Effects of pH Values of Hydrogen Peroxide Bleaching Agents on Enamel Surface Properties

2011 ◽  
Vol 36 (5) ◽  
pp. 554-562 ◽  
Author(s):  
B Xu ◽  
Q Li ◽  
Y Wang
Keyword(s):  
Hydrogen Peroxide ◽  
Chemical Composition ◽  
Ph Value ◽  
Negative Control ◽  
Enamel Surface ◽  
Control Group ◽  
Solution Ph ◽  
Peroxide Bleaching ◽  
Color Changes ◽  
Ph Values

SUMMARY This study investigated the influence of pH values of bleaching agents on the properties of the enamel surface. Sixty freshly extracted premolars were embedded in epoxy resin and mesiodistally sectioned through the buccal aspect into two parts. The sectioned slabs were distributed among six groups (n=10) and treated using different solutions. Group HCl was treated with HCl solution (pH=3.0) and served as a positive control. Group DW, stored in distilled water (pH=7.0), served as a negative control. Four treatment groups were treated using 30% hydrogen peroxide solutions with different pH values: group HP3 (pH=3.0), group HP5 (pH=5.0), group HP7 (pH=7.0), and group HP8 (pH=8.0). The buccal slabs were subjected to spectrophotometric evaluations. Scanning electron microscopy investigation and Micro-Raman spectroscopy were used to evaluate enamel surface morphological and chemical composition alterations. pH value has a significant influence on the color changes after bleaching (p<0.001). Tukey's multiple comparisons revealed that the order of color changes was HP8, HP7>HP5, HP3>HCl>DW. No obvious morphological alterations were detected on the enamel surface in groups DW, HP7, and HP8. The enamel surface of groups HCl and HP3 showed significant alterations with an erosion appearance. No obvious chemical composition changes were detected with respect to Micro-Raman analysis. Within the limitations of this study, it was concluded that no obvious morphological or chemical composition alterations of enamel surface were detected in the neutral or alkaline bleaching solutions. Bleaching solutions with lower pH values could result in more significant erosion of enamel, which represented a slight whitening effect.

Influence of Hydrogen Peroxide Bleaching Gels on Color, Opacity, and Fluorescence of Composite Resins

2012 ◽  
Vol 37 (5) ◽  
pp. 526-531 ◽  
Author(s):  
CRG Torres ◽  
CF Ribeiro ◽  
E Bresciani ◽  
AB Borges
Keyword(s):  
Hydrogen Peroxide ◽  
Composite Resin ◽  
Color Change ◽  
Composite Resins ◽  
Control Group ◽  
Peroxide Bleaching ◽  
Color Changes ◽  
Tukey Test ◽  
Bleaching Gels ◽  
Bleaching Treatment

SUMMARY The aim of the present study was to evaluate the effect of 20% and 35% hydrogen peroxide bleaching gels on the color, opacity, and fluorescence of composite resins. Seven composite resin brands were tested and 30 specimens, 3-mm in diameter and 2-mm thick, of each material were fabricated, for a total of 210 specimens. The specimens of each tested material were divided into three subgroups (n=10) according to the bleaching therapy tested: 20% hydrogen peroxide gel, 35% hydroxide peroxide gel, and the control group. The baseline color, opacity, and fluorescence were assessed by spectrophotometry. Four 30-minute bleaching gel applications, two hours in total, were performed. The control group did not receive bleaching treatment and was stored in deionized water. Final assessments were performed, and data were analyzed by two-way analysis of variance and Tukey tests (p<0.05). Color changes were significant for different tested bleaching therapies (p<0.0001), with the greatest color change observed for 35% hydrogen peroxide gel. No difference in opacity was detected for all analyzed parameters. Fluorescence changes were influenced by composite resin brand (p<0.0001) and bleaching therapy (p=0.0016) used. No significant differences in fluorescence between different bleaching gel concentrations were detected by Tukey test. The greatest fluorescence alteration was detected on the brand Z350. It was concluded that 35% hydrogen peroxide bleaching gel generated the greatest color change among all evaluated materials. No statistical opacity changes were detected for all tested variables, and significant fluorescence changes were dependent on the material and bleaching therapy, regardless of the gel concentration.

scholarly journals Influence of pH Value of Bleaching Gels on Surface Roughness of Bovine Enamel

2019 ◽  
pp. 311-321
Author(s):  
Jocelyn G. Lugo-Varillas DDS ◽  
Pedro L. Tinedo-López DDS,MSc ◽  
Gustavo Watanabe Oshiro DDS,MSc ◽  
Alberth Correa Medina DDS,MSc,PhD ◽  
Evelyn Álvarez Vidigal DDS,MSc,PhD ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Surface Roughness ◽  
Ph Value ◽  
Tooth Enamel ◽  
Wilcoxon Test ◽  
Peroxide Bleaching ◽  
Ph Values ◽  
Bovine Enamel ◽  
Spearman Test ◽  
Bleaching Gels

