L*, C*, and h* coordinates.

Shade determination using camouflaged visual shade guides and an electronic spectrophotometer.

The aim of the present study was to compare a camouflaged visual shade guide to a spectrophotometer designed for restorative dentistry. Two operators performed analyses of 66 subjects. One central upper incisor was measured four times by each operator; twice with a camouflaged visual shade guide and twice with a spectrophotometer Both methods had acceptable repeatability rates, but the electronic shade determination showed higher repeatability. In general, the electronically determined shades were darker than the visually determined shades. The use of a camouflaged visual shade guide seems to be an adequate method to reduce operator bias.

Implementation of a laboratory quality assurance program: the Louisville experience.

Remakes, or the refabrication of dental prostheses, can occur as a result of inherent inaccuracies in both clinical and laboratory procedures. Because dental schools manage large numbers of predoctoral dental students with limited familiarity and expertise as related to clinical prosthodontic techniques, it is likely these schools will experience an elevated incidence of laboratory remakes and their ramifications. The University of Louisville School of Dentistry, not unlike other dental schools, has experienced remakes associated with both fixed and removable prosthodontic procedures. Limitations in faculty standardization and variable enforcement of established preclinical protocols have been identified as variables associated with the high percentage of remakes documented. The purpose of this study was to introduce the implementation of a new multidepartmental quality assurance program designed to increase consistency and quality in both information provided to commercial dental laboratories and the prostheses returned. The program has shown to be advantageous in terms of cost-effectiveness and treatment outcomes. A statistically significant decrease in remake percentages has been recorded from inception of this program in December 2010 until December 2012. Furthermore, this program has resulted in more consistent communication between the dental school and commercial dental laboratories, among faculty members, and between faculty and students.

Shade matching quality among dental students using visual and instrumental methods.

OBJECTIVES: Study aims were to compare shade matching quality between visual and machine-aided shade selection among dental students and to evaluate the effect of experience and gender. METHODS: A total of 204 undergraduates and interns participated. They were briefed about colour matching using a visual method with a Vita-3D Master system and a spectrophotometer. Participants with colour vision deficiency were excluded. Six maxillary anterior teeth of a maxillary blue stone cast were replaced with six maxillary artificial teeth. Participants selected the best shade match using each method. A daylight illuminator with the GTI mini-matcher colour viewing system was used during the test. The results were statistically analysed with SPSS version 19 with 95% confidence intervals. Frequencies and Chi-square tests were used to analyse the data, at α=0.05 and with P<0.05 indicating significance. RESULTS: Among the participants, 36.3% visually selected the correct shade, and 80.4% did so using the Easy Shade Compact machine. Experience (P=0.177) and gender (P=0.560) did not affect visual shade selection; in addition, with the Easy Shade Compact device, males and females equally mastered its use (P=1.0), and experience did not influence outcomes (P=0.552). CONCLUSIONS: The shade matching device was significantly better than the conventional visual method. With both techniques, neither experience nor gender influenced shade matching quality. CLINICAL SIGNIFICANCE: Visual tooth colour matching is unreliable and inconsistent because of various subjective and objective factors, and the use of a colour measuring device might improve the quality of shade matching among dental students.

Differences between the human eye and the spectrophotometer in the shade matching of tooth colour.

OBJECTIVES: The aim of this work was to assess the agreement between instrumental and visual colour matching. METHODS: Shade selection with the 3DMaster Toothguide (Vita-Zahnfabrik) was performed for 1361 maxillary central incisors and compared with the shade obtained with the EasyShade Compact (Vita-Zahnfabrik) spectrophotometer. RESULTS: We observed a greater correlation between the objective method and the subjective one in the colour dimension of lightness (Kappa 0.6587), followed by hue (Kappa 0.4337) and finally chroma (Kappa 0.3578). CONCLUSION: The colour dimension in which the greatest agreement is seen between the operator and the spectrophotometer is value or lightness. CLINICAL SIGNIFICANCE: This study reveals differences between the measurement of colour via spectrophotometry and the visual shade selection method. According to our results, there is better agreement in the value or lightness colour dimension, which is the most important one in the choice of tooth colour.

Reliability of conventional shade guides in teeth color determination.

