scholarly journals Aggregation of Gold Nanoparticles Caused in Two Different Ways Involved in 4-Mercaptophenylboronic Acidand Hydrogen Peroxide

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1802
Author(s):  
Runmei Li ◽  
Xuefan Gu ◽  
Xingtang Liang ◽  
Shi Hou ◽  
Daodao Hu
Keyword(s):  
Hydrogen Peroxide ◽  
Boric Acid ◽  
Color Change ◽  
H2o2 Concentration ◽  
Ph Change ◽  
Detection Range ◽  
Color Changes ◽  
New Strategy ◽  
Colorimetric Assays ◽  
The Difference

The difference in gold nanoparticle (AuNPs) aggregation caused by different mixing orders of AuNPs, 4-mercaptophenylboronic acid (4-MPBA), and hydrogen peroxide (H2O2) has been scarcely reported. We have found that the color change of a ((4-MPBA + AuNPs) + H2O2) mixture caused by H2O2 is more sensitive than that of a ((4-MPBA + H2O2) + AuNPs) mixture. For the former mixture, the color changes obviously with H2O2 concentrations in the range of 0~0.025%. However, for the latter mixture, the corresponding H2O2 concentration is in the range of 0~1.93%. The mechanisms on the color change originating from the aggregation of AuNPs occurring in the two mixtures were investigated in detail. For the ((4-MPBA + H2O2) + AuNPs) mixture, free 4-MPBA is oxidized by H2O2 to form bis(4-hydroxyphenyl) disulfide (BHPD) and peroxoboric acid. However, for the ((4-MPBA+AuNPs) + H2O2) mixture, immobilized 4-MPBA is oxidized by H2O2 to form 4-hydroxythiophenol (4-HTP) and boric acid. The decrease in charge on the surface of AuNPs caused by BHPD, which has alarger steric hindrance, is poorer than that caused by -4-HTP, and this is mainly responsible for the difference in the aggregation of AuNPs in the two mixtures. The formation of boric acid and peroxoboric acid in the reaction between 4-MPBA and H2O2 can alter the pH of the medium, and the effect of the pH change on the aggregation of AuNPs should not be ignored. These findings not only offer a new strategy in colorimetric assays to expand the detection range of hydrogen peroxide concentrations but also assist in deepening the understanding of the aggregation of citrate-capped AuNPs involved in 4-MPBA and H2O2, as well as in developing other probes.

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 Impact of Bleaching before or after Veneer Preparation on Color Masking Ability of Laminate Veneers: An In Vitro Study

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Gollshang Ahmad Mhammed Dalloo ◽  
Bestoon Mohammed Faraj ◽  
Abdulsalam Rasheed Al-Zahawi
Keyword(s):  
Hydrogen Peroxide ◽  
Color Change ◽  
In Vitro Study ◽  
Tooth Discoloration ◽  
Significant Difference ◽  
Color System ◽  
The Difference ◽  
Laminate Veneers ◽  
Cielab Color

Purpose. This study evaluates the effect of bleaching before or after veneer preparation and the depth of preparation on color masking ability of laminate veneers. Methods. Sixty extracted premolars were artificially stained to vita shade A4, verified by digital spectrophotometer (Vita Easy Shade V), and then divided into three groups: NB = nonbleached , BBP = bleaching before preparation, and BAP = bleaching after preparation. Based on the preparation depths, each group was further divided into two subgroups: S 1 = 0.5   mm and S 2 = 1.0   mm . BBP and BAP were subjected to one session of in-office bleaching using 35% hydrogen peroxide. IPS e-max CAD veneers of 0.5 and 1.0 mm thickness (corresponding to the preparation depths) of the same shade and translucency (HT A1) were cemented immediately to the bleached surfaces. Immediately after cementation, the color change Δ E between the baseline (after staining) and the resulted shades was measured using the Vita Easy Shade V digital spectrophotometer and CIELab color system. Results. Bleached groups exhibited a significant Δ E value compared to the nonbleached group ( p < 0.05 ). BAP showed the highest Δ E value. No significant difference was found between BBP and BAP. S2 revealed a significant Δ E value than S1 ( p < 0.05 ). No significant difference was found between S1of BAP and S2 of NB, BBP, and BAP ( p > 0.05 ). Regarding the color coordinates, the difference between the tested groups was highly significant in lightness ( Δ L ∗ ) ( p < 0.001 ), while no significant differences were found in green/red value ( Δ a ∗ ) and yellow/blue value ( Δ b ∗ ) ( p > 0.05 ). Conclusions. In cases of severe tooth discoloration, one session of in-office bleaching before or after veneer preparation and the preparation depth do not influence the color masking ability of laminate veneers.

