Effect Of Hydrogen Peroxide Bleaching Research Articles

Effect of Neodymium-Doped Yttrium Aluminum Garnet (Nd:YAG) Laser Enamel Pre-Treatment on the Whitening Efficacy of a Bleaching Agent.

There are a number of different substances and treatments that are effective in mitigating the negative effects of tooth bleaching. It is essential, however, to consider whether or not the presence of these factors affects the efficiency of the bleaching agent. The purpose of this study is to determine how the pretreated enamel with a Neodymium-Doped Yttrium Aluminum Garnet (Nd:YAG) laser affects the bleaching effect of hydrogen peroxide at a concentration of 35%. Thirty samples were prepared from human-extracted permanent anterior teeth and stained using a tea solution. Based on the pre-treatment protocol, the samples were split into two equal groups (n = 15): In Group I, samples were submerged in saline solution for five minutes, while in Group II, Nd:YAG laser treatment was performed. Following pretreatment, samples from both groups were bleached with 35% hydrogen peroxide. Colour analysis of all samples was done before and after bleaching using a spectrophotometer. For the colour analysis, the CIE L*a*b* (Commission Internationale de l'Eclairage) System of colour measurement was used. For statistical analysis, Student t-tests (two-tailed, unpaired) were used to compare the means of two groups on a continuous scale. Samples from both groups became lighter in colour following bleaching. After bleaching, there was no discernible difference in the totalcolour change between the two groups. The application of the Nd:YAG laser before bleaching did not influence the whitening efficacy of 35% hydrogen peroxide.

Enhancing the wash fastness of disperse dyes on wool with oxidants

AbstractDisperse dyes are not currently applied to wool commercially, in large part because of inadequate wash fastness, but they do have potential, especially for wool‐polyester blends. In this study, for the first time hydrogen peroxide was investigated to increase the wash fastness of disperse dyes on wool. In the absence of oxidants, 10 disperse dyes from seven classes imparted colours with a range of depths (K/S 2‐26) with wash fastness (grey scale ratings for colour change) grades of 3 to 4‐5. Hydrogen peroxide had only small effects on colours and gave only small enhancements to wash fastness, which were limited to anthraquinone, nitrodiphenylamine, disazo and coumarin dyes. The bleach activators Prestogen W and citric acid enhanced the bleaching effect of hydrogen peroxide but did not assist with raising wash fastness. Hydrogen peroxide in post‐dyeing scouring made the dyeings brighter but did not significantly enhance wash fastness. Ammonium persulphate, which was included for benchmarking with earlier studies, yellowed the wool and decomposed some dyes. This study extends the range of dye classes whose wash fastness on wool can be improved by ammonium persulphate to now include diazo, coumarin and methine, and confirms that oxidants/free radical initiators have potential for enabling the disperse dyeing of wool.

In vitro bleaching effect of hydrogen peroxide with different time of exposition and concentration on shear bond strength of orthodontic brackets to human enamel: A meta-analysis of in vitro studies

Controversy exists regarding the effect of bleaching on shear bond strength (SBS) of orthodontic brackets to enamel. This study aims to do a review and meta-analysis on the effect of bleaching with hydrogen peroxide on SBS according to the interval between bleaching and bonding to human enamel and the concentration of Hydrogen Peroxide. An electronic search of the literature was performed in Scopus, PubMed and Cochrane databases including CENTRAL and Cochrane library for relevant in vitro studies on the effect of bleaching with hydrogen peroxide on shear bond strength of human enamel, published until June 2018. Modified Cochrane Risk of Bias tool was used to assess the quality of the individual studies. AMSTAR tool was used for assessing the quality of the study. Nineteen studies were included in the qualitative analysis. Regardless of the interval between bleaching and bonding, reduction in SBS was not statistically significant when the hydrogen peroxide of less than 35% is used. Bleaching with 35% hydrogen reduces SBS when the bonding is conducted immediately (P<0.0001) or the time interval was shorter than one day (P<0.0005). On the other hand, use of high dose hydrogen peroxide resulted in a statistically significant reduction in SBS irrespective of the time interval between the procedures (P<0.05 for all categories of time interval). Bleaching with hydrogen peroxide decreases the SBS of brackets in patients undergoing orthodontic treatment especially if the time interval between bleaching and bonding procedures is short and a high concentration of hydrogen peroxide is used.

