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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.

This article describes a simple method for painting an artificial iris for the manufacturing of an ocular prosthesis with dark and light tones, both with excellent esthetic results. The challenge of choosing colors around the pupil and medium zone during painting is aided by the application of Newton's color wheel theory. This technique provides a safer choice of color during the painting procedure by using a mixture of ceramic pigments.

Zirconia is the most preferred ceramic restoration in posterior areas because of its flexural strength. The aim of the study is the evaluation of biaxial flexural strength of different colored zirconium oxide core materials after cyclic loading.Zirconia discs (12 mm diameter and 1.2 mm thickness) were divided into 6 groups of 12 discs each. Groups were colored according to the Vita Classic shade guide: A3 and D4. One group was not colored and left as control. Each group was randomly divided into subgroups and subjected to mechanical cycling prior to biaxial flexural strength test. Cyclic loading was applied as 50 N loads for 20,000 times for the loaded groups. Samples were subjected to biaxial flexural strength test in a universal testing machine with a crosshead speed of 1 mm/min. Two-way analysis of variance (ANOVA) and Tukey's HSD tests were used for comparisons of the groups.Biaxial flexural strength values did not vary significantly depending on coloring procedure or loading process tested (p.05). XRD analysis displayed that the monoclinic volume fraction of zirconia was highest in cyclic loaded D4 and was lowest in non-loaded control group. The SEM image revealed that A3 color solution created metallic coloring pigments at grain boundaries.Coloring procedures and cyclic loading did not affect the biaxial flexural strength of zirconia core material; however, microstructural analysis displays changes, which may weaken the zirconia structure on the long term.

Cilj istraživanja bio je odrediti utjecaj različitih boja pozadine I to redom bijele, crvene, plave, žute i zelene na odabir boje zuba pri izradi zubnog nadomjeska., The aim of this study was to determine the influence of different background colors and in order of white, blue, yellow and green to choose color when making dental replecement.

This study aimed to compare the effect of D55 and D65 light sources on the visual colorimetry performance of dental students by using a homemade light-source shelf.Two Vitapan 3D-Master shade guides were randomly selected. One set was used as shade guides. Ten commonly used shade tabs of 2L2.5, 2M2, 2R2.5, 3M2, 3R2.5, 3L1.5, 3R1.5, 3L2.5, 4R1.5, and 4L1.5 were selected from the other set with covered value marks and numbered from 1 to 10. After the colorimetric training, 49 undergraduate dental students were randomly divided into two groups. Each student randomly selected two of the 10 shade tabs, and the colors were subsequently matched under D65 and D55 light sources from a distance of approximately 40 cm. The average color difference (ΔE) between the color selected by each participant and the actual color of shade tabs was calculated. Paired t test was used for statistical analysis.The ΔE values between the color selected by each participant and the actual color of the shade tabs under the D55 light source varied from 0 to 6.540. The average value was 2.501. The ΔE values between the color selected by each participant and the actual color of the shade tabs under the D65 light source varied from 0 to 6.610. The average value was 2.530. No statistically significant difference was observed between the results under the two light sources (P=0.921).Both D55 and D65 daylight lamps can be used for daily dental colorimetry. These two different color temperatures showed no significant difference.目的 对标准化比色环境中口腔医学生在D55和D65光源条件下的比色结果进行比较。方法 随机抽取市售Vitapan 3D-Master比色板2套，其中一套作为比色板，从另一套比色板中选出来10个比色片，分别为2L2.5、2M2、2R2.5、3M2、3R2.5、3L1.5、3R1.5、3L2.5、4R1.5、4L1.5色片，用胶布遮盖比色片下字标，用阿拉伯数字标记1~10号。对49名口腔医学生进行比色方法的培训后，要求其抽取10个色片中的任意两个色片，在D65以及D55日光灯下对所抽取的色片比色，分别计算2种光源下每位参与者选择的颜色和牙面实际颜色的平均色差值ΔE，并进行统计学分析。结果 在D55光源下每位参与者选择的牙片颜色与牙片实际颜色的ΔE范围为0~6.540，平均为2.501；在D65光源下，每位参与者选择的牙片颜色与牙片实际颜色的ΔE范围为0~6.610，平均为2.530。二者差异无统计学意义（P=0.921）。结论 D55和D65日光灯均可以用于日常的牙科比色，2种不同的色温下比色结果无明显差异。.

The purpose of this study was to evaluate the effect of the different color of resin cements and zirconia cores on the translucency parameter (TP) of the restoration that simulates the implant-supported fixed prosthesis using titanium base on the bottom.Zirconia core plates (Zr-Zahn) were prepared in A2 shades (n = 11). Resin cement plates (3M ESPE) were prepared in A2, A1, translucent (TR) shades (n = 11). The initial color measurements and were measured on zirconia core plates, and resin cements plates using a spectrophotometer. Then, the resin cement plates were placed below the zirconia core plates, and the second measurements were done. The final measurements were done after placing the titanium discs in the bottom. The data were analyzed with two-way analysis of variance and Tukey honestly significant differences tests (α = 0.05).The highest TP values were recorded for A1-colored resin specimens and the lowest for zirconia core plates in the first measurement (P0.05). The addition of zirconia core decreased the TP values in all tested resin cement groups (P0.05). The highest TP value was recorded for A1-colored resin cement with zirconia core plates and the lowest for A2 and TR with zirconia core plates after second measurements (P0.05). The addition of titanium decreased the TP of the zirconia core plate and resin cement combination (P0.05).The addition of a zirconia core under the resin cement dramatically reduced the TP values, and the presence of a titanium layer decreased the TP value and caused a darker appearance.

Color matching of the restoration to the adjacent teeth can be difficult due to the translucency of the ceramic and the visual exposure of the polymerized resin cement through the ceramic material. The aim of this study was to identify color differences between try-in pastes and the corresponding luting resin composites.The materials tested were Variolink Veneer, Variolink Try-In, Variolink Esthetic LC, and Variolink Esthetic Try-In. Blocks of IPS e.max CAD were bisected along the vertical axis, producing specimens of different thicknesses. The surfaces to be evaluated were finely polished with a metallographic machine using 6000 grit SiC paper. The IPS e.max CAD specimens cemented with resin cement or with the try-in pastes were superimposed on a resin composite specimen reproducing the tooth structure. Evaluation of the color differences between the try-in pastes and polymerized cements of the same shade was performed with a spectrophotometer and a visual evaluation by three observers.The measurements showed that for shades of Variolink Veneer and Variolink Esthetic LC resin cements and the corresponding try-in pastes there were significant color differences (ΔE2.23). Among the groups of different thicknesses, specimens of 0.5-mm thickness exhibited the highest ΔE values, while the specimens of 2-mm thickness exhibited the lowest.The present study suggests that dentists should not rely on try-in pastes for the final color evaluation because they do not perfectly match the color shade of the cement used for the final luting of ceramic restorations. The originality of this study was the interpretation of color differences utilizing both a scientific spectrophotometer and visual observation.

