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Journal articles on the topic 'Bleaching materials'
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Wang, Wu Wen, Ji Hong Lao, and Ya Qin Yang. "The Study of Bleaching Silk Sanitary Materials." Advanced Materials Research 175-176 (January 2011): 765–68. http://dx.doi.org/10.4028/www.scientific.net/amr.175-176.765.
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The silk Sanitary Materials in hydrogen peroxide bleaching process, various experimental factors affect on the raw materials’ whiteness and tension. And through the single factor experiments and orthogonal test research and analysis, the significant influencing order of the whiteness of silk fiber is: temperature, concentration of hydrogen peroxide, and bleaching time; the significant influencing order of breaking tension is: bleaching time, temperature, and concentration of hydrogen peroxide. The optimum experimental program is as follows: hydrogen peroxide concentration of 22.5g / L, bleaching temperature of 80 °C, bleaching time, 60min, PH value of 9, sodium silicate concentration of 11.25g / L.
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CASTRO, Camila Maria Lima de, Higor Catta Preta BORGES, Karoline Cardoso Ferro BARROS, Natanael Barbosa dos SANTOS, and Larissa Silveira de Mendonça FRAGOSO. "Spectrophotometric assessment of tooth bleaching under orthodontic braquets bonded with different materials." Revista de Odontologia da UNESP 46, no. 5 (October 19, 2017): 267–72. http://dx.doi.org/10.1590/1807-2577.03617.
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Abstract Introduction patients have been submitted to tooth bleaching during orthodontic treatment for aesthetic purposes or to anticipate the replacement of restorations after completion of the treatment. Objective to evaluate the effectiveness of tooth bleaching under orthodontic brackets bonded with different materials. Material and method a hundred bovine enamel blocks were divided into two groups, at-home and in-office tooth bleaching. In-office bleaching was subdivided into five groups (n = 10): HP (control - without brackets); SA(t) - brackets bonded with Transbond XT, without bleaching; SA(fm) - brackets bonded with Orthodontic Fill Magic, without bleaching; HP(t) - brackets bonded with Transbond XT subjected to bleaching; and HP(fm) - brackets bonded with Orthodontic Fill Magic subjected to bleaching. At-home bleaching followed the same treatments, only replacing the bleaching agent. Spectrophotometric assessment was used for tooth color determination at three moments: 1) before staining (baseline); 2) after staining; 3) after bonding the brackets and bleaching procedures. Data were submitted to ANOVA and analyzed by Tukey's test (p < 0.05). Result For both types of bleaching, the control group had an effective bleaching action. Groups using Transbond XT presented greater bleaching potential among the groups with orthodontic accessory, but the bleaching action differed from the positive control. Groups using Orthodontic Fill Magic presented no bleaching action, resembling the negative control groups (artificial saliva). Conclusion the orthodontic bracket impaired the effectiveness of the at-home and in-office bleaching treatment, regardless of the resin used for bonding.
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Taher, Manal, Nsar Aziz, and Intesar Toma. "Effect of bleaching materials and whitening mouth wash on surface roughness of two types of composite resin materials nanohybrid and nanofill: an In‐vitro Study." Erbil Dental Journal 4, no. 2 (December 25, 2021): 118–26. http://dx.doi.org/10.15218/edj.2021.16.
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Background and objective: Bleaching teeth is one of the effective, comparatively safe, aesthetic treatments in dentistry. Many systems are available now in clinical practice that has a peroxide mechanism. The purpose of this study was to evaluate the effect of three different bleaching system on the surface roughness of two different composite resin materials (nanohybride and nanofilled). Methods: A total of 60 samples of two types of composite resin were used (nanohybrid and nanofill), 30 samples for each material were prepared. The total samples then divided into six groups, ten samples for each group. Each group were analyzed and tested before exposing to bleaching system that considered as control, by using surface roughness (Ra) machine using atomic force microscopy. Three bleaching system then used, hydrogen peroxide 35% with laser and carbamide peroxide 10% three times each time for 15 min‐ utes while whitening mouth wash for 1 minute/ day for one month. After bleaching ended, the surface roughness of all the samples were re‐evaluated. Results:Whiting mouth wash thtcontaing peroxide bleaching agents showed a significant differences for the two composite materials(nano hybrid and nano filled). While for the another bleaching systems(hydrogen peroxide and carbamide peroxide) there is no significant differences Conclusion:Whiting mouth wash showed more surface roughness for the two materials when compared with the another bleaching materials and Increased surface roughness of composites as a result of bleaching appears to be dependent on the bleaching agent used as well as the composite material types.
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Razeen, Hadeer Magdy, Mahmoud A. A. Shakal, and Radwa A. El-dessouky. "Evaluation of color changes produced by different bleaching techniques on stained two different ceramic materials." Tanta Dental Journal 20, no. 4 (2023): 275–80. http://dx.doi.org/10.4103/tdj.tdj_13_23.
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Objective The aim of this in vitro study was to evaluate the color changes produced by different bleaching techniques on two different stained ceramic materials. Material and methods The total 40 specimens of IPS e.max and shofu were stained by immersing in coffee 30 min daily for 14 days and color assessment was done by spectrophotometer, then the specimens were divided into two subgroups according to the bleaching technique home bleaching (white smile) and office bleaching (pola office), the bleaching was done according to manufacturer instruction for pola office: an adequate thickness of the bleaching agent by the brush was applied for 8 min. This procedure was repeated for 3 times. And for home bleaching (white smile): specimens were placed in the mold to receive home bleaching agent by immersion 60 min daily for 6 days. Then the color was assessed after bleaching procedure to determine the changes. The data were statistically analyzed by one-way ANOVA test and Correlation analysis. Results Shofu recorded higher staining affinity with mean value 6.72 ± 2.33 than (IPS) e.max group with mean value 4.92 ± 2.08. For bleaching: Shofu HC group home bleaching group recorded higher bleaching affinity with mean value 7.86 ± 1.93 whereas shofu office bleaching group recorded mean value 6.04 ± 0.65. As for e.max home bleaching group recorded also higher ∆ E with mean value 5.68 ± 0.86 whereas e.max office bleaching group recorded mean value 4.37 ± 1.01. And a strong relation was recorded between ∆E1 and ∆E2 in all groups as r greater than 0.5. Conclusion Shofu HC and IPS e.max showed affinity to staining but Shofu HC showed higher stain ability than IPS e.max, Office and home bleaching techniques affected the color of both ceramics materials and home bleaching showed higher significant difference. And Shofu HC showed higher color change after home and office bleaching than IPS e.max.
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Zanconato-Carvalho, Erica Moreno, João Felipe Bruniera, Natália Spadini de Faria, Vivian Colucci, and Danielle Cristine Messias. "Impact of Intracoronal Dentin Treatment Prior to Bleaching on Bond Strength of Restorative Materials." Brazilian Dental Journal 25, no. 6 (December 2014): 519–23. http://dx.doi.org/10.1590/0103-6440201302441.
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Surface treatment of dentin before the bleaching procedure may affect its permeability and influence the bond strength of restorative materials. This study evaluated the influence of surface treatment before the bleaching on shear bond strength (SBT) of restorative materials to intracoronal dentin. Dentin slabs were subjected to surface treatment: no bleaching (control - CON), no surface treatment + bleaching (HP), 37% phosphoric acid + bleaching (PA) and Er:YAG laser + bleaching (L). After the bleaching procedure, specimens (n=10) were restored with: microhybrid composite resin (MH), flowable composite resin (F), and resin-modified glass-ionomer cement (RMGIC). The shear test was carried out. ANOVA and Tukey's test (α=0.05) showed significant difference for surface treatment and restorative materials (p<0.05). CON presented higher STB and was statistically different from HP (p<0.05). PA and L showed intermediate values and were statistically similar to CON and HP (p>0.05). STB for MH and F were higher than RMGIC (p<0.05), and did not differ from each other (p>0.05). The surface treatments with phosphoric acid and Er:YAG laser before the bleaching procedure provided shear bond strength at the same level of unbleached dentin and the composite resins presented superior bond strength to the intracoronal dentin.
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Goldstein, Ronald E. "Bleaching teeth: new materials—new role." Journal of the American Dental Association 115 (December 1987): 44E—52E. http://dx.doi.org/10.14219/jada.archive.1987.0316.
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Wille, T., E. C. Combe, I. J. Pesun, and D. W. Giles. "Rheological characteristics of tooth bleaching materials." Journal of Oral Rehabilitation 27, no. 12 (December 2000): 1060–63. http://dx.doi.org/10.1046/j.1365-2842.2000.00647.x.
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Wille, T., E. C. Combe, I. J. Pesun, and D. W. Giles. "Rheological characteristics of tooth bleaching materials." Journal of Oral Rehabilitation 27, no. 12 (July 7, 2008): 1060–63. http://dx.doi.org/10.1111/j.1365-2842.2000.00647.x.