scholarly journals Spectrophotometric Evaluation of Enamel Color Variation Using Infiltration Resin Treatment of White Spot Lesions at One Year Follow-Up

2020 ◽  
Vol 8 (2) ◽  
pp. 35 ◽  
Author(s):  
Roberto Lo Giudice ◽  
Frank Lipari ◽  
Francesco Puleio ◽  
Angela Alibrandi ◽  
Fabrizio Lo Giudice ◽  
...  
Keyword(s):  
Color Change ◽  
Statistical Significance ◽  
Color Variation ◽  
White Spot ◽  
White Spot Lesions ◽  
Color Changes ◽  
The Difference ◽  
One Year ◽  
The Stability

The aim of this study is to evaluate the color changes and the stability at a 1-year follow-up of white spot lesions (WSLs) treated with an infiltrating technique by using etching and TEGDMA resin. The color of 22 white spot lesions and the sound adjacent enamel (SAE) were assessed with a spectrophotometer at T0 (baseline), T1 (after treatment), and T2 (1 year after). The color change ΔE (WSLs-SAE) at T0 vs. T1 were compared to evaluate the camouflage effect efficiency, and at T1 vs. T2 to assess the stability of outcomes. To evaluate the effect on the treatment outcome of gender, the presence or not of previous orthodontic treatment, WSLs onset more/less than 10 years, the age of the patient, and the ΔE WSL (T0 vs. T1) was analyzed. The difference between ΔE (WSLs-SAE) at T0 and T1 resulted in statistical significance (p < 0.01). No statistical difference was found between ΔE (WSLs-SAE) at T1 vs. T2. The variables considered showed no statistical differences in treatment outcomes. The results of our investigation show that the technique used is immediately effective and the camouflage effect keeps up and steady one year after treatment. Such results do not appear to be influenced by analyzed clinical variables.

scholarly journals Can ozone or violet light improve the color change or physicochemical properties of hydrogen peroxide-bleached tooth?

2021 ◽  
Vol 32 (4) ◽  
pp. 19-30
Author(s):  
Nayara Rodrigues Nascimento Oliveira Tavares ◽  
Alexia da Mata Galvão ◽  
Lia Dietrich ◽  
Roberta Furtado Carvalho ◽  
Robinson Sabino Silva ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Surface Roughness ◽  
Color Change ◽  
Repeated Measure ◽  
Color Changes ◽  
Violet Light ◽  
Atomic Force ◽  
Measure Anova ◽  
Before And After ◽  
To Receive

Abstract: This study investigated the bleaching effectiveness and the physicochemical effects on enamel of violet light and ozone, associate or not to hydrogen peroxide, compared to 35%-hydrogen peroxide. Enamel-dentin blocks from human molars were randomly allocated to receive one of the following bleaching protocols (n=15): (HP) 35%-hydrogen peroxide, (VL) violet light, (OZ) ozone, the association between hydrogen peroxide with ozone (OZ+HP) or violet light (VL+HP). All protocols were performed in two sessions with a 48h interval. Color (spectrophotometer) and mineral composition (Raman spectroscopy) were measured before and after the bleaching. Color changes were calculated by ΔEab, ΔE00, and whitening index (WI). The surface roughness was measured with an atomic force microscope. Data were analyzed by One-way or Two-way repeated measure ANOVA followed by the Tukey’s test (α = 0.05). The lowest color change values (either measured by WI, ΔEab, or ΔE00) were observed for VL and OZ used with no HP. Violet light associate with HP was unable to improve the color changes observed for the peroxide alone, in combination with OZ and HP, the highest color changes were verified. Regardless of bleaching protocol, the bleached enamel presented higher contents of PO4 and CO3 -2 than those observed at baseline. All bleaching protocols resulted in similar enamel surface roughness. Both the VL and the OZ caused reduced effects on the enamel color change when used alone. The ozone therapy improved the bleaching effect in the group that received the association of HP.

scholarly journals Effect of the Purple Corn Beverage “Chicha Morada” in Composite Resin during Dental Bleaching

