Optical Whitening Research Articles

Whitening Optical Effect of New Chewing Gums

Background: Today, many treatments are available to enhance the color of teeth, but they require a few days to weeks to deliver this effect. Objective: To evaluate the instantaneous optical whitening effect of two new sugar-free chewing gums and one dentifrice of proven efficacy versus one placebo chewing gum. Methods: This was a single-blind, parallel trial. 424 participants entered the study and were randomly allocated to four groups. They received a personal silicone mask with a calibrated hole at one upper incisor to apply a dental colorimeter. The tools tested were chewing-gum containing indigotine (E132-FD&C Blue 2) and spirulina, chewing-gum containing only spirulina, chewing-gum placebo, and dentifrice containing Blue Covarine. Vita® Easyshade scored the tooth color, and the WIO and WID whiteness indexes were calculated. For chewing gums, the color of the teeth was scored before the assumption and after 2’30” of mastication. For dentifrice, participants brushed for 1’30”, then rinsed, and the color was scored before brushing and after 2’30”. Statistical analysis was performed by ANOVA and Tukey post-hoc. Results: The two experimental whitening chewing gums and the dentifrice significantly increased the WIO and the WID indexes from the baselines (p<0.001). Moreover, their effects were statistically greater than those reported for the placebo chewing gum (p<0.05) but not significatively different among them (p=NS). Conclusion: All the tested whitening tools showed an instant optical whitening perception. Further studies are required to assess the intensity of the effect over a prolonged time to meet the people's request for fast whitening tools. The clinical trial registration no. is PVM-2020-01.

The influence of the CIELAB parameters on the perception of color after the use of whitening toothpastes

Aim: To evaluate the influence of the parameters L* a* b* on the variation of the color of bovine tooth enamel submitted to artificial darkening, after simulated brushing, with whitening toothpastes containing blue covarine. Methods: To undertake this study in vitro, 60 specimens (SP) were divided into 6 groups (n=10): control group (CGwater) and 5 test groups (GT1-Colgate Total 12, GT2-Oral-B 3D White Perfection, GT3- Colgate Luminous Instant White, GT4-CloseUp White Diamond Attraction, GT5-Sorriso Xtreme White). The specimens were darkened with coffee and submitted to simulated brushing for 6, 12, and 24 months. The alteration in the color was evaluated using CIELAB parameters and the ΔL, Δa, Δb and ΔE were calculated. The data was analyzed through generalized linear models using the R program and considering a level of significance of 5%. Results: The parameters L*, a* and the ΔL, Δa obtained better results in the test group than in the control group. There were no statistical differences between CG and the test groups for the evaluation of the b* parameter. In the evaluation of the Δb, the GT3 differed statistically from the CG. In relation to the ΔE, all the group tests showed a variation in color statistically greater than that of the CG and the GT4 showed the greatest variation, not differing from the GT3 during the periods studied. Conclusion: The mechanical and optical whitening agents positively influenced the values L*a* and b*, as well as in its variations and in the ΔE. It is important to emphasize, however, that to analyze tooth whitening it is necessary to evaluate their parameters together.

Whiteness evaluation: A review and new proposals

AbstractThis publication carries out an in‐depth study of whiteness, various numerical evaluation methods that have been developed over the past 75 years, and review their application and deficiencies in the context of a new proposed Commission Internationale de l'Eclairage (CIE) whiteness formula. The publication first introduces the basic principle of whiteness evaluation from the work of Judd and Selling around 1950, then that of Ganz in the 1970s and finally that of the CIE from 1969 to 1986. The defects of the Judd and Selling formulas became apparent with the use of fluorescent whitening agents. The CIE linear formula cannot predict an optimum for the optical whitening process. Hyperbolic formulas published are much too complicated and are unable to predict correctly the best conditions for that optical whitening. We present a new formula derived from that of the CIE, much simpler than the hyperbolic formulas, and able to predict an optimal shade in the optical whitening process. The formula takes into account the limitations of the white domain; when the blue saturation becomes too great, or when a tint deviation toward green or toward red is too noticeable. The formula gives results identical to those of the CIE formula when the materials are far from commercial whiteness limits. In addition, the formula can be very easily adapted to the CIELAB system and so, gives promising results.

