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Sample records for carbamide

  1. REMINERALIZATION POTENTIAL OF A CARBAMIDE BLEACHING AGENT

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    Borislavova Marinova-Takorova Mirela

    2016-03-01

    Full Text Available Background: Bleaching has gradually became a popular procedure for people searching for aesthetic improvement. The aim of this in vitro study was to investigate the effect of bleaching with 45% carbamide peroxide on the level of mineralization of enamel, using laser fluorescence. Materials and methods: Sixty extracted human teeth were treated with 45% carbamid peroxide (Opalescence, Ultradent, 4 consecutive days for one hour each day. The effect of the bleaching agent on the level of mineralization of enamel was measured with DIAGNO dent pen. The statistical method we use was descriptive analysis. Results: The average values, measured before the applications of the carbamid peroxide were 6.33. On the first day they were 5.41, on the second 5.38, on the third 5.11 and 5.35 on the forth. Conclusion: There was observed a slight remineralization effect due to the incorporated Ca2+ and F- ions in the bleaching agent that we have used.

  2. OPTICAL PROPERTIES OF CARBAMIDE AQUEOUS SOLUTIONS

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    E. V. Avramenko

    2016-03-01

    Full Text Available Subject of Research. The paper presents the results of measurements of refractometric properties (refractive index n, its temperature factor dn/dt and the ultraviolet spectral absorption in carbonic acid diamide aqueous solutions (carbamide depending on solid residue mass fraction md = 0-50 % and on temperaturet = 10-70 °C.Method of Research. Laboratory methods ofliquid-phase medium refractometry and ultraviolet spectrophotometry were applied for the research. We carried out computational modeling of electronic states spectrum for the carbonic acid diamide molecule and theoretical calculation of the fundamental electronic absorption of the molecule in the ultraviolet wavelenght region.Main Results. We have established that the solution concentration md has a nonlinear character and may be represented by the quadratic polynomial with the error Δn= ± 0,0005. We have shown the refractive indexdependence on temperature n(t changes in linear fashion att = 10-70 °C.At that, the inclination of lines n(t increases at the increase of md; so, the temperature factor dn/dt may be approximated by the quadratic polynomial. Transmission spectra of solutions in the spectral region λ= 225-760 nm have no special features except for the sharp edge in the short-wavelength region; the fundamental electronic absorptionis responsible for it. We have established that dispersion dependences of the refraction index n(λ;md in aqueous solutions of carbamide at λ= 360-760 nm and at md = 0-50 % may be calculated with the satisfactory error without additional adjustable parameters from the ultraviolet absorption data in terms of the one-dimentional oscillator Lorentz model.PracticalRelevance. Representedmeasurements of carbonic acid diamide aqueous solutions optical properties may be applied for the adjustment and calibration of commercial refractometers at processing lines of the AdBlue reagent manufacture for the selective catalytic reduction (SCR of motor transport

  3. In vitro antibacterial effect of carbamide peroxide on oral biofilm

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    Chao Shu Yao

    2013-06-01

    Full Text Available This study compared the effects of carbamide peroxide (CP and chlorhexidine (CHX on oral biofilm in vitro. Collagen-coated hydroxyapatite discs were inoculated with subgingival plaque. After 3 weeks, the emergent biofilms were subjected to 1-, 3-, and 10-min exposures of a 1% CHX gel, a 5% CP gel and rinse, and a 10% CP gel and rinse. Subsequently, the biofilms were stained using a two-colour fluorescent dye kit for confocal laser scanning microscopy, and the volume ratio of dead bacteria to all bacteria was analysed. Compared to a non-treated gel control, the active agents killed bacteria on all the discs, with higher concentration and longer exposure times killing more bacteria. The rinse form disrupted the biofilm quicker than the gel form. Overall, 10% CP showed more disruption of biofilm and a greater proportion of killed bacteria than 1% CHX (p<0.05.

