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.

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.

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 Mechanical and Chemical Degradation in the Surface Roughness, Gloss, and Color of Microhybrid Composites

2017 ◽  
Vol 18 (4) ◽  
pp. 283-288 ◽  
Author(s):  
Cleidiel AA Lemos ◽  
Silvio J Mauro ◽  
Paulo H dos Santos ◽  
André LF Briso ◽  
Ticiane C Fagundes
Keyword(s):  
Surface Roughness ◽  
Clinical Significance ◽  
Composite Resin ◽  
Color Change ◽  
Wilcoxon Test ◽  
Chemical Degradation ◽  
Color Changes ◽  
Final Data ◽  
Properties Of Materials ◽  
Spearman Test

ABSTRACT Aim The aim of this study was to investigate the association of different degradations on the roughness, gloss, and color changes of microhybrid composites. Materials and methods Ten specimens were prepared for Charisma, Amelogen Plus, Point 4, and Opallis resins. Surfaces were polished and baseline measurements of roughness, gloss, and color were recorded. Specimens were then submitted to chemical and mechanical challenges, and the specimens were reevaluated. Roughness and gloss were analyzed by Kruskal – Wallis and Dunn's test (p < 0.05). Color change (ΔE) was analyzed by one-way analysis of variance and Tukey's tests (p < 0.05). The initial and final data were compared using the Wilcoxon test (p < 0.05). Spearman test checked the correlation between the roughness and gloss (p < 0.05). Results Regarding surface roughness and gloss, there was no difference between composites before challenges. However, all composites showed a significant increase of roughness after challenges, with highest values for Charisma. The gloss was influenced by challenges, evidencing the best gloss for Point 4. Charisma showed the highest value of color change. There was no correlation between surface roughness and gloss for the initial analysis, and after the challenges. Conclusion Composites were influenced by association of challenges, and Charisma showed the highest changes for roughness, gloss, and color. Clinical significance The type of composite resin influenced the properties of materials, which are surface roughness, gloss, and color change. The dentist should be aware of the performance of different brands, to choose the correct required composite resin for each type of patient or region to be restored. How to cite this article Lemos CAA, Mauro SJ, dos Santos PH, Briso ALF, Fagundes TC. Influence of Mechanical and Chemical Degradation in the Surface Roughness, Gloss, and Color of Microhybrid Composites. J Contemp Dent Pract 2017;18(4):283-288.

scholarly journals Influence of Fluoride Concentration and pH Value of 35% Hydrogen Peroxide on the Hardness, Roughness and Morphology of Bovine Enamel

2014 ◽  
Vol 15 (4) ◽  
pp. 392-398 ◽  
Author(s):  
Wilcilene Costa Nascimento ◽  
Yasmin do Socorro Batista de Lima Gomes ◽  
Larissa Dias Alexandrino ◽  
Hilton Tulio Costi ◽  
José Otávio Carrera Silva ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Ph Value ◽  
Morphological Changes ◽  
Fluoride Concentration ◽  
Knoop Hardness ◽  
Scanning Electron Micrographs ◽  
High Concentration ◽  
Acidic Group ◽  
Bovine Enamel

