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Carbamide Peroxide (carbamide + peroxide)
Selected AbstractsScanning Electron Microscopy Study of Dental Enamel Surface Exposed to 35% Hydrogen Peroxide: Alone, With Saliva, and With 10% Carbamide PeroxideJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 3 2003MARIANNE SPALDING MS ABSTRACT Several vital bleaching systems have been introduced in response to the demand in esthetic dentistry. The active agents are commonly hydrogen peroxide or carbamide peroxide used in at-home or in-office techniques. Although generally positive results have been reported concerning the whitening ability of these agents, concerns still remain as to their effects on dental tissues. The purpose of this investigation was to evaluate the effect of these bleaching agents on the enamel surface morphology. Twelve extracted teeth were used according to three experimental protocols. In experimental protocol 1, specimens were treated with 35% hydrogen peroxide. In experimental protocol 2, after treatment with 35% hydrogen peroxide the specimens were immersed in natural saliva for 1 week. In experimental protocol 3, 35% hydrogen peroxide was applied once and 10% carbamide peroxide was applied for 1 week (12 h of 10% carbamide peroxide alternating with 12 h saliva). Scanning electron microscopy evaluation revealed that regional variation in tooth morphology surface sometimes exceeded the effects of the peroxide used according to experimental protocols. Thirty-five percent hydrogen peroxide had a tendency to promote an increase in density of pits. Precipitates were observed on specimen surfaces immersed in natural saliva according to protocol 2. A smooth and shiny surface was observed in specimens treated according to protocol 3. The potential relationship between surface alterations and differences in enamel permeability is currently under investigation. CLINICAL SIGNIFICANCE The differences in various articles written on the subject cannot be reconciled because of the lack of standardization of baseline data regarding factors such as location on the tooth, type of tooth, eruption or noneruption, and age in the oral cavity. This article demonstrates that, despite changes observed in the enamel surface after bleaching, normal variation in tooth morphology may exceed the effects of 35% hydrogen peroxide and 10% carbamide peroxide on the teeth. Hence, considering the morphologic features of the tooth surface, bleaching, as described in this study, can be considered safe for enamel. [source] Protective effect of Copalite surface coating on mercury release from dental amalgam following treatment with carbamide peroxideDENTAL TRAUMATOLOGY, Issue 3 2000I. Rotstein Abstract , The effect of Copalite coating on mercury release from dental amalgam following treatment with 10%, 20%, 30% and 40% carbamide peroxide was assessed in vitro, using a cold-vapour atomic absorption Mercury Analyzer System. Eighty samples of dental amalgam were automatically mixed in a dental amalgamator and condensed into silicon embedding molds. Forty amalgam samples were coated with three uniform layers of Copalite intermediary varnish and the other 40 samples were left uncoated. The coated and non-coated amalgam samples were exposed for 24 h to 10%, 20%, 30% or 40% carbamide peroxide preparations and compared with samples exposed to phosphate buffer. In the non-coated samples a significant increase of mercury concentration in solution was found following exposure to all carbamide peroxide preparations tested. Mercury concentration was directly related to carbamide peroxide concentration. In the Copalite-coated samples, significantly lower concentrations of mercury in solution were found as compared to the non-coated samples (P<0.01). In conclusion, exposure of amalgam restorations to 10%,40% carbamide peroxide-based bleaching agents increased the mercury release. Pre-coating of the external amalgam surfaces with Copalite significantly reduced the release of mercury. [source] Cytotoxicity and genotoxicity of sodium percarbonate: a comparison with bleaching agents commonly used in discoloured pulpless teethINTERNATIONAL ENDODONTIC JOURNAL, Issue 2 2010M. R. Fernández Fernández MR, Carvalho RV, Ogliari FA, Beira FA, Etges A, Bueno M. Cytotoxicity and genotoxicity of sodium percarbonate: a comparison with bleaching agents commonly used in discoloured pulpless teeth. International Endodontic Journal, 43, 102,108, 2010. Abstract Aim, To evaluate the cytotoxicity and genotoxicity of sodium percarbonate (SPC) in comparison with bleaching agents used on discoloured pulpless teeth. Methodology, The cytotoxicity and genotoxicity of bleaching agents were evaluated both in their pure form as well as at concentrations commonly used in clinical practice. Hydrogen peroxide (HP), carbamide peroxide (CP), sodium perborate (SP) and SPC were diluted in Dulbecco's modified Eagle's medium (DMEM) in series. To evaluate the cytotoxicity, the survival of 3T3/NIH mouse fibroblasts was measured photometrically using an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay after a 24 h-exposure period. Genotoxicity was indicated by micronuclei (MN) formation, and