Effect of hydrogen peroxide bleaching on anionic groups and structures of sulfonated chemo-mechanical pulp fibers

The properties of the chemo-mechanical pulp were determined by the position and quantity of anionic groups in the pulp fibers. In this study, the effects of anion group content and structure in sulfonated mulberry stem chemo-mechanical pulp (SCMP) were investigated during the hydrogen peroxide (H2O2) bleaching process. Surface morphology and anion group structure of the pulp fibers were analyzed by scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and gas chromatography-mass spectrometry (GCMS). The results indicate that the sulfonic group content in bleached pulp decreases with the concentration of H2O2 to a minimum content of 71.53 μmol g−1, which is reduced by 22.68% in comparison to the unbleached pulp content of 92.51 μmol g−1. The content of carboxyl groups in pulp first increases and then decreases with the concentration of H2O2. The maximum carboxyl group content is 164.79 μmol g−1, which is increased by 53.97% compared with unbleached pulp at 107.03 μmol g−1. The total anion groups content of SCMP first increases and then decreases with the concentration of H2O2. FTIR and XPS analysis show that the content of anion groups on the surface of the pulp fibers increases slightly after H2O2 bleaching. GCMS analysis demonstrates that the content of uronic acid increases after H2O2 bleaching and the order of increase is 4-O-MeGlcA > GlcA > GalA. The contents of sulfonic acid group, total anion groups (TAGs) and surface anion groups (SAGs) of bleached pulp increase because of the hydroxyl group oxidation, terminal group reduction, methyl esterification of pectin and decomposition of polyxylose, resulting in the formation of new carboxyl groups and more uronic acid. This study reveals the mechanism of the effect of hydrogen peroxide bleaching on the anionic groups in the SCMP pulp, which is conducive to the development of bleaching technology for high yields of mulberry stem pulp.

Non-invasive analysis of bleaching effect of hydrogen peroxide on enamel by reflectance confocal microscopy (RCM): study of series of cases.

The aim of this study is to evaluate in vivo the effects of in-office tooth whitening hydrogen peroxide (HP) agent on enamel-microstructured surface by a reflectance confocal microscopy (RCM). Ten healthy volunteers assisted at the Dental School presenting teeth with vital pulp were selected. The 35% HP whiteness product was applied in two visits on discolored teeth, 1-week interval between, via 20-min applications. A commercially available hand-held RCM (Vivascope3000®, Lucid, Rochester, NY, USA) was used to image in vivo the dental surface of the selected tooth of each volunteer. Twenty upper central incisors' vestibular surfaces were imaged, before bleaching (T0), immediately after (T1) and 1 week later (T2). The peculiar structure of the enamel was seen at T0. After bleaching, white reflective circular bodies were found all over the teeth surfaces, which disappear 1 week later (T2). When the HP gel® was imaged, the same white circular areas were observed. Going deeper, the regular enamel architecture was preserved. Textural analysis of the images in T0 and T2 was performed: GLCM parameters were extracted. Mann-Whitney U test was performed to evaluate statistical differences between two groups of data (p > 0.05). Finally, 35 prisms were randomly selected from T0 and T2 image and diameters were measured; a paired t test was performed (p = 0.381). The RCM is a promisor tool for investigating the features of enamel in vivo, immediately after bleaching procedures, as well as longitudinally.

Enhanced bleaching effect of bovine tooth by hydrogen peroxide via calcium phosphate spheres

In the study, calcium phosphate spheres (CPS) were prepared using phosphate buffer solutions by hydrothermal method and were used to manufacture a lab-made bleaching paste. The obtained paste was used to whiten bovine teeth in order to investigate whitening effect with CPS in the paste. The results showed that the bleaching paste made by CPS does not affect bleaching effect of hydrogen peroxide (HP). On the contrary, it can prolong the bleaching effect compared the pure HP.

Influence of pH on the effectiveness of hydrogen peroxide whitening.

To evaluate the influence of pH on the bleaching effect of hydrogen peroxide on chromogen agents. Hydrogen peroxide 50% was mixed with red wine or with an alcoholic solution of tobacco in glass cuvettes, resulting in final peroxide concentrations of 16.97% and 21.12%, respectively. The pH of this mixture was measured and adjusted with 3.3 M HCl solution or 2.5 M NaOH solution to obtain the final pH values of 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, and 9.0. After mixing, the color of these solutions was evaluated in a reflectance spectrophotometer; readings were repeated after 10 minutes for the wine solution and 20 minutes for the tobacco solution. Ten samples were prepared for each solution at each pH. Color changes (Delta E) were calculated. The data were statistically analyzed using analysis of variance one-way and Tukey tests, with a significance level of 5%. There were significant differences among the different pH values for the wine and tobacco solutions (p=0.0001). The Tukey test showed that for both solutions, pH 9.0 resulted in a significantly greater bleaching effect than the other values tested. The efficacy of hydrogen peroxide bleaching is directly proportional to the increase in its pH.