ABSTRACT Aim The aim of this in vitro study was to evaluate the effects of different sodium fluoride (NaF) concentrations and pH values on the Knoop hardness (KHN), surface roughness (SR), and morphology of bovine incisors bleached with 35% hydrogen peroxide (HP). Materials and methods Sixty-five bovine incisors were fragmented (5 mm2 × 2 mm) and distributed in 5 groups: Control (unbleached), Low NaF/Acidic (35% HP + 1.3% NaF, pH 5.5), Low NaF/Neutral (35% HP + 1.3% NaF, pH 7.0), High NaF/ Acidic (35% HP + 2% NaF, pH 5.5), and High NaF/Neutral (35% HP + 2% NaF, pH 7.0). KHN analysis was performed with a microhardness tester under a load of 25 gf for 5 seconds. The average SR was obtained with a rugosimeter. KHN and SR were analyzed before and after treatments. For morphological analysis, specimens were dehydrated and gold-sputtered, and scanning electron micrographs were obtained and analyzed by 3 examiners with a double-blinded technique. KHN and SR results were analyzed by one-way ANOVA and Tukey's test (p < 0.05). Results Only the Low NaF/Acidic and Low NaF/Neutral groups showed significant differences between the initial and final KHN values. All bleached groups presented significant differences between the initial and final SR values. Among the bleached groups, the least and most morphological changes were shown by the High NaF/Neutral and the Low NaF/Acidic group, respectively. Conclusion Treatment with 35% HP and 2% NaF at pH 7.0 promoted the least changes in morphology, hardness and roughness among the bleached groups. Clinical significance In-office bleaching with high-concentration HP and 2% NaF at neutral pH promoted the least changes in enamel hardness, SR, and morphology compared to other treatments. How to cite this article Nascimento WC, Gomes YSBL, Alexandrino LD, Costi HT, Silva JOC Jr, Silva CM. Influence of Fluoride Concentration and pH Value of 35% Hydrogen Peroxide on the Hardness, Roughness and Morphology of Bovine Enamel. J Contemp Dent Pract 2014;15(4):392-398.

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 Effects of 16% Carbamide Peroxide Bleaching on the Surface Properties of Glazed Glassy Matrix Ceramics

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Necla Demir ◽  
Muhammet Karci ◽  
Mutlu Ozcan
Keyword(s):  
Surface Roughness ◽  
Surface Properties ◽  
Glassy Matrix ◽  
Bleaching Agent ◽  
Carbamide Peroxide ◽  
Peroxide Bleaching ◽  
Cad Cam ◽  
Ceramic Restorations ◽  
Bleaching Gels ◽  
Scanning Electron

Objective. To determine the influence of the home bleaching agent, Opalescence PF, on the surface roughness and microhardness of glazed glassy matrix CAD-CAM ceramics. Materials and Methods. The 28 sintered leucite- and lithium disilicate-reinforced ceramic specimens (IPS Empress CAD and IPS e.max CAD) were divided into control and bleached groups. The home bleaching agent was applied to specimens of bleached groups for 7 days. The surface roughness and microhardness of all specimens were measured. A scanning electron microscope was used to evaluate the surface properties. The data were statistically analyzed by two-way ANOVA. Results. The control e.max CAD showed the lowest surface roughness values. For both Empress and e.max CAD, surface roughness was significantly higher for the bleached group (p<0.05). No significant differences in microhardness were observed. Conclusions. According to our study, patients should be careful when using home bleaching agents because whitening agents can affect the mechanical properties of full ceramic restorations like e.max CAD and Empress CAD. Ceramic polishing may be required in clinical situations where ceramic restorations are accidentally exposed to bleaching gels.

scholarly journals Bleaching Gels Containing Calcium and Fluoride: Effect on Enamel Erosion Susceptibility

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Alessandra B. Borges ◽  
Carlos R. G. Torres ◽  
Paulo A. B. de Souza ◽  
Taciana M. F. Caneppele ◽  
Luciana F. T. F. Santos ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Calcium Gluconate ◽  
Artificial Saliva ◽  
Bleaching Agent ◽  
Enamel Erosion ◽  
Agent Control ◽  
Bovine Enamel ◽  
Enamel Wear ◽  
Bleaching Gels

