• Journal of Korean society of Dental Hygiene
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• v.12 no.3
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• pp.533-541
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• 2012

Objectives : The purpose of this study was to evaluate the effects of tooth bleaching agent contained 35% hydrogen peroxide on the color, microhardness and surface roughness of tooth-colored restorative materials. Methods : Four types of tooth-colored restorative materials, including a composite resin(Filtek Z350 ; Z350), a flowable composite resin(Filtek P60 : P60), a compomer(Dyract$^{(R)}$ AP ; DY), and a glass-ionomer cement(KetacTM Molar Easymix ; KM) were used in the study. The specimens($8mm{\times}5mm$) were made by using a customized acrylic mold. Each material was divided into two groups equally(n=40) : experimental group(35% HP) and control group(distilled water). 35% HP group was treated 30 mim/5 days for 15 days. Each 30 minute treatment session consisted of two 15 minute cycles of gel application with 20 second light exposure. The authors measured the color, microhardness, and roughness of the specimens before and after bleaching. The data were analyzed with ANOVA and T-test. Results : 35% HP group showed an apparent color change(${\Delta}E^*$) than control group. In particular, DY and KM showed a noticeable color change and statistically significant differences(p<0.05). 35% HP group showed a reduction in microhardness. Z350 and P60 does not have a statistically significant difference(p>0.05), DY and KM showed a statistically significant difference(p<0.05). Percentage microhardness loss(PML) of control group was 0.6 to 5.5% in the group, 35% HP group was 6.6 to 34.6%. Roughness was increased in 35% HP group after bleaching. Especially DY and KM were significantly increased(p<0.05). Conclusions : Bleaching agents may affect the surface of existing restorations; therefore, they should not be used indiscriminately when tooth-colored restorations are present.

• Journal of dental hygiene science
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• v.21 no.2
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• pp.96-103
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• 2021

Background: We aimed to investigate the effect of Citrous limon extract (CLE) on oxidative stress-induced cytotoxicity and nitric oxide (NO) generation and the tooth bleaching effect of CLE as a substitute for hydrogen peroxide (H₂O₂) and determine the feasibility and application of CLE as a safe and effective natural tooth bleaching agent. Methods: The protective effect of CLE on H₂O₂-induced cytotoxicity in Raw264.7 macrophages was investigated by the MTT assay. The inhibitory effect of CLE on the generation of H₂O₂-induced NO was confirmed by the NO assay, and the changes in inducible nitric oxide synthase (iNOS) protein expression were confirmed by western blotting. Stained bovine teeth were treated with/without 15% and/or 35% CLE and H₂O₂, 15% sodium bicarbonate (NaHCO₃) for 3 hours, and were irradiated with/without bleaching light (BL) for 15 minutes. The color change of the treated bovine tooth surface was measured using a colorimeter. Results: The viability of Raw264.7 cells treated with each concentration of CLE and 500 μM H₂O₂ significantly increased as CLE increased, and NO generation and iNOS protein expression were significantly reduced in cells treated with 300 ㎍ CLE+/500 μM H₂O₂+ and 300 ㎍ CLE+/500 μM H₂O₂+/150 ㎍ NaHCO₃+. The bleaching effect of 35% CLE+ was higher than that of 15% CLE+ and 15% NaHCO₃+, and the effect was similar to that of 15% H₂O₂+. The 35% CLE+/15% NaHCO₃+ showed the greatest bleaching effect and was higher than that of the groups irradiated with the BL. The greatest bleaching effect was observed with 35% CLE+/15% NaHCO₃+, followed by 35% H₂O₂+/BL+. Conclusion: CLE inhibited oxidative stress-induced cytotoxicity and NO generation in Raw264.7 cells and, could replace H₂O₂, which causes side effects and risks in teeth breaching treatment. It showed greatest teeth bleaching effect when combined with NaHCO₃. CLE is an effective and safe natural tooth bleaching substitute.