The effect of hydrogen peroxide bleaching of canola meal on product colour, dry matter and protein extractability and molecular weight profile

SummaryThe aim of this study was to bleach canola meal by hydrogen peroxide to understand the treatment effect on product colour, dry matter and nitrogen extractability. Meal suspensions at 2.5%, 5% and 10% (w/v) were treated in 3, 6 and 10% H2O2 at pH 3, 7 and 10. The bleached meal was extracted under acidic and alkaline conditions. The results showed a high bleaching effectiveness of canola meal by H2O2. The L* parameter was increased from 47.18 ± 0.56 up to 86.80 ± 1.05. Effect of pH was significant and the highly bleached meal was obtained at pH 10. Extractability of dry matter was increased when the meal was treated with H2O2, from 26.87 ± 0.10% for the control meal up to 83.20 ± 0.59% for the meal treated in 10% H2O2 in a 2.5% (w/v) suspension. Sodium dodecyl sulphate‐polyacrylamide gel electrophoresis showed a depolymerisation effect of H2O2 on the high molecular weight proteins.

Effect of hydrogen peroxide treatment on the properties of wool fabric

In this study, hydrogen peroxide treatment was applied to improve the surface wettability, moisture transfer properties and other related properties of wool fabric. SEM images showed the tip of wool scale was smoothened and parts of the scale were peeled off after hydrogen peroxide treatment. The time for a water droplet to sink into the fabric could decrease to less than 1s and the wicking properties of wool fabrics were dramatically improved after hydrogen peroxide treatment. Shrinkage and whiteness of the fabric were improved due to the modification of scale and the bleaching effect of hydrogen peroxide, respectively. The fabrics became weaker and ductile with less than 4% weight loss. This study would benefit further application of wool fiber in summer clothing in which the surface wettability and moisture transfer properties are essential and determinative.

Laccase-mediated system pretreatment to enhance the effect of hydrogen peroxide bleaching of cotton fabric

This study evaluates the bleaching efficiency of the hydrogen peroxide bleaching process combined with laccase-mediated system pretreatment (LMS-HPBP) in the treatment of scoured cotton fabric. By changing the factors of laccase-mediated system pretreatment and the hydrogen peroxide bleaching process and examining the subsequent whiteness value and retained tensile strength of the samples, we find three LMS-HPBP processes that are more environment friendly than the conventional hydrogen peroxide bleaching process (CHPBP): (i) bleaching with lower dosage of hydrogen peroxide; (ii) bleaching at reduced temperature; (iii) bleaching for shortened duration. Whiteness, retained tensile strength and K/S values of cotton fabric samples treated by i–iii processes were similar to or higher than those by CHPBP. X-ray diffraction (XRD) analysis also demonstrated that the three processes rendered fabric of both lower crystallinity and bigger crystallite size than those by CHPBP. In addition, the “green” short-flow process was developed to treat cotton fabric and the results obtained shows this method is feasible as a new energy-saving process.

DMD Pretreated H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; Bleaching Technologyof Massion Pine Dissolving Pulp

Dimethyldioxirane (DMD) pre-treatment of Massion Pine dissolving pulp has been studied in order to improve the effect of hydrogen peroxide bleaching. The influence of the dosage of acetone and peroxymonosulfate (PMS), the ratio of acetone to PMS, temperature and time of reaction were studied. The optimum parameters of DMD pre-bleaching process were at the 0.7% dosage of acetone and PMS while the ratio of the two was 3:4, and pretreated at 60°C for 100 minute. Pretreated with DMD at this condition, the brightness of final pulp increased 11.14% and the content of α-cellulose increased 9.62% compared with the pulp which bleached by hydrogen peroxide without DMD pretreatment.

The evaluation of hydrogen peroxide bleaching of &lt;i&gt;Gonometa postica&lt;/i&gt; silk

The effect of hydrogen peroxide bleaching on Gonometa postica silk and the influence that temperature, pH and time duration had on hydrogen peroxide release , colour change, breaking load and stiffness were determined. The best bleaching (81 delta E) of the Gonometa postica silk fabric was obtained with 60 minutes exposure to hydrogen peroxide at 90°C and pH 8. Bleaching lowered the strength of the Gonometa postica silk fabric 7, 6% at pH10 but 12, 8% at pH 8. Rigidity of Gonometa postica silk fabric increased as a result of bleaching at 60°C, 70°C and 90°C at pH 8 and pH 10. The bending length was the highest (5.28 cm) after bleaching at 90°C and pH 8. Although acceptable bleaching of Gonometa postica silk fabric is reached with 60 minute exposure to hydrogen peroxide at 90°C and pH 8 or 180 minutes at 70°C at pH 8, bleaching cannot be recommended because the fabric becomes too rigid and requires a lower load to break. Gonometa postica silk fabric should be used in its natural colour or dyed in darker colours until a bleaching practice that would not cause the fabric to be harsh and stiff is developed.