To evaluate the effect of shading technique and thickness on the color stability and translucency of translucent zirconia after coffee thermocycling.Specimens in different thicknesses (1; 1.5; 2 mm) (n = 4 for each thickness) were sectioned from translucent preshaded zirconia (Pre) and externally shaded zirconia (Ext). After sintering, specimens were glazed and subjected to 10,000 thermocycling in coffee solution. The color coordinates of specimens were measured with a spectroradiometer before and after coffee thermocyling. Color differences and relative translucency parameter (RTP) values were calculated with CIEDE2000 color difference and TPAccording to 2-way ANOVA, no significant effect of shading technique and thickness on the color difference values was found (P .05). According to 3-way ANOVA, a significant interaction between the shading technique and thickness (P .0001) was found for RTP. The RTP parameter decreased with the increase in the thickness. Ext specimens presented significantly higher RTP than Pre specimens (P .0001), except for between Ext 1 mm and Pre 1 mm (P = .179).Neither shading technique nor tested thicknesses affected the color of translucent zirconia. Shading technique and thickness affected the RTP of translucent zirconia. The RTP was inversely affected with the thickness of the material. Externally shaded zirconia presented higher RTP than preshaded zirconia for specimens thicker than 1 mm.Discoloration with coffee was insignificant for the tested translucent zirconia in tested thicknesses (1, 1.5, 2 mm). When a translucent restoration is intended, thinner externally shaded translucent zirconia restorations should be preferred instead of preshaded translucent zirconia.

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 (p0.05).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.

Three-dimensional (3D) intraoral scanning systems allow for the simultaneous acquisition of 3D information about tooth surfaces and a photorealistic view of the patient's tooth colors.The goal of this study was the in vivo comparison of a new 3D scanner with a color acquisition mode and conventional visual and digital color measurements.The colors of 40 teeth of 20 patients were evaluated in seven ways: 1) By dentists using the Vita 3D-Master; 2) By dental technicians using the Vita 3D-Master; 3) With the 3Shape Trios device; 4) With the Vita Easyshade device; 5) With the Vita Easyshade Advance device; 6) With the SpectroShade device; and 7) With the SpectroShade Micro device. Digital measurements of Groups 3 to 7 were repeated three times for each tooth. For all groups, both the CIE Lab values and the Vita 3D-Master values were recorded. The repeatability and relative accuracy of the Vita 3D-Master values were analyzed statistically using Pearson's chi-squared test (α0.05). ΔE values were calculated from the CIE Lab values, which served as a basis for performing multidimensional scaling (MDS) and evaluating differences between the groups using the one-way ANOVA with post hoc Tamhane's test (α0.05).The results of the ΔE values showed that clinically relevant differences between the evaluation by dentists, dental technicians, and the intraoral scanning device (3Shape) are negligible. The intraoral 3D scanning device (Group 3) and the digital systems (Groups 4 to 7) did not differ significantly in the repeatability of color shade management. The SpectroShade Micro (Group 7) had significantly better relative accuracy than the other devices.The results demonstrate that intraoral scanning systems can be used to measure both tooth color and tooth surface in 3D.Intraoral optical scanning devices allow for the acquisition of accurate 3D surface data. Tooth color can be evaluated simultaneously and can be used to determine the color of restorations without requiring additional conventional color-measurement methods.

Svrha: Istraživanjem se nastojalo procijeniti utjecaj razine kliničkog iskustva na točnost u procjeni boje u različitim stomatološkim profesionalnim skupinama. Materijali i postupci: U istraživanju je ukupno sudjelovalo 80 ispitanika te su, ovisno o razini njihova kliničkog iskustva u određivanju boje, raspoređeni u četiri skupine: dentalni tehničari (DT), specijalizanti stomatološke protetike (RP), specijalisti stomatološke protetike (SP) i studenti dentalne medicine – dentalni studenti (DS). Ispitanici su se koristili Toothguide Training Boxom (TTB) i odredili 15 standardnih boja iz ključa VITA 3D-Master. U završnom testu zabilježen je broj pogrešaka svakog ispitanika te je izračunata njegova točnost. Razlika u procjeni (ΔE) za svaku odabranu boju izračunata je s pomoću L*, a* i b* vrijednosti. Ispitane su razlike u točnosti srednjih ΔE vrijednosti i srednjih vrijednosti pogreške ΔE-a u četirima skupinama. Rezultati: Statistički značajna razlika u točnosti i srednjim ΔE vrijednostima unutar četiriju skupina nije pronađena (p > 0,05). Točnost u njima iznosila je 0,51 ± 0,20 (DT), 0,54 ± 0,18 (RP), 0,49 ± 0,16 (SP) i 0,55 ±0,14 (DS). Srednje ΔE vrijednosti iznosile su 2,10 ± 0,98 (DT), 2,18 ± 0,97 (RP), 2,51 ± 0,97 (SP) i 2,08 ± 0,86 (DS). S obzirom na srednje vrijednosti pogreške ΔE-a, pronađena je statistički značajna razlika s DT skupinom koja je imala znatno manja odstupanja u usporedbi s ostalima (p < 0,05). Zaključci: Rezultati ovog istraživanja dokazali su da kliničko iskustvo nije značajan čimbenik točnosti u određivanju boje. No ispitujući srednje vrijednosti pogreške ΔE-a ustanovljeno je da su DT-i uspješniji u određivanju od ostalih ispitanika., Objectives: The aim of this study was to evaluate the effect of clinical experience level on the shade matching accuracy in different dental occupational groups. Materials and methods: A total of 80 participants, assigned to one of four groups depending on the level of their clinical experience in shade matching: dental technicians (DTs), residents in prosthodontics (RPs), specialists in prosthodontics (SPs) and dental students (DSs) took part in the study. They were asked to use Tooth guide Training Box (TTB) and determine 15 standardized shade tabs using VITA 3D-Master shade guide. The number of mistakes in final test for each participant was recorded and accuracy was calculated. Color difference (ΔE) values for each shade were calculated from L*, a* and b* values. Differences in accuracy, mean ΔE values and mean error ΔE values between four different groups were examined. Results: No statistically significant differences were found between the groups regarding accuracy and mean ΔE values (p>0.05). The accuracy rate in four groups was 0.51±0.20 (DTs), 0,54±0.18 (RPs), 0.49±0.16 (SPs) and 0.55±0.14 (DSs), respectively. Mean ΔE values were 2.10±0.98 (DTs), 2.18±0.97 (RPs), 2.51±0.97 (SPs) and 2.08±0.86 (DSs), respectively. Regarding mean error ΔE values, DTs made errors with significantly less deviations compared to other groups (p

