Different Concentrations Of Carbamide Peroxide Research Articles

Effects of Different Concentrations of Carbamide Peroxide on Color, Surface Roughness, and Hardness of CAD/CAM Dental Ceramics.

This study assessed the effects of 15% and 20% carbamide peroxide (CP) on color, surface roughness, and hardness of computer-aided design/computer-aided manufacturing (CAD/CAM) dental ceramics. This in vitro study was conducted on 120 Vita Mark II, Celtra Duo, and Suprinity CAD/CAM ceramic specimens. The ceramic specimens in each group (n = 40) were randomly assigned to two subgroups (n = 20) for polishing and glazing, and their baseline color, surface roughness (Ra), and hardness were assessed. In each subgroup, half of the specimens were exposed to 15% CP, while the other half were exposed to 20% CP. Their color change (ΔE), surface roughness, and hardness were then measured again. Surface roughness, hardness, and color were analyzed sequentially by profilometer, Vickers hardness tester, and spectrophotometer, respectively. Data were analyzed by repeated measures ANOVA, one-way ANOVA, and post hoc Bonferroni test (α = 0.05). The surface roughness of all groups significantly increased after bleaching treatment (p < 0.05). Surface hardness of all groups decreased after bleaching treatment, but this reduction was only significant in Vita Mark II subgroups (glazed, polished, 15%, and 20% CP). The ΔE was not clinically and visually perceivable in any group. The present results revealed that concentration of CP and type of surface treatment affected the surface properties of CAD/CAM ceramics. Type of surface treatment only affected the surface hardness of Vita Mark II ceramics (p < 0.05). Concentration of CP had a significant effect only on polished Vita Mark II.

Evaluation of the efficacy of diode laser in bleaching of the tooth at different time intervals using spectrophotometer: An in vitro study.

Aim:This study aimed at comparative evaluation of the efficacy of tooth bleaching using different concentrations of carbamide peroxide (CP) with and without diode laser at 980 nm for 2.5 and 5 min time duration.Materials and Methods:Hundred intact human incisors were selected. Teeth were artificially stained using black tea solution. Samples were randomly allocated into four groups: Group I: distilled water, Group II: 15%, 20%, and 35% CP without laser, Group III: 15%, 20%, and 35% CP using diode laser for 2.5 min, and Group IV: 15%, 20%, and 35% CP using diode laser for 5 min. Color measurements were made using spectrophotometer. Data were statistically analyzed by ANOVA, repeated measures of ANOVA, and Tukey post hoc test.Results:35% concentration of CP gave similar mean shade (ΔE) value at T2, as 15% CP at T3. At T3, 15% concentration of CP using diode laser for 2.5 min gave similar mean shade (ΔE) value, as 35% concentration of CP using diode laser for 2.5 min.Conclusion:35% CP causes change in chroma and whitens the tooth at a faster rate with a significantly more lightening effect. Bleaching twice weekly produces a similar effect when using high or low concentrations of CP. Laser-assisted bleaching decreases the time of whitening process.

Effect of Delaying tooth brushing on Enamel surface roughness during bleaching with different concentrations of carbamide peroxide: An In vitro study

Effect of Delaying tooth brushing on Enamel surface roughness during bleaching with different concentrations of carbamide peroxide: An <i>In vitro</i> study

Qualitative and quantitative analysis of Mercury ions on the surface of amalgam restorations after home bleaching

ABSTRACT Objective The bleaching agents may interact with restorative materials, such as dental amalgam, providing an increase mercury ions (Hg) release, whose toxic effect is known. Whereas many patients have amalgam restorations (AR) and seek bleaching treatments, the present study aimed to evaluate in vitro the amount of Hg released from AR made with spherical alloy, after being subjected to different concentrations of carbamide peroxide (CP) for home bleaching. Methods 40 class I AR were prepared in bovine teeth. Afterthe restoration, the samples were randomly allocated into 4 groups (n = 10): C (control group), CP10 (CP 10%) CP15 (CP 15%) CP20 (CP 20%) and its treatments were simulated for 14 days for 6 hours daily. The Hg ions released was measured by energy dispersive X-ray spectroscopy (EDS) and surface changes were assessed in the Scanning Electron Microscope (SEM). Hg levels (percent mass) were recorded and the differences were statistically analyzed using the Kruskal-Wallis test and Dunn’s “Post hoc” test. Results Statisticalanalysis showed the bleaching treatment resulted in a higher Hg release (p &lt;0.05), although no visible changes were identified in micrographs when comparing the control group with the other groups (CP10, CP15, CP20). Conclusion Increased Hg release may be observed during simulated home bleaching.