Objective: The purpose of this study was to evaluate the influence of the pH levels of three in-office bleaching gels on the surface roughness of bovine enamel, after the bleaching protocol. Materials and methods: 36 samples of bovine enamel were obtained, which were cut and divided into three groups (n=12): 40%hydrogen peroxide (Opalescence Boost40%), 35% hydrogen peroxide (Whiteness HP AutoMixx) and 35% hydrogen peroxide (Whiteness HP Blue), receiving a 40-minute application of bleaching. The average pH values were determined using a pH meter during the initial and final application of the gel. A roughness meter was used to assess surface roughness (Ra) before and after bleaching. Data were analyzed with the Friedmann and wilcoxon test (difference between groups); the Kruskall Wallis and U Mann test (difference in each group), as well as Pearson or Spearman test for correlation. Results: There is an increase in pH values from the beginning to the end of bleaching in all groups, except for the 35% hydrogen peroxide group (Whiteness HP Automixx). For surface roughness results there is an increase in all groups. No correlation was found between pH values of the bleaching gels and the surface roughness of the enamel after bleaching. Conclusions: Hydrogen peroxide bleaching gels with high concentrations that have a high or low pH could cause alterations in the surface of the tooth enamel, such as increase in surface roughness.

Influence of pH on the Effectiveness of Hydrogen Peroxide Whitening

2014 ◽  
Vol 39 (6) ◽  
pp. E261-E268 ◽  
Author(s):  
CRG Torres ◽  
E Crastechini ◽  
FA Feitosa ◽  
CR Pucci ◽  
AB Borges
Keyword(s):  
Hydrogen Peroxide ◽  
Red Wine ◽  
Alcoholic Solution ◽  
Bleaching Effect ◽  
Significance Level ◽  
Peroxide Bleaching ◽  
Color Changes ◽  
Ph Values ◽  
Naoh Solution ◽  
Influence Of Ph

SUMMARY Objective To evaluate the influence of pH on the bleaching effect of hydrogen peroxide on chromogen agents. Method 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%. Results 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. Conclusion The efficacy of hydrogen peroxide bleaching is directly proportional to the increase in its pH.

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 Comparison of the Efficacy of Hydrogen Peroxide and Salt for Control of Fungal Infections on Brown Trout (Salmo trutta) Eggs

2018 ◽  
Vol 46 (1) ◽  
pp. 5 ◽  
Author(s):  
Nikolina Novakov ◽  
Vladislav Mandić ◽  
Brankica Kartalović ◽  
Bojana Vidović ◽  
Nenad Stojanac ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Sodium Chloride ◽  
Malachite Green ◽  
Brown Trout ◽  
Active Ingredient ◽  
Fungal Infections ◽  
Negative Control Group ◽  
Negative Control ◽  
Control Group ◽  
Hatching Rate

Background: Fungal infections can cause serious problems infecting fish eggs, especially unfertilized or dead eggs. In the past, this problem was solved by using very effective chemicals such as malachite green and formalin. But, due to its toxicity and carcinogenicity, malachite green was banned for use in fish intended for human consumption. Formalin also has been banned in most countries. Chemicals and drugs recommended for use to treat fungal infections are hydrogen peroxide, salt, potassium permanganate etc. The goal of the present study was to determine and compare the efficacy of antifungal effects of hydrogen peroxide and sodium chloride on brown trout eggs.Materials, Methods & Results: The experiment was conducted in the brown trout hatchery, Šipovo, Bosnia and Herzegovina. The experimental groups contained 500 and 1000 mg/L of hydrogen peroxide with 15 and 30 min of exposition; 1 and 2.5% of sodium chloride with 15 and 30 min of exposition and a negative control group (no chemical treatment). The treatment concentrations were calculated and prepared from hydrogen peroxide of 35% active ingredient, and sodium chloride (sterilized) of 100% active ingredient. Eggs for the study were spawned from 11 females and 4 males. The first treatment was performed on the fourth day, and each next treatment was performed at 3-day intervals. Six treatments were administered until the 19th day after the fertilization. The treatment of the eggs was provided until the eggs reached the eyed stage. The effectiveness of the chemical treatments was measured by a hatch rate. There was a significant difference between all treated groups and the negative control group (P < 0.05). Hydrogen peroxide with a concentration of 500 mg/L for 30 min was the most effective and demonstrated a higher hatching rate (75.7%). Sodium chloride treatments resulted in statistically significantly lower hatching rates than hydrogen peroxide treatments. The hatching rate in salt treatment with a concentration of 2.5% for 30 min was 27.3% lower than in hydrogen peroxide treatment with a concentration of 500 mg/L for 30 min.Discussion: Hydrogen peroxide is an effective antifungal, antibacterial and antiviral compound, and according to the Food and Drug Administration (FDA), hydrogen peroxide and salt are approved and classified as a low regulatory priority for the control of oomycetes on all species and life stages of fish. It is considered to be a very environmentally compatible chemical because it does not produce any toxic bioproducts when it decomposes. Hydrogen peroxide stood out as the best candidate substance for fungal control. The fact that the treatment with hydrogen peroxide at a concentration of 500 mg/L for 30 min was more effective than treatments at a concentration of 1000 mg/L can be explained by temperature dependency and treatment frequency of this chemical. Salt was not such an effective fungicide as hydrogen peroxide. When using salt, toxicity to the eggs should also be considered. Salt solutions may cause egg deaths at levels of 2.5% or higher. It is possible that high salinities have an inhibitory effect on the movement of fish embryo due to the high osmotic impact on the perivitelline layer. Thus, hydrogen peroxide has proven to be efficient, inexpensive, easy to use and environmentally safe in preventing fungal infections on brown trout eggs.