Statement of problem In restorative prostheses, color is important, but the choice of color difference formula used to quantify color change in acrylic resins is not straightforward. Purpose The purpose of this in vitro study was to choose a color difference formula that best represented differences between the calculated color and the observed imperceptible to unacceptable color and to determine the corresponding perceptibility and acceptability threshold of color stability for denture base acrylic resins. Material and methods A total of 291 acrylic resin denture base plates were fabricated and subjected to radiation tests from zero to 42 hours in accordance with ISO 7491:2000. Color was measured with a portable spectrophotometer, and color differences were calculated with 3 International Commission on Illumination (CIE) formulas: CIELab, CMC(1:1), and CIEDE2000. Thirty-four observers with no deficiencies in color perception participated in psychophysical perceptibility and acceptability assessments under controlled conditions in vitro. These 2 types of assessments were regressed to each observer by each formula to generate receiver operator characteristic (ROC) curves. Areas under the curves (AUCs) were then calculated and analyzed to exclude observers with poor color discrimination. AUCs were subjected to 1-way ANOVA (α=.05) to deter the statistical significance of discriminability among the 3 formulas in terms of perceptibility and acceptability judgments. Student-Newman-Keuls tests (α=.05) were used for post hoc comparison. Results CMC(1:1) and CIEDE2000 formulas performed better for imperceptible to unacceptable color differences, with corresponding CMC(1:1) and CIEDE2000 values for perceptibility of 2.52 and 1.72, respectively, and acceptability thresholds of 6.21 and 4.08, respectively. Conclusions Formulas CMC(1:1) and CIEDE2000 possess higher discriminability than that of CIELab in the assessment of perceptible color difference threshold of denture base acrylic resin. A statistically significant difference exists between perceptibility and acceptability thresholds for denture base acrylic resin.

Visual shade selection is subjective and influenced by factors that might be operator-dependent or not. The objective was to evaluate influence of observer nonrelated factors (background/surrounding area, and light) and observer-related factors (gender and color competence) on shade-matching quality and to identify the most often mismatched shades in correlation with the background.Ten observers with average or superior color discrimination competence according to ISO TR 28642:2011 were asked to match 48 shade tabs of three VITA Classical shade guides, in a viewing booth under two light sources: D65 and D50. Gray, white, black, red, and light blue background/surrounding area simulated various clinical situations. The results were statistically analyzed using Kruskal-Wallis test and Mann-Whitney U test. Post hoc power analyses and sample size calculations were also conducted.The matching scores ranged between 72.7 % (using blue background) and 85.9 % (using white and black backgrounds). There was a statistically significant difference between matching scores on the five backgrounds (χ (2)(4) = 12.67, p = 0.01). When neutral gray was used as reference, Mann-Whitney U value was statistically significant only for the blue background (U = 107.00, Z = -2.52, p = 0.01). The influence of gender and lighting condition was also assessed, no statistically significance being found, but in both cases, the effect size and the achieved power were small. However, color discrimination competence did influence the results (p 0.01). Background influenced shade matching results for tabs A3, B3, B4, and D4.Within the limitations of this study, it was concluded that 1. When it comes to the influence of the background/surround area on quality of color matching, no difference among achromatic backgrounds was recorded. Significantly worse results were recorded when the blue background was used. 2. Observers with superior color matching competence performed significantly better than the ones with average competence 3. The most frequently mismatched shade tabs were A3.5, B3, B4, and D4.

Objective: To investigate the surfaces and principal elements of the colorants of cosmetically tinted contact lenses (Cos-CLs). Methods: We analyzed the surfaces and principal elements of the colorants of five commercially available Cos-CLs using scanning electron microscopy with energy-dispersive x-ray analysis. Results: In two Cos-CLs, the anterior and posterior surfaces were smooth, and colorants were found inside the lens. One lens showed colorants located to a depth of 8 to 14 μm from the anterior side of the lens. In the other lens, colorants were found in the most superficial layer on the posterior surface, although a coated layer was observed. The colorants in the other three lenses were deposited on either lens surface. Although a print pattern was uniform in embedded type lenses, uneven patterns were apparent in dot-matrix design lenses. Colorants used in all lenses contained chlorine, iron, and titanium. In the magnified scanning electron microscopy images of a certain lens, chlorine is exuded and spread. Conclusions: Cosmetically tinted contact lenses have a wide variety of lens surfaces and colorants. Colorants may be deposited on the lens surface and consist of an element that has tissue toxicity.

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.

Summary To evaluate the success, clinical performance and patient satisfaction of directly placed fibre-reinforced composite (FRC) fixed partial dentures (FPDs) in 2 years. One hundred sixty-seven FRC FPDs (120 subjects) were directly fabricated to restore a single missing tooth by six Advanced Education in General Dentistry (AEGD) residents. The FRC FPDs recipients were rando-mised into two groups according to the fibre materials (pre-impregnated glass or polyethylene). Clinical performance was evaluated at baseline (2 weeks), 6, 12 and 24 months by two calibrated evaluators for prosthesis adaptation, colour match, marginal discoloration, surface roughness, caries and post-operative sensitivity using modified United State Public Health Service (USPHS) criteria. Prosthesis appearance, colour, chewing ability and overall satisfaction were evaluated by patients using a visual analogue scale (VAS). Kaplan–Meier estimation was used to estimate the prosthesis success. Ninety-four patients with 137 FRC FPDs returned (21·67% attrition rate for study subjects, 17·94% for FRC FPDs). Seventeen FRC FPDs failed, due to one-end (n = 4) or two-ends (n = 4) debonding or pontic fracture (n = 9). The cumu-lative 2-year success rate was 84·32% and survival rate was 92·7%; there were no statistically significant differences between the groups according to different missing tooth location, retention type or fibre materials (P > 0·05). Patient satisfaction regarding prosthesis appearance, col-our, chewing ability and overall satisfaction was rated high on the VAS (mean >80 mm) for all criteria at all time points. The FRC FPDs (restoring single tooth) fabricated by AEGD residents achieved acceptable success and survival rates in a 2-year follow-up.

Purpose To evaluate the effect of three brands of resin cement on the final color of ceramic veneers. Methods 50 disk-shaped ceramic specimens (IPS e.Max, 0.6mm×8.0mm diameter) and disk-shaped composite resin background specimens (4.0mm×8.0mm diameter) were prepared and divided into 10 groups ( n =5). These paired specimens were bonded using ten shades of resin cement (Variolink Veneer, shades LV-3, LV-2, MV, HV+2, HV+3; Panavia F, shades light and brown; and RelyX™ Veneer, shades WO, TR, A3). A spectrophotometer (VITA Easyshade) was used to measure the color parameters (CIE L * a * b * values) of the paired disks before and after cementation. The color differences (Δ E values) after cementation were calculated and statistically analyzed by the One-way ANOVA (at the significant level p Results The color parameters of the ceramic disks were measured in terms of the increase in L * value, and the decrease in C a b * value after bonding with the resin cement. The Δ E values of ceramic disks after cementation ranged from 1.38 to 7.16. The Δ E values were more than 3.3 when the ceramic disks were cemented with resin cements in shade HV+3 (4.90) and shade WO (7.16). One-way ANOVA of Δ E values revealed significant differences in the resin cement shades. Conclusions Resin cements can affect the final color of ceramic veneer restorations, and the extent of this effect varies according to the resin cement shades.

