Sequential Oxidative/Reductive Bleaching and Dyeing of Wool in a Single Bath at Low Temperatures

1992 ◽  
Vol 62 (3) ◽  
pp. 123-130 ◽  
Author(s):  
Mustafa Arifoglu ◽  
William N. Marmer
Keyword(s):  
Hydrogen Peroxide ◽  
Bleaching Agent ◽  
Sulfate Anion ◽  
Peroxide Bleaching ◽  
Dyeing Process ◽  
Thiourea Dioxide ◽  
Residual Hydrogen ◽  
Single Bath ◽  
Almost All ◽  
Sulfonate Anion

A new bleaching and dyeing process applicable to wool involves a sequential oxidative/reductive bleaching combined with a subsequent dyeing in a single bath. Apart from dyebath bleaching processes in which the bleaching agent is added towards the end of the dyeing process when almost all the dye is exhausted, bleaching and subsequent dyeing are normally done in separate baths due to the sensitivity of the dyes to bleaching agents. In the latter process, it is important that all bleaching agents be thoroughly washed off before dyeing, because any residual bleaching agent (hydrogen peroxide, reductive bleach) may adversely affect the results. The newly developed single-bath process begins with an oxidative hydrogen peroxide bleaching followed by addition of thiourea to the residual hydrogen peroxide in the same bath. Thiourea dioxide formed by the resulting chemical reaction hydrolyzes in solution to sulfonate anion and urea. Sulfinate anion is a strong reducing agent and effects reductive bleaching. At the end of the reductive bleaching stage, a small amount of hydrogen peroxide is added to oxidize all the reductive sulfur species in solution to the sulfate anion, which together with the urea serves subsequently as a dye assist. Once the temperature of the bath is lowered, dyes may be added to the same bath. The new sequential single-bath bleaching/dyeing process results in much brighter pastel shades upon dyeing, due to better whiteness obtained initially with sequential oxidative/reductive bleaching. Furthermore, there is a reduction in processing time, temperature, and effluent compared with conventional procedures and the utilization of byproducts from the initial bleaching assists during the subsequent dyeing step.

scholarly journals Changes in Bovine Enamel after Treatment with a 30% Hydrogen Peroxide Bleaching Agent

2004 ◽  
Vol 23 (4) ◽  
pp. 517-521 ◽  
Author(s):  
Hyun-Jin PARK ◽  
Tae-Yub KWON ◽  
Soon-Hyun NAM ◽  
Hyun-Jung KIM ◽  
Kyo-Han KIM ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Bleaching Agent ◽  
Peroxide Bleaching ◽  
Bovine Enamel

scholarly journals Indirect cytotoxicity of a 35% hydrogen peroxide bleaching gel on cultured odontoblast-like cells

2009 ◽  
Vol 20 (4) ◽  
pp. 267-274 ◽  
Author(s):  
Cármen Regina Coldebella ◽  
Ana Paula Dias Ribeiro ◽  
Nancy Tomoko Sacono ◽  
Flávia Zardo Trindade ◽  
Josimeri Hebling ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Cell Morphology ◽  
Total Protein ◽  
Cell Metabolism ◽  
Control Group ◽  
Bleaching Agent ◽  
Morphological Alterations ◽  
Peroxide Bleaching ◽  
Cytopathic Effects ◽  
Halogen Light

The aim of this study was to evaluate the trans-enamel and trans-dentinal effects of a 35% hydrogen peroxide (H2O2) bleaching gel on odontoblast-like cells. Enamel/dentin discs obtained from bovine incisors were mounted in artificial pulp chambers (APCs). Three groups were formed: G1- 35% H2O2; G2- 35% H2O2 + halogen light application; G3- control. The treatments were repeated 5 times and the APCs were incubated for 12 h. Then, the extract was collected and applied for 24 h on the cells. Cell metabolism, total protein dosage and cell morphology were evaluated. Cell metabolism decreased by 62.09% and 61.83% in G1 and G2, respectively. The depression of cell metabolism was statistically significant when G1 and G2 were compared to G3. Total protein dosage decreased by 93.13% and 91.80% in G1 and G2, respectively. The cells in G1 and G2 exhibited significant morphological alterations after contact with the extracts. Regardless of halogen light application, the extracts caused significantly more intense cytopathic effects compared to the control group. After 5 consecutive applications of a 35% H2O2 bleaching agent, either catalyzed or not by halogen light, products of gel degradation were capable to diffuse through enamel and dentin causing toxic effects to the cells.