modification of the normal cell was analysed by light microscopy (400×). Statistical analysis was performed by one-way anova, followed by a multiple-comparison Tukey post hoc test (P < 0.05). Results, All groups exhibited a dose-dependent cytotoxicity. However, CP showed a similar cytotoxic effect when compared with DMEM-untreated control (UC) group. HP and SPC were significantly more cytotoxic than SP. The genotoxicity test showed that SPC and SP had an intermediate rate of MN frequency when compared with the UC group. The mean rate of MN frequency for HP was higher and statistically more significant than for the other groups tested. No difference was observed when CP and UC groups were compared. Conclusions, Sodium percarbonate showed cytotoxicity and genotoxicity similar to those of the other products tested. However, before SPC is used clinically, studies should be conducted to confirm its safety in vivo. [source] Influence of intracoronal bleaching agents on the ultimate strength and ultrastructure morphology of dentineINTERNATIONAL ENDODONTIC JOURNAL, Issue 7 2009V. Cavalli Abstract Objective, To evaluate the effects of intracoronal bleaching on ultimate tensile strength (UTS) of sound and etched dentine and its ultrastructure morphology. Methodology, Bovine dentine specimens with (e) or without previous etching with 37% phosphoric acid for 15 s were used for the intracoronal bleaching experiments. Teeth were randomly assigned to five treatments (n = 10): (C) control , no bleaching, (SP) sodium perborate, (CP) 35% carbamide peroxide, (25% HP) 25% hydrogen peroxide and (35% HP) 35% hydrogen peroxide. Bleaching was performed four times within a 72 h interval and afterwards, dentine pulp chamber blocks were obtained. The blocks were sectioned in 0.7 mm-thick slices and these were trimmed to reduce the inner dentine to a dumbbell shape with a cross-sectional area of 0.8 mm2. Specimens were tested with the microtensile method (0.5 mm min,1) and data were analysed (two-way anova -Tukey test, P < 0.05). Additional teeth were prepared for transmission electron microscopy (TEM) to evaluate dentine ultramorphology. Results, The mean values of the UTS (SD) in MPa for sound dentine were: C = 48.3(8.5)a, SP = 34.6 (8.2)b, CP = 32.9 (8.9)b, 25% HP = 28.0(4.6)b, 35% HP = 26.4(6.6)b, and pre-etched dentine: Ce = 38.9(13.8)a, SPe = 31.3 (9.3)ab, CPe = 28.4 (6.2)ab, 25% HPe = 30.0 (7.9)ab, 35% HPe = 19.9(4.6)b. Significant differences between the means are indicated by the letters. TEM observations exhibited demineralization areas for all bleaching treatments. Conclusion, Bleaching decreased dentine UTS after treatment. Pre-etched not-bleached dentine (Ce) presented UTS similar to pre-etched bleached dentine, except for 35% HPe. The decrease of UTS of bleached dentine could be attributed to ultrastructural alterations such as loss of inorganic components. [source] Radicular peroxide penetration from carbamide peroxide gels during intracoronal bleachingINTERNATIONAL ENDODONTIC JOURNAL, Issue 7 2008O. Gökay Abstract Aim, To evaluate and compare radicular peroxide diffusion from different concentrations of carbamide peroxide bleaching gels. Methodology, Fifty maxillary premolar teeth were separated into five groups (n = 10). Standardized endodontic access cavities were prepared in the occlusal surfaces, and the root canals were prepared using a step back technique and filled using the lateral compaction technique. The gutta-percha filling was removed 4 mm short of the cemento-enamel junction (CEJ) and a 2-mm-thick glass,ionomer cement base was placed. Outer root surfaces were sealed with wax and nail polish, leaving the coronal third of the tooth and the CEJ exposed. All teeth were immersed in a plastic tube containing 2 mL of distilled water, and the experimental groups were treated with a bleaching agent of either 10%, 17% or 37% carbamide peroxide (CP) or a mixture of 30% hydrogen peroxide (HP) and sodium perborate (SP) placed into the coronal pulp chamber of teeth and left for 24 h. Peroxide penetration was measured using the ferrothiocyanate method. Statistical analysis of data was conducted by using the Kruskal,Wallis Analysis of Variance and Mann,Whitney U test. Results, Higher peroxide penetration occurred with the 30% HP-SP mixture than with the CP bleaching gels, and the 37% CP group also promoted greater peroxide penetration than the other CP groups (P < 0.05). There was no statistically significant difference between 10% and 17% CP groups (P > 0.05). Conclusion, Peroxide penetration of CP gels was significantly lower than that of a HP-SP mixture. [source] Bleaching Agents with Varying Concentrations of Carbamide and/or Hydrogen Peroxides: Effect on Dental Microhardness and RoughnessJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 6 2008JULIANA JENDIROBA FARAONI-ROMANO DDS ABSTRACT Purpose:, To evaluate the effect of low and highly concentrated bleaching agents on microhardness and surface roughness of bovine enamel and root dentin. Methods:, According to a randomized complete block design, 100 specimens of each substrate were assigned into five groups to be treated with bleaching agents containing carbamide peroxide (CP) at 10% (CP10); hydrogen peroxide (HP) at 7.5% (HP7.5) or 38% (HP38), or the combination of 18% of HP and 22% of CP (HP18/CP22), for 3 weeks. The control group was left untreated. Specimens were immersed in artificial saliva between bleaching treatments. Knoop surface microhardness (SMH) and average surface roughness (Ra) were measured at baseline and post-bleaching conditions. Results:, For enamel, there were differences between bleaching treatments for both SMH and Ra measurements (p = 0.4009 and p = 0.7650, respectively). SMH significantly increased (p < 0.0001), whereas Ra decreased (p = 0.0207) from baseline to post-bleaching condition. For root dentin, the group treated with CP10 exhibited the significantly highest SMH value differing from those groups bleached with HP18/CP22, HP7.5, which did not differ from each other. Application of HP38 resulted in intermediate SMH values. No significant differences were found for Ra (p = 0.5975). Comparing the baseline and post-bleaching conditions, a decrease was observed in SMH (p < 0.0001) and an increase in Ra (p = 0.0063). Conclusion:, Bleaching agents with varying concentrations of CP and/or HP are capable of causing mineral loss in root dentin. Enamel does not perform in such bleaching agent-dependent fashion when one considers either hardness or surface roughness evaluations. CLINICAL SIGNIFICANCE Bleaching did not alter the enamel microhardness and surface roughness, but in root dentin, microhardness seems to be dependent on the bleaching agent used. [source] Evaluation of Side Effects and Patients' Perceptions during Tooth BleachingJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 6 2007RALPH H. LEONARD JR. DDS ABSTRACT Objective:, The objective of this nightguard vital bleaching (NGVB) study was to compare tooth sensitivity (TS), gingival irritation (GIr), and other side effects, as well as patients' perceptions during tooth bleaching, from treatment with experimental 5 and 7% hydrogen peroxide (HP) bleaching solutions with those of a commercially available 10% carbamide peroxide (CP) product. Materials and Methods:, Sixty-one participants completed the study wearing a scalloped maxillary treatment tray without reservoirs with the different concentrations of bleaching gels for 30 minutes twice a day for 7 days. Parameters evaluated were changes in gingival index (GI), nonmarginal gingival index, nongingival oral mucosal index, and tooth vitality. Participants were seen pretreatment, after 7 treatment days, and 1 week post-treatment. A daily log form to record TS and GIr was completed by each participant as well as a sensitivity questionnaire at each appointment. Additionally, at 10 months post-treatment, a questionnaire was sent to the participants concerning TS and GIr relative to the treatment process. Results:, Data from end-of-treatment questionnaires, daily log forms, and clinical examination revealed a statistical difference (p, 0.05) in the patients' ranking of and days of TS and GIr between group S (7% HP) and group T (10% CP, control group) at the end of active treatment. There also existed a statistical clinical change in the GI levels for groups R and S compared with the control group T. There was no statistical difference (p > 0.05) in any of the parameters evaluated among the three products at 7 days or 10 months post-treatment. Conclusions:, Participants in group S reported significantly more TS, GIr, and days of each compared with the control. There also existed a significant clinical change in the GI levels for groups R and S compared with the control group T. There was no significant difference among the three products at 7 days post-treatment. After ending treatment, TS/GIr was resolved in 2 to 3 days and did not recur during the 10 months post-treatment. CLINICAL SIGNIFICANCE The experimental HP bleaching solutions, as described in this study, can be used in NGVB with no long-term side effects as evaluated in this study for up to 10 months post-treatment. (J Esthet Restor Dent 19:355,366, 2007) [source] The Influence of Time Interval between Bleaching and Enamel BondingJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 2 2007Jéfferson Da Silva Machado dds ABSTRACT Objectives:, The purpose of this study was to investigate the penetration of a conventional adhesive material into enamel bleached with 16% carbamide peroxide and 38% hydrogen peroxide using optical light microscopy. Methods:, Extracted human teeth were randomly divided into eight experimental groups with six specimens each, according to the bleaching material and time interval after bleaching and before the bonding procedure. Groups were designated as follows: control group, restorations in unbleached teeth; restorations performed immediately after bleaching; restorations performed 7 days after bleaching; restorations performed 14 days after bleaching; and restorations performed 30 days after bleaching. The length of resin tags was measured with an Axiophot photomicroscope at 400× magnification for the calculation of the proportion of tags of study groups compared to the respective control groups. Analysis of variance was applied for comparison between groups; data were transformed