A digitally captured, designed, and fabricated facial prosthesis is presented as an alternative to customary maxillofacial prosthodontics fabrication techniques, where a facial moulage and patient cooperation may be difficult.

Statement of problem Little is known about the clinical performance of ceramic cantilever fixed dental prostheses on natural teeth. Purpose The purpose of this randomized controlled pilot study was to evaluate the clinical performance of ceramic and metal ceramic cantilever fixed dental prostheses (CFDPs) after 3 years of service. Material and methods Twenty-one participants were randomly allocated to 2 treatment groups. Participants in the ceramic (ZC) group (n=11) each received 1 CFDP made of yttria-stabilized, tetragonal zirconia polycrystal; the others (n=10) were fitted with a metal ceramic (MC) CFDP. All CFDPs were retained by 2 complete crown abutments and replaced 1 tooth. The clinical target variables were survival, incidence of complications, probing pocket depth (PPD), probing attachment level (PAL), plaque index (PI), gingival index (GI), and esthetic performance as rated by the participants. The United States Public Health Service (USPHS) criteria were used to evaluate chipping, retention, color, marginal integrity, and secondary caries. Descriptive statistics and nonparametric analyses were applied to the target variables in the 2 groups. The esthetic performance of the CFDPs was also visualized by using a pyramid comparison. Results The overall survival of the CFDPs was 100% in both groups. During the 3-year study, 6 clinically relevant complications requiring aftercare were observed among 5 participants (4 in the ZC group and 2 in the MC group). Changes in the PI, GI, PPD, and PAL of the abutment teeth were similar for both groups ( P >.05). The participants regarded the esthetic performance of ZC-CFDPs and MC-CFDPs as satisfactory. Conclusions Within the 3-year observation period, the clinical performance of MC-FDPs and ZC-FDPs was acceptable. More extensive research with larger sample sizes is encouraged, however, to confirm the evaluation of the survival of Y-TZP hand-veneered cantilever FPDs.

Objectives: Studies on the effect of coloring procedures on the bond strength of zirconia to resin cement are lacking in the literature. This study evaluated the effect of dipping of zirconia ceramic in different liquid color shades on the microtensile bond strength (MTBS) of zirconia ceramic to resin cement. Materials and Methods: This in vitro study was conducted on 100 microbar specimens divided into five groups of B2, C1, D4, A3 and control (not colored). To prepare the microbars, 20 white zirconia ceramic blocks, measuring 5×11×11 mm, were dipped in A3, B2, C1 or D4 liquid color shades for 10 seconds (five blocks for each color shade) and five blocks were not colored as controls. All the zirconia blocks were sintered in a sintering furnace. Composite blocks of similar dimensions were fabricated and bonded to zirconia ceramic blocks using Panavia F 2.0 resin cement. Zirconia-cement-composite blocks were sectioned into microbars measuring 1×1×10 mm. The MTBS of microbars was measured by a testing machine. Data were analyzed using one-way ANOVA and Tukey’s test. All tests were carried out at 0.05 level of significance. Results: Statistically significant differences were found among the groups in MTBS (P

Aim This study aimed to evaluate the repeatability of color measurements of an intraoral spectrophotometer with the use of three different methods by two operators. Materials and methods A total of 60 teeth were obtained, comprising 30 human maxillary teeth [central incisors (n = 10); canines (n = 10); molars (n = 10)] and 30 artificial teeth [lateral incisors (n = 10); premolar (n = 20)]. Multiple repeated color measurements were obtained from each tooth using three measuring methods by each of the two operators. Five typodonts with alternating artificial and human teeth were made. Measurements were taken by two operators with the Vita EasyShade spectrophotometer using the custom tray (CT), custom jig (CJ) and free hand (FH) method, twice, at an interval of 2 to 7 days. Friedman test was used to detect difference among the three color measuring methods. Post hoc Wilcoxon signed-rank test with Bonferroni correction applied was used for pair-wise comparison of color measurements among the three methods. Additionally, a paired-sample t-test was used to assess a significant difference between the two duplicated measurements made on the same tooth by the same operator for each color parameter and measuring method. Results For operator A, mean (SD) overall color change-ΔE* (SD) perceived for FH, CT and CJ were 2.21(2.00), 2.39 (1.58) and 2.86 (1.92), respectively. There was statistically significant difference in perceived ΔE* in FH vs CJ (p = 0.0107). However, there were no significant differences between FH and CT (p = 0.2829) or between CT and CJ (p = 0.1159). For operator mean ΔE* (SD) for FH, CT and CJ were 3.24 (3.46), 1.95 (1.19) and 2.45 (1.56), respectively. There was a significant difference between FH and CT (p = 0.0031). However, there were no statistically significant differences in ΔE* in FH vs CJ (p = 0.3696) or CT vs CJ (p = 0.0809). Conclusion The repeatability of color measurements was different among the three measuring methods by operators. Overall, the CT method worked well for both operators. Clinical significance The use of a custom tray with apertures can improve the repeatability of color measurements of an intraoral spectrophotometer. How to cite this article Hemming M, Kwon SR, Qian F. Repeatability in Color Measurements of a Spectrophotometer using Different Positioning Devices. J Contemp Dent Pract 2015;16(12):933-938.

In this study, the influence of restoration type, symmetry, and color on the perception of dental appearance was evaluated. An esthetic questionnaire was completed by 29 patients before and after esthetic rehabilitation. In addition, 94 dentists from four countries (Germany, the United Kingdom [UK], China, and Switzerland) evaluated the influence of the above factors using before-and-after rehabilitation pictures. The most invasive treatment was recommended by Chinese dentists, while German, Swiss, and UK dentists recommended comparable treatment options. As for restorative symmetry, restoration type, and color, significant differences could be found among and within the dentists of the four countries (P ± .05).

This study investigated the effects of different colored tetragonal zirconia polycrystal (TZP) core on the optical properties of TZP framework restorations. Three various colors of TZP discs (Katana Zirconia) 14 mm in diameter and 0.5 mm thickness were layered with 2 shades of veneering ceramics (shade A1 and A4: Cerabian ZR). These specimens were polished to approximately 1.5 mm. CIE L*a*b* coordinates, translucency (TP), and opalescence (OP) on the TZP restorations were evaluated. Consequently, TZP core color affected CIE L*a*b* values of TZP restorations however TP and OP did not significantly differ among the 3 core colors. Translucency and opalescence for colored TZP framework restorations were not influenced by the underlying TZP core color when veneering ceramics were layered to thicknesses of 1.0±0.1 mm.