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.

scholarly journals Enamel Surface Changes After Exposure to Bleaching Gels Containing Carbamide Peroxide or Hydrogen Peroxide

2016 ◽  
Vol 41 (1) ◽  
pp. E39-E47 ◽  
Author(s):  
B Cvikl ◽  
A Lussi ◽  
A Moritz ◽  
S Flury
Keyword(s):  
Hydrogen Peroxide ◽  
Surface Roughness ◽  
Elastic Modulus ◽  
Color Change ◽  
Surface Hardness ◽  
Enamel Surface ◽  
Carbamide Peroxide ◽  
Peroxide Bleaching ◽  
Bleaching Gels ◽  
Bleaching Treatment

SUMMARY Objective This study evaluated the differences in enamel color change, surface hardness, elastic modulus, and surface roughness between treatments with four bleaching gels containing carbamide peroxide (two at 10% and one each at 35%, and 45%) and two bleaching gels containing hydrogen peroxide (two at 40%). Methods Enamel specimens were bleached and color changes were measured. Color change was calculated using either ΔE or the Bleaching Index (BI). Then, surface hardness, elastic modulus, and surface roughness of the enamel specimens were evaluated. All measurements were performed at baseline and directly after the first bleaching treatment for all carbamide peroxide– and hydrogen peroxide–containing bleaching gels. In addition, final measurements were made 24 hours after each of a total of 10 bleaching treatments for carbamide peroxide bleaching gels, and 1 week after each of a total of three bleaching treatments for hydrogen peroxide bleaching gels. Results After the last bleaching treatment, respective ΔE scores were 17.6 and 8.2 for the two 10% carbamide peroxide gels, 12.9 and 5.6 for the 45% and 35% carbamide peroxide gels, and 9.6 and 13.9 for the two 40% hydrogen peroxide gels. The respective BI scores were −2.0 and −2.0 for the two 10% carbamide peroxide gels, −3.5 and −1.5 for the 45% and 35% carbamide peroxide gels, and −2.0 and −3.0 for the two 40% hydrogen peroxide gels. Each bleaching gel treatment resulted in significant whitening; however, no significant difference was found among the gels after the last bleaching. Whitening occurred within the first bleaching treatments and did not increase significantly during the remaining treatments. Surface hardness significantly decreased after the last bleaching treatment, when 10% carbamide peroxide was used. Furthermore, significant changes in the elastic modulus or surface roughness occurred only after treatment with 10% carbamide peroxide. Conclusion All six bleaching gels effectively bleached the enamel specimens independent of their concentration of peroxide. Gels with low peroxide concentration and longer contact time negatively affected the enamel surface.

scholarly journals Effect of a carbamide peroxide bleaching gel containing calcium or fluoride on human enamel surface microhardness

2005 ◽  
Vol 16 (2) ◽  
pp. 103-106 ◽  
Author(s):  
Rogério de Oliveira ◽  
Adriana Franco Paes Leme ◽  
Marcelo Giannini
Keyword(s):  
Artificial Saliva ◽  
In Vitro Study ◽  
Enamel Surface ◽  
Control Group ◽  
Carbamide Peroxide ◽  
Surface Microhardness ◽  
Treatment Groups ◽  
Peroxide Bleaching ◽  
Human Enamel