Tooth Bleaching with Nonthermal Atmospheric Pressure Plasma

We demonstrated that room temperature plasma could be used for tooth bleaching. A nonthermal, atmospheric pressure, helium plasma jet device was developed to enhance the tooth bleaching effect of hydrogen peroxide (H 2O 2). All teeth were sectioned sagittally into halves, which were assigned randomly to either the experimental group or the control group. The experimental group was treated with H 2O 2 (28%, 20 μL every 30 seconds) plus plasma (5 W) for 10 minutes; the control group was treated with H 2O 2 alone for the same duration. Removal of the tooth surface protein was demonstrated by scanning electron microscopy images and Ponceau staining. Production of hydroxyl radicals (·OH) was measured by using electron spin resonance spin-trapping. Combining plasma and H 2O 2 improved the bleaching efficacy by a factor of 3 compared with using H 2O 2 alone. Tooth surface proteins were noticeably removed by plasma treatment. When a piece of tooth was added to a solution of H 2O 2 as a catalyst, production of ·OH after plasma treatment was 1.9 times greater than when using H 2O 2 alone. We suggest that the improvement in tooth bleaching induced by plasma is due to the removal of tooth surface proteins and to increased ·OH production.

Charge aspects of hydrogen peroxide bleached de-inked pulps

The aim of this study was to evaluate the effect of hydrogen peroxide bleaching on fibre charge of a commercial de-inked recycled pulp. The pulp was bleached with hydrogen peroxide for brightness improvement. The results indicated that the brightness gain was a function of H 2O 2 dosage. The yield loss associated with the peroxide bleaching was significant due to the presence of alkali-soluble components in the de-inked recycled pulp. The loss of the total fibre charge was apparently linearly related to the yield loss, but the change of the fibre surface charge was insignificant.

Effect of Hydrogen Peroxide Bleaching on Bone Mineral/Matrix Ratio

It is shown that bone fluorescence reduction by bleaching in 30% hydrogen peroxide causes a change in the mineral/matrix ratio as measured by Raman spectroscopy. However, there are no observable spectral shifts in the mineral Raman spectrum or in the matrix Raman spectrum. Possible sources of the change in ratio are discussed. Peroxide bleaching is not recommended for fluorescence reduction in quantitative Raman spectroscopy.

Structure and Reactivity of Lignins and Associated Phenolic Acids in Wheat Straw TMP and CTMP Pulps

Summary The effect of hydrogen peroxide bleaching on the structure of thermomechanical (TMP) and chemothermomechanical (CTMP) wheat straw paper pulps was investigated. The results obtained by thioacidolysis indicated that the TMP treatment did not significantly affect the ß-0-4 structures of lignins whereas, the alkali conditions of sulfonation (CTMP) and bleaching induced the cleavage of the ß-0-4 bonds and an increase in the S/G ratio. Moreover, it was concluded that bleaching and sulfonation are responsible for the partial solubilisation of the p-coumaric and ferulic acid esters. The ethers of p-coumaric acid are not significantly affected by these treatments whereas, the ethers of ferulic acid are degraded, as shown by acidolysis data. These results underline the structural differences of wheat straw pulps compared to wood pulps.

Decomposition rate of hydrogen peroxide bleaching agents under various chemical and physical conditions

The decomposition rate of 30% hydrogen peroxide was measured when hydrogen peroxide was mixed with 36% hydrochloric acid and anaesthesia ether in 5:5:1 solution and in a solution of 20% sodium hydroxide at temperatures of 16 ° to 20 ° C and at 45 °C, respectively. The effect of ferris chloride on the decomposition of hydrogen peroxide was also observed. The decomposition of 30% hydrogen peroxide in sodium hydroxide solution was faster than that in the mixture of hydrochloric acid and ether at low temperature (16 ° to 20 °C). The decomposition of hydrogen peroxide was accelerated by heat. The experiment implies that the bleaching effect of hydrogen peroxide can be achieved without heat by use of a sodium hydroxide solution. Further study on the rationale of the compound of the McInnes solution (hydrogen peroxide, hydrochloric acid, and anaesthesia ether mixed at a ratio of 5:5:1) is needed.