BACKGROUND/AIM: Color matching in prosthodontic therapy is a very important task because it influences the esthetic value of dental restorations. Visual shade matching represents the most frequently applied method in clinical practice. Instrumental measurements provide objective and quantified data in color assessment of natural teeth and restorations. In instrumental shade analysis, the goal is to achieve the smallest deltaE value possible, indicating the most accurate shade match. The aim of this study was to evaluate the reliability of commercially available ceramic shade guides. METHODS: VITA Easyshade spectrophotometer (VITA, Germany) was used for instrumental color determination. Utilizing this device, color samples of ten VITA Classical and ten VITA 3D - Master shade guides were analyzed. Each color sample from all shade guides was measured three times and the basic parameters of color quality were examined: deltaL, deltaC, deltaH, deltaE, deltaElc. Based on these parameters spectrophotometer marks the shade matching as good, fair or adjust. RESULTS: After performing 1,248 measurements of ceramic color samples, frequency of evaluations adjust, fair and good were statistically significantly different between VITA Classical and VITA 3D Master shade guides (p = 0.002). There were 27.1% cases scored as adjust, 66.3% as fair and 6.7% as good. In VITA 3D - Master shade guides 30.9% cases were evaluated as adjust, 66.4% as fair and 2.7% cases as good. CONCLUSION: Color samples from different shade guides, produced by the same manufacturer, show variability in basic color parameters, which once again proves the lack of precision and nonuniformity of the conventional method.

A clinical study to correlate maxillary anterior natural teeth with that of the commercially available acrylic and porcelain shade guides.

The success of the dental treatment as perceived by our patients is often preferentially evaluated on the appearance of the restoration. Usually visual determination is unreliable and inconsistent, complicated by the inability of the shade guide to cover the entire dental color range and also there is lack of logical order of arrangement of the tabs. Hence a clinical study is planned to perform visual shade selection in standardized conditions to correlate the shades of maxillary anterior natural teeth in adult subjects of Davengere district origin to one acrylic and three porcelain shade guides commercially available in India.

Evaluation of an anatomic dual-laminate composite resin shade guide.

BACKGROUND: Color assessment in aesthetic dentistry is one of the most challenging steps for direct restorative treatment. Shade selection tools should be able to mimic closely the materials and layering technique used in the final restoration, hence the development of prefabricated anatomic dual-laminate shade guides. OBJECTIVE: This study aims to compare different shade selection techniques and determine the suitability of a prefabricated anatomic dual-laminate shade guide and its best mode of use compared to a conventional guide and a layered custom guide. MATERIALS AND METHODS: CIELab coordinates of different shade guides were assessed: Vitapan Classical (tab A2; Vita); Miris2 prefabricated anatomic dual-laminate shade guide, enamel WR tab on top of dentine S3 tab and nothing in-between (M2air) or glycerin gel (M2gly) or water (M2w); custom shade guide using prefabricated silicon moulds, Miris2 enamel WR composite resin moulded directly on dentine S3 pre-polymerised base (M2cus). The average values were obtained to calculate DE and compare the different shade selection techniques. Additional samples and measurements were made to compare Vitapan Classical shade tabs A1, A2 and A3 and all possible combinations of Miris2 and establish the closest matching shade (DE 3.3). RESULTS: High DE values were found (6.51­9.11) when comparing M2air to Vita, M2gly M2w M2cus. Differences appeared acceptable (DE 2.09­2.99) between Vita, M2gly and M2w and M2cus. Seven combinations of M2 were found to match Vita tab A1 and A2 and three Miris2 combinations for Vita A3 (DE 3.3). CONCLUSIONS: The use of Miris2 prefabricated anatomic dual-laminate shade guide with interposition of water or glycerin between the enamel­dentine tabs demonstrated acceptable DE values when compared to Vitapan Classical and custom guides. A chart for matching Vita shades with various combinations of Miris2 enamel/dentine shades was produced to assist the clinician in obtaining acceptable restorations. CLINICAL SIGNIFICANCE: The prefabricated anatomic dual-laminate shade guide is as efficient as a custom shade guide, facilitating clinical steps and saving material when doing compositeresin restorations.

Developing a custom dental porcelain shade system for computer color matching.

OBJECTIVES: This study aims to update the computer color matching method by generating a new ceramic shade system that covers the entire spectrum of natural tooth color and has an efficient design. METHODS: First, the color map of 176 maxillary natural incisors and two commercially available and commonly used shade guide systems (Vitapan classic and 3D master) were drawn. Then, 15 shades of layered disks (NW-0: neutral white-0, A1, A2, A3, A4, B1, B4, C4, and D4, and six modifiers; white, pink, grey, blue, cervical-1 and cervical-2, Cerabien ZR) were plotted on the tooth color distribution map. Ultimately, 12 target shades were selected around the perimeter of the natural tooth color space, and nine different shades were selected within the cluster. By trial and error informed by known formulations published previously, the formulations of Cerabien ZR porcelain powders necessary to achieve these 21 target shades in thickness of 1.0mm layered on zirconia substrate were then determined and ceramic disks were fabricated. RESULTS: Color distribution L*-C* and a*-b* maps showed that new 21 shade system covers a slightly broader range than the natural tooth distribution, and its distribution is larger than the 3D Master shade's range. CONCLUSIONS: In the present study, a 21 custom dental porcelain shade system was developed with a 1.0mm porcelain thickness overlying a zirconia substrate, which can be incorporated into the computer color matching system. This new shade system has homogeneity with 3D Master, and has a slightly wider color distribution than that of natural teeth.