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Ozdogan, Alper, and Nihan Kaya. "Effectiveness and safety of bleaching agents on lithium disilicate glass ceramics." Journal of Dental Research, Dental Clinics, Dental Prospects 16, no. 4 (December 30, 2022): 251–57. http://dx.doi.org/10.34172/joddd.2022.040.
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Background. Aesthetic expectations have increased the use of aesthetic materials in dentistry. Lithium disilicates are frequently used materials for these expectations. Bleaching is another method used to provide aesthetics. Bleaching processes on restorative materials are not fully known. This study investigated the effect of at-home and in-office bleaching methods on the color change, surface roughness, and topography of lithium disilicate glass-ceramic materials produced with two different techniques and subjected to different polishing procedures. Methods. A total of 144 disc-shaped pressed and computer-aided design (CAD) lithium disilicate glass-ceramic specimens were randomly divided into four groups. Glazing and three different chair-side polishing procedures were performed. The specimens in each group were randomly divided into two groups and subjected to at-home and in-office bleaching processes (n=9). The home bleaching process was repeated with 16% carbamide peroxide agent for six hours for seven days, while the in-office bleaching process was applied with 40% hydrogen peroxide agent for two sessions of 20 minutes. After the bleaching processes, the final color and surface roughness experiments of the specimens were carried out, and the results were recorded. ANOVA and Tukey multiple comparison tests were used FOR the statistical analysis of the data (α=0.05). Results. The material*polish*bleaching, polish*bleaching, material*bleaching, and material*polishing interactions were not statistically significant regarding color and roughness changes of both specimens (P>0.05). Conclusion. Both bleaching processes can be safely applied to lithium disilicate glass-ceramic materials.
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Dziedzic, Dilcele Silva Moreira, Lucia Helena Ramos da Silva, Bruna Luiza do Nascimento, Marina Samara Baechtold, Gisele Maria Correr, and Carla Castiglia Gonzaga. "Effect of hydrogen peroxide application on color and surface roughness of two restorative materials." Brazilian Journal of Oral Sciences 15, no. 3 (August 11, 2017): 185. http://dx.doi.org/10.20396/bjos.v15i3.8649978.
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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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Ragnar, Martinr, and Kenji Umemura. "COMPACT BLEACHING™." JAPAN TAPPI JOURNAL 60, no. 2 (2006): 191–96. http://dx.doi.org/10.2524/jtappij.60.191.
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Walawska, Anetta, Magdalena Olak-Kucharczyk, Anna Kaczmarek, and Marcin H. Kudzin. "Environmentally Friendly Bleaching Process of the Cellulose Fibres Materials Using Ozone and Hydrogen Peroxide in the Gas Phase." Materials 17, no. 6 (March 15, 2024): 1355. http://dx.doi.org/10.3390/ma17061355.
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The paper presents the new eco-friendly method of bleaching process of the cellulose fibre materials. Cellulose materials were bleached using hydrogen peroxide (both in aqueous solution, vapours, ozone and by the combined action of gaseous hydrogen peroxide and ozone. The method using hydrogen peroxide in aqueous solution presents the standard procedure and was used as the comparison technique. The bleaching processes using gaseous oxidants were carried out in a prototype device for dry, low-temperature treatment of fibrous materials with the use of oxidising agents in the gas phase. The influence of the innovative gas-phase bleaching method on the cotton samples’ properties was analysed by Scanning Electron Microscopy (SEM), evaluation of the colour and whiteness, assessment of the polymerisation degree (DP), analysis of the mechanical properties and sorption capacity as well as microbiological assessment against colonies of Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The comparison of the obtained results led to the conclusion that the bleaching processes using gas-phase agents—vaporised hydrogen peroxide, ozone or their combination—are non-invasive. The applied bleaching processes resulted in a slightly lower whiteness parameters than standard bath bleaching. After the bleaching processes with ozone and vaporised hydrogen peroxide separately, the decrease in the DP and tensile strength was similar to that observed after the bleaching with aqueous H2O2. When both processes were used together, a higher reduction in DP and tensile strength was noticed. Both oxidising agents showed a strong biocidal effect against bacteria. Gas-phase bleaching procedures, due to the lower temperature (35 °C vs. 98 °C) and minimal water consumption, have economic and environmental advantages, which allows their use in semi-industrial applications. It has been shown that the treatment of cotton fabrics using ozone and hydrogen peroxide in the gas phase allows to simultaneously obtain the bleaching and disinfection effect.
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Juntavee, Apa, Niwut Juntavee, and Phuwiwat Saensutthawijit. "Influences of Light-emitting Diode Illumination Bleaching Technique on Nanohardness of Computer-aided Design and Computer-aided Manufacturing Ceramic Restorative Materials." Journal of Contemporary Dental Practice 19, no. 2 (2018): 196–204. http://dx.doi.org/10.5005/jp-journals-10024-2236.
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ABSTRACT Aim This study evaluated the effect of light-emitting diode (LED) illumination bleaching technique on the surface nanohardness of various computer-aided design and computer-aided manufacturing (CAD/CAM) ceramic materials. Materials and methods Twenty disk-shaped samples (width, length, and thickness = 10, 15, and 2 mm) were prepared from each of the ceramic materials for CAD/CAM, including Lava™ Ultimate (LV), Vita Enamic® (En) IPS e.max® CAD (Me), inCoris® TZI (IC), and Prettau® zirconia (Pr). The samples from each type of ceramic were randomly divided into two groups based on the different bleaching techniques to be used on them, using 35% hydrogen peroxide with and without LED illumination. The ceramic disk samples were bleached according to the manufacturer's instruction. Surface hardness test was performed before and after bleaching using nanohardness tester with a Berkovich diamond indenter. Results The respective Vickers hardness number upon no bleaching and bleaching without or with LED illumination [mean ± standard deviation (SD)] for each type of ceramic were as follows: 102.52 ± 2.09, 101.04 ± 1.18, and 98.17 ± 1.15 for LV groups; 274.96 ± 5.41, 271.29 ± 5.94, and 268.20 ± 7.02 for En groups; 640.74 ± 31.02, 631.70 ± 22.38, and 582.32 ± 33.88 for Me groups; 1,442.09 ± 35.07, 1,431.32 ± 28.80, and 1,336.51 ± 34.03 for IC groups; and 1,383.82 ± 33.87, 1,343.51 ± 38.75, and 1,295.96 ± 31.29 for Pr groups. The results indicated surface hardness reduction following the bleaching procedure of varying degrees for different ceramic materials. Analysis of variance (ANOVA) revealed a significant reduction in surface hardness due to the effect of bleaching technique, ceramic material, and the interaction between bleaching technique and ceramic material (p < 0.05). Conclusion Bleaching resulted in a diminution of the surface hardness of dental ceramic for CAD/CAM. Using 35% hydrogen peroxide bleaching agent with LED illumination exhibited more reduction in surface hardness of dental ceramic than what was observed without LED illumination. Clinical significance Clinicians should consider protection of the existing restoration while bleaching. How to cite this article Juntavee N, Juntavee A, Saensutthawijit P. Influences of Light-emitting Diode Illumination Bleaching Technique on Nanohardness of Computer-aided Design and Computer-aided Manufacturing Ceramic Restorative Materials. J Contemp Dent Pract 2018;19(2):196-204.
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Yilmazer, Duygu, and Mehmet Kanik. "Bleaching of Wool with Sodium Borohydride." Journal of Engineered Fibers and Fabrics 4, no. 3 (September 2009): 155892500900400. http://dx.doi.org/10.1177/155892500900400305.
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An untreated wool fabric was bleached both with sodium borohydride (SBH) in the presence of sodium bisulphite (SBS) solution and with a commercial H2O2 bleaching method. The concentration effects of SBH and SBS, bleaching time, pH and temperature on SBH bleaching process were investigated. Whiteness, yellowness and alkali solubility results were assessed for both bleaching methods. The results showed that whiteness degrees obtained with SBH bleaching was comparable with that of H2O2 bleaching method; whereas the alkali solubility values of the SBH bleaching was superior to the H2O2 bleaching.
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Baroudi, Kusai, Rasha Said Mahmoud, and Bassel Tarakji. "Fluoride release of glass ionomer restorations after bleaching with two different bleaching materials." European Journal of Dentistry 07, no. 02 (April 2013): 196–200. http://dx.doi.org/10.4103/1305-7456.110171.
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ABSTRACT Objective: This study was designed to evaluate the effect of two bleaching agents on the fluoride release of three types of glass ionomer materials. Materials and Methods: A total of 90 specimens of the tested materials (Ketac Fil, Photac Fil and F2000) were prepared by a split Teflon ring with an internal diameter of 5 mm and thickness of 2 mm. The tested materials were applied and bleached according to manufacturer instructions. Fluoride release measurements were made by using specific ion electrode. Results: Results revealed that bleaching with opalescence Xtra caused little increase in fluoride release from Ketac Fil and Photac Fil but has no effect on F2000. However, Opalescence Quick had no significant effect on the three tested materials. Conclusions: Bleaching effect on fluoride release is material dependent and time has a significant role on fluoride release.