Effect of delaying Toothbrushing on Enamel surface Roughness during bleaching with different Concentrations of Carbamide peroxide: An In vitro study

Effect of delaying Toothbrushing on Enamel surface Roughness during bleaching with different Concentrations of Carbamide peroxide: An <i>In vitro</i> study

The degree of tooth colour change after using different concentrations of carbamide peroxide

Background: Depending on the cause of discoloration, bleaching materials and other factors, vital dental bleaching techniques may be professional (in-office dental bleaching), at-home night-guard bleaching and combined. The main objective of this study was to determine, in vitro, tooth colour change using external dental bleaching techniques with 16% and 30% carbamide peroxide gel and to investigate the effect of concentration of carbamide peroxide gel on the bleaching success. Method: This study included 20 extracted intact human teeth. Teeth were divided into two groups of ten each: the first group was bleached with 16% and the second group with 30% carbamide peroxide gel. The procedure was repeated three times for each tooth. The existing colour on each tooth was recorded using VITA classical shade guide A1-D4 before treatment, after each session and after bleaching was completed. Results: A significant difference (p < 0.01) was found between the first and the second bleaching treatment, for both concentrations (Exact binomial test). A significant difference (p <0.05) was also present between the second and the third treatment, while no statistically significant difference was found between the first and the third bleaching treatment, for both concentrations. There was no statistically significant difference between groups based on degree of tooth shade (χ2 test). Conclusion: The teeth bleaching technique with 16% carbamide peroxide gel and the teeth bleaching technique with 30% carbamide peroxide gel have shown the same efficiency in changing the tooth colour.

Effect of carbamide peroxide bleaching on enamel characteristics and susceptibility to further discoloration

Statement of problemWhether tooth whitening alters the surface topography of enamel causing an increase in surface roughness that could increase susceptibility to restaining is unclear. PurposeThe purpose of this in vitro study was to evaluate whether immersing enamel in common solutions produces a color change of ΔE greater than 2; whether the highest concentration carbamide peroxide bleaching agent produces the greatest ΔE; whether bleaching increases the susceptibility to further staining by common solutions; and whether morphologic changes to the enamel surface are observed after staining and bleaching as evidenced by scanning electron microscopy (SEM) analysis and energy-dispersive X-ray spectroscopy (EDS). Material and methodsForty-five extracted human teeth were immersed in 5 solutions (wine, coffee, tea, soda, and water) for 15 days at 80°C, and the change in ΔE was assessed with a colorimeter. The teeth were bleached using different concentrations of carbamide peroxide (20%, 35%, and 44%) and ΔE was measured at different time intervals. The teeth were then restained with the same solutions. The ΔE after initial staining was compared with the ΔE after bleaching and restaining of the same teeth. SEM was performed at baseline, after staining, bleaching, and restaining to evaluate the changes in the enamel surface topography. EDS was used to determine the elemental composition of tooth surfaces after restaining. ResultsAll liquids caused a ΔE greater than 2 after 15 days. The concentration of bleaching agent was not significantly associated with ΔE for any stain types. No significant difference was found in the rate of staining between initial staining and restaining after bleaching. However, a significant effect of time was found for the staining, where the overall ΔE increased by 0.34 for each day in the solution (P<.001). SEM images showed no major changes to enamel topography after bleaching. However, a coating was noted on teeth stained with wine and tea, which had different elemental compositions when compared with the tooth surface. ConclusionsBased on SEM observation, bleaching teeth with carbamide peroxide does not increase the susceptibility of enamel to staining and does not alter the topography of the enamel. Using higher bleaching concentrations did not increase tooth whitening as a function of time.