Optical Whitening and Brightening of Pearls: A Fluorescence Spectroscopy Study

Optical Whitening and Brightening of Pearls: A Fluorescence Spectroscopy Study

Effect of an Optical Whitening Toothpaste on Color Stability of Tooth-Colored Restorative Materials.

Objectives This study aimed to assess the effect of an optical whitening toothpaste on color stability of microhybrid, nanofilled, and microfilled composite resins and resin-modified glass ionomer (RMGI) cement in comparison of two other toothpastes. Materials and Methods In this experimental study, disc-shaped composite samples were fabricated. The samples were then polished using silicon carbide papers. Twenty-seven samples of each material were fabricated and subjected to colorimetry using a spectrophotometer. Each group of material was then divided into three subgroups for the application of conventional whitening and whitening containing blue covarine toothpastes. One operator brushed the samples with an electric soft toothbrush with circular motion twice a day, each time for 30 seconds. Colorimetry was performed at 0, 1, 7, 30, and 90 days. Statistical Analysis Two-way analysis of variance (ANOVA), one-way ANOVA, and Tukey’s honestly significant difference (HSD) test were used for statistical analysis. Results The interaction effect of type of restorative material and time on ∆E was not significant at baseline or 1 day ( p > 0.05). The effect of type of toothpaste on ∆E was not significant at baseline or 1 day ( p = 0.78) but the effect of type of material was significant ( p < 0.05). The toothpastes had significantly different effects on ∆E of Z250 at all time points ( p < 0.05) except for ∆E0–30 ( p = 0.106). The toothpastes had significantly different effects on ∆E of Z350 and Gradia at all time points ( p < 0.05). The same was true for RMGI except for ∆E0–7 ( p = 0.43) and ∆E0–90 ( p = 0.52). The majority of color changes caused by toothpastes were not clinically perceivable (∆E < 3.3), except for ∆E0–90 by the whitening toothpaste (∆E = 9), ∆E0–90 by the conventional toothpaste for Z350 (∆E = 3.9), and ∆E0–1 by the whitening toothpaste for RMGI (∆E = 3.7). Conclusion The color change of all composite samples was not clinically perceivable (<3.3) at all time points, which shows that the tested toothpastes do not cause a significant change in color of composite materials.

Investigation of the perceptual thresholds of tooth whiteness

ObjectiveTo investigate the tooth whiteness perceptibility thresholds of the average observer to changes in the CIELAB values and an optimised whiteness Index for dentistry (WIO) based on psychophysical studies. MethodsA psychophysical experiment based on visual assessments of digital images of teeth on a calibrated display with a group of observers (n=32) has been conducted to determine the perceptual thresholds in tooth whiteness. Digital simulations of a tooth that is identical in shape to the left incisor in the image of teeth were superimposed on to images. The colour of the simulated tooth was varied and observers were asked to respond whether there was a difference in whiteness between the left incisor and the simulated tooth. Thresholds for detection of differences in whiteness were independently determined in four conditions: ΔL*, Δa*, Δb* and a blue optical whitening direction. Raw data were fitted using a non-parametric approach and thresholds of CIELAB and WIO for each conditions were calculated. ResultsEstimates of the threshold of the four conditions of ΔL*, Δa*, Δb* and a blue covarine optical tooth whitening direction were 1.14, 3.24, 1.11 and 1.51 respectively, with the corresponding WIO thresholds of 2.77, 6.52, 3.09 and 1.99 respectively. ConclusionsThe thresholds for tooth whiteness perception in CIELAB space and WIO space were determined. The findings demonstrate that for a whitening treatment with a blue covarine optical technology, a colour change of about 2 WIO units would be noticeable. Clinical significanceThis study gives a better understanding of the tooth whiteness perception threshold, and will help clinicians identify perceivable differences in tooth colour during matching and whitening procedures.