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Alshali, Ruwaida Z., and Mohammed A. Alqahtani. "The Effect of Home and In-Office Bleaching on Microhardness and Color of Different CAD/CAM Ceramic Materials." Materials 15, no. 17 (August 28, 2022): 5948. http://dx.doi.org/10.3390/ma15175948.
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The aim of this study is to assess the effect of different bleaching agents on microhardness and color of CAD/CAM ceramics including IPS e.max CAD (lithium disilicate), VITA ENAMIC (polymer-infiltrated ceramic), and Celtra Duo CAD (zirconia-reinforced lithium silicate). Materials’ samples were divided into three groups (n = 10) and each received a different bleaching treatment; 20% carbamide peroxide, 35% carbamide peroxide, and 40% hydrogen peroxide. A fourth group was stored in water acting as a control. Vickers microhardness and spectrophotometric color measurements were taken at baseline and after bleaching. IPS e.max CAD showed a significant reduction (about 14%), while VITA ENAMIC showed a significant increase (about 78%) in microhardness after bleaching (p ˂ 0.001). Celtra Duo CAD did not demonstrate a significant change in microhardness (p ≥ 0.609). The color difference (ΔEab) after bleaching was 0.29 (±0.08), 2.84 (±0.64), and 1.99 (±0.37) for IPS e.max CAD, VITA ENAMIC, and Celtra Duo CAD, respectively. It could be concluded that the effect of bleaching on color and microhardness was mainly material-dependent. Bleaching significantly affected the microhardness of IPS e.max CAD and VITA ENAMIC. The color difference was within the clinically imperceptible range for IPS e.max CAD, while VITA ENAMIC and Celtra Duo CAD demonstrated perceptible color change.
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Kurita, Kohei, and Takeshi Oitani. "Ozone Bleaching. Kvaerner Ozone Bleaching System." JAPAN TAPPI JOURNAL 51, no. 5 (1997): 744–50. http://dx.doi.org/10.2524/jtappij.51.744.
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Kobayashi, Toru. "Ozone Bleaching. High Consistency Ozone Bleaching." JAPAN TAPPI JOURNAL 51, no. 5 (1997): 762–71. http://dx.doi.org/10.2524/jtappij.51.762.
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Parén, A. "Hydrogen Peroxide Bleaching. GreenOx Bleaching Process." JAPAN TAPPI JOURNAL 52, no. 5 (1998): 630–38. http://dx.doi.org/10.2524/jtappij.52.630.
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Ekwonu, A. M., and E. O. Egolum. "A Study of the Adsorptive and Oxidative Bleaching of Palm Oil Using Clay and Potassium Tetraoxomanganate V11 Materials." International Journal of Chemistry 9, no. 2 (April 17, 2017): 67. http://dx.doi.org/10.5539/ijc.v9n2p67.
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Fats and oils undergo hydrolysis reaction. They hydrolyse to yield propane-1,2,3 triol and the corresponding alkanoic acids if it is acid hydrolysis. Alkaline hydrolysis yields sodium or potassium salt of the alkanoic acid and propane-1,2,3-triol. A common approach for bleaching palm oil has been the use of clay materials, particularly the commercially available fuller’s earth. In this study, the suitability of chemical bleaching of palm oil using acidified (0.1M H2SO4) and non-acidified 1.0M KMnO4 was examined. This is compared to the adsorptive procedure using clay materials. Average bleaching absorbance values of 0.017+0.005 and 0.115+0.004 for acidified and non-acidified KMnO4 were respectively obtained from the oxidative bleaching procedure. Those for fuller’s earth and its blend with sodium sesquicarbonate (trona, a locally obtained clay) gave absorbance values of 0.121+0.011 and 0.186+0.006 respectively; while that for trona/activated carbon blend was 0.234+0.007. These are in comparison to 0.881 for the unbleached palm oil. Thus, a relatively better bleaching was achieved with the oxidative process. A first order rate reaction with respect to the bleaching agents was obtained for both procedures. Rate constants of 0.079+014 (acidified) and 0.055+0.020min-1 (non-acidified) at 800C were recorded for the oxidative bleaching. These are compared to 0.034+0.009 obtained for the clay mixture. Half-life values of 10min for acidified oxidative process, and 28min for adsorptive clay mixture method, were obtained. Efficiency of 98% was obtained for the acidified oxidative compared to approximately 70% for the clay blend. A significance, p< 0.05, between the absorbance values for the acidified oxidative and each of the adsorptive clay bleaching procedures was obtained.These observations indicate the potentials of oxidizing agents especially the acidified KMnO4 in the bleaching of palm oil, and therefore, suggest its usage industrially for this purpose.
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Хакимова, Фирдавес Харисовна, Olga Alekseevna Noskova, Roman Rashidovich Khakimov, and Ilya Igorevich Fonarev. "AN EFFECTIVE RESOURCE-SAVING OPTION IN THE SPHERE OF WOOD PROCESSING AND ITS PROCESSING IN THE PULP AND PAPER INDUSTRY." chemistry of plant raw material, no. 1 (March 6, 2024): 320–28. http://dx.doi.org/10.14258/jcprm.20240113014.
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The possibility and expediency of obtaining and bleaching sulfite pulp from young small-sized spruce wood from thinning (thinning) fellings was studied in comparison with ripe wood. In the process of thinning, a significant amount of young small-sized wood is formed, which can serve as a significant reserve of wood raw materials for the production of pulp and paper.
Sulfite pulping from young and ripe spruce wood obtained two samples of pulp of different degrees of penetration.
Comparative pulp bleachings were carried out according to the traditional economical but effective D/C-EG-G-D-A scheme; For comparison, pulp samples from ripe and young spruce wood were bleached according to the modern ecological scheme Pa-E-Ch1-E-Ch2-A (ECF technology).
It is shown that young small-sized spruce wood is delignified by sulfite cooking solution without difficulty, but somewhat more slowly than ripe wood.
Sulfite spruce pulp obtained from thinnings is easier to grind and bleach, has higher mechanical strength than from ripe wood. Bleached pulp was obtained from young thin spruce wood by bleaching according to the scheme D/C–EG –G–D–A of pulp from young thin spruce wood, which in all quality indicators meets the standards for grade AK-II (GOST 3914), which is used mainly in the production of "cultural" grades of paper (written and printed). Comparative bleaching of pulp of approximately the same degree of penetration from ripe and young wood using ECF technology using only two oxidative bleaching agents (hydrogen peroxide and chlorine dioxide) significantly increases the efficiency of pulp bleaching in all quality indicators, but the cost of bleaching, in modern conditions, may be will be slightly higher than in the traditional scheme.
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Lee, Wei-Fang, Hidekazu Takahashi, Shiun-Yi Huang, Jia-Zhen Zhang, Nai-Chia Teng, and Pei-Wen Peng. "Effects of At-Home and In-Office Bleaching Agents on the Color Recovery of Esthetic CAD-CAM Restorations after Red Wine Immersion." Polymers 14, no. 18 (September 17, 2022): 3891. http://dx.doi.org/10.3390/polym14183891.
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The aim of this study was to evaluate the effects of at-home and in-office bleaching agents on esthetic CAD-CAM materials after red wine immersion by measuring their optical properties. Sixty specimens were prepared out of three esthetic CAD-CAM materials: Vita Enamic, Celtra Duo, and Ceresmart (n = 20). All specimens were immersed in a red wine solution, and color measurements were performed. Specimens were randomly divided (n = 10) according to the bleaching procedure (in office, at home), bleaching durations were set to 3 time points, and color measurements were performed. According to the Commission Internationale de l’Eclairage (CIE) L* a* b* parameters, CIEDE2000 color differences (ΔE00), translucency parameters (TP00), and whiteness index values (ΔWID) after wine staining and after bleaching were calculated. Data were analyzed using the Mann–Whitney U-test, the Kruskal–Wallis test, and a two-way analysis of variance (ANOVA) (α = 0.05). ΔE00, ΔTP00, and ΔWID decreased with an increase in bleaching treatment. ΔE00 after the final bleaching treatment of in-office bleaching ranged from 1.7 to 2.0, whereas those of in-office treatment ranged from 0.4 to 1.1. All ΔTP00 and ΔWID after the final treatment were below the 50:50% perceptibility thresholds (ΔTP00 < 0.6, and ΔWID < 0.7). Significant differences in ΔE00, ΔTP00, and ΔWID among esthetic CAD-CAM materials were found between CD and CE. In the present study, color recovery after at-home and in-office bleaching appeared to be material-dependent. In-office bleaching showed more effective recovery comparing to at-home bleaching.
