• Restorative Dentistry and Endodontics
• /
• v.22 no.2
• /
• pp.769-781
• /
• 1997

The tristimulus values of 180 extracted maxillary and mandibular anterior teeth were measured by colorimeter. And it were colnverted to Munsell color order system(Hue, Value, Chroma) and CIE $L^*a^*b^*$ color coordinates. The commonly used Vita, and Bioform shade guides, 2 composite resin shade guides(Prisma APH and Z-100), and a glass-ionomer shade guide(Fuji II) were compared with these teeth. At the middle facial surface, color distributions of teeth were Hue(0.56YR to 9.77Y), Value(2.46 to 7.9), and Chroma(0.14 to 2.02). And the aberaged values and standard deviations for $L^*a^*b^*$ were $63.18{\pm}10.44$, $1.11{\pm}1.66$, and $5.79{\pm}2.36$. The shade guide did not match well with the color space of the human teeth. Especially, the lacks of the Yellow-red Hues and higher values were prominent. Compare with other measurements, the Hues of the teeth measured in this study were broadly distributed(most of ranges in Y and YR were included), while the Value and chroma were shown to the lower.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.28 no.2
• /
• pp.213-221
• /
• 2012

The purpose of this study was to evaluate the stability of external stain that long term attrition caused by tooth brushing affected the color variation of external stain of IPS e.max Press Porcelain. The specimen was made by IPS e.max Press LT ingots, and treated the shade of external staning as Orange, A, B, C, D After conducting horizontal toothbrush strokes about 11,000 / 22,000 / 44,000 / 66,000 / 88,000, Color changers of the external stained layer was measured with SpectroShade$^{tm}$ MICRO(MHT, Italy). The result of this study was obtained as follows: 1. After 11,000 strokes, the color changes of shade were greater in Orange shade than the other 4 shade groups. And even though toothbrush strokes were increased until 88,000, there were no statistical significant color changes about the external stain shade variation. 2. The amount of color variation about increasing of toothbrushing strokes was irregular(no consistent increasing, or decreasing), and it was no statistical significant changes According to these results, the long term tooth-brushing doesn't affect the changes of external stain about IPS e.max press porcelain. And it doesn't reduce the stability of external stain clinically. Later, it will be needed to study other factors affecting the external stain.

• The Journal of Advanced Prosthodontics
• /
• v.10 no.3
• /
• pp.252-258
• /
• 2018

PURPOSE. The purpose of this study was to evaluate the repeatability and matching accuracy between two identical intraoral spectrophotometers. MATERIALS AND METHODS. The maxillary right central incisor, canine, and mandibular left central incisor of each of 30 patients were measured using 2 identical intraoral spectrophotometers with different serial numbers (EasyShade V). The color of each shade tab from 3 shade guides (VITA 3D-Master) was also determined with both devices. All measurements were performed by a single operator. Statistical analyses were performed to verify the repeatability, accuracy, and the differences between the devices with paired t-tests, one-way ANOVA, and intra-class correlation coefficients (ICCs) (${\alpha}=.05$). RESULTS. A high level of measurement repeatability (ICC>0.90) among $L^*$, $a^*$, and $b^*$ color components was observed within and between devices (P<.001). Intra-device matching agreement rates were 80.00% and 81.11%, respectively, while inter-device matching agreement rate was 51.85%. ANOVA revealed no significant different color values within each device, while paired t-test provided significant different color values between both devices. The CIEDE2000 color differences between both devices were $2.28{\pm}1.61$ ${\Delta}E_{00}$ for in-vivo readings. Regarding the clinical matching accuracy of both devices, ${\Delta}E_{00}$ values between teeth and matching shade tabs were $3.05{\pm}1.19$ and $2.86{\pm}1.02$, respectively. CONCLUSION. Although two EasyShade V devices with different serial numbers show high repeatability of CIE $L^*$, $a^*$, and $b^*$ measurements, they could provide different color values and shade for the same tooth.

• The Journal of Korean Academy of Prosthodontics
• /
• v.43 no.3
• /
• pp.314-321
• /
• 2005

Objectives. The purpose of this study was to compare the shade changes in wet and dry conditions of natural teeth using two different intra-oral colorimeters. Materials and methods. Twenty volunteer subjects have no restorations and fillings in the maxillary central incisors were involved in this clinical study. The color of tooth was measured by two different instruments that were a Shade $Scan^{TM}$ System and a VITA $Easyshade^{(R)}$, Five times consecutive measurements were done for each subject with both instruments. Groups of measurement are an initial wet condition as control, dry in 5 minutes, 15 seconds after re-wetting with saliva, re-wetting after 5minutes and re-wetting after 30 minutes. Using ShadeScan $System^{TM}$, tooth image was captured and converted to the mapping image of Vitapan 3D master. Three main shades were chosen from each subject and calculated the area in Global Lab Image software. Data were analyzed using paired T-Test and Wilcoxon Signed Ranked Test. Using VITA $Easyshade^{(R)}$, color differences($\Delta$E) between measurements were analyzed with one sample T-test. Results. Using ShadeScan $System^{TM}$, there were significant differences between control group and dry(P=.023), dry and re-wetting 15 seconds, 5 minutes, 30 minutes as well(P=.021, P=.017, P=.030) in comparison of primary shade. However, comparing three main shades, there was no significant difference between control and dry(P=.105). Using VITA $Easyshade^{(R)}$, color differences($\Delta$E) between control and dry, dry and re-wetting 30 minutes were statistically different(P=.002, P=.022). Conclusion. Primary shade could be changed in dry and wetting procedure in time, however there was no significant shade changes in overall.

