• Journal of the korean academy of Pediatric Dentistry
• /
• v.44 no.3
• /
• pp.306-316
• /
• 2017

The purpose of this study was to evaluate the effects of exposure to various children's drinks on the color stability of anterior primary teeth and different esthetic restorative materials clinically used in pediatric dentistry. Exfoliated maxillary primary central incisors that had been unaffected by caries were chosen as control group. Maxillary primary central incisor-shaped specimens made of strip crown and Nu-smile zirconia crowns were chosen as test groups. Polished strip resin crowns were additionally prepared to compare with unpolished strip resin crown. Each specimen and teeth were divided into 4 groups in which the test samples (n=5 each) were immersed in 4 different drinks (distilled water, cola, grape juice, jelly juice) for 6 days. In all 4 drink groups, all specimens generally showed increasing ${\Delta}E^*$ value (color difference) with time. Polished resin strip crown had higher ${\Delta}E^*$ value than the unpolished in cola, grape juice and jelly juice groups. ${\Delta}E^*$ value of zirconia crown in cola, grape juice and jelly juice groups were significantly different (p < 0.05). In conclusion, dietary control of children's drinks is required for preventing discoloration of restorative materials.

• 대한치과보철학회:학술대회논문집
• /
• 2002.11a
• /
• pp.121-121
• /
• 2002

• Journal of the korean academy of Pediatric Dentistry
• /
• v.44 no.1
• /
• pp.1-10
• /
• 2017

The present study aimed to evaluate the validity of resin infiltration in improving color stability after tooth whitening. Enamel samples were extracted from 40 healthy bovine upper incisors, and primary staining and whitening were performed. After that, specimens were randomly divided into 3 groups : resin infiltration group (n = 15, RI group), resin adhesive group (n = 15, RA group), and control group (n = 10). Secondary staining was performed on all samples. Coloration was assessed 5 times as follows: initial color, immediately after staining, after whitening, after resin application, and after secondary staining. Color was measured using a spectrophotometer and recorded by using the CIE $L^*a^*b^*$ color space. The color changes after primary staining for the RI, RA, and control groups were $12.16{\pm}3.50$, $12.16{\pm}3.38$, and $15.81{\pm}6.39$, whereas those after secondary staining were $15.21{\pm}7.19$, $15.93{\pm}4.31$, and $26.62{\pm}17.89$. Color changes after secondary staining showed a significant difference between the RI and control groups. In the within-group comparison between primary and secondary staining, there was no significant difference found in the RI group only (p = 0.26). The results suggest that Color stability after tooth whitening can be improved using resin infiltration.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.48 no.3
• /
• pp.280-290
• /
• 2021

Color stability of pulp-capping material is considered vital to the final aesthetic result since the material is placed in the coronal area. The purpose of this study was to compare the color stability of various pulp-capping materials by analyzing color change of tooth over time. A cavity was formed in the crown of the extracted premolar, and 4 types of pulp-capping materials were filled. Color assessment was performed with a spectrophotometer at different intervals: before placement; immediately after material placement; 1 day, 1 week, 2 weeks, 4 weeks, 8 weeks, 12 weeks, and 16 weeks after placement. Proroot white MTA^® and TheraCal LC^® showed a significant decrease in the L^* value and an increase in the ∆E^* value over time. In contrast, Biodentine^® and Well-Root^TM PT showed no significant change in the L^* value and maintained a steady ∆E^* value. The application of pulp-capping materials containing bismuth oxide as a radiopacifier may result in a color change of teeth. Long-term color stability of pulp-capping materials should be considered when treating teeth with thin enamel thickness or in aesthetically important area.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.46 no.4
• /
• pp.353-361
• /
• 2019

The aim of this study was to evaluate the color stability of bulk-fill and conventional resin composites with respect to different storage media and thickness of composites. Filtek™ Z250 and Filtek™ Z350XT were evaluated as conventional resin composites. Filtek™ Bulk-fill Posterior Restorative and Tetric^® N-Ceram Bulk Fill were evaluated as bulk-fill resin composites. CIE L^*a^*b^* values of baseline were measured after 24 hours of storage in distilled water, and each resin composite group was divided into three subgroups and stored in distilled water, red wine, and coffee media respectively. Again after 1, 7 and 28 days of immersion, color changes (ΔE^*) were calculated using the CIE L^*a^*b^* values. The greatest ΔE^* was observed in red wine for all resin composites, and the mean color changes were ranked in the increasing order of distilled water, coffee, red wine. Filtek™ Z350XT exhibited the greatest color change in all media, followed by Filtek™ Bulk-fill Posterior Restorative. Filtek™ Z250 and Tetric^® N-Ceram Bulk Fill followed with similar mean color change values. According to the 2 different thicknesses of 2 mm and 4 mm of bulk-fill resin composites, there was no thickness-related difference on color changes.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.10 no.1
• /
• pp.93-101
• /
• 1981

This study is designed to investigate the properties of caramel color made by corn sugar molasses, a new material. Com sugar refined and then caramelized in the solution of pH 2-10 ranges using catalysts such as ammonium carbonate, glycine and lysine. The control solution are 10% hydrochloric acid and sodium carbonate. The result were as follow; The caramelization showed the intensity of very strong color when added 0.4% ammonium carbonate as a catalyst. Color hue appeared to have the same color hue of the yellow belt and the red belt when compared with standard color hue in alkali, but the samples blue belt in all pH ranges showed a strong color hue than the standard color hue. Also, the stability of tannin, table salt and alcohol was transparent in all pH ranges, but the stability of acid appeared hazy at pH 9-10. In the case of glycine as a catalyst, caramelization showed the intensity of strong color when added 0.8% glycine at pH 9. Color hue showed in the yellow belt, strong in the red belt and very strong in the blue belt in all pH ranges when compared with standard color hue. Stability of tannin, table salt, acid alcohol was quite stable. In the case of lysine as a catalyst, caramelization showed strong color intensity when added 0.4% lysine in pH 9. Stability of tannin, table salt, acid and alcohol was quite stable.