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Knezevic, Natasa, Aleksandra Djeri, Renata Josipovic, Irena Kuzmanovic-Radman, and Zeljka Kojic. "Bond strength of composite materials after internal teeth bleaching using 30% carbamide peroxide." Serbian Dental Journal 61, no. 4 (2014): 196–202. http://dx.doi.org/10.2298/sgs1404196k.
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Introduction. Bond between composite materials and bleached teeth depends on the change of micro-morphological structure of enamel and dentin after the application of bleaching agent. Bleaching procedure can weaken adhesion of composite materials to hard tissues, where even just a presence of hydrogen peroxide may affect their polymerization. The aim of this study was to determine bond strength of composite materials after internal teeth bleaching using 30% carbamide peroxide. Material and Methods. The study was conducted on 20 extracted, endodontically treated human teeth. After internal teeth bleaching with 30% carbamide peroxide a class V cavity was prepared and restored with Tetric EvoCeram nanocomposite material. Microleakage was determined using dye method (silver nitrate) and measured on the incisal and gingival walls using stereoloupes. Results. Linear dye penetration on the incisal wall (7.25 ?m) of bleached teeth was greater than on the incisal wall in non-bleached (control group) teeth (5.75 ?m) but with no statistically significant difference. Dye penetration on the gingival wall of bleached teeth (20.00 ?m) was greater than on the gingival wall of the control group (14.25 ?m). This difference was statistically significant (p<0.05). Conclusion. Greater microleakage and inferior bond of composite material was observed in teeth bleached with internal bleaching technique (30% carbamide peroxide) compared to non-bleached teeth.
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Vojdani, Mahroo, Kianoosh Torabi, Sasan Rasaeipour, Safoura Ghodsi, and Amir Ali Reza Khaledi. "Evaluation of the Effect of a Home Bleaching Agent on Surface Characteristics of Indirect Esthetic Restorative Materials—Part II Microhardness." Journal of Contemporary Dental Practice 15, no. 4 (2014): 438–43. http://dx.doi.org/10.5005/jp-journals-10024-1559.
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ABSTRACT Background The exponential usage of esthetic restorative materials is beholden to society needs and desires. Interaction between the bleaching agents and the esthetic restorative materials is of critical importance. Aim This in vitro study has been conducted to evaluate the effect of a home bleaching agent, carbamide peroxide (CP) 38%, on the microhardness of the fiber reinforced composite (FRC), overglazed, autoglazed, or polished porcelain specimens. Materials and methods For overglazed, autoglazed, polished ceramics and also FRC cylindrical specimens (n = 20 per group) were prepared. The specimens were stored in distilled water at 37°C for 48 hours prior to testing. Six samples from each group were selected randomly as negative controls which were stored in distilled water at 37°C that was changed daily. CP 38% was applied on the test specimens for 15 minutes, twice a day for 14 days. By using Knoop-microhardness tester microhardness testing for baseline, control and test specimens was conducted. Data were statistically analyzed using paired t-test, Mann- Whitney test, and Kruskal-Wallis test. Results Home bleaching significantly decreased the surface microhardness of all the test samples (p < 0.05), whereas the control groups did not show statistically significant changes after 2 weeks. The polished porcelain and polished composite specimens showed the most significant change in microhardness after bleaching process (p < 0.05). Conclusion Although the type of surface preparation affects the susceptibility of the porcelain surface to the bleaching agent, no special preparation can preclude such adverse effects. Clinical Significance The contact of home bleaching agents with esthetic restorative materials is unavoidable. Therefore protecting these restorations from bleaching agents and reglazing or at least polishing the restorations after bleaching is recommended. How to cite this article Torabi K, Rasaeipour S, Ghodsi S, Khaledi AAR, Vojdani M. Evaluation of the Effect of a Home Bleaching Agent on Surface Characteristics of Indirect Esthetic Restorative Materials — Part II Microhardness. J Contemp Dent Pract 2014;15(4):438-443.
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Mendes Tribst, João Paulo, João Henrique Rodrigues Rangel, Rayssa Ferreira Zanatta, Ana Luisa Albuquerque, Laís Regiane Silva-Concílio, Kusai Baroudi, and Marina Amaral. "The effect of bleaching gel application on the physical properties of different CAD/CAM restorative materials." Journal of Dental Health, Oral Disorders & Therapy 12, no. 2 (2022): 41–44. http://dx.doi.org/10.15406/jdhodt.2021.12.00547.
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Objective: To evaluate the surface roughness and microhardness of CAD/CAM lithium disilicate, feldspathic ceramic, polymer infiltrated ceramic and nanohybrid composite before and after the application of bleaching gel. Material and methods: Disc shaped specimens were polished and divided into quadrants for roughness (Ra) and microhardness (Vickers, 19.61 N, 20 s) measurements. The 35% hydrogen peroxide was applied simulating three in-office bleaching sessions. Results: Paired t-test (α=0.05) showed that bleaching gel application did not affect the surface roughness of the tested material. The microhardness of polymeric materials (polymer infiltrated ceramic and nanohybrid composite) presented statistical significant increase (2 % increase, which may be clinically insignificant). Conclusion: Microhardness of polymeric CAD/CAM materials may be affected by bleaching gel application.
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Scott, D. A. "Discoloration of restorative materials after bleaching application." Yearbook of Dentistry 2007 (January 2007): 10. http://dx.doi.org/10.1016/s0084-3717(08)70298-8.
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Jiang, Yu, Yangmei Chen, Qitang Wu, and Zebin Wei. "Fiber structures and properties of eucalyptus kraft pulp via different bleaching methods." Nordic Pulp & Paper Research Journal 34, no. 3 (September 25, 2019): 280–88. http://dx.doi.org/10.1515/npprj-2019-0030.
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Abstract The fiber morphology, the content of hydrogen bonds (HBs) of different models, cellulose crystalline structure, water retention value (WRV), and strength properties of eucalyptus pulp bleached by different bleaching methods (hydrogen peroxide bleaching and sodium dithionite bleaching) were investigated. The results of fourier transform infrared spectrometer (FTIR) showed that the content of intramolecular hydrogen bonds (HBintra) increased by 11.6 % and 4.8 % after hydrogen peroxide bleaching and sodium dithionite bleaching, respectively. The energy of the hydrogen bonds was changed after bleaching treatment. The hydrogen bonding distances showed a small change after different bleaching treatment. The results of X-ray diffraction (XRD) demonstrated a decrease in the average width of crystallite size in the (002) lattice plane after different bleaching treatment, which was the same trend with the variability of cellulose crystallinity. Compared with the unbleached pulp, the WRV and strength properties of the bleached pulp increased after each bleaching process. Tear index of handsheets made from the hydrogen peroxide and sodium dithionite bleaching pulps were 46.0 % and 54.8 %, respectively. The sodium dithionite bleaching treatment had more significant effects on fiber swelling capability.
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Elmarakby, Ahmed, Mohamad Merwah, Mohamad Alghamdi, Faisal Albaitouni, Mohammed Alshreef, and Fahad Alkahtani. "Evaluation of the Surface Roughness of Resin Composites before and after Applying Different Bleaching Materials." Open Access Macedonian Journal of Medical Sciences 10, no. D (October 7, 2022): 429–34. http://dx.doi.org/10.3889/oamjms.2022.10869.
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Abstract:
Background: Bleaching is a conservative treatment and has been shown to be both efficient and safe but the effects of bleaching on teeth and dental materials have been studied in several studies.
Objective: The aim of the current study was to evaluate the surface roughness of resin composites before and after applying different bleaching materials.
Material and method: Three types of resin composites were used in this in vitro study. Two types of bleaching techniques were used: in office and at home bleach. Sixteen specimens of each resin composite type were fabricated and used in this study. Surface roughness of the samples was measured using a profilometer (Talysurf CLI 1000, Leicester, England). The surface roughness measurements and data were statistically analyzed using the one-way ANOVA and Tukey's tests through SPSS version 21 (SPSS Inc. Chicago, IL, USA). The assessment of surface roughness was done using one-way ANOVA and Tukey's post hoc tests. P < 0.05 was considered statistically significant.
Results: The assessment of surface roughness by one-way ANOVA and Tukey's post hoc tests showed significant differences for composite material types as well as an interaction between these parameters for each tested bleaching gels (P<.05).
Conclusion: The composition of both resin composite and bleaching material play an important role in initiation and conduction of surface roughness at the outer surface of resin composite restoration.
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Taxiarchou, M., and I. Douni. "The effect of oxalic acid activation on the bleaching properties of a bentonite from Milos Island, Greece." Clay Minerals 49, no. 4 (September 2014): 541–49. http://dx.doi.org/10.1180/claymin.2014.049.4.04.