• Restorative Dentistry and Endodontics
• /
• v.47 no.1
• /
• pp.9.1-9.11
• /
• 2022

Objectives: This study investigated the microhardness, flexural strength, and color stability of bleach-shade resin composites cured with 3 different light-curing units. Materials and Methods: In this in vitro experimental study, 270 samples were fabricated of bleach and A2 shades of 3 commercial resin composites (Point 4, G-aenial Anterior, and Estelite Sigma Quick). Samples (n = 5 for each trial) were cured with Bluephase N, Woodpecker LED.D, and Optilux 501 units and underwent Vickers microhardness and flexural strength tests. The samples were tested after 24 hours of storage in distilled water. Color was assessed using a spectrophotometer immediately after preparation and 24 hours after curing. Data were analyzed using 3-way analysis of variance and the Tukey test (p ≤ 0.001). Results: Samples cured with Optilux exhibited the highest and those cured with LED.D exhibited the lowest microhardness (p = 0.023). The bleach shade of Point 4 composite cured with Optilux displayed the highest flexural strength, while the same composite and shade cured with Sigma Quick exhibited the lowest (p ≤ 0.001). The color change after 24 hours was greatest for the bleach shade of G-aenial cured with Bluephase N and least for the A2 shade of Sigma Quick cured with Optilux (p ≤ 0.001). Conclusions: Light curing with polywave light-emitting diode (LED) yielded results between or statistically similar to those of quartz-tungsten-halogen and monowave LED in the microhardness and flexural strength of both A2 and bleach shades of resin composites. However, the brands of light-curing devices showed significant differences in color stability.

• Restorative Dentistry and Endodontics
• /
• v.48 no.1
• /
• pp.7.1-7.10
• /
• 2023

Objectives: This study aimed to evaluate the surrounding and underlying shades' effect on the color adjustment potential (CAP) of a single-shade composite used in a thin layer. Materials and Methods: Cylinder specimens (1.0 mm thick) were built with the Vittra APS Unique composite, surrounded (dual specimens) or not (simple specimens) by a control composite (shade A1, A2, or A3). Simple specimens were also built only with the control composites. Each specimen's color was measured against white and black backgrounds or the simple control specimens with a spectrophotometer (CIELAB system). The whiteness index for dentistry (WI_D) and translucency parameters (TP₀₀) were calculated for simple specimens. Differences (ΔE₀₀) in color between the simple/dual specimens and the controls were calculated. The CAP was calculated based on the ratios between data from simple and dual specimens. Results: The Vittra APS Unique composite showed higher WID and TP₀₀ values than the controls. The highest values of ΔE₀₀ were observed among simple specimens. The color measurements of Vittra APS Unique (simple or dual) against the control specimens presented the lowest color differences. Only surrounding the single-shade composite with a shaded composite barely impacted the ΔE₀₀. The highest CAP values were obtained using a shaded composite under simple or dual specimens. Conclusions: The CAP of Vittra APS Unique was strongly affected by the underlying shade, while surrounding this composite with a shaded one barely affected its color adjustment.

• The Journal of Advanced Prosthodontics
• /
• v.14 no.1
• /
• pp.56-62
• /
• 2022

PURPOSE. The aim of this study was to investigate shade changes in fully- and pre-crystalized CAD-CAM lithium disilicate crowns after the required and additional firing processes. MATERIALS AND METHODS. One hundred and five crowns of shade A1 with high translucency were milled out of CAD-CAM lithium disilicate blocks and categorized as follows (n = 15): (1) restorations fabricated from Straumann n!ce with no additional sintering process; (2) restorations fabricated from Straumann n!ce with one additional sintering process; (3) restorations fabricated from Straumann n!ce with two additional sintering processes; (4) restorations fabricated from Amber Mill with one sintering process; (5) restorations fabricated from Amber Mill with two sintering processes; (6) restorations fabricated from IPS e.max CAD with one sintering process; (7) restorations fabricated from IPS e.max CAD with two sintering processes. All restorations were evaluated with a color imaging spectrophotometer. RESULTS. All restorations presented some color alteration from the original shade both after a single and after two firing processes. CONCLUSION. The required and additional sintering processes for restorations fabricated with chairside CAD-CAM lithium disilicate blocks cause an alteration of the original shade selected. Shade A1 high translucency restorations tend to change to a more yellowish B1 shade after a sintering process.

