• The Journal of Korean Academy of Prosthodontics
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• v.44 no.4
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• pp.374-382
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• 2006

Purpose: This study was designed to investigate the present conditions of illumination techniques in dental clinics in order to contribute improvement of operating environment. This study also aimed exploring qualitative and quantitative luminous intensity required for color temperature in dental clinic illumination, which was a critical part of esthetic dentistry. Materials and methods: A total of forty-eight local dental clinics were selected for sampling a) luminous intensity, and b) color temperature. The author measured the luminous intensity and the color temperature with lux meter and color meter respectively between 12pm and 2pm. The dental unit chair placed in the general operation positions were kept the distance 60 cm then all dental units were measured three times and averaged. The author measured the luminous intensity and color temperature with both common dental operating light and then without operating light in different office environments. The study was conducted under three conditions: 1 artificial illumination in clear day light 2. artificial illumination in cloudy day light, and 3. artificial illumination alone. Results : The results obtained were as follows. 1. The average luminous intensity in dental clinic lighting was 425 lux which was not sufficient to produce the optimal shade of the patient's teeth. Furthermore, the average luminous intensity even in full operating lighting was 9532 lux which fell short of the required level of 10,000 lux. 2. The average color temperature of all dental clinics surveyed was 5169 K which met the optimal range. However, only 33.3% fell in the correct region between 5,000-5,500 K as 25% were over 5,500 K and 41.6% were below 5,000 K. As a result, 66.7% were under insufficient color temperature conditions. 3. The dental unit chair placed next to a window, hence exposure to natural lighting, had significantly higher luminous intensity and color temperature compared to the dental unit chair which didn't have a window or natural lighting. 4. The data analysis revealed that only 6.3% of the dental clinic were met the standard of the average luminous intensity and color temperature.

• The Journal of Advanced Prosthodontics
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• v.6 no.4
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• pp.309-316
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• 2014

PURPOSE. The color of the ceramic restorations is affected by various factors such as brand, thickness of the layered the ceramic, condensation techniques, smoothness of surface, number of firings, firing temperature and thickness of dentin. The aim of this study was to evaluate the color change and surface roughness in dental porcelain with different thicknesses during repeated firings. MATERIALS AND METHODS. Disc-shaped (N=21) metal-ceramic samples (IPS Classic; Ivoclar Vivadent; Shaar, Liechtenstein) with different thickness were exposed to repeated firings. Color measurement of the samples was made using a colorimeter and profilometer was used to determine surface roughness. ANOVA and Tukey tests with repeated measurements were used for statistical analysis. RESULTS. The total thickness of the ceramics which is less than 2 mm significantly have detrimental effect on the surface properties and color of porcelains during firings (P<.05). CONCLUSION. Repeated firings have effects on the color change and surface roughness of the dental ceramics and should be avoided.

• Journal of Technologic Dentistry
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• v.38 no.3
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• pp.165-173
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• 2016

Purpose: This study was conducted to examine the color stability of temporary prosthetic materials for dental CAD-CAM. Method: 2 kinds of existing acrylic resin temporary filling materials and 2 kinds of polymer prosthetic materials for dental CAD-CAM were used for testing, and five specimens respectively were absorbed in soy sauce, red pepper paste, and coffee. A Chroma Meter was used as analysis equipment. The color change of the specimens was observed to calculate ${\Delta}E$ value throughout 2 days, 3 days, 4 days, and 5 days and this was analyzed and the following result was obtained. Results: Snap's ${\Delta}E$ value was bigger than Vipi block(p<0.05). Red pepper paste had the largest impact on the color change of resin(${\Delta}E$), followed by soy sauce and coffee(p<0.000). With the passage of time, ${\Delta}E$ value was inversely(-) related and decreased somewhat(p<0.000).