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AbstractA bentonite from Milos, Greece, was activated with oxalic acid and the effect of acid activation conditions on bleaching of sunflower oil was investigated. The activation parameters studied were temperature, retention time and oxalic acid to bentonite mass ratio. The activated materials produced had good bleaching properties and were suitable for industrial use as bleaching earths. Optimum bleaching properties could be achieved using a variety of combinations of acid to bentonite ratios and activation times. Bleaching efficiency tests indicated that 24 h activation at 100°C with 1m oxalic acid and 25% pulp density (w/v) gave results equivalent to that of a commercial bleaching earth (Tonsil Optimum 210 FF). The combination that is likely to be more preferable on an industrial scale was 100°C, 25% pulp density (w/v), 1m initial oxalic acid concentration, 60% recycling of the oxalate solution (making up an acid to bentonite ratio 0.2 w/w) and 6 h activation time. The materials produced under these conditions have acceptable bleaching properties, corresponding to bleaching capacity greater than 78% compared to commercial Tonsil, and colour index (in red and yellow units) equal or even better than Tonsil.
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ALSaadi, Dr Amaal kadhim. "The effect of 30% at-home bleaching on surface hardness of esthetic restorative materials." Mustansiria Dental Journal 7, no. 2 (March 19, 2018): 166–73. http://dx.doi.org/10.32828/mdj.v7i2.394.
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in vitro study to evaluate the effect of an at-home bleaching product on thesurface hardness of three composite restorative materials.The aim of this study was to evaluate the effect of at-home bleaching on thesurface hardness of the tooth colored restorative materials.Thirty specimens were prepared; 10 specimens of each material 5 specimenscontrol of each group. All specimens were stored in distilled water at roomtemperature for 24 hrs before testing. A universal testing machine (Micromet microhardness testers) was used for testing brinell surface hardness for the three groups&for every tested material. Three tested materials was assessed by ANOVA& furtherexploration between all possible paired combination of tested material was assessedby bonferroni adjusted t-test p value less than 0.05 was considered statisticallysignificant .The statistical analysis showed that at home bleaching technique have statisticallysignificant effect of the micro hardness of composite resin.At-home bleaching agents have a softening effect on some toothcolored restorative material, and the patient must be aware before using them.
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Popescu, Alexandru Dan, Mihaela Jana Tuculina, Oana Andreea Diaconu, Lelia Mihaela Gheorghiță, Claudiu Nicolicescu, Cristian Niky Cumpătă, Cristiana Petcu, Jaqueline Abdul-Razzak, Ana Maria Rîcă, and Ruxandra Voinea-Georgescu. "Effects of Dental Bleaching Agents on the Surface Roughness of Dental Restoration Materials." Medicina 59, no. 6 (June 1, 2023): 1067. http://dx.doi.org/10.3390/medicina59061067.
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Background and Objectives: This study aimed to evaluate the surface roughness evolution of several finished and polished composites when bleaching materials are applied. The research was conducted on four microhybrid or nanofilled composites that are used in dental restorations. Materials and Methods: For each composite type, 5 samples were selected for control, 5 samples were subjected to the bleaching protocol “office bleach” with 40% hydrogen peroxide, and 5 other samples were subjected to the “home bleach” protocol with 16% carbamide peroxide, resulting in a total number of 60 samples. The surfaces of all the samples were tested for roughness, and the values of the most relevant parameter (Ra), were collected. Comparisons between composites and samples were performed using one-way ANOVA (in Statistical Package for Social Sciences). Results: After the bleaching protocol with 40% hydrogen peroxide gel, it was found that the roughness of the group increased considerably compared to the control group, so the highest roughness was found at GC Gradia direct anterior group, and the lowest value was registered for the 3M ESPE Valux Plus group. Following the bleaching protocol with 16% carbamide peroxide (home bleach), it was noted that the sample surfaces were not as affected. In this case, the lowest roughness was found at 3M ESPE Valux Plus group, and the highest roughness was registered for the GC G-aenial anterior group. Following the interpretation of the results, all four types of dental composites tested showed significant surface roughness differences between the groups subjected to bleaching protocols and those kept as control (p < 0.05). Conclusions: The surfaces of the samples were affected by the bleaching protocols by increasing the roughness compared to the control samples.
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Shakouei, Sahar, Negin Ghasemi, Parvin Zakeri-Milani, Afsaneh Shahali, and Mahdieh Alipour. "The sealing ability of different endodontic biomaterials as an intra-orifice barrier: evaluation with high-performance liquid chromatography." Biomaterial Investigations in Dentistry 11 (July 24, 2024): 91–96. http://dx.doi.org/10.2340/biid.v11.41069.
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Objective: This study evaluated the sealing ability of different biomaterials as intra-orifice barriers in the internal bleaching of discolored teeth with the walking bleaching technique. The release of hydroxyl ions from the bleaching materials can cause cervical root resorption, making it necessary to use intra-orifice barrier materials to prevent this issue. Materials and methods: In the current study, the high-performance liquid chromatography (HPLC) method was used to measure the released hydroxyl ions. The study included 90 single-rooted and single-canal premolars, which were divided into four groups based on the intra-orifice barrier materials used (mineral trioxide aggregate [MTA], calcium-enriched mixture [CEM], Biodentine, and MTA+PG) and the type of bleaching material (sodium perborate + water or sodium perborate + hydrogen peroxide 30%). Two control groups were also considered in this study: a positive control group, where sodium perborate and hydrogen peroxide were placed inside the pulp chamber without any intra-orifice barriers; and a negative control group, where no bleaching agent or surgical obstruction was used, and the root surface was covered with wax up to the cemento-enamel junction (CEJ) level. Results: The results showed that there was a significant difference in the concentration of hydroxyl ions released among the studied groups. The amount of hydroxyl ion released was highest in the positive control group and lowest in the CEM group. Among the intra-orifice barrier materials used, CEM cement was found to be the most appropriate material for use in the step-by-step internal bleaching method. Conclusions: The study highlights the importance of using appropriate intra-orifice barrier materials to prevent root cervical resorption in internal bleaching procedures.
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Knezevic, Natasa, Marija Obradovic, Olivera Dolic, Valentina Veselinovic, Zeljka Kojic, Renata Josipovic, and Marijana Arapovic-Savic. "Clinical Testing of Walking Bleach, In-Office, and Combined Bleaching of Endodontically Treated Teeth." Medicina 59, no. 1 (December 21, 2022): 18. http://dx.doi.org/10.3390/medicina59010018.
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Objective. The causes of internal posteruptive discoloration of teeth are bleeding, necroses, infections, and endodontic filling materials. The aim of this study was to establish the results of bleaching endodontically treated teeth using walking bleach, in-office, and combined techniques, using 30% carbamide peroxide and 35% hydrogen peroxide, as well as the effect of etiological factors, and the time elapsed after endodontic treatment on the success of bleaching. Materials and Methods. The research involved 30 endodontically treated teeth in healthy patients. Retroalveolar X-rays were taken to check the quality of root canal obturation. Endodontic treatment and obturation were carried out on the discolored non-vital teeth without any previous endodontic treatment. Before bleaching, two millimeters of the filling were removed from the root canal and the very entry into the canal was protected with glass ionomer cement. The teeth were divided into three groups, depending on the bleaching technique: walking bleach technique (10 patients), in-office technique (10 patients), and combined technique (10 patients). The teeth were bleached with 30% carbamide peroxide and 35% hydrogen peroxide. The bleaching procedure was repeated in all the patients three times. The color of all teeth was determined based on the Vita Classic guide before and after bleaching. The Χ² square and Kruskal–Wallis tests were used to identify differences in teeth bleaching results. Results. A statistically significant difference (p < 0.05) was established between bleaching success and the time elapsed after endodontic treatment. There were no statistically significant differences observed between the bleaching success and etiological factors, bleaching techniques, or bleaching agents. Conclusions. The effectiveness of non-vital tooth bleaching is affected by the time elapsed after endodontic treatment.
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Polydorou, O., E. Hellwig, and T. M. Auschill. "The Effect of Different Bleaching Agents on the Surface Texture of Restorative Materials." Operative Dentistry 31, no. 4 (July 1, 2006): 473–80. http://dx.doi.org/10.2341/05-75.
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Clinical Relevance In-office and home bleaching agents do not cause changes that would demand replacement of the restorations when the agents are applied on the polished surfaces of aesthetic dental restorative materials. Repolishing of the composites is suggested in order to overcome possible problems that might result from slight surface changes produced by bleaching.
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Vojdani, Mahroo, Kianoosh Torabi, Sasan Rasaeipour, Amir Alireza Khaledi, and Safoura Ghodsi. "Evaluation of the Effect of a Home-bleaching Agent on the Surface Characteristics of Indirect Esthetic Restorative Materials: Part I—Roughness." Journal of Contemporary Dental Practice 15, no. 3 (2014): 326–30. http://dx.doi.org/10.5005/jp-journals-10024-1537.