Effect of home bleaching on surface of zinc phosphate cement: A scanning electron microscopic study.

The effect of home bleaching on surfaces of dental cements is controversial. The aim of this study was to microscopically evaluate and compare the effect of different concentrations of carbamide peroxide (CP) home bleaching agents on the surface of zinc phosphate cement. Forty 10 mm × 2 mm specimens of zinc phosphate cement were prepared following the manufacturer's directions. All specimens were immersed in artificial saliva at 37°C for 24 h. The specimens were equally divided into four groups (n = 10). One control group received no CP bleaching. Three experimental groups were exposed to 10%, 16%, and 22% of CP home bleaching agents. The bleaching agents were applied daily for 4 h for 14 days. Specimens were stored in artificial saliva at 37°C for 24 h and then examined under a scanning electron microscope. The surface micromorphology of the specimens was carefully evaluated and compared. The zinc oxide particles in the specimens of the control group were tightly packed with well-defined plate-like crystals. When specimens were exposed to 10% CP gels, the particles became flat and irregular with few areas of eroded matrix. When 16% CP gel was used, the crystals became flatter and irregular with rounded edges. Bleaching with 22% CP gel showed little more erosion of the surface of the matrix of the cement. Fewer flat and irregular crystals were observed on the surface of the cement. At-home bleaching using 10%, 16%, and 22% CP may be safely used in the presence of zinc phosphate-luted crown restorations without adverse effects.

Effect of different concentrations of carbamide peroxide on the staining susceptibility of resin composites.

Context:Bleaching can affect the surface properties of resin composites.Aims:The aim of this study was to evaluate the effect of three regimens of carbamide peroxide (CP) on staining susceptibility of silorane and methacrylate-based resin composites.Methods:In this study, 80 composite disks were prepared from A2 shade of P90 and Z250 composite resins (40 each). Samples were divided into three test groups based on the CP concentration (10%, 16%, and 22%) and bleached for 14 days. Controls were kept in distilled water. Then, specimens were immersed in a tea solution for 14 consecutive days. A spectrophotometer was used to measure the specimen colors in CIE L*a*b system, initially and after staining. Data were analyzed using SPSS 16 software using two-way ANOVA, t-test, and Tukey honestly significant difference tests at α = 0.05.Results:The color susceptibility of Z250 samples were significantly affected in groups bleached with 22% CP compared to the controls (P = 0.001). The different concentrations of CP did not affect the staining susceptibility of the P90 samples (P > 0.05).Conclusions:Bleaching of the tested resin composites did not increase their susceptibility to extrinsic staining in vitro except for the Z250 samples bleached with 22% CP.

Effects of different bleaching agent concentrations on surface roughness and microhardness of esthetic restorative materials

Abstract Objectives The study assessed the changes in surface roughness and microhardness of three esthetic restorative materials after bleaching with 10%, 20% and 35% carbamide peroxide (CP). Methods Standardized cylindrical specimens ( n = 210) of 3 esthetic materials (nano composite resin (NC), resin modified glass ionomer (GI), feldspathic porcelain (FP) were fabricated ( n = 70). They were divided into 3 groups ( n = 20) and a control group ( n = 10). Each group was bleached with different concentrations of CP. The specimens of group 1 and 2 (10% CP and 20% CP) were immersed in the bleaching gels for 6 h daily, while group 3 (35% CP) was immersed for 30 min weekly. The control group was stored in artificial saliva. After 21 days, the morphological changes of the specimens were investigated with surface texture analyzer, while the hardness was assessed by performing superficial microhardness analysis. The data were analyzed with one-way ANOVA, and Scheffe test at α = 0.05. Results No significant differences in roughness average (Ra) were recorded among the control group and 10% CP bleached groups of all tested restorative materials (NC ( p = 0.1495), GI ( p = 0.0761), FP ( p = 0.2848)). However, there were significant differences in Ra among the control group, 20% CP, and 35% CP ( p p = 0.0786), 20% ( p = 0.1041), and 35% ( p = 0.2066). While nano composite resin and resin modified glass ionomer specimens were significantly affected by concentration of 20% and 35% CP ( p Conclusion The effect of bleaching depends on the concentration of CP. The higher surface roughness was produced by 35% CP. Bleaching with different concentrations did not reduce the microhardness of the feldspathic porcelain. However, microhardness of nano composite resin and resin modified glass ionomer specimens was affected by 20% CP and 35% CP.