• Journal of the Korean Applied Science and Technology
• /
• v.34 no.1
• /
• pp.116-124
• /
• 2017

A plate-type inorganic pigment complex was manufactured in a manner that treats the surface of the complex by adjusting zeta potential between talc, an inorganic pigment used as a material for color cosmetics, and hydrophobic silica. Talc, which is usually used in the prescription of color cosmetics, is a plate-type, white-colored inorganic substance with good application and spreadability to skin. Furthermore, it features excellent dispersibility and extensibility as well as outstanding heat tolerance, light stability, and chemical resistance. In general, silica contributes to durable makeup and stabilized formulation. This paper covers a process of manufacturing an inorganic pigment complex, where hydrophobic silica was applied to the surface of talc by using differences in zeta potential after the surface charges of talc and hydrophobic silica had been adjusted with cationic and anionic surfactants, respectively. The resulting inorganic pigment complex was composed of talc whose surface is coated hydrophobic silica to the thickness of $1{\mu}m$ or less, which developed an effective hydrophobic property. Zeta potential was measured to analyze the surface charge of an inorganic pigment, and FT-IR, used to check the functional group of a surfactant, was applied to treat the surface of the pigment. The surface of the inorganic pigment complex was observed employing SEM, EDS, and FIB, while its structure was confirmed with XRD and FT-IR.

• Journal of Convergence for Information Technology
• /
• v.9 no.7
• /
• pp.159-167
• /
• 2019

This study aimed to evaluate the effects of oral rinsing solution on the color stability, surface microhardness and surface roughness change of composite resin. In this in-vitro study, 80 disc-shaped specimens were fabricated of Filtek P60 and Filtek Z250(A2 shade). The samples of each group were randomly divided into eight subgroups (n=10). The baseline color values ($L^*$, $a^*$, $b^*$) of each specimen were measured according to CIE LAB system using a colorimeter. After baseline color measurements, the control samples were immersed in distilled water and the test groups were immersed colorless, green and purple mouthrinses three times a day for thirty minutes. This process was repeated for two weeks. Green and purple oral rinsing solutions displayed color, microhardness and roughness change of all composite resin after immersion in the mouthrinses. Therefore, prescription of oral rinsing solution for a minimum of two weeks is a common practice, which may cause discoloration of aesthetic composite restorations of patients.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.48 no.3
• /
• pp.344-351
• /
• 2021

The purpose of this study was to compare surface hardness between titanium-nitride coated crowns (TiNCs) and stainless steel crowns (SSCs), and to evaluate the corrosion resistance and color sustainability of TiNCs. Ten TiNCs and 10 SSCs were used for the hardness test. Measurement was performed 30 times for each type of crowns, and the mean values were compared. Metallic raw material plates (before being processed into crowns) of TiNCs and SSCs were prepared for the corrosion resistance test. The total amounts of metal ion releases in the test solution were detected by inductively coupled plasma-optical emission spectrometry. Five TiNCs were subjected to the color sustainability test by applying repetitive brushing forces. The mean hardness values of TiNC group and SSC group were 395.53 ± 105.90 Hv and 278.70 ± 31.45 Hv respectively. Hardness of TiNCs were significantly higher than that of SSCs. The total amounts of metal ion releases from the materials of TiNCs and SSCs satisfied the criterion in International Organization for Standardization 22674. The results mean that TiNCs and SSCs were not harmful in an acidic environment. The golden coating was stable against the repetitive physical stimulations for a given period time.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.32 no.1
• /
• pp.29-34
• /
• 2003

In development of the processed food, it is important not only to make the food delicious but to enhance its storage span and thermal stability without change in color, which greatly affects the tastes. Protopectinase (PPase) from Bacillus subtilis EK11 hydrolyses or dissolves protopectin in the middle lamella of plant tissues with the resultant separation of plant cells from each other, called enzymatic maceration. With the PPase, persimmon was enzymatically macerated to separate cells to primary cell wall without damage. Recovery rates of persimmon treated with PPase and mechanical maceration were 95% and 85%, respectively. Total and reducing sugars, crude protein and fat in the enzymatic maceration were well preserved as in the mechanical maceration. Importantly, over 50% of vitamin C, which is the most unstable component during the mechanical maceration, remained with an intact form for one day after the enzymatic treatment. When the suspensions of persimmon macerated with both treatments were stored at 4$^{\circ}C$ for 9 days, the mechanically macerated persimmon suspension was decolorized, whereas decolorization, was not found in the enzymatically macerated persimmon suspension. Moreover the mechanically macerated persimmon was greatly deteriorated after heat treatment at 10$0^{\circ}C$ for 60 min, whereas cells of the enzymatically separated persimmon suspension appeared to be stable, indicating increased thermal stability Thus, the PPase treatment of persimmon could be a better choice for preparation of highly valuable and functional processed food as well as for increase in preservation period.