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ABSTRACT Background Pressing esthetic demands of good looking make people undergo bleaching procedures. However, the effect of bleaching agents on esthetic restorative materials with different surface preparations has been poorly studied. Aim The aim of this study was to examine the effect of a homebleaching agent (carbamide peroxide: CP 38%) on the surface roughness of the polished fiber reinforced composite (FRC), overglazed, autoglazed, or polished ceramic samples. Materials and methods Twenty standardized cylindrical specimens were made of each of the following groups: overglazed, autoglazed, polished porcelain and also FRC. The test specimens exposed to the CP 38%, 15 minutes, twice a day for 2 weeks according to the manufacturer's recommendation. Six samples from each group were selected randomly to form negative controls. Surface roughness measurements (Ra, micrometer) for baseline, test and control specimens were performed by use of a profilometer. Paired t-test, Mann-Whitney test, and Kruskal-Wallis test were used for statistical analyses. Results The data showed that bleaching with CP 38% significantly increased the surface roughness of all the test samples (p < 0.05). The type of surface preparation caused significant differences between the susceptibility of porcelain subgroups to bleaching (p < 0.05). The polished porcelain specimens showed the highest changes after bleaching. Conclusion CP 38% significantly increases the surface roughness of the porcelains and FRC. The type of surface condition affects the amenability of the porcelain surface to the bleaching agent. Glazed porcelains were more resistant to roughness than the polished porcelains and also the composite. Clinical significance Roughening of porcelain and FRC occur following bleaching procedure. No special surface preparation of indirect esthetic restorative materials can completely preserve these materials from adverse effects of bleaching agents. How to cite this article Torabi K, Rasaeipour S, Khaledi AA, Vojdani M, Ghodsi S. Evaluation of the Effect of a Homebleaching Agent on the Surface Characteristics of Indirect Esthetic Restorative Materials: Part I—Roughness. J Contemp Dent Pract 2014;15(3):326-330.
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Basting, RT, FLB Amaral, FMG França, and FM Flório. "Clinical Comparative Study of the Effectiveness of and Tooth Sensitivity to 10% and 20% Carbamide Peroxide Home-use and 35% and 38% Hydrogen Peroxide In-office Bleaching Materials Containing Desensitizing Agents." Operative Dentistry 37, no. 5 (September 1, 2012): 464–73. http://dx.doi.org/10.2341/11-337-c.
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SUMMARY The aim of this study was to compare the effectiveness of and tooth sensitivity to 10% and 20% carbamide peroxide (CP) home-use bleaching agents and 35% and 38% hydrogen peroxide (HP) in-office bleaching agents, all of which contain desensitizing agents, in a clinical trial. Four agents were evaluated: 10% CP and 20% CP (Opalescence PF 10% and Opalescence PF 20%, Ultradent, both with 0.5% potassium nitrate and 0.11% fluoride ions), 38% HP (Opalescence Boost PF, Ultradent, with 3% potassium nitrate and 1.1% fluoride ions), and 35% HP (Pola Office, SDI, with potassium nitrate). The initial screening procedure included 100 volunteers, aged 18 to 42, with no previous sensitivity or bleaching treatment and with any tooth shade. Volunteers were randomly assigned among the technique/bleaching agent groups. A run-in period was performed 1 week before the beginning of the bleaching treatment. For the home-use bleaching technique, each volunteer was instructed to dispense gel (10% CP or 20% CP) into the trays and then insert them into his or her mouth for at least two hours per night for three weeks. For the in-office bleaching technique, the bleaching agents (38% HP or 35% HP) were prepared and used following the manufacturer's instructions, with three applications performed in each session. Three sessions were carried out with an interval of seven days between each session. The participants were evaluated before, at one week, two weeks, and three weeks after the beginning of the bleaching treatment, and again one and two weeks after the bleaching treatment ended. A shade guide (Vita Classical, Vita) was used by a blinded examiner to perform shade evaluations before bleaching and two weeks after the end of bleaching. At the time of the shade evaluations, tooth sensitivity was also recorded by asking the volunteers to classify the sensitivity during bleaching treatment as absent, mild, moderate, or severe. The present study found that 13.8% of the volunteers withdrew from the study due to tooth sensitivity, and 43.2% of the participants experienced some type of sensitivity during bleaching treatment. The χ2 test showed that there was a significant prevalence of tooth sensitivity during bleaching treatment using the home-use 20% CP agent, with 71.4% of volunteers reporting any level of tooth sensitivity (p=0.0032). A low prevalence of tooth sensitivity was observed for volunteers who used the in-office 38% HP agent (15.0%). The Wilcoxon test (p<0.05) showed that all of the bleaching treatments were effective in bleaching teeth and that there were no differences between the final color shade results among the treatments (Kruskal-Wallis, p<0.05). This study showed that 43.2% of all the volunteers experienced mild or moderate tooth sensitivity during the treatment with bleaching agents. A higher prevalence of tooth sensitivity was observed for 71.4% of the volunteers who used the 20% CP home-use bleaching agent, which may be ascribed to the peroxide concentration and/or the time/length the agent was in contact with the dental structures.
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EL-SAKHAWY, MOHAMED, AMAL H. ABD EL-KADER, TAMER Y. A. FAHMY, ESSAM S. ABD EL-SAYED, and NESRINE F. KASSEM. "OPTIMIZATION OF DITHIONITE BLEACHING OF HIGH YIELD BAGASSE PULP." Cellulose Chemistry and Technology 55, no. 5-6 (June 30, 2021): 667–73. http://dx.doi.org/10.35812/cellulosechemtechnol.2021.55.55.
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Non-wood raw materials are an essential fiber source in regions where forest resources are limited. Therefore, chemi-mechanical high-yield bagasse pulp was prepared and then bleached with a dithionite bleaching agent. One- and two-stage bleaching of the pulp was carried out by using sodium dithionite (Y) as a sole bleaching agent, or after bleaching with hydrogen peroxide to achieve high brightness for the prepared pulp. Different parameters, such as consistency, concentration, temperature, time and pH were investigated. The effect of various additives, such as diethylenetriaminepentaacetic acid (DTPA) as chelating agent or Zn compounds and hexamethylenetetramine to stabilize the bleaching solution, was studied. The effect of dissolved oxygen in liquor was also considered.
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Scribante, Andrea, Claudio Poggio, Simone Gallo, Paolo Riva, Antonella Cuocci, Manuel Carbone, Carla Arciola, and Marco Colombo. "In Vitro Re-Hardening of Bleached Enamel Using Mineralizing Pastes: Toward Preventing Bacterial Colonization." Materials 13, no. 4 (February 11, 2020): 818. http://dx.doi.org/10.3390/ma13040818.
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The search for materials able to remineralize human hard tissues is a modern medical challenge. In this study, the protective effect on the enamel microhardness by a paste based on hydroxyapatite and sodium fluoride (Remin Pro) was evaluated after two different enamel bleaching procedures. Forty sound human incisors were randomly assigned to different treatments: bleaching with an in-office agent (Perfect Bleach Office+); bleaching with an at-home agent (Perfect Bleach); bleaching with the in-office agent followed by the prophylaxis paste; bleaching with the at-home agent followed by the prophylaxis paste; no treatment (control). Bleaching was performed at 0, 8, 24 and 32 h, followed by a 3-min re-mineralizing treatment in the subgroups designed to receive it. Specimens underwent a micro-hardness tester and a mean Vickers Hardness number was considered for each specimen. ANOVA exhibited significant differences among groups. Post-hoc Tukey testing showed significant micro-hardness decrease after the application of both the two bleaching agents. The treatment with prophylaxis paste significantly increased the micro-hardness values of bleached enamel.
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Lima, AF, RT Sasaki, LS Araújo, LA Gaglianone, MS Freitas, FHB Aguiar, and GM Marchi. "Effect of Tooth Bleaching on Bond Strength of Enamel-Dentin Cavities Restored With Silorane- and Dimethacrylate-based Materials." Operative Dentistry 36, no. 4 (July 1, 2011): 390–96. http://dx.doi.org/10.2341/10-332-l.
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Clinical Relevance Prior bleaching treatment, with both low and high concentrations of bleaching agents, does not affect the push-out bond strength of dimethacrylate- and silorane-based materials to enamel-dentin cavities.
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Susi, Susi, Makhmudun Ainuri, Wagiman Wagiman, and Mohammad Affan Fajar Falah. "High-Yield Alpha-Cellulose from Oil Palm Empty Fruit Bunches by Optimizing Thermochemical Delignification Processes for Use as Microcrystalline Cellulose." International Journal of Biomaterials 2023 (February 16, 2023): 1–15. http://dx.doi.org/10.1155/2023/9169431.