Thisin vitrostudy evaluated the effect of 35% hydrogen peroxide (HP) bleaching gel modified or not by the addition of calcium and fluoride on enamel susceptibility to erosion. Bovine enamel samples (3 mm in diameter) were divided into four groups (n=15) according to the bleaching agent: control—without bleaching (C); 35% hydrogen peroxide (HP); 35% HP with the addition of 2% calcium gluconate (HP + Ca); 35% HP with the addition of 0.6% sodium fluoride (HP + F). The bleaching gels were applied on the enamel surface for 40 min, and the specimens were subjected to erosive challenge with Sprite Zero and remineralization with artificial saliva for 5 days. Enamel wear was assessed using profilometry. The data were analyzed by ANOVA/ Tukey’s test (P<0.05). There were significant differences among the groups (P=0.009). The most enamel wear was seen for C (3.37±0.80 μm), followed by HP (2.89±0.98 μm) and HP + F (2.72±0.64 μm). HP + Ca (2.31±0.92 μm) was the only group able to significantly reduce enamel erosion compared to C. The application of HP bleaching agent did not increase the enamel susceptibility to erosion. However, the addition of calcium gluconate to the HP gel resulted in reduced susceptibility of the enamel to erosion.

Effect of Acetic Acid/Water Ratio on the Microstructure and Properties of LaNiO3 Thin Films by Metal Organic Solution Deposition

2015 ◽  
Vol 815 ◽  
pp. 89-93
Author(s):  
Yuan Yuan Zhang ◽  
Xiao Dong Tang ◽  
Gen Shui Wang ◽  
Xian Lin Dong
Keyword(s):  
Thin Films ◽  
Surface Roughness ◽  
Acetic Acid ◽  
Ph Value ◽  
Precursor Solution ◽  
Organic Solution ◽  
Solution Deposition ◽  
Ph Values ◽  
Metal Organic ◽  
Acetic Acid Water

Highly (100)-oriented LaNiO3 (LNO) thin films were prepared on p-type Si (100) substrates by metal organic solution deposition (MOSD). The LNO thin films were driven by series precursor solutions with different ratio of acetic acid to deionized water (Raaw) and pH values. The dependences of viscosity, pH value and the thermal property of the gel-derived powders of the precursor solution on Raaw values were systematically investigated. AFM images showed that Raaw can dramatically influence the surface roughness. When Raaw changed from 7:1 to 1:1, the surface roughness decreased from 3.695 nm to 1.488 nm. The resistivities of all the films are less than 2.1×10-3Ω·cm. It shows that the precursor solution has strong effect on the microstructure of the thin films and relatively slight effect on the resistivity.

scholarly journals Effect of hydrogen peroxide application on color and surface roughness of two restorative materials

2017 ◽  
Vol 15 (3) ◽  
pp. 185
Author(s):  
Dilcele Silva Moreira Dziedzic ◽  
Lucia Helena Ramos da Silva ◽  
Bruna Luiza do Nascimento ◽  
Marina Samara Baechtold ◽  
Gisele Maria Correr ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Surface Roughness ◽  
Repeated Measures ◽  
Glass Ionomer Cement ◽  
Color Variation ◽  
Glass Ionomer ◽  
Peroxide Bleaching ◽  
Bleaching Procedure ◽  
Resin Modified Glass Ionomer ◽  
Ionomer Cement

Aim: This study investigated the effect of an in-office bleaching technique on lightness, color and surface roughness of two commercially available materials: a resin-modified glass-ionomer cement and a nanohybrid resin composite. Methods: Twelve disk-shaped specimens were prepared with both materials. The samples were bleached with 35% hydrogen peroxide. Bleaching was tested initially onto a smooth surface and later onto a polished one of the same specimens. The effect of the treatments on lightness and color was verified with a spectrophotometer. Surface roughness was measured with a digital surface roughness tester. The data were statistically analyzed by repeated measures ANOVA and post hoc Tukey’s test (alpha = 0.05). Results: Significant variation in lightness and color was observed on the resin-modified glass-ionomer cement after the first bleaching procedure. Roughness increased significantly only after polishing the resin-modified glass-ionomer cement surface. Composite color variation was evident in the last observation period, but roughness and lightness variation due to bleaching and polishing was not significant. Conclusion: The bleaching treatment caused significant color alterations on the materials tested. This study observed that the application of in-office bleaching onto the glass-ionomer cement promoted clinically observable color alteration, and polishing after bleaching is contraindicated for this material.

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