Summary The purpose of this study was to evaluate the training effect and to determine the optimal training protocol for a recently developed online colour training system. Seventy students participated in the evaluation. They first completed a baseline test with shade guides (SGT) and the training system (TST), and then trained with one of the three system training methods (Basic colour training for group E1, Vitapan Classical for E2, and Vitapan 3D-Master for E3) or shade guides (group C1) for 4 days. The control group (C2) received no training. The same test was performed after training and they finally completed a questionnaire. The correct matches after training increased in three experimental groups and group C1. Among experimental groups, the greatest improvement of correct matching number was achieved by group E3 (4·00 ± 1·88 in SGT, 4·29 ± 2·73 in TST), followed by E2 (2·29 ± 2·73 in SGT, 3·50 ± 3·03 in TST) and E1 (2·00 ± 2·60 in SGT, 1·93 ± 2·96 in TST). The difference between E3 and E1 was statistically significant (P = 0·036 in SGT, 0·026 in TST). The total average training time was shorter in group E2 (15·39 ± 4·22 min) and E3 (17·63 ± 5·22 min), with no significant difference between them. Subjective evaluations revealed that self-confidence in colour matching were improved greater in group C1 and E3. In conclusion, all tested sections of the system effectively improved students' colour-matching ability. Among system training methods, Vitapan 3D-Master showed the best performance; it enabled greater shade-matching improvement, it saved time and was superior in subjective evaluations.

Color errors associated with current shade guides and problems with color selection and duplication are still challenging for restorative dentists.The purpose of this study was to evaluate an optimized shade guide for visual shade duplication.Color distributions (L*, a*, and b*) of the maxillary left central incisors of 236 participants, whose ages ranged from 20 to 60, were measured with a spectrophotometer. Based on this color map, an optimized shade guide was designed with 14 shade tabs evenly distributed within the given color range of the natural incisors. The shade tabs were fabricated with porcelain powder mixtures and conventional laboratory procedures. A comparison of shade duplication by using the optimized and Vitapan Classical shade guides was conducted. Thirty Chinese participants were involved, and the colors of the left maxillary incisors were selected by using 2 shade guides. Metal ceramic crowns were fabricated according to the results of the shade selection. The colors of the shade tabs, natural teeth, and the ceramic crowns were measured with a spectrophotometer. The color differences among the natural teeth, the shade tabs, and the corresponding metal ceramic crowns were calculated and analyzed (α=.017).Significant differences were found in both phases of shade determination and shade duplication (P.017). The total number of color errors with the optimized shade guide was 3.5, which was significantly less than that of Vitapan, 5.1 (P.001).The optimized shade guide system improved performance not only in the color selection phase but also in the color of the fabricated crowns.

The ability of dental technician students to match tooth shade with the Vita 3D-Master shade guide and Toothguide Training Box has not been investigated.The purpose of this study was to evaluate and compare the shade-matching ability of dental technician students and graduate dentists using the Vita 3D-Master shade guide.Twenty-nine dental technician students (DTS group) and 30 graduate dentists (GD group) participated in this study. The Toothguide Training Box (TTB) was used to train the participants and test their shade-matching abilities. Shade-matching ability was evaluated with 3 exercises and a final test, all of which are components of the TTB. The number of mistakes for each participant for value (L), chroma (c), and hue (h) were recorded during the exercises and the final test, and the mistake ratios were calculated. Color difference (ΔE) values for each shade were calculated from the L*, a*, and b* values of the Vita 3D-Master shade guide for each participant in both groups. The Mann-Whitney U test was used to determine statistically significant differences between the L, c, and h mistake ratios of the 2 groups, and the Student t test was used to determine statistically significant differences between the final test scores and the ΔE values of the groups (α=.05).The mistake ratio for L in the GD group was significantly higher than that of the DTS group (P.05), whereas the mistake ratio for h in the DTS group was higher (P.001). No significant differences were observed between the groups regarding the mistake ratios for c (P.05). With regard to the final test scores and the ΔE values, no significant differences were found between the groups (P.001), and the DTS group received higher scores than the GD group (912 and 851). The mean ΔE values for the DTS and GD groups were 1.72 and 2.92.DTSs made more mistakes in the h parameter than GDs, and GDs made more mistakes in the L parameter than DTSs. With regard to the final test scores and the ΔE values, DTSs were more successful in shade matching than GDs.

Ceramic veneers of minimum thickness provide satisfactory esthetic outcomes while preserving the dental structure. Dental ceramics can both improve the esthetic appearance and reestablish the strength and function of teeth. In worn anterior teeth, functional surfaces, for example, anterior and lateral guidance, can be restored effectively. The characteristics of dental ceramics, such as color stability and mechanical and optical properties, make this material a good choice for indirect restorations, especially when optimum function and esthetics are required. This clinical report presents an occlusal, periodontal, and restorative solution with minimum thickness glass ceramic veneers for worn anterior teeth with multiple diastemas.

Statement of problem Maxillofacial prostheses made of silicone elastomers undergo undesirable color degradation over time. How this color change can be prevented is unclear. Purpose The purpose of this in vitro study was to evaluate the ability of an oxide nanocoating to prevent color degradation of maxillofacial silicone elastomers after artificial accelerated aging. Material and methods A silicone elastomer with functional intrinsic pigment was tested. Specimens (N=20) were fabricated, and half of them were coated with a nanolayer of titanium dioxide (TiO2) using atomic layer deposition. Both coated and noncoated specimens (control) were exposed to artificial aging at 450 kJ/m2 of total energy. Changes in the color of all the specimens with and without TiO2 nanocoating were measured before and after the atomic layer deposition coating and before and after aging. The obtained color data were analyzed by using independent t tests and the 1-sample t test (α=.05). Results Color change (ΔE1=3.4 ±1.4) was observed for the silicone elastomers after the specimens were surface coated with TiO2 nanofilm, although this change was not statistically significant (P=.369) compared with the acceptability threshold (ΔE=3.0). Upon exposure to artificial aging, the noncoated control specimens underwent color change (ΔE2=2.5 ±0.7, P=.083 compared with the acceptability threshold). The specimens with TiO2 nanocoated surface experienced the least color change (ΔE3=1.4 ±0.6) when subjected to artificial aging, and this change was significantly lower (P Conclusions TiO2 nanocoating was shown to be effective in reducing color degradation of the silicone elastomer exposed to artificial aging for 120 hours with 450 kJ/m2 of total energy.

This study aimed to evaluate the effect of core shade and core and veneering thickness on color parameters and translucency of polyether ether ketone (PEEK). Sixty PEEK discs (0.5 and 1 mm in thickness) with white and dentine shades were veneered with A2 shade indirect composite resin with 0.5, 1 and 1.5 mm thickness (n=5). Cores without the veneering material served as controls for translucency evaluation. Color parameters were measured by a spectroradiometer. Color difference (ΔE₀₀) and translucency parameters (TP) were computed. Data were analyzed using one-way ANOVA and Tukey's test (for veneering thickness) and independent t-test (for core shade and thickness) via SPSS 20.0 (p⟨0.05). Regarding the veneering thickness, white cores of 0.5 mm thickness showed significant differences in all color parameters. In white cores of 1 mm thickness and dentine cores of 0.5 and 1 mm thickness, there were statistically significant differences only in L∗, a∗ and h∗. The mean TP was significantly higher in all white cores of 1 mm thickness than dentine cores of 1 mm. Considering ΔE₀₀=3.7 as clinically unacceptable, only three groups had higher mean ΔE₀₀ values. Core shade, core thickness, and the veneering thickness affected the color and translucency of PEEK restorations.