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Oil palm empty fruit bunches (OPEFB) are lignocellulosic materials that are a by-product of the palm oil industry, which have less use and utilization is still limited. OPEFB’s high cellulose content could potentially develop into various bioproducts, especially biomaterials. The thermochemical delignification process can obtain high-yieldalpha-cellulose. The cellulose extraction process can be done by combining the bleaching process under acidic conditions and alkaline delignification to obtain high-purity cellulose. The bleaching conditions vary in the concentration of NaClO2, the length of bleaching, the temperature, and the number of stages. The research obtains high α-cellulose by optimizing bleaching conditions under acidic conditions in cellulose’s OPEFB extraction with variability on NaClO2 concentration and bleaching time using response surface methodology (RSM). The bleaching process was implemented at an early stage with a concentration of 3% NaClO2 and a bleaching time of 2 hours as a center point with a bleaching cycle of twice at pH 4–4.5 using acetic acid. Bleached fibers were delignified using 10% NaOH for 2 hours at room temperature. The RSM analysis resulted in optimum bleaching conditions at a concentration of 3.22% NaClO2 for 1 hour, yielding OPEFB’s cellulose of 82.96% ± 2.53, hemicellulose of 9.27% ± 2.28, and lignin of 1.68% ± 0.58. The validation and verification process in the bleaching conditions obtained cellulose of 84.87% and α-cellulose of 88.51%, with a crystallinity index of 70.55% and crystallite size of 2.35 nm. Scanning electron microscopy on surface cellulose morphology at optimum bleaching helped remove hemicellulose impurities, lignin, and inorganic materials and a more intensive opening of cellulose fibrils. The bleaching process optimization point was verified to improve the delignification performance and potentially produce high yield α-cellulose content for microcrystalline cellulose use.
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Peng, Pei-Wen, Chiung-Fang Huang, Ching-Ying Hsu, Ann Chen, Ho-Him Ng, Man-Si Cheng, Shiang Tsay, Jia-Yi Lai, Tzu-Sen Yang, and Wei-Fang Lee. "Color Stability and Staining Susceptibility of Direct Resin-Based Composites after Light-Activated In-Office Bleaching." Polymers 13, no. 17 (August 31, 2021): 2941. http://dx.doi.org/10.3390/polym13172941.
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This study evaluated color stability and staining susceptibility of five direct resin-based composites (RBCs) subjected to light-activated in-office bleaching with 40% hydrogen peroxide (HP). The test materials included 5 RBCs, which consisted of one nano-filled, one sub-micron, one bulk-filled, and two nano-hybrid RBC types. Ten disc-shaped specimens of each RBC were fabricated and divided into bleaching (BLE) and non-bleaching (CON) groups (n = 5 for each group). Specimens were then immersed in red wine solution over 4 h. A spectrophotometer was used to obtain Commission Internationale de l’Eclairage (CIE) L*a*b* parameters for each of the following periods tested: before bleaching (TBA), after bleaching (TBL), and after staining (TST). Color stability and staining susceptibility were evaluated using two metrics, CIEDE2000 color differences (ΔE00) and whiteness variations using the whiteness index (ΔWID). Data were analyzed using repeated measures two-way analysis of variance (ANOVA) (α = 0.05). Statistically significant and clinically unaccepted ΔE00 and ΔWID were observed for all tested specimens between TBA and TBL. The nano-hybrid type RBCs showed the highest discoloration among materials after bleaching treatment. The BLE group exhibited significantly higher ΔE00 and ΔWID than the CON group for all the tested RBCs between TBA and TST. The sub-micron type RBC showed the highest discoloration among materials after immersion in the red wine. Conclusion. The light-activated in-office bleaching with 40% HP’s influences on color and whiteness index were material-dependent. The use of bleaching treatment also increased the susceptibility to red wine for all RBCs.
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Rikhtegaran, Sahand, Mahdi Rahbar, Narmin Mohammadi, Shadieh Mowlaie, Siavash Savadi-Oskoee, Mohammad E. Ebrahimi, and Tahereh Pirzadeh. "Effect of 15% Carbamide Peroxide on the Surface Roughness and Adhesion of Streptococcus mutans to Microhybrid Composite Resin and Giomer." World Journal of Dentistry 8, no. 4 (2017): 288–95. http://dx.doi.org/10.5005/jp-journals-10015-1452.
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ABSTRACT Introduction Adhesion of bacteria, especially Streptococcus mutans (S. mutans), to the surface of tooth restorations is a factor in the etiology of secondary caries. Given the ever-increasing popularity of bleaching procedures, the aim of the present study was to evaluate adhesion of S. mutans and surface roughness (SR) of microhybrid composite resin and giomer subsequent to the application of 15% carbamide peroxide. Materials and methods Twenty disk-shaped samples were prepared from each material, measuring 8 mm in diameter and 2 mm in thickness. Then, the samples of each material were divided into two groups (n = 10): (a) microhybrid without bleaching; (b) microhybrid with bleaching; and (c) giomer without bleaching; and (d) giomer with bleaching. The samples in groups I and III were immersed in artificial saliva for 14 days without any bleaching procedure; the samples in groups II and IV underwent a bleaching procedure on their polished surfaces with 15% carbamide peroxide for 14 days (4 hours of bleaching and 20 hours of immersion in artificial saliva). The SR of all the samples was determined with the use of a profilometer. The samples were added to the culture medium after 4 hours of placement in a microbial suspension at 37°C; after 24 hours of incubation at 37°C, the bacterial counts, indicating the number of bacteria adhering to the surface, were determined by counting them in the plates containing the solid culture medium. Results The type of the restorative material had a significant effect on SR, with greater SR in giomer (p = 0.03). However, bleaching had no significant effect on SR (p = 0.099). In relation to the rate of bacterial adhesion (BA), both the types of the restorative materials and bleaching procedures were significantly effective; in this context, there was more BA in microhybrid composite resin samples that did not undergo bleaching (p < 0.001). Bleaching resulted in the adhesion of S. mutans to the surface of both materials decrease. Pearson's correlation coefficient did not reveal any correlation between BA and SR (p = 0.42). Conclusion The BA was higher in microhybrid composite resin, and SR was higher in giomer. The BA was higher in samples that did not undergo a bleaching procedure. Clinical significance There is no change in the SR of microhybrid composite resin and giomer after application of 15% carbamide peroxide; therefore, it is not necessary to polish or replace these restorative materials after bleaching. In addition, use of 15% carbamide peroxide does not increase caries risk. How to cite this article Mohammadi N, Mowlaie S, Savadi- Oskoee S, Ebrahimi ME, Rikhtegaran S, Rahbar M, Pirzadeh T. Effect of 15% Carbamide Peroxide on the Surface Roughness and Adhesion of Streptococcus mutans to Microhybrid Composite Resin and Giomer. World J Dent 2017;8(4):288-295.
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Pan, G. X. "Relationship between dissolution of fiber materials and development of pulp strength in alkaline peroxide bleaching of mechanical pulp." Holzforschung 58, no. 4 (July 7, 2004): 369–75. http://dx.doi.org/10.1515/hf.2004.056.
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Abstract This study elucidates the relationship between the dissolution of pulp components and the development of fiber bonding properties in alkaline peroxide bleaching of aspen mechanical pulp. In general, bleaching reactions cause the removal of pulp substances from the fibers, which in turn improves pulp strength properties. Nonetheless, alkaline hydrolysis is particularly important to the development of strength because this reaction mechanism plays a key role in imparting additional carboxylic acid groups onto the fibers. The strong correlation between fiber carboxylic acid group concentration and the amount of anionic dissolved substances makes it possible for us to predict the strength properties of bleached pulps by estimating the anionicity of bleaching filtrates using analytical methods such as cationic demand. The paper also provides insights into the importance of the alkalinity in peroxide bleaching to the dissolution of pulp materials and the strength development.
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Chakraborty, Anindita, Tina Purayil, Kishore Ginjupalli, Kalyana-Chakravarthy Pentapati, and Neetha Shenoy. "Effect of in-office bleaching agent on the surface roughness and microhardness of nanofilled and nanohybrid composite resins." F1000Research 12 (May 18, 2023): 129. http://dx.doi.org/10.12688/f1000research.130071.2.
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Background: To compare the surface roughness and microhardness of Ceram.x® SphereTEC™ one and Filtek Z350 XT after in-office bleaching with Pola office. Methods: Twenty samples each of (10 mm diameter and 2 mm height) Ceram.x® SphereTEC™ one and Filtek Z350 XT were prepared. The samples were subjected to three bleaching sessions with 35% hydrogen peroxide (Pola office) with a seven-day interval between each session. Surface roughness and microhardness of the prepared samples prior to and after the bleaching regimen were measured using a profilometer and Vickers hardness tester, respectively. Results: A significant reduction (p <0.001) in the surface hardness of Filtek Z350 XT from 27.67 ± 2.10 to 17.83 ± 1.36 Vickers hardness number (VHN) was observed after the bleaching whereas no significant reduction in surface hardness was observed with Ceram.x® SphereTEC™ one. The adjusted mean (estimated marginal mean) microhardness after bleaching for Ceram.x ® SphereTEC™ one (35.79 ± 1.45) was significantly higher than Filtek Z350 XT (19.54 ± 1.45) (p < 0.001). However, in-office bleaching of these materials did not significantly alter their surface roughness. Conclusions: In office-bleaching with 35% hydrogen peroxide can reduce the microhardness of nanofilled composite. However, the surface roughness was not influenced by the bleaching procedure in both nanohybrid and nanofilled composite resin materials.