• Journal of Technologic Dentistry
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• v.44 no.4
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• pp.118-125
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• 2022

Purpose: The color of dental zirconia is very important in terms of aesthetics. To reproduce the color tone, a colorant is applied to zirconia to express the color tone. I would like to point out that the color, brightness, and saturation of the colorant used to express the color A3 may vary depending on the manufacturer. Methods: Each zirconia block received a total of 25 circular specimens for the experiment. The zirconia specimen was then deposited by colorant type to reproduce the color tone. Color differences and translucency were measured using a spectrophotometer. To compare and analyze the zirconia color according to the type of colorant, one-way ANOVA was used. Results: For each type of zirconia colorant, there was no statistically significant difference in translucency or b^* (p>0.05). There was a statistical difference in L^* and a^* (p<0.05). Conclusion: The ΔE^*ab (D65) value is less than 5.5 or less, and the color difference is within an acceptable range.

• Restorative Dentistry and Endodontics
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• v.48 no.4
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• pp.40.1-40.8
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• 2023

Objectives: The purpose of this study was to evaluate the influence of eye dominance on color perception, and shade matching. Materials and Methods: A total of 104 participants were selected for the study. There were 3 groups: Group I: 3rd and 4th year dental students and interns (n = 40); Group II: postgraduates (n = 34); Group III: senior residents and faculty members (≥ 6 years of clinical experience) (n = 30). All participants were evaluated for congenital color blindness with Ishihara plates, their dominant eye with Mile's test, and their color perception with the Farnsworth-Munsell 100 hue test. The shade guide test was used for shade matching with a second corresponding set of Vitapan classical shade guides. Results: The results of Mile's test revealed that 60.6% were right-eye dominant and 39.4% were left-eye dominant. There was a statistically significant difference among all participants between the dominant eye and the non-dominant eye in shade matching. Conclusions: The dominant eye has a positive effect on shade matching and the ability to match shades becomes better with an increase in clinical experience.

• The Journal of the Korean dental association
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• v.58 no.8
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• pp.476-485
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• 2020

The purpose of this study was to analyze the color distribution of the maxillary primary central and lateral incisors using a dental spectrophotometer. Color measurements of maxillary primary central and lateral incisors of 32 pediatric patients aged 2 to 6 years were performed using SpectroShade Handy Dental Type 713000 (Serial No. HDL2678, MHT, Verona, Italy) by one researcher in the same clinic. CIE L*, a*, b* values of total surfaces and cervical, middle, incisal region were recorded. L* values were higher and a* values were lower in the primary central incisors than those in primary lateral incisors, but b* values didn't show statistical difference. L* values of the middle region were the highest, and a* and b* values decreased from the cervical region to the incisal region. There were significant color differences between each region, and ΔE*_ab between each region were greater than ΔE*_ab between the primary central and lateral incisors. For esthetic restorations of primary incisors, it is necessary to consider the color differences between each region rather than those between the primary central and lateral incisors.

• Journal of Technologic Dentistry
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• v.30 no.1
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• pp.33-39
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• 2008

Recently natural characteristics and esthetics have been interested increasing in clinical dentistry. Thus the evaluation of the shade of dental porcelain has become an important part in dental research. Noritake Super Porcelain EX-3 Vita shade A2 (Noritake, Japan) Vintage HaLo Vita shade A2 (Shofu, Japan), Vita omega 900 Vitapan 3D-master shade 2M2 (Vita, Germany) were conducted for six times for repeated firing in a way to observe the change of color with respect to the number of firing. The repeated firing was implemented with the vacuum firing and air firing, and by using Shade Eye-EX Chroma meter (Shofu, U.S.A.), the changes in values of shade, value and chroma were compared. With the above results, the change of color was not noticed only in Vita when repeated firing was applied.