Spectrophotometric evaluation of a novel aesthetic composite resin with respect to different backgrounds in vitro.

Tooth colour matching of composite materials is often a common problem caused by a dark background from the oral cavity. Therefore, the aim of the study was to evaluate a novel aesthetic composite material and to assess the influence of white and black backgrounds. Tooth shades of 30 freshly extracted upper front teeth were determined using a spectrophotometer (SpectroShade™) both against a white and a black background. Two class IV cavities in each tooth were prepared and restored using three different composite resins: Arabesk™ (AB), Synergy™ (SE) and the novel material Amaris™ (AM). After water storage for 1 week, differences in hue, saturation and lightness were measured to assess changes from baseline. After thermocycling, teeth were evaluated once more to assess the reliability of the treatment outcomes. Compared to baseline, differences in hue were not statistically different for all restoration materials (p > 0.05) with respect to the white or black background. Delta values for saturation were not different in the AB and AM groups (p > 0.05) with higher values for SE (p < 0.05). Regarding lightness, values in the AB group were statistically higher (p < 0.05) than values for AM with no difference between AB and SE and with no difference between the AM and SE groups (p > 0.05). Employing the novel aesthetic composite resin, a minor impact of white and black backgrounds could be observed compared to conventional composites. Therefore, it might effectively mask the dark background from the oral cavity.

Spectrophotometric assessment of peri-implant mucosa after restoration with zirconia abutments veneered with fluorescent ceramic: a controlled, retrospective clinical study.

OBJECTIVES: The purpose of this study was to investigate the optical appearance of the soft tissue labial to dental implants restored with fluorescent ceramic-veneered zircona abutments. It was hypothesized that the tested abutment design leads to an increased brightness in the marginal peri-implant tissue, which does not differ from that of natural teeth. Moreover, a reduction of the color difference that has been reported from other abutment materials was expected. MATERIALS AND METHODS: A total of 12 patients with single titanium implants in the maxillary anterior region were recruited. All implants (N = 12) were restored with zirconia abutments veneered with fluorescent ceramic and full-ceramic crowns. Color measurements of the peri-implant mucosa at the test sites were made of the facial aspect of the teeth using a Spectroshade-spectrophotometer. The gingiva of a contralateral or adjacent natural tooth served as a control. Color data (CIE-L*a*b* color coordinates) were obtained in five incremental areas of 1 × 2 mm in both test and control sites. ∆E-values were calculated from the ΔL*, Δa* and Δb* values for each patient. RESULTS: Data acquisition from the test site demonstrated lower mean values of L*, a* and b* than the control site. Statistical significance between the test site and control site was reached in the L* values only in the second of the five incremental areas (P < 0.05, Wilcoxon test). However, discrepancies in a*- and b*-values reached a statistically significant difference in the incremental areas 1, 2 and 4, and in b* in area 5 (P < 0.05, Wilcoxon test). Medians of the ∆E-values in all five increments were found to be higher than the clinical perceptual threshold of 3.7. However, considering the original data, five individual patients did not reach the threshold in increment 1 and 2, two in increment 3 and three in increment 4. None of the patients showed lower ∆E-values than the perceptual threshold of 3.7 in increment 5, which had the largest distance from the gingival margin. CONCLUSION: The tested abutment design leads to a peri-implant soft tissue color that, in the critical marginal area, in five of 12 patients did not statistically differ from the tissue of the gingiva of natural teeth. Particularly, the brightness of the peri-implant soft-tissue seemed to be more adapted to the natural situation using a fluorescent abutment design.

A systematic review of visual and instrumental measurements for tooth shade matching.

OBJECTIVE: Common methods for matching tooth shade can be classified into two categories: visual and instrumental measurements. This systematic review evaluated these two methods in terms of precision and accuracy using the agreement percentage rate. METHOD AND MATERIALS: The following databases were searched for studies comparing different shade-matching methods: MEDLINE (PubMed), Embase, and Google Scholar. Reference lists of relevant articles were also searched. Screening, data abstraction, and quality assessment were conducted independently and in duplicate. RESULTS: Twenty-six studies were included. Seventeen studies provided data on the precision of the evaluated shade-matching methods, eight provided data on accuracy, and one provided data on both precision and accuracy. CONCLUSION: Instrumental measurements using a spectrophotometer may provide the most precise and accurate shade-matching outcomes. However, the limitations of the available articles suggest that high-quality studies are still needed verify this claim.