Scientifica ◽  
2016 ◽  
Vol 2016 ◽  
pp. 1-6
Author(s):  
Eric Dario Acuña ◽  
Leyla Delgado-Cotrina ◽  
Francisco Aurelio Rumiche ◽  
Lidia Yileng Tay
Keyword(s):  
Hydrogen Peroxide ◽  
Green Tea ◽  
Composite Resin ◽  
Color Change ◽  
Color Measurement ◽  
Distilled Water ◽  
Dental Bleaching ◽  
Color Changes ◽  
Bleaching Procedure ◽  
Purple Corn

During dental bleaching the staining potential of the surface would increase. This study aims to evaluate the staining susceptibility of one bleached composite resin after the exposure to three different beverages: Peruvian purple corn based beverage (chicha morada), green tea, and distilled water. Thirty disk-shaped specimens of one nanofill composite resin were prepared. The specimens were then divided into six groups (n=5): purple corn (P), purple corn + bleaching (PB), green tea (T), green tea + bleaching (TB), distilled water (W), and distilled water + bleaching (WB). In groups that received bleaching, two sessions of bleaching with 35% hydrogen peroxide were done. Following bleaching, specimens were exposed to each liquid thirty minutes daily. Color was measured with a digital spectrophotometer. For statistical analysis, color measurement differences between the obtained results were used: during bleaching, after bleaching, and during + after bleaching. Two-way ANOVA was used to compare the color changes in the resins of all groups (p<0.05). We conclude that all the evaluated beverages produced changes of color in the composite resin regardless of the bleaching procedure. However, purple corn was the only beverage that caused a perceptible color change (ΔE>3.3).

Administration of Ascorbic Acid to Prevent Bleaching-induced Tooth Sensitivity: A Randomized Triple-blind Clinical Trial

2014 ◽  
Vol 39 (2) ◽  
pp. 128-135 ◽  
Author(s):  
EA de Paula ◽  
S Kossatz ◽  
D Fernandes ◽  
AD Loguercio ◽  
A Reis
Keyword(s):  
Clinical Trial ◽  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Color Change ◽  
Absolute Risk ◽  
Tooth Sensitivity ◽  
Parallel Design ◽  
Color Changes ◽  
The Absolute ◽  
Similar Risk

SUMMARY This study evaluated the effect of ascorbic acid, 500 mg every eight hours, on bleaching-induced tooth sensitivity. A triple-blind, parallel design, and placebo-controlled randomized clinical trial was conducted on 39 adults. The pills (placebo or ascorbic acid) were administered three times per day for 48 hours; the first dose was given one hour prior to each bleaching session. Two bleaching sessions with 35% hydrogen peroxide gel were performed with a one-week interval. Tooth sensitivity was recorded up to 48 hours after bleaching. The color evaluation was performed before and 30 days after bleaching. The absolute risk and intensity of tooth sensitivity were evaluated by Fisher exact and Mann-Whitney U-tests, respectively. Color changes were evaluated by unpaired t-test (α=0.05). There were no significant differences in the absolute risk and intensity of tooth sensitivity and color change between the groups. Both groups showed a similar risk of tooth sensitivity (p&gt;0.05). The perioperative use of an antioxidant, such as ascorbic acid (500 mg, three times daily) perorally, was not able to prevent bleaching-induced tooth sensitivity or reduce its intensity.

The Effect of Bleaching Agents on the Color Stability of Ceromer and Porcelain Restorative Materials In Vitro

2012 ◽  
Vol 38 (1) ◽  
pp. E1-E8 ◽  
Author(s):  
HB Kara ◽  
F Aykent ◽  
B Ozturk
Keyword(s):  
Color Change ◽  
Glass Ceramics ◽  
In Vitro Study ◽  
Color Stability ◽  
Color Changes ◽  
Bleaching Procedure ◽  
Significant Difference ◽  
Restorative Materials ◽  
The Difference