into arcsine (p < 0.05). Results:, The specimens of experimental groups, in which restorations were performed 7, 14, and 30 days after bleaching, showed better penetration of adhesive material into enamel than specimens restored immediately after bleaching. There was no statistically significant difference between the bleaching materials employed or in the interaction between bleaching agent and time interval. Conclusions:, This suggests that a time interval of at least 7 days should be allowed between enamel bleaching and placement of adhesive bonding agents for accomplishment of composite resin restorations. CLINICAL SIGNIFICANCE Establishment of adequate time after bleaching is fundamental to allow the normal penetration of a one-bottle conventional adhesive onto the enamel surface. [source] Effects of a 10% Carbamide Peroxide Bleaching Agent on Roughness and Microhardness of Packable Composite ResinsJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 4 2005ROBERTA TARKANY BASTING DDS ABSTRACT Purpose:: Bleaching agents containing 10% carbamide peroxide may be applied to the surface of preexisting packable resin-based composite restorations. The aim of this in vitro study was to evaluate the effect of a 10% carbamide peroxide bleaching agent (Review, SS White, Rio de Janeiro, Brazil) on surface roughness and microhardness of three packable resin-based composites (Fill Magic condensable, Vigodent, Rio de Janeiro, Brazil; Alert, Jeneric Pentron, Wallingford, CT, USA; Definite, Degussa, Hanau, Germany). Materials and Methods: For the control (no bleaching) and experimental (bleaching treatment) groups, 12 specimens of each material were prepared in cylindrical acrylic molds. The experimental specimens were exposed to the bleaching agent for 6 hours a day for 3 weeks. During the remaining time (18 h), they were stored in artificial saliva. The control specimens remained immersed in artificial saliva throughout the experiment. Surface roughness and microhardness measurements were performed on the top surface of each specimen. Results: Analysis of variance and the Tukey test showed no significant differences in roughness among the packable composites evaluated (p=.18), but those submitted to the treatment with a 10% carbamide peroxide bleaching agent displayed significantly higher mean surface roughness than did the corresponding control group for each material. For the microhardness tests, there were significant differences among materials (p < .0001). Alert showed the highest microhardness values followed by Definite and Fill Magic condensable. Conclusions: Ten percent carbamide peroxide bleaching agents may change the surface roughness of packable composites, but they do not alter their microhardness. [source] Shear Bond Strength of Enamel Treated with Seven Carbamide Peroxide Bleaching AgentsJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 4 2004ROBERTA TARKAN. ABSTRACT Purpose:: 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. Materials and Methods: 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 ×30. Results: 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. Conclusion: 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. [source] Nightguard Vital Bleaching of Tetracycline-Stained Teeth: 90 Months Post TreatmentJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 3 2003RALPH H. LEONARD JR DDS ABSTRACT Purpose: The purpose of this longitudinal whitening study was to determine the stability, post-treatment side effects, and patient satisfaction at 90 months post treatment after 6 months of active treatment of tetracycline-stained teeth with 10% carbamide peroxide. Materials and Methods: Fifteen of 21 participants enrolled in the study (71%) were contacted and asked to participate in a survey concerning their whitening experience. Participants were asked whether there had been any change in the shade of their teeth after treatment and if they had experienced any side effects that they believed were treatment related. Eight of the 15 participated in a clinical examination. Results: Nine participants (60%) reported no obvious shade change or only a slight darkening not noticed by others. None reported darkening back to the original shade; however, four had re-treated their teeth. Examiners were in agreement with the participants' perception of shade change upon comparing pretreatment and post-treatment photographs and Vita® shade (Vita Zahnfabrik D-79713, Bad Sackingen, Germany) values. The degree of improvement over the pretreatment shade was significant for the 90-month post-treatment shade (p < .01). All respondents (n = 15) denied having to have a crown or root canal or tooth sensitivity that they believed was treatment related. CLINICAL SIGNIFICANCE The results of this study of nightguard vital bleaching indicate that tetracycline-stained teeth can be whitened successfully using extended treatment time and that shade stability may last at least 90 months post treatment (range 84,100 mo). Patients participating in this study were over-whelmingly positive about the procedure in terms of shade retention and lack of post-treatment side effects. [source] Scanning Electron Microscopy Study of Dental