Effectiveness of In-office Hydrogen Peroxide With Two Different Protocols: A Two-center Randomized Clinical Trial

2018 ◽  
Vol 43 (4) ◽  
pp. 353-361 ◽  
Author(s):  
IEB Martins ◽  
S Onofre ◽  
N Franco ◽  
LM Martins ◽  
A Montenegro ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Color Change ◽  
Absolute Risk ◽  
Rank Test ◽  
Bleaching Agent ◽  
Tooth Sensitivity ◽  
Peroxide Bleaching ◽  
Color Changes ◽  
Ph Values ◽  
The Absolute

SUMMARY Objectives: The aim of this study was to compare the bleaching efficacy and tooth sensitivity (TS) of a 38% hydrogen peroxide bleaching agent used for in-office bleaching, applied under different time protocols: a 40-minute application or two 20-minute applications. Methods and Materials: Forty-four patients from Brazil and Colombia, with right superior canines darker than C2, were selected for this multicenter, single-blind, randomized trial. The teeth were bleached in two sessions, with a one-week interval between them, in a split-mouth design. The bleaching agent was applied in two 20-minute (2×20) applications or one 40-minute (1×40) application in each session according to the manufacturer's instructions. The color changes were evaluated by using subjective (Vita Classical and Vita Bleachedguide) and objective (Easyshade Spectrophotometer) methods at baseline and 30 days after the second session. Tooth sensitivity was recorded up to 48 hours with a 0-10 visual analog scale. Also, the pH values during the application of bleaching were recorded. Color change in shade guide units and ΔE were analyzed by using the Student t-test (α=0.05). The absolute risk and intensity of TS were evaluated with the McNemar test, the Wilcoxon signed-rank test, and the Friedman test, respectively (α= 0.05). Results: Significant whitening was observed in both groups after 30 days of clinical evaluation. The use of a 40-minute application did not significantly influence the absolute risk of TS (68%, 95% confidence interval [CI] = 53-80) as well as the intensity of TS compared with the acid bleaching gel (absolute risk of 82%, 95% CI = 68-91). The pH values did not differ significantly between groups and at the different assessment periods (p=0.42). Conclusion: The use of a 40-minute in-office bleaching agent gel application produced the same whitening degree and TS that the two 20-minute bleaching agent applications did. The former preferably should be applied because one 40-minute application does not require gel refreshing.

scholarly journals Influence of Time on Bond Strength After Bleaching with 35% Hydrogen Peroxide

2008 ◽  
Vol 9 (2) ◽  
pp. 81-88 ◽  
Author(s):  
Flávia Martão Flório ◽  
Cinthia Maria Barbosa ◽  
Robson Tetsuo Sasaki ◽  
Robera Tarkany Basting
Keyword(s):  
Hydrogen Peroxide ◽  
Bond Strength ◽  
Composite Resin ◽  
Artificial Saliva ◽  
Testing Machine ◽  
Adhesive System ◽  
Bleaching Agent ◽  
Peroxide Bleaching ◽  
Bleaching Treatment

Abstract Aim The aim of this in vitro study was to evaluate the influence of time after treatment with a 35% hydrogen peroxide bleaching agent on the shear bond strength between composite resin and sound enamel and dentin. Methods and Materials Eighty dental slabs - 40 enamel (E) slabs and 40 dentin (D) slabs - were embedded, flatted, and divided into four groups (n=10). In G1 the E and D slabs were kept in artificial saliva for 14 days. For the G2, G3, and G4 groups the E and D slabs were submitted to bleaching treatment with a 35% hydrogen peroxide bleaching agent. At different times after bleaching treatments (G2=immediate; G3=seven days; G4= fourteen days), composite resin cylinders were made using an adhesive system. Tests were performed in a universal testing machine at a speed of 0.5 mm/min to obtain the values in MPa. Results For enamel, the Kruskal-Wallis test and Dunn Method showed G1 differed significantly from G2 (G1=13.40 a; G2=6.64 b; G3=16.76 a; G4=11.64 ab). For dentin, the analysis of variance (ANOVA) and Tukey tests showed that G1 differed significantly from G2 and G3 (G1=12.11 a; G2=4.97 b; G3=8.67 c; G4=11.86 ac). Conclusion It is recommended adhesive restorative procedures in enamel be delayed for seven days postbleaching treatment with 35% hydrogen peroxide, while restorations in dentin should be delayed for 14 days following bleaching treatment. Citation Barbosa CM, Sasaki RT, Flório FM, Basting RT. Influence of Time on Bond Strength After Bleaching with 35% Hydrogen Peroxide. J Contemp Dent Pract 2008 February;(9)2:081-088.