To evaluate the efficacy of a realistic staining/cleansing protocol for long-term prevention of discoloration of denture base resins.Sixty discs (20 × 2.5 mm) of auto- and heat-polymerizing denture acrylic resins were fabricated following manufacturer's instructions, polished on one side and stored in water (37°C) for 24 hours before they were assigned randomly into 6 groups (3 for each material, n = 10) to receive 220 cycles of three immersion protocols. Group A was immersed in the following baths: (1) filtered coffee at 45°C for 2 minutes, (2) tap water at 24°C for 20 seconds, (3) as bath 1, (4) as bath 2, (5) Corega Extradent cleansing solution at 45°C for 3 minutes, and (6) water at 24°C for 20 seconds. Group B was immersed in the four first baths of group A (without cleansing action) and group C in bath 1 for the cumulative action of 20 cycles (80 minutes in 45°C coffee) and bath 2 for 40 seconds. A noncontact optical interferometric profilometer was used for qualitative evaluation of the specimens and a contact colorimeter to estimate color change values (ΔΕ*ab) at baseline and every 20 cycles in the baths for a total of 220 cycles. Data were statistically analyzed using a 2-way-repeated measures ANOVA with Bonferoni multiple comparisons and trend analysis at α = 0.05 level of significance.Data indicated changes in color from 1.7 to 14.2 ΔΕ*ab units. The highest values were related to the number of cycles and group B immersion protocol. Significant differences were found among immersion protocols (p0.001) and immersion cycles (p0.001) with a significant interaction between protocols and cycles (p0.001) but not between denture resins (p = 0.991).The evaluated protocol A was found effective in preventing color changes in both denture resins even after a long period of action. Protocol C had a much lower staining effect on both resins than protocol B and behaved similarly to protocol A until 140 to 160 cycles. Therefore, it is probably not appropriate for use in short-term color stability experiments.

Statement of problem The color stability and translucency of preshaded and externally shaded monolithic and veneered new generation translucent zirconia are not well known. Purpose The purpose of this in vitro study was to investigate the effect of fabrication (veneered or monolithic) and shading (preshaded or externally shaded) techniques on the color and relative translucency of translucent zirconia after coffee thermocycling. Material and methods Specimens of different thicknesses (0.5 mm for veneered and 1.5 mm for monolithic) were sectioned from preshaded and externally shaded translucent zirconia. Externally shaded specimens were colored by using the dipping technique. Externally shaded (Ext Mono) and preshaded (Pre Mono) monolithic zirconia specimens were sintered and glazed. Externally shaded (Ext Vene) and preshaded (Pre Vene) 0.5-mm-thick specimens were sintered, veneered with feldspathic porcelain (1 mm), and glazed. The color coordinates of specimens were measured with a spectroradiometer before and after 10 000 thermocycles in coffee solution. Color differences were calculated using CIEDE2000, and relative translucency parameter (RTP) values were calculated using the RTPCIEDE2000 formula. Analysis of variance (ANOVA) was used to analyze the CIEDE2000 color differences and RTP values (α=.05). Results Shading technique had a significant effect on the color difference values (P=.018). For the translucency data, the 3-way ANOVA revealed a significant interaction between the fabrication technique and shading technique (P=.002). Each pair of material subgroups within each combination of fabrication technique and shading technique was found to have a significantly different RTP, except between Ext Vene and Pre Vene (P=.115). Conclusions Externally shaded translucent zirconia had a greater color change in coffee than the preshaded translucent zirconia, either in monolithic or veneered form. Fabrication technique significantly affected the RTP, and the monolithic zirconia was more translucent than the veneered zirconia.

Purpose The purpose of this study was to investigate the combined effects of fiber loading and pigmentation on the color differences and flexural properties of glass fiber-reinforced thermoplastics (GFRTPs), for use in non-metal clasp dentures (NMCDs). Methods The GFRTPs consisted mainly of E-glass fibers, a polypropylene matrix, and a coloring pigment: the GFRTPs with various fiber loadings (0, 10, and 20mass%) and pigmentations (0, 1, 2, and 4mass%) were fabricated by using an injection molding. The color differences of GFRTPs were measured based on the Commission Internationale de l'Eclairage (CIE) Lab color system, by comparing with a commercially available NMCD. The flexural properties of GFRTPs were evaluated by using a three-point bending test, according to International Standards Organization (ISO) specification number 20795-1. Results The visible colors of GFRTPs with pigment contents of 2mass% were acceptable for gingival color, and the glass fibers harmonized well with the resins. The Δ E * values of the GFRTPs with pigment contents of 2mass% obtained by using the CIE Lab system were lowest at all fiber loadings. For GFRTPs with fiber contents of 10 and 20mass% at 2mass% pigment content, these GFRTPs surpassed the ISO 20795-1 specification regarding flexural strength (> 60MPa) and modulus (> 1.5GPa). Conclusions A combination of the results of color difference evaluation and mechanical examination indicates that the GFRTPs with fiber contents of 10 or 20mass%, and with pigment contents of 2mass% have acceptable esthetic appearance and sufficient rigidity for NMCDs.

Current commercially available restorative materials vary in their esthetic properties, depending on brand and shade. Variations are related not only to basic color parameters such as hue, chroma, and value, but also to other important properties that affect the overall esthetic restorative outcome, such as opalescence, fluorescence, translucency, and metamerism. Fluorescence and bluish opalescence, though associated with the ingredients and chemical composition of the material, may be controlled and refined by a proper layering technique if that pretreatment analysis has been performed with the aid of appropriate photographic techniques. Digital cameras and dental photography have long been imperative tools for clinicians in their daily practice. Traditionally, digital photography has been used for recordkeeping, documentation, presentation, and informing patients of their oral status before and after treatment. Today, evolved techniques facilitate clinicians' ability to compare the esthetic properties of restorative materials with those of natural teeth for delivery of natural-looking restorations. Moreover, documentation obtained before and after restoration may be used for more comprehensive information for the patient.

Objective To compare the effect of material and thickness on the color stability and relative translucency parameters (RTP) for monolithic ceramics subjected to coffee thermocycling. Methods Four specimens each at thicknesses of 0.5, 0,7 and 1 mm were sectioned from monolithic ceramics [preshaded monolithic zirconia (MonZr), lithium disilicate (LDS) and zirconia reinforced lithium silicate (ZLS)]. The specimens were glazed and subjected to 5000 coffee thermocycling. The color coordinates of specimens were determined with a spectroradiometer and color differences and RTP values were calculated with CIEDE2000 color difference and TPCIEDE2000 formulas. ANOVA was used to analyze CIEDE2000 color difference and RTP values (α = .05). Results For the color difference data, the 2-way ANOVA revealed a significant interaction between material and different thickness (P = .002). Except for 0.5 mm thick ZLS material, all materials in all thicknesses studied presented color changes within the clinically acceptable limits after coffee thermocycling. For the RTP data, the 3-way ANOVA revealed a highly significant interaction between material and different thicknesses (P Conclusions Material type and thickness can be expected to affect color change and relative translucency of the restorations made with preshaded MonZr, LDS and ZLS materials. Except for 0.5 mm thick ZLS material, color changes of all studied materials were within the clinically acceptable limits. Except ZLS material, color changes of other materials were not significantly affected by thickness. Staining in coffee was not found to affect translucency, and the materials’ translucency parameters were ranked from high to low as LDS, ZLS and MonZr at each thickness studied.