Enamel Surface Exposed to 35% Hydrogen Peroxide: Alone, With Saliva, and With 10% Carbamide PeroxideJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 3 2003MARIANNE SPALDING MS ABSTRACT Several vital bleaching systems have been introduced in response to the demand in esthetic dentistry. The active agents are commonly hydrogen peroxide or carbamide peroxide used in at-home or in-office techniques. Although generally positive results have been reported concerning the whitening ability of these agents, concerns still remain as to their effects on dental tissues. The purpose of this investigation was to evaluate the effect of these bleaching agents on the enamel surface morphology. Twelve extracted teeth were used according to three experimental protocols. In experimental protocol 1, specimens were treated with 35% hydrogen peroxide. In experimental protocol 2, after treatment with 35% hydrogen peroxide the specimens were immersed in natural saliva for 1 week. In experimental protocol 3, 35% hydrogen peroxide was applied once and 10% carbamide peroxide was applied for 1 week (12 h of 10% carbamide peroxide alternating with 12 h saliva). Scanning electron microscopy evaluation revealed that regional variation in tooth morphology surface sometimes exceeded the effects of the peroxide used according to experimental protocols. Thirty-five percent hydrogen peroxide had a tendency to promote an increase in density of pits. Precipitates were observed on specimen surfaces immersed in natural saliva according to protocol 2. A smooth and shiny surface was observed in specimens treated according to protocol 3. The potential relationship between surface alterations and differences in enamel permeability is currently under investigation. CLINICAL SIGNIFICANCE The differences in various articles written on the subject cannot be reconciled because of the lack of standardization of baseline data regarding factors such as location on the tooth, type of tooth, eruption or noneruption, and age in the oral cavity. This article demonstrates that, despite changes observed in the enamel surface after bleaching, normal variation in tooth morphology may exceed the effects of 35% hydrogen peroxide and 10% carbamide peroxide on the teeth. Hence, considering the morphologic features of the tooth surface, bleaching, as described in this study, can be considered safe for enamel. [source] Greening of the Tooth,Amalgam Interface during Extended 10% Carbamide Peroxide Bleaching of Tetracycline-Stained Teeth: A Case ReportJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 1 2002VAN B. HAYWOOD DMD ABSTRACT At-home bleaching with 10% carbamide peroxide in a custom-fitted tray has been shown to have some minor effects on certain brands of amalgam, pertaining to mercury release, but generally, effects on amalgam are not considered clinically significant. However, in this case report, a greening of the tooth structure in certain areas immediately adjacent to amalgam restorations in the maxillary and mandibular first molars occurred during tooth whitening. Other amalgam restorations in mandibular and maxillary second molars in the same mouth did not demonstrate any green discoloration of the teeth. Upon removal of the affected amalgam restorations, recurrent decay was present in the areas of tooth greening but not in other areas adjacent to the restoration. The teeth were restored with posterior composite restorations. Whether the green discoloration was a result of some loss of material from a particular brand of amalgam, indicating leakage, or indicative of original or recurrent tooth decay is unclear in this single-patient situation. Other patients in the same study did not demonstrate this occurrence. Dentists should be ready to replace amalgam restorations should this green discoloration in adjacent tooth structure occur during bleaching, in case decay is present. CLINICAL SIGNIFICANCE The unusual discoloration cited suggests that amalgam restorations in potentially esthetic areas, including the lingual of anterior teeth, should be replaced prior to bleaching, to avoid the problem of difficult stain removal or translucency allowing restoration visibility following bleaching. [source] In vitro evaluation of the effect of a current bleaching agent on the electrochemical corrosion of dental alloysJOURNAL OF ORAL REHABILITATION, Issue 10 2002enay Canay summary, The nightguard bleaching of discoloured teeth is currently performed by using % 10 carbamide peroxide. While the material is effective on the bleaching of natural teeth, it may deteriorate crowns, bridges and amalgam restorations placed in the mouth. The purpose of the present study was to investigate the effect of 10% carbamide peroxide on the electrochemical corrosion of various dental casting alloys used for fixed partial dentures and dental amalgam. Tafel extrapolation curves were obtained by the corrosion cell that facilitated simulation of the oral enviroment and comparison of the corrosion rates of alloys and amalgam was accomplished. The results revealed that unpolished amalgam and nickel-chromium alloy samples had the most and noble alloys had the least corrosion rate. [source] | ||||||||||