Fluorescent pyridopyrimidine fused pyranones - design, synthesis, fluorescent whitening and DFT studies

Four novel fluorescent whitening agents based on 4-methyl-2H,5H-pyrano derivatives of 2H-pyrido[1,2-a]pyrimidine-2,4(3H)-dione were synthesized using a simple two step route. The structures were characterized by spectroscopy techniques such as, 1H, 13C NMR, and HRMS. Photophysical properties in various microenvironments were evaluated experimentally and correlated with optical absorption and fluorescence emission using global hybrid (B3LYP) and long range separated functional (CAM-B3LYP) with the Pople's 6–31G(d) basis set and in combination with polarizable continuum model. The experimental and theoretical photophysical properties were found in good agreement with each other. The excited state calculations revealed that the excitation values were in the range of 350–370nm and emission values were in the range of 400–425nm suggesting their potential application as fluorescent whitening agents. Dyes 4a-d were applied to polyester fabric and their performance was evaluated by means of measuring the degree of whiteness, the degree of brightness, color values, and reflectance spectrum in comparison with a standard fluorescent whitening agent, Hostalux ESR. Interestingly our synthesized optical whitener, 4a showed pronounced enhancement in the whitening properties over the Hostalux ESR.

Synthesis and properties of novel stilbene-twelve alkyl quaternary ammonium salts as antibacterial optical whitening agents

Four novel stilbene-twelve alkyl quaternary ammonium salts 5a–d were synthesized. All synthesized compounds were characterized by FT-IR, 1H-NMR and elemental analysis. Compounds 5a–d showed efficient whitening effect on cotton fiber and high fastness. Furthermore, compound 5c showed better stability to light than C186 in aqueous solution. The preliminary biological experiment demonstrated compounds 5a–d possessed significant antibacterial activities. Among them, compound 5d turned out to be the most active compound against Candida albicans with MIC50 4 μg/mL as well as E. coli with MIC50 16 μg/mL.

Optical Dental Whitening Efficacy of Blue Covarine Toothpaste in Teeth Stained by Different Colors.

Evaluate the immediate and cumulative optical whitening efficacy of a blue covarine toothpaste. 180 bovine tooth specimens with similar shade (ΔE < 3.5) were staining of different beverage: black tea(BT), green tea (GT), red wine (RW), orange soda (OS), and brazilian açai juice (AJ), and then submitted to tooth brushing with a blue covarine toothpaste (Op) or a control abrasive toothpaste (Ab). The whitening effect was evaluated at baseline (B), after staining (S), after 1 day (1D) and 7 days of cumulative use of toothpastes (7D). The color shade chances were assessment by Vita Easyshade reflectance spectroscope and the data of CIELab color coordinates (L*, a*, and b*), color difference (ΔE) and the whiteness index optimized (WIO), were analyzed by two-way mixed analysis of variance (ANOVA) for repeated measures and Bonferroni-corrected t-tests (α = 0.05). The analysis showed statistically significant differences before and after staining by colored beverages (p < 0.05), but no differences were found due to the action of toothpaste (p > 0.05), in the CIELab coordinates, ΔE and WIO index. The use of toothpastes (Op or Ab) reduced the dental staining caused by different colored beverage, but the whitening effect of blue covarine toothpaste could not be confirmed (p > 0.05).

Development of a Piezoelectric Ultrasonic Tooth-whitening Apparatus

The aim of this study was to develop an ultrasonic tooth-whitening apparatus using piezoelectric transducers, which enhance bleaching efficiency by applying ultrasound, while performing a teeth whitening procedure. For this purpose, an ultrasonic transducer was designed and manufactured, and the effects of reduction in the whitening material's concentration and in the whitening treatment time through using the ultrasound cavitation phenomenon were confirmed. Also, the validity of this study was investigated by comparing the whitening performance with a commercialized optical whitener, through color comparison. The results revealed that the ultrasound whitener produced color values that were enhanced by as much as double that of the conventional LED light whitening method. Even when the operational time was reduced by half, the ultrasound method showed superior performance by over 54% compared to the conventional light whitener, revealing that the ultrasound method showed a remarkable treatment reduction effect.