Aim The aim of this study is to compare the color space of Vita Lumin shade guide (SG) with the natural teeth of the local population. Materials and methods A total of 100 maxillary central incisors (100 patients) were subjected to color measurement with a spectrocolorimeter. For each tooth, L*, a*, b* values were recorded. All the shade tabs of Vita Lumin SG were analyzed with a spectrocolorimeter to define the color space covered by the Vita Lumin SG. The L*a*b* values of natural teeth were plotted on separate scattered diagrams and compared. Results About two out of three attributes (luminance and blue spectrum) of the local population of Bengaluru displayed a broader range than those available in Vita Lumin SG. Conclusion The local population requires an SG with an extended range, covering a higher luminance spectrum and broader blue spectrum. Clinical significance Esthetic restorations require accurate shade matching with the adjacent natural teeth, SGs being the mean of shade selection and communication should be comparable to the natural teeth. How to cite this article Shetty RM, Bhat AN, Gupta N, Mehta D, Srivatsa G, Singh I. Comparison between Color Spaces of Vita Lumin Shade Guide with Natural Teeth in Bengaluru Population using Spectrocolorimeter: An in vivo Study. J Contemp Dent Pract 2017;18(8):683-687.

To assess the correspondence of shades between try-in pastes and resin cements and their influence on the final color of veneers.Bovine teeth (n = 140) were prepared and divided into 2 groups (a or b) according to ceramic veneer thickness (0.35 or 0.70 mm). Seventy teeth (n = 70) were distributed in 7 groups (groups 1 to 7a and groups 1 to 7b; n = 10). Try-in pastes and their corresponding resin cements were used according to the value: groups 1a and 1b (value -3); groups 2a and 2b (-2); groups 3a and 3b (-1); groups 4a and 4b (0); groups 5a and 5b (+1); groups 6a and 6b (+2); groups 7a and 7b (+3). Color measurements were performed with spectrophotometer, and the coordinates LThe results indicated no statistically significant difference between the groups comparing ΔE0 and ΔE1 for 0.35 mm thickness laminate veneers, except for groups 2a and 5a. For 0.70 mm thickness laminate veneers, no statistically significant differences were observed between the groups comparing ΔE0 and ΔE1. ΔE2 values for 0.35 mm and 0.70 mm thickness laminate veneers ranged from 1.77 ± 0.81 to 4.99 ± 3.80 and from 1.01 ± 0.73 to 4.66 ± 2.96, respectively.Try-in pastes correspond with their respective resin cements for most colors investigated. The color of the resin cement may influence the final color of laminate veneers. Thickness of the ceramic was the most relevant variable for color change.

Objective The aim of this investigation was to evaluate intrarater and inter-rater reliability of visual and instrumental shade matching. Materials and Methods Forty individuals with normal color perception participated in this study. The right maxillary central incisor of a teaching model was prepared and restored with 10 feldspathic all-ceramic crowns of different shades. A shade matching session consisted of the observer (rater) visually selecting the best match by using VITA classical A1-D4 (VC) and VITA Toothguide 3D Master (3D) shade guides and the VITA Easyshade Advance intraoral spectrophotometer (ES) to obtain both VC and 3D matches. Three shade matching sessions were held with 4 to 6 weeks between sessions. Intrarater reliability was assessed based on the percentage of agreement for the three sessions for the same observer, whereas the inter-rater reliability was calculated as mean percentage of agreement between different observers. The Fleiss' Kappa statistical analysis was used to evaluate visual inter-rater reliability. Results The mean intrarater reliability for the visual shade selection was 64(11) for VC and 48(10) for 3D. The corresponding ES values were 96(4) for both VC and 3D. The percentages of observers who matched the same shade with VC and 3D were 55(10) and 43(12), respectively, while corresponding ES values were 88(8) for VC and 92(4) for 3D. Conclusions The results for visual shade matching exhibited a high to moderate level of inconsistency for both intrarater and inter-rater comparisons. The VITA Easyshade Advance intraoral spectrophotometer exhibited significantly better reliability compared with visual shade selection. CLINICAL SIGNIFICANCE This study evaluates the ability of observers to consistently match the same shade visually and with a dental spectrophotometer in different sessions. The intrarater and inter-rater reliability (agreement of repeated shade matching) of visual and instrumental tooth color matching strongly suggest the use of color matching instruments as a supplementary tool in everyday dental practice to enhance the esthetic outcome.

The objective of this study was to compare the performance of visual shade matching and spectrophotometric measurements.A total of 100 observers matched pairs of corresponding shade tabs from two VITA classical A1-D4 shade guides. The tab identifiers on one shade guide were masked. Lack of visible color differences between the corresponding tabs was confirmed by means of an intraoral spectrophotometer. Means and standard deviations were calculated. Analysis of variance (ANOVA) (α = 0.05) with a Bonferroni correction was performed to detect significance of differences between groups.A total of 72.5% of tab pairs (or 11.6 tabs) were matched using the visual method, and 98.9% were matched using the spectrophotometer (P 0.001). Female observers showed significantly better results than male observers (P = 0.027). Both genders showed the highest visual scores in group B, followed by groups C, A, and D.Instrumental shade-matching systems have the potential to improve color matching in dentistry. Results were influenced by gender.The dental spectrophotometer exhibited a significantly higher percentage of correct matches of corresponding shade tabs compared with conventional visual shade matching.

Direct composite resin restorations have been recognized for their valuable clinical service and respect of intact hard tissue. The cost-effectiveness and inherent minimally invasive approach of resin-based materials means that they are also gaining popularity for use in computer-aided design/computer-aided manufacture (CAD/CAM) procedures. Several cases from the student clinics at the Herman Ostrow School of Dentistry of USC are presented that could have been resolved either with direct composite resin restorations or with indirect porcelain veneers. A novel semi-indirect CAD/CAM approach, characterized by its absolute noninvasiveness and simplicity, was chosen instead. The bilaminar restoration consists of a customized histoanatomical CAD/CAM dentin base (incisoproximal cutback), and a generic enamel skin. The patients can be treated either in one clinical session (semi-directly) or in two clinical sessions (semi-indirectly). The purpose of this article is to present another tool from the anterior restorative armamentarium to bridge the gap between direct and indirect techniques.