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Z. Osman, Eman, Naeima M. Betamar, Nagat H. Bubteina, and Rafa A. Mohamed. "Effect of Staining and Bleaching on Color Change of Resin Composite Restorative Materials." Libyan Journal of Dentistry 6, no. 1 (March 1, 2022): 27–35. http://dx.doi.org/10.37376/ljd.v6i1.3731.
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Aims: To evaluate the color change of three resin composites (nanohybrid; Filtek Z250XT, microhybrid, DenFil, and nanoceram; Zenit) after exposure to tea, coffee, artificial saliva, and bleaching procedure.
Materials and Methods: A total of 162 disc-shaped specimens (12.2mm diameter, and 2.2mm thickness) from the three resin composites were prepared in a silicon mold, then divided into 3 groups according to the type of resin composite. Each group was subdivided into three experimental groups (n=18), and immersed into staining solutions; tea, coffee, and artificial saliva for 3h/day over 28 days. A bleaching agent (Opalescence 20 home bleach) was applied to previously stained specimens for 3h/day over 14 days. The color measurement for each specimen was performed according to CIE L*a*b* system using a spectrophotometer on three occasions: i) at baseline, ii) after staining, and iii) after bleaching. The color differences delta E (ΔE) between the three measurements were calculated and the obtained data was statistically analyzed.
Results: The three composites showed significant color change after immersion in tea, and coffee solutions (P˂0.05), and after the bleaching (P˂0.05). DenFil showed the most color change followed by Z250XT. Zenit was the least affected by staining solutions. Tea solution caused more color change than the coffee solution. Artificial saliva showed insignificant color change for all groups (P=0.07).
Conclusions: Exposure to drinks with staining ability such as tea and coffee can significantly affect the color stability of the tested composites. The bleaching agent was effective in removing the stains and restoring the color of all composites near or at baseline color.
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Li, Zhijiang, Tianru Yu, and Lichao Yu. "Study on the scouring-bleaching technology of Xinjiang scutched flax." Journal of Engineered Fibers and Fabrics 15 (January 2020): 155892502095765. http://dx.doi.org/10.1177/1558925020957650.
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This study explored and improved the optimal scouring-bleaching process of Xinjiang scutched flax, based on its characteristics and the scouring-bleaching process of existing mature flax. The physical properties, such as length, strength, split degree and fineness, and the chemical composition of Xinjiang scutched flax, such as the content of cellulose, lipowax, pectin, hemicellulose, water-soluble matter, lignin, etc., were measured and analyzed. The approximate range of bleaching process parameters was determined referring to the existing general flax scouring-bleaching process. Thirdly, the orthogonal experiment of three factors and three levels interaction is designed, and the optimal scouring-bleaching process scheme is obtained after analysis and verification.
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Irawan, Bryant Anthony, Stacey Natalie Irawan, Sam’an Malik Masudi, Ninin Sukminingrum, and Mohammad Khursheed Alam. "3D Surface Profile and Color Stability of Tooth Colored Filling Materials after Bleaching." BioMed Research International 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/327289.
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This study aims to evaluate the effects of vital tooth bleaching with carbamide peroxide home bleaching and in-office bleaching on the color stability and 3D surface profile of dental restorative filling materials. Thirty discs (n=30) measure 6 mm in diameter and 2 mm thick for each of three restorative materials. These are nanofilled composite Filtek Z350 XT, the submicron composite EsteliteΣQuick, and nanofilled glass ionomer Ketac N100 nanoionomer and were fabricated in shade A2. Each group was further divided into three subgroups (n=10): subgroup A (Opalescence PF), subgroup B (Opalescence Boost in-office bleaching), and subgroup C (distilled water) serving as control. Samples were bleached according to the manufacturer’s instructions for a period of two weeks. The Commission Internationale de L’Eclairage (CIEL*,a*,b*) system was chosen for image processing, while 3D surface profile was tested with atomic force microscopy (AFM). Statistical analyses were performed with the Mann-Whitney tests and Krusal-Wallis with aPvalue of ≤0.05. The three restorative materials showed significant color changes (ΔE);P≤0.05. In diminishing order, the mean color changes recorded were EsteliteΣ(3.82 ± 1.6) > Ketac Nano (2.97 ± 1.2) > Filtek Z350 XT (2.25 ± 1.0). However, none of the tested materials showed statistically significant changes in surface roughness;P>0.05.
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Altınışık, Hanife, Sinem Akgül, Merve Nezir, Suat Özcan, and Esra Özyurt. "The Effect of In-Office Bleaching with Different Concentrations of Hydrogen Peroxide on Enamel Color, Roughness, and Color Stability." Materials 16, no. 4 (February 7, 2023): 1389. http://dx.doi.org/10.3390/ma16041389.
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The aim of this study is to evaluate the effectiveness of in-office bleaching in esthetic dentistry on the roughness and color stability of the enamel surface, using different concentrations of hydrogen peroxide (HP). Fifty human incisors were randomly divided into 5 groups (n = 10). No bleaching was performed in the control group. For these groups, concentrations of 40% HP with fluoride (F), 35% HP with calcium (Ca), 25% HP with nano-hydroxyapatite (nHA) and 18% HP with nHA were used for bleaching in the test groups. Surface roughness was assessed at baseline after bleaching occurred. Color measurements were first obtained at baseline, then after the first and second sessions of bleaching, and, finally, after the staining protocol. Scanning electron microscopy and atomic force microscopy were performed. Statistical analysis was conducted with a one-way ANOVA, followed by a post hoc Tukey’s test and a paired-samples t-test (p < 0.05). All the bleaching gels used exhibited a similar color change (p > 0.05). Bleaching gels containing 18% HP with nHA and that containing 35% HP with Ca caused less surface roughness of the enamel. Of these concentrations, 25% HP with nHA caused the most surface roughness and no significant difference was observed, compared with 40% HP with F. The highest coloration after bleaching was observed in 40% HP with F and 25% HP with nHA. The lowest coloration was obtained in 35% HP with Ca and 18% HP with nHA but no significant difference was observed between them and the control group. A concentration above 18% HP does not increase the bleaching effectiveness. The results show that 18% HP with nHA and 35% HP with Ca resulted in the least increase in enamel surface roughness when compared to high-concentrate HP; however, it also prevented recoloration after bleaching.
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Rounsaville, Jeff. "Ozone Bleaching. Ozone Technology for Pulp Bleaching Applications." JAPAN TAPPI JOURNAL 51, no. 5 (1997): 738–43. http://dx.doi.org/10.2524/jtappij.51.738.
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Khan, Aftab Ahmed, Abdulaziz Abdullah Alkhureif, Leonel S. J. Bautista, Hanan Alsunbul, and Sajith Vellappally. "Peroxide-Free Bleaching Gel: Effect on the Surface and Mechanical Properties of Nano- and Micro-Hybrid Restorative Composite Materials." Applied Sciences 13, no. 10 (May 11, 2023): 5935. http://dx.doi.org/10.3390/app13105935.
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This laboratory investigation was designed to test the influence of a novel bleaching formulation based on phthalimidoperoxycaproic acid (PAP) with additives on the surface and mechanical properties of nano- and micro-hybrid restorative composites. Twenty-four bar-shaped and twelve disk-shaped samples from each restorative composite were prepared. The samples from each restorative composite were randomly divided into two groups according to the treatment, i.e., experimental and control. The treated groups went through the bleaching process: by Opalescence Regular or novel PAP+-containing gel (HiSmile™). The treated group underwent a bleaching process for seven consecutive days (a 10-min session of bleaching application every day) before the properties were tested. A paired sample t-test was performed to compare the results between the experimental and the control groups. The level of significance was set at 0.05. The surface roughness of the nanohybrid composite using Opalescence Regular (p < 0.05) was significant. Additionally, a significant difference in nanohardness and elastic modulus between the experimental and the control groups of the microhybrid composite using Opalescence Regular was observed: p = 0.041 and p = 0.023, respectively. While a marked difference in flexural strength was observed in the experimental and control groups using Opalescence Regular, Hismile™ bleaching gel caused a diminutive and insignificant reduction in tested properties (p > 0.05). It was found that Opalescence Regular bleaching gel affects the surface and bulk properties of restorative composite materials, whereas the novel PAP+ formulation has no deleterious effect on either nano- or micro-hybrid restorative composites.