Effect of xenon arc irradiation on optical whitened polyester woven fabrics

In this study, the CIE whiteness (CIE WI) and whiteness tint (Tw) of optically whitened (OWA) woven (plain and twill) polyester fabrics irradiated with xenon arc light were investigated. The fabrics were whitened in four concentrations using nine different commercial optical whitening agents, and were irradiated with xenon arc light under specific conditions between 0 and 100 h at 10-h intervals. The reflectance of the OWA fabrics was measured by using spectrophotometer, whereas the CIE WI and Tw values were calculated by using computer software. The results were investigated by statistical methods using analysis of variance and regression curves in which of the CIE WI of OWA polyester fabrics was found to decrease, while the Tw was also affected depending on irradiation time from the xenon arc light. © 2011 Wiley Periodicals, Inc. Col Res Appl, 2013

Optical whitening of cationised cotton: effect on whiteness and whiteness tint

In this study, the effect of cationisation on optical whitening was examined. For this purpose, the whiteness index and whiteness tint of optically whitened pre-cationised knitted cotton fabrics were analysed. The cationisation and optical whitening processes were carried out under different concentration levels, using the exhaustion method. The whiteness index and whiteness tint were calculated after colour measurements were taken. The experimental results were also analysed statistically using ANOVA. The whiteness index obtained from cationised fabric was lower than that of non-cationised fabrics. While the whiteness tint of cationised cotton fabric had a blue to greenish nuance, the non-cationised fabric had a reddish nuance.

Analysis of the CIE whiteness and whiteness tint of optically whitened cellulosic fabrics

In this study, the CIE whiteness (CIE WI) and whiteness tint (Tw) of optically whitened woven or knitted cellulosic fabrics (cotton, viscose, modal and tencel) irradiated with xenon arc light was investigated. The fabrics were whitened with four concentrations of eight different commercial optical whitening agents and these fabrics were irradiated with xenon arc light under specific conditions between 0—100 hours at 10-hour intervals. The reflectance of the optical whitened fabrics was measured by using spectrophotometry, while CIE WI and the Tw values were calculated using computer software. The results were investigated by statistical methods using ANOVA and regression curves in which CIE WI of optically whitened cellulosic fabrics were found to decrease seriously depending on irradiation time and Tw was also affected by xenon arc light.

Contact allergy to an optical whitener, "CPY", in washing powders.

SUMMARY.— In 16 months contact dermatitis from an optical whitener, Tinopal CH 3566, was diagnosed in 167 patients at the Finsen Institute. The dermatitis presented as a textile dermatitis. Since “Tinopal” covers a wide range of chemically unrelated optical whiteners, the designation “CPY” is introduced for the particular pyrazoline derivative implicated in this dermatitis. This product sensitized 16 of 20 animals in the guinea-pig maximization test: this rates this optical whitener as a strong sensitizer. The result of patch testing in some of the patients with a number of pyrazoline derivatives points to the 4-position in the pyrazoline ring and the para-position in the l-benzyl-ring as key positions. Benzylsalicylate evoked a positive reaction in 16 of 88 patients. Seven of 13 patients showed a positive patch test to “Nylon” washed in a detergent containing the brightener.

Anionic surface binders

The MELAMIN Chemical Factory in Kocevje manufactures synthetic resins and binders for the paper industry. Binders based on AKD (alkyl ketene dimer) are produced which are used for binding paper and cardboard in the range of neutral and partially basic pH. Cationic and, lately, anionic binders are mostly used for the bulk binding of paper and board. The possibility of using AKD binders on paper or board surfaces is presented. In this case partially cationic AKD binders may be applied. When optical whiteners are used, the application of AKD binders is recommended. In the case of paper it is possible to substitute acrylate binders by AKD binders. The best results are obtained when the paper is first partly treated in bulk and subsequently surface treated.

Photolysis of Optical Whiteners in the Presence of Haloarenes

Halobenzenes and sodium salts of halobenzenesulfonic acids decelerate photochemical degradation of optical whiteners in aqueous 2-propanol or in a polyvinyl alcohol matrix owing to T-T transfer of the electronic excitation energy from the substrate to the additive and also to the quenching effect of the heavy atom of the additive. In all the cases, the efficiency of deceleration of luminophore photodegradation grows in going from chloro to bromo and then iodo derivatives.