Hydrogen Peroxide Bleaching of Cationized Cotton Fabric

2019 ◽  
Vol 6 (5) ◽  
pp. 21-29
Author(s):  
Sha Fu ◽  
Matthew J. Farrell ◽  
Mary A. Ankeny ◽  
Edwin T. Turner ◽  
Victoria Rizk
Keyword(s):  
Hydrogen Peroxide ◽  
Statistical Model ◽  
Magnesium Sulfate ◽  
Cotton Fabric ◽  
Significant Loss ◽  
Bleaching Agent ◽  
Color Strength ◽  
Whiteness Index ◽  
Peroxide Bleaching ◽  
Screening Experiment

Hydrogen peroxide (H2O2) is the most commonly used bleaching agent for cotton fabric. However, the conventional H2O2 bleaching formula is not applicable for cationized cotton due to the low whiteness index after bleaching, fabric weakening, and a significant loss of cationic sites. In this work, magnesium sulfate (MgSO4) was added in the H2O2 bleaching formula to stabilize the bleaching system for cationized cotton. Additionally, a screening experiment with temperature and time, and sodium hydroxide (NaOH), H2O2, and MgSO4 concentrations as the factors, and whiteness index, bursting strength, and color strength from dyeing as the responses, was formulated. A statistical model was created using JMP software, which demonstrated how the bleaching conditions influenced the fabric properties. This procedure can be useful for bleaching cationized cotton in production settings.

scholarly journals Effects of pre-operative air-powder polishing and rubber-cup prophylaxis on tooth bleaching : Randomized controlled split-mouth clinical study

2020 ◽  
Author(s):  
zeliha gonca bek kurklu ◽  
mustafa ozcan
Keyword(s):  
Hydrogen Peroxide ◽  
Similar Efficacy ◽  
Tooth Bleaching ◽  
Bleaching Agent ◽  
Color Parameters ◽  
Peroxide Bleaching ◽  
Color Changes ◽  
Randomized Controlled ◽  
Assessment Period ◽  
Bleaching Treatment

Abstract Background: The aim the study to compare the effects of pre-operative air-powder polishing and rubber-cup prophylaxis on tooth bleaching Methods: 23 subjects suffering from discoloration, were enrolled in a randomized controlled split mouth experimental study. Before bleaching, air powder polishing (APP) and rubber-cup polishing (RCP) techniques were applied on either side of the mouth. A 40% hydrogen peroxide bleaching agent applied two 15-minute applications for in-office bleaching. The tooth bleaching effects assessed immediately after and 1 week. Results: There were no significant differences between prophylaxis groups with respect to all color parameters (ΔL, Δa, Δb, ΔEab, ΔE00 and ΔSGU) at immediate period (p>0,05). At 1 week assessment period there were no significant differences between prophylaxis groups with respect to all color parameters (p>0,05) except delta E00 (p<0,05). Conclusions: Two prophylaxis techniques produced similar efficacy in bleaching treatment and the APP technique produced higher levels of color changes.

scholarly journals Assessing the effects of hydrogen peroxide bleaching agent on the shear bond strength of orthodontic brackets

2016 ◽  
Vol 27 (4) ◽  
pp. 410 ◽  
Author(s):  
AugustoRicardo Andrighetto ◽  
EduardoHenrique de Leão Withers ◽  
KarlosGiovani Grando ◽  
AldrieliRegina Ambrosio ◽  
RobertoHideo Shimizu ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Bond Strength ◽  
Shear Bond Strength ◽  
Orthodontic Brackets ◽  
Bleaching Agent ◽  
Peroxide Bleaching

The role of copper ions in hydrogen peroxide bleaching: Their origin, removal, and effect on pulp quality

TAPPI Journal ◽  
2012 ◽  
Vol 11 (7) ◽  
pp. 37-46 ◽  
Author(s):  
PEDRO E.G. LOUREIRO ◽  
SANDRINE DUARTE ◽  
DMITRY V. EVTUGUIN ◽  
M. GRAÇA V.S. CARVALHO
Keyword(s):  
Hydrogen Peroxide ◽  
Copper Ions ◽  
Peroxide Bleaching ◽  
Metals Removal ◽  
Peroxide Decomposition ◽  
Equipment Corrosion ◽  
And Performance ◽  
And Control ◽  
Main Effects

This study puts particular emphasis on the role of copper ions in the performance of hydrogen peroxide bleaching (P-stage). Owing to their variable levels across the bleaching line due to washing filtrates, bleaching reagents, and equipment corrosion, these ions can play a major role in hydrogen peroxide decomposition and be detrimental to polysaccharide integrity. In this study, a Cu-contaminated D0(EOP)D1 prebleached pulp was subjected to an acidic washing (A-stage) or chelation (Q-stage) before the alkaline P-stage. The objective was to understand the isolated and combined role of copper ions in peroxide bleaching performance. By applying an experimental design, it was possible to identify the main effects of the pretreatment variables on the extent of metals removal and performance of the P-stage. The acid treatment was unsuccessful in terms of complete copper removal, magnesium preservation, and control of hydrogen peroxide consumption in the following P-stage. Increasing reaction temperature and time of the acidic A-stage improved the brightness stability of the D0(EOP)D1AP bleached pulp. The optimum conditions for chelation pretreatment to maximize the brightness gains obtained in the subsequent P-stage with the lowest peroxide consumption were 0.4% diethylenetriaminepentaacetic acid (DTPA), 80ºC, and 4.5 pH.

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