• Restorative Dentistry and Endodontics
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• v.41 no.3
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• pp.225-230
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• 2016

Enamel microabrasion has become accepted as a conservative, nonrestorative method of removing intrinsic and superficial dysmineralization defects from dental fluorosis, restoring esthetics with minimal loss of enamel. However, it can be difficult to determine if restoration is necessary in dental fluorosis, because the lesion depth is often not easily recognized. This case report presents a method for analysis of enamel hypoplasia that uses quantitative light-induced fluorescence (QLF) followed by a combination of enamel microabrasion with carbamide peroxide home bleaching. We describe the utility of QLF when selecting a conservative treatment plan and confirming treatment efficacy. In this case, the treatment plan was based on QLF analysis, and the selected combination treatment of microabrasion and bleaching had good results.

• Journal of Ginseng Research
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• v.13 no.1
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• pp.98-104
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• 1989

In order to determine the specific active oxygen species directly related to chlorophyll bleaching in the leaf-burning disease, we investigated the effects of singlet oxygen (1O2), superoxide radical (O2-), and hydrogen Peroxide (H2O2) on isolated chloroplast suspension and leaf discs from Panax ginseng C.A. Meyer. When the singlet oxygen was added to the chloroplast suspension, the chlorophyll and carotenoid contents were decreased by more than 809), similar to treatment with high light intensity (100 KLux). We assumed that the conversion of dioxygen (O2) produced either in photolysis or in breakdown of hydrogen peroxide to singlet oxygen resulted from photorespiration. On the basis of these experiments , :he inhibitory effects of active oxygen scavengers propylgallic acid (PGA), 2,5-ditetrabutyl hydroquinon (DBH), sodium pyrosulfate (SPS), and ascorbic acid (ABS) were examined. In chloroplast suspension all four scavengers inhibited chlorophyll bleaching by more than 75fl , and in the leaf discs the inhibition rates of SPS, PGA and ABS were 46%, 51%, and 96% respectively.

• Restorative Dentistry and Endodontics
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• v.36 no.4
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• pp.306-312
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• 2011

Objectives: This clinical study evaluated the effect of light activation on the whitening efficacy and safety of in-office bleaching system containing 15% hydrogen peroxide gel. Materials and Methods: Thirty-three volunteers were randomly treated with (n = 17, experimental group) or without light activation (n = 16, control group), using Zoom2 white gel (15% $H_2O_2$, Discus Dental) for a total treatment time of 45 min. Visual and instrumental color measurements were obtained using Vitapan Classical shade guide and Shadepilot (DeguDent) at screening test, after bleaching, and 1 month and 3 month after bleaching. Data were analyzed using t-test, repeated measure ANOVA, and chi-squared test. Results: Zoom2 white gel produced significant shade changes in both experimental and control group when pre-treatment shade was compared with that after bleaching. However, shade difference between two groups was not statistically significant (p > 0.05). Tooth shade relapse was not detected at 3 months after bleaching. The incidence of transient tooth sensitivity was 39.4%, with being no differences between two groups. Conclusions: The application of light activation with Zoom2 white gel system neither achieved additional whitening effects nor showed more detrimental influences.

• Journal of Korean Society on Water Environment
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• v.23 no.3
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• pp.303-308
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• 2007

Three types dyeing wastewater (dark, medium, light color) discharged from cotton textile dyeing with reactive dye was collected at each step of process. Each process dying wastewater was analyzed and treated by ionized gas. The analysis focused on $COD_{Cr}$, SS and color. Bleaching & scouring process wastewater has the highest $COD_{Cr}$ value in the three type dyeing wastewater. SS shows the highest value at dyeing process wastewater in dark and medium color but light color has at finishing process wastewater. The result of process wastewater treatment by ionized gas was that the ionized gas was effective in $COD_{Cr}$ removing of bleaching & scouring process and finishing process wastewater but was not good at dyeing process wastewater. From that result it is estimated that the ionized gas could not work in opening the aromatic ring and react only in aliphatic component of the molecule. Because the surfactants contained in bleaching & scouring process and finishing process wastewater have only one aromatic ring in its molecular structure, in contrast with the reactive dye compounds consist of aromatic rings great part of its molecular structure. The color almost removed in 1.5 hrs reaction time but $COD_{Cr}$ removal effiency was only 30.7% through 3hrs in 1500 mL of total dyeing wastewater treated by 10 L/min ionized gas.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.11a
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• pp.13-13
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• 2011