This in vitro study evaluated the surface microhardness of human enamel submitted to bleaching with 10% carbamide peroxide (CP) containing calcium or fluoride. Ninety-eight dental blocks (5 x 5 mm²) with polished enamel surfaces were randomly assigned to 7 treatment groups (n=14), as follows: without bleaching and storage in artificial saliva (control); 10% CP; 10% CP + 0.05% calcium; 10% CP + 0.1% calcium; 10% CP + 0.2% calcium; 10% CP + 0.2% fluoride; and 10% CP + 0.5% fluoride. During 14 days, enamel surfaces were daily exposed to a 6-h bleaching regimen followed by storage in artificial saliva. Surface microhardness was measured before (baseline), during (7th day), immediately after bleaching (14th day) and 1 week post bleaching. Data were analyzed by two-way ANOVA and Tukey's test (p<0.05). All treatments reduced SM significantly during the bleaching cycle (7th day), immediately after bleaching (14th day) and 1 week post bleaching, compared to baseline and to the unbleached control group. In conclusion, in spite of the addition of calcium and fluoride, all bleaching treatments affected the enamel surface microhardness.

scholarly journals Influence of Restoration Type on the Cytotoxicity of a 35% Hydrogen Peroxide Bleaching Gel

2016 ◽  
Vol 41 (3) ◽  
pp. 293-304 ◽  
Author(s):  
DG Soares ◽  
N Marcomini ◽  
FG Basso ◽  
TN Pansani ◽  
J Hebling ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Cell Viability ◽  
Resin Composite ◽  
Glass Ionomer Cement ◽  
Hydrolytic Degradation ◽  
Control Group ◽  
Pulp Chamber ◽  
Peroxide Bleaching ◽  
Alp Activity

SUMMARY Objectives: The tooth/restoration interface may act as a pathway for hydrogen peroxide (H2O2) diffusion into the pulp chamber. Therefore, the influence of resin-modified glass ionomer cement (RMGIC) and resin composite simulated restorations on the cytotoxicity of an in-office bleaching gel was assessed in vitro. Materials and Methods: Cavities in enamel/dentin discs restored with RMGIC Vitremer (3M ESPE) or Single Bond/Filtek Z350 (3M ESPE) resin composite (RC) were subjected or not subjected to hydrolytic degradation (HD). A 35%-H2O2 bleaching gel was applied to simulated restored and nonrestored enamel surfaces, and culture medium in contact with the dentin substrate (extract) was collected and applied to MDPC-23 cells. Nonrestored discs subjected or not subjected to bleaching were used as positive and negative controls, respectively. Cell viability, oxidative stress, interleukin (IL)-1β expression, alkaline phosphatase (ALP) activity, and mineralized nodule deposition were evaluated. The H2O2 in the extracts was quantified. Data were subjected to statistical analysis. Results: Higher oxidative stress associated with reduced cell viability, ALP activity, and mineralized nodule deposition was observed for all bleached groups compared with the negative control group. The RMGIC/HD group, which presented the highest H2O2 diffusion, had the lowest values of cell viability, ALP activity, and mineralized nodule deposition, as well as significantly increased IL-1β expression. Conclusions: Dental cavities restored with the RMGIC subjected to hydrolytic degradation allowed for more intense diffusion of H2O2 into the pulp chamber, intensifying the toxicity of a 35%-H2O2 bleaching gel to pulp cells.

Dyeing Properties to Wool Fabrics of Catechu Dye Purified by Micro-Filtration Membrane

2008 ◽  
Vol 12 (1) ◽  
pp. 32-38 ◽  
Author(s):  
Xiuliang Hou ◽  
Li Wei ◽  
Xinlong Zhang ◽  
Huihui Wu ◽  
Qicheng Zhou ◽  
...  
Keyword(s):  
Ph Value ◽  
Wool Fabric ◽  
Color Fastness ◽  
Color Changes ◽  
Ph Values ◽  
Filtration Membrane ◽  
Wool Fabrics ◽  
Characteristic Values ◽  
The Stability ◽  
Different Levels

Catechu liquor, which is deep brown-red in color, was purified with a micro-filtration membrane and the stability of catechu dye to different levels of temperatures and pH were investigated in this paper. The effects of the dyeing conditions on color characteristic values and color fastnesses of the dyed wool fabrics were also investigated. The results show that the liquor of catechu dye is stable at pH values of 3-7 and its color changes to a deeper brown-red when its pH value is above 8. The preferable dyeing conditions for wool fabric with refined powder catechu dye are as follows: dyeing temperature of 100±C, pH value of 6.5 for the dye bath and catechu dye of 1-4% (o.w.f). The dyed wool fabric has good color fastnesses to washing, alkali perspiration and dry rubbing. However, its color fastness rating to wet rubbing is poor, ranging from 2-3. Further research will be needed on this aspect.

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