SUMMARY Purpose The aim of this in vitro study was to determine the color changes of five different restorative materials after exposing these materials to two different home bleaching agents. Methods This study applied bleaching agents to an ultralow-fusing porcelain, a low-fusing porcelain, two types of heat-pressed glass ceramics, and a ceromer. A total of 24 disc-shaped specimens were fabricated (with a diameter of 10 mm and a thickness of 2 mm) from each material (n=12). The initial color measurements were taken with a spectrophotometer. The first set of specimens were bleached with 10% hydrogen peroxide (HP) for one hour daily for 10 days. The other set of specimens were bleached with 10% carbamide peroxide (CP) bleaching gel for eight hours daily for 14 days. Data were analyzed with the one-way analysis of variance and Kruskal-Wallis statistical test. The difference in the prebleaching and postbleaching color of each material was considered to be statistically significant at p &lt; 0.05. Results The study found a statistically significant difference among the color changes of the test groups after exposing them to both bleaching agents (p&lt;0.05). Appreciable color change was observed in the Estenia (ΔE=3.99) specimens that were bleached with the HP, and noticeable color changes were observed in the Estenia (ΔE=1.89) and IPS Empress 2 (ΔE=1.66) groups when they were treated with the CP. Conclusions Restorations (especially polymer-containing restorative materials) should be protected before any bleaching procedure due to the high risk of color change.

scholarly journals PROSES PEMBUNGAAN BEBERAPA VARIETAS Hoya coronaria DARI KAWASAN HUTAN KERANGAS AIR ANYIR, BANGKA

2018 ◽  
Vol 2 (1) ◽  
pp. 10-19
Author(s):  
Risti Annisa ◽  
Yulian Fakhrurrozi ◽  
Sri Rahayu
Keyword(s):  
Flower Development ◽  
Development Process ◽  
Color Change ◽  
Flower Color ◽  
Color Changes ◽  
Light Yellow ◽  
Heath Forest ◽  
The Difference ◽  
Different Color ◽  
Flowering Process

Hoya coronaria found in heath forest of Air Anyir, Bangka has diverse colors. Flowers color diversity sometimes correlated varieties or the result of color changes during flowering process. The flowers development process observed from 5 H. coronaria varieties with different color from heath forest of Air Anyir, Bangka.The purpose of this research to know the flowering process and flower color change process some varieties of H. coronaria. This research done from September 2015-January 2016. This study used qualitative method to made detail and systematic description about flowering phase. H.coronaria flowering process consists of flower initation, flower estabilisment and flower development. Flower initation needs 13-15 days, flower estabilisment needs 10-12 days and flower development consists of early blooming process, full blooming and senescene. Early blooming process needs 1-3 days, full blooming needs 5-12 days and senescene needs 1-3 days. During the development process changes from rounded to pentagonal shape and there is a change in size. The observation result showed that 5 varieties are different from one another based on the difference between the colors of the flowers. Variety 1 has yellow corolla without honey line and deep pink corona. Variety 2 has light yellow green corolla with strong pink honey line and moderate red corona. Variety 3 has moderate red corolla with moderate red honey line and moderate red corona. Variety 4 has light yellow green corolla with moderate pink honey line and light yellow green corona. Variety 5 has moderate red without honey line and grayish red corona

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 Polishing can reduce discoloration of the nanofiller composite resin filling due to the use of chlorhexidine

2020 ◽  
Vol 9 (3) ◽  
pp. 252-256
Author(s):  
I Gusti Ketut Armiati
Keyword(s):  
Composite Resin ◽  
Color Change ◽  
Chlorhexidine Gluconate ◽  
Control Group ◽  
Control Group Design ◽  
Treatment Groups ◽  
Color Changes ◽  
Long Time ◽  
Cavity Design ◽  
The Difference

Nanofiller composite resin (NCR) restoration has a major problem, namely color changes. Polishing are factors that determi-ne color change and if accompanied by the use of mouthwash for a long time can cause more significant color changes. The 0.2% chlorhexidine gluconate mouthwash is a mouthwash that is often used in the community because it has low toxicity. However, using the chlorhexidine gluconate 0.2% mouthwash in the long term can cause more significant discoloration. This study is aimed to determine the difference between discoloration of polished and unpolished NCR on the soaking of 0.2% chlorhexidine gluconate mouthwash. This purely experimental research with a pretest and posttest with control group design, using 24 samples of premolar teeth prepared with class II cavity design and then filled with NCR. The samples were then di-vided into 4 treatment groups, namely polished and non-polished NCR, 0.2% chlorhexidine gluconate mouthwash and aqua-dest. Soaking was carried out 24 hours a day for 5 days in an incubator at 37ºC. Color changes of each group were measured using shade guide Vita Classical. The results were analyzed descriptively and the normality was tested by the Shapiro-Wilk and Levene's homogenity test with significance value of 0.05. Mann-Whitney for the different test. Based on the results of this study, it is concluded that the discoloration of the polished NCR was smaller than that was not polished on the soaking of chlorhexidine mouthwash 0.2%

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