Effect of different concentrations of carbamide peroxide and green tea extract on the color and shear bond strength of enamel – an in vitro study

Effect of different concentrations of carbamide peroxide and green tea extract on the color and shear bond strength of enamel – an in vitro study

Effects of different concentrations of carbamide peroxide and bleaching periods on the roughness of dental ceramics

The wide use of dental bleaching treatment has brought concern about the possible effects of hydrogen peroxide on dental tissue and restorative materials. The objective of this study was to evaluate in vitro the effect of nightguard bleaching on the surface roughness of dental ceramics after different periods of bleaching treatment. Fifteen specimens of 5 × 3 × 1 mm were created with three dental ceramics following the manufacturers' instructions: IPS Classic (Ivoclar-Vivadent); IPS d.Sign (Ivoclar-Vivadent); and VMK-95 (Vita). A profilometer was used to evaluate baseline surface roughness (Ra values) of all ceramics by five parallel measurements with five 0.25 mm cut off (Λc) at 0.1 mm/s. Afterwards, all specimens were submitted to 6-h daily bleaching treatments with 10% or 16% carbamide peroxide (Whiteness- FGM) for 21 days, while control groups from each ceramic system were stored in artificial saliva. The surface roughness of all groups was evaluated after 18 h, 42 h, 84 h, and 126 h of bleaching treatment. The surface roughness of each specimen (n = 5) was based on the mean value of five parallel measurements in each time and all data were submitted to two-way repeated measures ANOVA and Tukey's post-hoc test (α = 0.05). No significant differences in ceramic surface roughness were observed between untreated and bleached ceramic surfaces, regardless of bleaching intervals or bleaching treatments. This study provided evidence that at-home bleaching systems do not cause detrimental effects on surface roughness of dental ceramics.

OPTICAL MONITORING OF BLEACHING AGENTS EFFECTS ON HUMAN DENTAL REMAINS

The time evolution of the bleaching effect, of hydrogen peroxide and two different concentrations of carbamide peroxide, on partially deteriorated human dental remains was analyzed by optical diffuse reflectance in the visible region of the spectrum. The optical measurements show that, after applying the first bleaching treatment, the reflectance increases. However for successive applications, a decrease of the reflectance is observed. This effect can be attributed to enamel teeth surface etching induced by the bleaching agents, allowing the inner dentin to contribute to the optical spectra and diminishing the reflectance. Additionally, in order to compare with previous studies in dentistry, colorimetric analysis of the process was also performed. The relevance in the use of protocols for cleaning valuable dental pieces in forensics, anthropology, and archeology is discussed.

A influência do peróxido de carbamida sobre a formação de colônias de estreptococos do grupo mutans

Due to the development of bleaching therapy, the evalDue to the development of bleaching therapy, the evaluation about the safety of its activity on the oral microbiota became necessary. This study aimed to test the effect of bleaching agents containing different concentrations of carbamide peroxide on the colonization of four strains of mutans streptococci. It was tested the bleaching gels containing 10%, 15%, 20% and 35% carbamide peroxide, in addition to the positive control (chlorhexidine 0,2%) and negative control (sterile saline solution). Most of the samples showed higher sensibility compared to the positive control, being the answer concentration dependent. We conclude that the carbamide peroxide makes a bad regulation the colonization by mutans streptococci at all concentrations tested.