Hair luster is a key objective for consumers in the hair care market. Recently, as consumers using hair coloring or bleaching product increase, measurement and quantification of hair luster become more important. A hair visual appearance measurement system called SAMBA can quantitate the luster and effectively separate specular and diffuse light. SAMBA usually has been employed to measure, mainly with the change of shine value, effects of cosmetic treatments on hair shine and surface smothness. We conducted a study on the effect of dyeing and bleaching on the luster, as a result, a strong bleaching caused large decline of the luster. But the large decline of luster was caused by increasing intensity of diffusion and width of chroma peak, not the shine value. The system of dye toning for higher luster can be developed on reference to the peak type of chroma and diffusion depends on kinds and combination of dye.

• Journal of the korean academy of Pediatric Dentistry
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• v.21 no.2
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• pp.593-598
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• 1994

There were two cases of esthetic improvement of discolored teeth. First case was 12-year-old girl whose upper right central incisor was discolored after traumatic injury. She was treated by walking bleaching technique. Endodontic retreatment was done, and then the mixture of Superoxol and sodium perborate was applied and changed every week. After 3 weeks, esthetic result was obtained and fracture site was rcovered with light-curing composite resin. Second cases was 11-year-old girl whose teeth were discolored by fluorosis. She was treated by vital bleaching technique. A resin splint was made and then 30% and 15% carbamide peroxide was applied using this splint. After 4 weeks, a noticeable improvement in the color and the brightness of the teeth was achieved.

• Korean Journal of Optics and Photonics
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• v.9 no.1
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• pp.31-37
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• 1998

We fabricated acrylamie photopolymer holographic recording materials by photopolymerization of acrylamide, and described hologram formation process. Light absorption and phtobleaching process by MB(methylene blue) dye and radical polymerization process due to TEA(triethanolamind) are explained in detail. We adopted the Beer-lambert law in order to explain the photobleaching kinetics. Dependencies of diffraction efficiency of the hologram on monomer amout and the exposure are investigated. The scattering effect caused by grain of polymer crystal, and fixing method are also illustrated.

• Journal of the Korean Society of Clothing and Textiles
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• v.35 no.12
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• pp.1477-1485
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• 2011

Dyeability and colorfastness of the blended knits of cotton/rayon (40/60; C/R) and wool/tencel (10/90; W/T) are examined using the natural dyestuff ($Pinux^{TM}$) manufactured from Pinus radiata pine bark extract. In addition, pre-treatments (such as bleaching, mercerization and cationization) are performed to improve dyeability and colorfastness. The $Pinux^{TM}$ powder dyestuffs produced by Pinux Co., Ltd. are used as dyestuffs and their properties are examined for dyeing concentration (0.5-2% (owb)), dyeing time (30-120 minutes) and dyeing temperature (30-$90^{\circ}C$). Dyeability is evaluated with K/S value at 400nm, which is the maximum absorption wavelength for $Pinux^{TM}$. The results show the dyeability of W/T sample containing protein fiber with $Pinux^{TM}$ is superior to all cellulose fiber C/R. A concentration of dyestuff greater than 1.5% (owb), dyeing time 120 minutes and dyeing temperature of $90^{\circ}C$ are the most optimized conditions. It shows that the dyeability of C/R and W/T samples are high in the condition of an acid-dyeing bath and that dyeability highly declined in alkaline bath due to the instability of the proanthocyanidin pigment. After analyzing the effect of bleaching, mercerizing and cationizing (as pre-treatments on dyeability) it was concluded that the dyeability of the C/R sample was enhanced by mercerization but no significant effect by cationization. However, the simultaneous treatment of cationizing and dyeing resulted in far improved dyeability compared to dyeing after cationizing pre-treatment. As for the W/T sample, the effect of cationization was more prominent than the C/R sample. Colorfastness to color changes in the control W/T sample was higher than that of C/R's level 1-2, and it increased to Level 2 when bleaching pre-treatment was given and when a simultaneous cationizing treatment was adopted to the dyeing process. Colorfastness to light in W/T control sample resulted in Level 3 and further increased to an excellent Level of 4 with bleaching and simultaneous cationizing during dyeing process.