Liquid chromatographic separation and determination of aromatic sulfonates in an aquatic environment using a photodiode array and electrospray ionization-mass spectrometer as detectors.

A simple and rapid method involving high-performance liquid chromatographic separation, followed by photodiode array (PDA) and electrospray ionization-mass spectrometric (ESI-MS) detection of aromatic sulfonates in waste-water effluents of industrial units producing optical whitening agents, has been developed. The separation was achieved on a reversed-phase Hypersil C18 column using gradient elution of a mobile phase consisting of 0.05 M ammonium formate-methanol with decreasing concentration of the buffer at room temperature. The minimum detection limits were determined to be in the range of 0.2 - 1.8 x 10(-9) g using PDA and ESI-MS detectors.

Oligo(phenylenevinylene)s with increased electron affinity: 1,3,4-oxadiazoles in the main chain

Stilbenoid chromophores and 2,5-diaryl-1,3,4-oxadiazoles are compounds with wide technical importance. Their intense fluorescence is used in szintillators and optical whiteners and their semiconducting properties makes them valuable emissive or electron conducting layers in organic light emitting diodes (OLED). The synthesis and the electronic spectra of soluble oligo(phenylenevinylene)s with 1,3,4-oxadiazoles in the main chain are presented. The Huisgen reaction of tetrazole-terminated stilbenoid compounds with aromatic acyl chlorides yields model compounds, isophthalic acid dichlorides lead to soluble polymers with well-defined conjugated segments, as can be seen in the electronic spectra. Besides connection of the stilbenoid sections, the electron deficient heterocycles promise to increase the electron affinity of the chromophore.

Atomic Hydrogen Effects on the Optical and Electrical Properties of Transparent Conducting Oxides For a-Si:H TFT-LCDs

AbstractThe effects of the atomic hydrogen treatment (H-treatment) of indium-tin oxide (ITO) and aluminum-doped zinc oxide (AZO) films have been investigated. The atomic hydrogen was generated by hot-wire chemical vapor deposition (HW-CVD) technique. Experimental results have shown that AZO films are chemically very stable under the H-treatment; almost no variation in the optical transmittance and electrical resistivity was observed. On the contrary, ITO films, either prepared by sputtering with ex-situ or in-situ thermal-annealing, have shown severe optical and electrical degradation and surface whitening after the H-treatment. SEM studies of the H-treated ITO surfaces have revealed that the surface whitening was due to the increase in surface roughness and the formation of granule-like metallic balls. Auger electron spectroscopy has indicated that the balls were mainly composed of indium atoms and the areas between balls were rich in oxygen atoms. These results were confirmed by X-ray diffraction and X-ray photoelectron spectroscopy measurements done on ITO before and after the H-treatment. Finally, we have demonstrated that a-SiO, deposited by PECVD will completely suppress the chemical reaction between ITO surfaces and atomic hydrogen generated by HW-CVD technique.

Polarographic and Voltammetric Determination of 4,4'-Bis[(4-diethanolamino-6-(2,5-disulfophenylamino)-1,3,5-triazin-2-yl)amino]stilbene-2,2'-disulfonic Acid

The polarographic and voltammetric behaviour was studied for 4,4'-bis[(4-diethanolamino-6-(2,5-disulfophenylamino)-1,3,5-triazin-2-yl)amino]stilbene-2,2'-disulfonic acid, which is the basis of many commercial optical whitening agents. The optimum conditions were found for quantitation of this substance in tetraethylammonium bromide solutions in dimethylformamide containing 5% (v/v) water using TAST polarography, differential pulse polarography, linear sweep voltammetry at a hanging mercury drop electrode, and differential pulse voltammetry at a hanging mercury drop electrode over the concentration regions of 100-500, 10-500, 10-500, and 1-100 mmol l-1, respectively. The practical applicability of the new analytical methods to the determination of the substance in technical products was verified.