• Restorative Dentistry and Endodontics
• /
• v.32 no.4
• /
• pp.356-364
• /
• 2007

The purpose of this study was to assess the background color-interceptive ability ana opacity of opaque shade composites (Universal composite, Filtek Z350, Charisma, Clearfil ST, Palpaque Estelite, Esthet-X, and Metafil Flo). Twenty four background specimens (diameter 5.5 mm, thickness 3.0 mm) with Root dentin Mustard (Bisco, Schaumburg, IL, USA) were made. The CIE $L^*a^*b^*$ value of background specimens was measured by a spectrophotometer (Spectrolino, GretagMacbeth, Regensdorf, Switzerland). Three specimens in every group were filled on the background specimens. The surface color of samples was measured by a spectrophotometer in 3.0 mm and every thickness to 0.5 mm while grinding. The color difference in the background color along with 3.0 mm specimen gauged the masking effect in each thickness while grinding and polishing. The opacity was calculated in 1 mm thick specimens. The opacity was in the decreasing order of Clearfil ST, Metafil Flo, Filtek Z350, Palpaque Estelite, Universal composite, Charisma, and Esthet-X (p < 0.05). As the thickness get reduced, $L^*$ value showed decreasing, $a^*$ increasing tendency. The surface color difference between pair of the 3.0 mm thick specimen and after grinding in same opaque resin was above 3.3 except Clearfil ST and Metafil Flo. The color difference (${\Delta}E^*$) between pair of background specimen and opaque resin built-up specimen showed more than 10.0 regardless kinds and thickness. The variance in opacity characteristics and color of the opaque composites is dependent upon manufacturer. When using the opaque resin, the optical properties of each material must be considered as well as cavity.

• The Journal of Korean Academy of Prosthodontics
• /
• v.45 no.2
• /
• pp.191-202
• /
• 2007

Statement of problems: Long-term success of esthetic restorations, depends on various factors, especially on color stability of the restorations. The color stability is affected by resin cements beneath the porcelain laminate veneers. Purpose: The purpose of this study was to comprehend the color stability of resin cements by comparing with 4 different kinds of resin cements (Choice, Variolink II, Nexus 2, Rely-X). Material and methods: Porcelain laminate disk samples were luted with resin cements. After thermocycling of each 1000, 2000 and 3000 cycle, specimens were measured by spectrophotometers and the color differences were. Results: 1. After thermocycling of 1000, 2000 and 3000cycle, color difference, $({\Delta}E^*)$ of all specimens were incresed, but were not statiscally significant differences. 2. In the Choice of A1 shade and the Nexus 2 of A3 shade, color difference$({\Delta}E^*)$ after thermocycling of 3000cycle was $incre^*ased$ significantly than after thermocycling of 1000cycle. However, other groups did not show any statistically significant differences (P<0.05). 3. After thermocycling of 3000cycle, color difference$({\Delta}E^*)$ between A1 shade and A3 shade of Nexus 2 showed statistically significant difference. However no statistically significant differences were observed in other groups (P<0.05). 4. The mean of color difference$({\Delta}E^*)$ is 1.0-2.06 after 3000 thermocycling and the data were ranked in the ascending order of Variolink II, Nexus 2, Choice and Rely-X in A1 shade group and Choice, Rely-X, Variolink II and Nexus 2 in A3 shade group. Conclusion: Above results revealed that, after 3000 thermocycing, the color difference $({\Delta}E^*)$ of experimental resin cements was within clinically acceptable ranges. Color stability of 4 different resin cements was comparatively excellent.

• Journal of Technologic Dentistry
• /
• v.29 no.1
• /
• pp.35-48
• /
• 2007

The purpose of this study was to evaluate shade selection using conventional visual assessment in vivo natural teeth and porcelain-fused-to-metal (PFM) crown. Maxillary central incisors, lateral incisors and canines of one hundred twenty four college women were used as vivo natural teeth. Fifty one PFM crown for maxillary central incisor fabricated by dental laboratory were used as experimental materials. Using Vitapan Classical Shade Guides, shade selection of natural teeth was measured by each college woman and shade selection of PFM crown was measured by three ceramists with more than ten years career. Both natural teeth and PFM crown shade selection were measured through Shade Eye-Ex. From the shade selection comparing, following results were obtained. The results were as follows: 1. The shade matching identification of natural teeth between the shade selection using Vitapan Classical Shade Guides and the shade selection using Shade Eye-Ex was 27.4% in maxillary central incisor, 13.7% in lateral incisor and 18.5% in canine. 2. Among the shade selection of PFM crown by three ceramists, the shade evaluation of three ceramists were same only in ten cases. In twenty case, those of two ceramists were same. 3. The shade matching identification of PFM crown between the shade selection using Vitapan Classical Shade Guides and the shade selection using Shade Eye-Ex was 38.6% in average. These results suggest that the shade selection using conventional visual assessment should be dealt with care in clinic and need a credible method for shade matching color.