• Journal of Dental Rehabilitation and Applied Science
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• v.30 no.4
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• pp.289-298
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• 2014

Purpose: This study was designed to investigate the present conditions of illumination techniques in dental laboratories in order to distinguish colors for esthetic dentistry. Materials and Methods: A total of forty-eight local dental laboratories were selected for sampling a) luminous intensity and b) color temperature. We measured the luminous intensity and the color temperature on a center point of porcelain table with lux meter and color meter respectively. The measurements were performed twice, once on a clear day and on a cloudy day between 12 pm and 2 pm (day light and artificial illumination) and between 7 pm and 10 pm (artificial illumination only). Results: The results obtained were as follows. 1. The average luminous intensity in dental laboratories lighting was 1871 lx, and 67% of dental laboratories had luminous intensity greater than 1600 lx, which was appropriate for operations related to colors, while 33% of dental laboratories had in sufficient lighting for appropriate luminous intensity. 2. The average color temperature in dental laboratories lighting was 6506 K, which was inappropriate for operations related to color. None of the dental laboratories had a color temperature range of 5000 - 5500 K, which is appropriate for operations related to colors. 3. Between daytime and nighttime, also between clear day and cloudy day, the average luminous intensity and color temperature in dental laboratories were not significantly different. Conclusion: Illumination in most dental laboratories selected in this study was inappropriate for operations related to color.

• Restorative Dentistry and Endodontics
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• v.40 no.4
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• pp.270-275
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• 2015

Objectives: This study examined the color changes of a resin composite with different shades upon exposure to water with different pH. Materials and Methods: Nanohybrid resin composites (Filtek Z350XT, 3M ESPE) with four different shades (A2, A3, B1, and B2) were immersed in water with three different pH (pH 3, 6, and 9) for 14 day. The CIE $L^*a^*b^*$ color coordinates of the specimens were evaluated before and after immersion in the solutions. The color difference (${\Delta}E^*$) and the translucency parameter (TP) were calculated using the color coordinates. Results: ${\Delta}E^*$ ranged from 0.33 to 1.58, and the values were affected significantly by the pH. The specimens immersed in a pH 6 solution showed the highest ${\Delta}E^*$ values (0.87 - 1.58). The specimens with a B1 shade showed the lowest ${\Delta}E^*$ change compared to the other shades. TP ranged from 7.01 to 9.46 depending on the pH and resin shade. The TP difference between before and after immersion in the pH solutions was less than 1.0. Conclusions: The resulting change of color of the tested specimens did not appear to be clinically problematic because the color difference was < 1.6 in the acidic, neutral, and alkaline solutions regardless of the resin shade, i.e., the color change was imperceptible.

• The Journal of Advanced Prosthodontics
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• v.6 no.6
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• pp.427-433
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• 2014

PURPOSE. Surface color is one of the main criteria to obtain an ideal esthetic. Many factors such as the type of the material, surface specifications, number of firings, firing temperature and thickness of the porcelain are all important to provide an unchanged surface color in dental ceramics. The aim of this study was to evaluate the color changes in dental ceramics according to the material type and glazing methods, during the multiple firings. MATERIALS AND METHODS. Three different types of dental ceramics (IPS Classical metal ceramic, Empress Esthetic and Empress 2 ceramics) were used in the study. Porcelains were evaluated under five main groups according to glaze and natural glaze methods. Color changes (${\Delta}E$) and changes in color parameters (${\Delta}L$, ${\Delta}a$, ${\Delta}b$) were determined using colorimeter during the control, the first, third, fifth, and seventh firings. The statistical analysis of the results was performed using ANOVA and Tukey test. RESULTS. The color changes which occurred upon material-method-firing interaction were statistically significant (P<.05). ${\Delta}E$, ${\Delta}L$, ${\Delta}a$ and ${\Delta}b$ values also demonstrated a negative trend. The MC-G group was less affected in terms of color changes compared to other groups. In all-ceramic specimens, the surface color was significantly affected by multiple firings. CONCLUSION. Firing detrimentally affected the structure of the porcelain surface and hence caused fading of the color and prominence of yellow and red characters. Compressible all-ceramics were remarkably affected by repeated firings due to their crystalline structure.