Contemporary dental patients present with high expectations and demand seamless optical integration of restorative interventions. As a result, clinicians and technicians are required to develop methodologies that remain practical yet increase the accuracy and objectivity of shade analysis and estimation. There have been significant advances in digital technologies over the past 20 years, with digital photography being at the forefront. Digital photography has made an immediate and profound impact on applied clinical dentistry, primarily due to instantaneous image visualization and distribution. However, standardization protocols in terms of image acquisition and objective analysis remain equivocal. By utilizing reflective cross-polarized light digital photography with a standardized white balance gray reference card serving as the known reference, in conjunction with a specific digital single-lens reflex (DSLR) camera profile and digital photographic processing software working in the CIE L*a*b* (1976) color space, one can achieve standardized image acquisition and subsequent objective image analysis. The goal of this systematic approach is to identify the most efficient and effective means to generate consistent and optimum visual integration and restorative outcomes through numerical quantification, in order to enable clinicians and technicians to work predictably even when they are in different geographic locations.

Objective The purpose of this prospective, randomized, controlled, multicenter clinical study was to analyze the optical effects of an anodized pink colored implant shoulder/abutment system in the peri-implant mucosa of immediately placed dental implants. Materials and Method Forty subjects with a restoratively hopeless tooth in the maxillary esthetic zone, were recruited and randomized to receive either a pink-neck implant, or a conventional gray implant. All patients received an immediate implant and immediate provisional and two identical CAD/CAM titanium abutments with different surface colors: pink and gray, and one zirconia all-ceramic crown. The color of the peri-implant mucosa was measured using a dental spectrophotometer and analyzed using CIELAB color system. Results The overall color difference between the peri-implant mucosa with a pink abutment and a gray abutment was ΔE = 4.22. Patients with gray implants presented a color change of ΔE = 3.86-4.17 with this abutment change, while patients with pink implants had a color change of ΔE = 3.84-4.69. The peri-implant mucosa with a pink abutment was significantly more red when compared with a gray abutment (P ≤ .01). Conclusions When a pink abutment was used, there is a significant color change of the peri-implant mucosa that is above the detectable color threshold. Clinical significance Esthetic outcomes are important for the success of implant treatment of maxillary anterior implants. The phenomenon of the gray color of a dental implant and abutment shining through the peri-implant mucosa has been documented in the literature. The objective of this study was to assess the optical effect of an anodized pink-neck implant and a pink abutment on the color of peri-implant mucosa. This study demonstrates that using pink-neck implant and a pink abutment would contribute positively to the overall esthetic outcome for an anterior implant.

Statement of problem The color degradation of maxillofacial prostheses in clinical service requires their frequent renewal. How different materials compare is unclear. Purpose The purpose of this in vitro study was to investigate the color stability of a nonpigmented and pigmented maxillofacial silicone when stored in darkness and exposed to accelerated aging in a weathering chamber and natural outdoor weathering. Material and methods M511 elastomer was colored with Spectromatch Pro colorants, stored in darkness, and exposed to accelerated aging and natural outdoor weathering for 1500 hours. Test groups included nonpigmented specimens (n=18), individually pigmented specimens (n=90), and Caucasian skin tone-colored specimens (n=18). The CIELab values of the test specimens were measured using the CM-2600d spectrophotometer (Konica Minolta Sensing) at base line (0 hours) and then every 100 hours up to 1500 hours of aging. Color changes (ΔE) were calculated based on the recorded CIELab values. All data were analyzed by using linear mixed models and the Sidak multiple comparison of means test (α=.05). Results A significant effect of time was found on the ΔE of all test specimens in all environments ( P =.001). All pigmented M511 specimens demonstrated good color stability with maximum ΔE below the acceptability threshold of 2 ΔE when stored in darkness and exposed to outdoor weathering. However, nonpigmented specimens crossed this acceptability threshold when exposed to outdoor weathering with maximum ΔE values of 3.65. The greatest color changes were observed for all specimens when exposed to accelerated aging and most exceeded the acceptability threshold. Nonpigmented (ΔE, 4.86) and Indian yellow (ΔE, 5.20) demonstrated the highest color changes after 1500 hours. Conclusions All environments resulted in visible color changes of nonpigmented and pigmented M511 elastomer. The lowest ΔE values were observed for specimens stored in darkness and the greatest for specimens exposed to accelerated aging. The organic pigment Logwood maroon demonstrated the best color stability with maximum ΔE values below the perceptibility threshold (PT) of 1 ΔE.

WOS:000448767900010 PubMed: 29703672 Statement of problem. The color of resin cements and computer-aided-design and computeraided-manufacturing (CAD-CAM) restorations may change with aging. Purpose. The purpose of this in vitro study was to analyze the influence of thermocycling on the color of CAD-CAM materials with underlying resin cement. . Material and methods. Seven different CAD-CAM materials, composite resins and glass-ceramics were cut into 0.7-mm and 1.2-mm thicknesses (n=10) and cemented with a dual-polymerizing resin cement, a light-polymerizing resin cement, and a preheated composite resin (N=420). Color values were measured by using spectrophotometry. Specimens were subjected to thermocycling (5 degrees C and 55 degrees C; 5000 cycles). The measured color difference (Delta E) data were analyzed by using descriptive statistics. Normality of data distribution was tested by using the Kolmogorov-Smirnov test. Three-way and 1-way ANOVA followed by the Scheffe post hoc test and unpaired 2-sample Student t test were computed to determine the significant differences among the tested parameters (alpha=.05). Results. Delta E values were significantly influenced by the CAD-CAM material (eta(2)(p)=0.85, P

Objectives The objective of this study was to develop a shade selection program that predicts the shade choice with the smallest CIEDE2000 color difference for dental composite resin restorations when given a backing and target shade. By utilizing previously generated regression models, a database of spectral reflectance information, and principles of Kubelka-Munk layering, a highly accurate shade selection program was designed. Methods Using SAS 9.3 Statistical Analysis Software, a shade selection program was developed that incorporated Kubelka-Munk layering data of Herculite Ultra and Estelite Omega composite resins from a characterized database of absorption and scattering information. Test scenarios represented an inquiry based off of a backing selection shade (Shade B) and a target selection shade (Shade T). For the simulation, the thickness of the layer on the backing was 1.9 mm and the CIE illuminant was D65. The selection program was designed to select the shade that would give the lowest CIEDE2000 color difference when selected for the specific target and backing. When using the 3-D Vita shade guide, analysis between direct reflectance data and RGB data regressed to reflectance data was included in order to verify accuracy of the regression. Results Test scenarios indicated a systematic and accurate shade selection system by suggesting a shade that resulted in a CIEDE2000 color difference of zero when using the same target and backing shades. Most scenarios of backing and target combinations gave at least one option that was beneath the acceptability threshold indicating a clinically acceptable shade match. Many test scenarios indicated options that were beneath the perceptibility threshold indicating a highly accurate process of shade selection. There was generally little variability in the CIEDE2000 color differences when using the reflectance data versus the RGB regression data as input into the shade selection program further verifying the accuracy of a previously generated regression model. Conclusions The shade selection program that was developed is a viable system that could reduce variability in observer selections while increasing patient satisfaction for potential use in clinical situations that require color matching a restoration to a tooth.