The effect of bleaching agents on human enamel microhardness

Introduction. Bleaching agents can cause alteration of hard tissues of the tooth. The aim of this study was to evaluate the effect of two different concentrations of carbamide peroxide (10% and 35%) on human enamel microhardness. Material and Methods. The study was conducted on ten extracted teeth divided into two groups. The teeth were sectioned in mesiodistal direction using the diamond disc in order to obtain experimental and control samples. First group was exposed to the concentration of 10% carbamide peroxide (Opalescence gel, Ultradent. Pro, US) at the time intervals that corresponded to home night bleaching technique of vital teeth. Second group was exposed to high concentration of 35% carbamide peroxide (Opalescence Quick, Ultradent. Pro, US) at the time intervals that corresponded to the professional bleaching technique of vital teeth. Control samples were exposed to artificial saliva for the same time intervals as the samples from experimental group. Knoop?s test for enamel microhardness was performed at the beginning, after the first phase of therapy, after the therapy was completed and after three weeks of exposure to artificial saliva. The results were statistically analyzed using analysis of variance (ANOVA) and Student t-test. Results. The microhardness values of enamel samples treated with 10% carbamide peroxide decreased after 8 hours (261 khn) and three weeks of treatment (222 khn) but increased after three weeks of exposure to artificial saliva (263 khn). The decrease of enamel microhardness of the samples treated with 10% carbamide peroxide was not statistically significant. The microhardness values of enamel samples treated with 35% carbamide peroxide were reduced after 1 hour (235 khn) and 3 hours (190 khn) and increased after three weeks of exposure to artificial saliva (241 khn). Microhardness of enamel treated with 35% carbamide peroxide was significantly decreased in experimental samples compared to controls. Conclusion. Carbamide peroxide in concentration of 35% leads to the significant decrease in enamel microhardness compared to 10% carbamide peroxide.

Tooth Bleaching by Different Concentrations of Carbamide Peroxide and Hydrogen Peroxide Whitening Strips: An In Vitro Study

To investigate the tooth whitening effects of various concentrations of carbamide peroxide (CP) gels and 6% hydrogen peroxide (HP) whitening strips used on an intrinsic, in vitro stain model in a simulated home-applied bleaching protocol. Extracted third molars were sectioned and stained to Vita shade C4 using a standardized tea solution. Stained specimens were then bleached with 10, 15, 20, 22, and 30% CP gels applied in custom-made trays for 8-hour sessions for 14 days. A 6% HP whitening strip product was also tested in a regimen of twice-daily 30-minute treatments for 14 days. Shades were assessed at baseline and at 2, 5, 7, 10, and 14 days of treatment using a shade guide (SG) and a shade vision system (SVS), recorded as shade guide unit (SGU) changes from baseline, and CIE L*a*b* recordings using a chromometer. By day 14, all CP treatments resulted in at least 12 SGU improvements by SG and SVS methods: the HP treatment mean was just less than 12 SGU. With the chromometer, the CP improvements ranged from approximately 19 to 28 units and 16 units for the HP whitening strips. Observationally, by SG and SVS, CP treatments achieved the maximum improvement (12-13 SGU) at different time points: day 5 for 30% CP, day 10 for 22% CP, and day 14 for the other three treatments. SG and SVS data were virtually binary, switching from 0 to scores of 9 or above as bleaching progressed. The differences between the six treatments in the mean day to achieve a positive SG or SVS score (9 or more units) approached significance. For each of the SG, SVS, and L*a*b* scores, the dose-response correlation with CP concentration was significant at one or more assessment times. SG and SVS showed extremely strong agreement in detecting change and substantial agreement with L*a*b*. This in vitro study supports the limited data available from the very few available randomized controlled clinical trials indicating that CP and HP home-use bleaching systems can achieve considerable tooth whitening outcomes, albeit at different rates, which appear to be concentration dependent. There is a clear significant relationship for both concentration and duration of exposure for CP bleaching agents. The final shade change is independent of the concentration of bleaching agent, with time as the dominant variable. Higher concentrations of CP that have not been investigated previously may be a treatment option for esthetic improvement of shade where time is at a premium, but caution must be exercised in view of the possible increased incidence of sensitivity.

Tooth bleaching by different concentrations of carbamide peroxide and hydrogen peroxide whitening strips: an in vitro study

tooth bleaching by different concentrations of carbamide peroxide and hydrogen peroxide whitening strips: an in vitro study

Effect of 10% sodium ascorbate on the shear bond strength of composite resin to bleached bovine enamel

The purpose of this study was to comparatively investigate the effect of antioxidant treatment and delayed bonding after bleaching with three different concentrations of carbamide peroxide (CP) on the shear bond strength of composite resin to enamel. One hundred flat buccal enamel surfaces obtained from bovine incisors were divided into three bleaching groups of 10, 16 and 22% CP (n = 30) and a control group. Each bleaching group was then divided into three subgroups (n = 10). Group 1 consisted of specimens bonded immediately after bleaching. Group 2 specimens were treated with antioxidant agent, 10% sodium ascorbate, while Group 3 specimens were immersed in artificial saliva for 1 week after bleaching. Specimens in the control group were not bleached. After the specimens were bonded with Clearfil SE Bond and Clearfil AP-X, they were thermocycled and tested in shear until failure. Fracture analysis of the bonded enamel surface was performed using scanning electron microscope. The shear bond strength data was subjected to one-way analysis of variance followed by Duncan's multiple range test at a significance level of P < 0.05. Shear bond strength of composite resin to enamel that was bonded immediately after bleaching with 10, 16 and 22% CP was significantly lower than that of unbleached enamel (P < 0.05). For all three bleaching groups, when the antioxidant-treated and delayed bonding (1 week) subgroups were compared with the control group, no statistically significant differences in shear bond strength were noted (P < 0.05).

Shear Bond Strength of Enamel Treated with Seven Carbamide Peroxide Bleaching Agents

Lower average values of bond strength of adhesive systems to enamel bleached with 10% carbamide peroxide agents have been reported, but the effects of higher concentrations of carbamide peroxide bleaching agents are still unknown. The aim of this in vitro study was to evaluate the shear bond strength of enamel treated with different concentrations of carbamide peroxide to an adhesive system after a postbleaching period of storage in artificial saliva for 15 days. Seven carbamide peroxide bleaching agents with concentrations varying from 10 to 22% were analyzed. A placebo agent was used as a control group. The agents were applied on the enamel fragments for 8 h/d for 42 days. During the remaining time, the specimens were stored in artificial saliva. After that time, the fragments were stored individually in artificial saliva for 15 days. An adhesive system was used to bond resin-based composite cylinders on the enamel surface. Shear bond strength tests were performed and the fractured surfaces of the specimens were visually examined with a stereomicroscope at x 30. The analysis of variance did not show differences in shear bond strength among the treatment agents. The fractures for all treatment agents were predominantly adhesive. After 15 days storage in artificial saliva, different concentrations of carbamide peroxide bleaching agents and a placebo agent had the same enamel shear bond strength values. Concentrations varying from 10 to 22% carbamide peroxide agents cause no differences in shear bond strength of enamel to an adhesive system after 15 days of storage in artificial saliva.

High-concentrated carbamide peroxide bleaching agents effects on enamel surface.

Concern has been expressed regarding the adverse effects of peroxide-containing tooth bleaching agents on enamel surface. This study examined enamel average surface roughness before (baseline) and after an in-office bleaching protocol and investigated the influence of high concentrations of carbamide peroxide gels on its surface staining and morphology. Flat enamel surfaces were submitted to 35 and 37% carbamide peroxide or to no bleaching treatment (n = 10) and evaluated with a profilometer. Eight specimens from each group were randomly selected and immersed in a 2% methylene blue solution. Afterwards, specimens were ground into powder and prepared for the spectrophotometric analysis. Two remained specimens of each group were examined using a scanning electron microscope. Data were subjected to analysis of variance and Tukey test (P > 0.05). Baseline roughness average was statistically similar for all groups, however, 35% carbamide peroxide produced the roughest enamel surfaces. Different concentrations of carbamide peroxide produced similar staining means and enamel surface morphological alterations.