  4. Comparing the Effect of Different Bleaching Regims of Carbamide Peroxide on Microhardness of Z250 Composite

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    B Esmaeili

    2015-11-01

    Full Text Available Introduction: Bleaching products with oxidizing mechanism can exert side effects on the restorative materials existing in the oral cavity. Since bleaching agents are applied in different concentrations, the present study aimed to compare the effect of different bleaching regims of carbamide peroxide on microhardness of Z250 microhybride composite. Methods: In this in vitro study , 32 specimens of micro hybride composite (Z250 were made which were randomly divided into 4 subgroups (n=8: G1: bleached with10% carbamide peroxide 4 hours a day for 2 weeks G2: bleached with 16%carbamide peroxide 3 hours a day for 2 weeks G3: bleached with 22%carbamide peroxide 1hour a day for 2 weeks G4: the control subgroup stored in distilled water at 37◦c for 2 weeks. Microhardness of specimens was measured before and after bleaching using Vickers hardness testing machine. Moreover, the study data were analyzed statistically applying Anova and t-test (&alpha= 0.05. Results: This study findings revealed that using bleaching agent significantly decreased the  microhardness of composite resin in the bleaching groups compared to the control group, though the concentration of carbamide peroxide produced no significant effect on the microhardness value. (p>0.13 Conclusion: Bleaching therapy can cause a reduction in microhardness of Z250 composite and different concentrations of carbamide peroxide can reduce microhardness of Z250 to the same value.

  5. Effect of Surface Polishing on Mercury Release from Dental Amalgam After Treatment 16% Carbamide Peroxide Gel

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    Z. Khamverdi

    2011-03-01

    Full Text Available Objectives: This study evaluated the effect of surface polishing on mercury release from dental amalgam after treatment with 16% carbamide peroxide gel.Materials and Methods: Ninety-six samples from two different amalgam brands were prepared in truncated cone-shaped PVC polymer molds with an external surface area of 195 mm². Half of the specimens were polished with green and red rubber, a brush and tin oxide paste at low speed. Samples were treated with 16% carbamide peroxide gel intubes containing 3 mL of carbamide peroxide gel and 0.1 mL of distilled water for 14 and 28 hours. Subsequently, carbamide peroxide gel on the sample surfaces was rinsed away with 7.0 mL of distilled water until the volume of each tube increased to 10 mL. Themercury level of each solution was measured using the VAV–440 mercury analyzer system.Considering the surface area of each amalgam disc, mercury amounts were calculated in μg ⁄mm². Data were analyzed using two-way ANOVA.Results: There were significant differences between the mean levels of mercury release from polished vs. unpolished amalgam surfaces after treatment with 16% carbamide peroxide.Increasing the storage time from 14 to 28 hours did not result in significant changes in the amount of mercury release. There was no significant interaction effect between amalgam surface polish and storage time statistically.Conclusion: Polished amalgam restorations release less mercury after treatment with carbamide peroxide bleaching gel in comparison with unpolished amalgam restorations.

  6. Effect of Surface Polishing on Mercury Release from Dental Amalgam After Treatment 16% Carbamide Peroxide Gel

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    Z. Khamverdi; Masoum, T.; Sh. Kasraei; Azarsina, M.

    2011-01-01

    Objectives: This study evaluated the effect of surface polishing on mercury release from dental amalgam after treatment with 16% carbamide peroxide gel. Materials and Methods: Ninety-six samples from two different amalgam brands were prepared in truncated cone-shaped PVC polymer molds with an external surface area of 195 mm2. Half of the specimens were polished with green and red rubber, a brush and tin oxide paste at low speed. Samples were treated with 16% carbamide peroxide gel in tubes co...

  7. Effectiveness of different carbamide peroxide concentrations used for tooth bleaching: an in vitro study

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    Sônia Saeger Meireles

    2012-04-01

    Full Text Available OBJECTIVES: This in vitro study evaluated the effectiveness of three carbamide peroxide concentrations used for tooth bleaching treatments. MATERIAL AND METHODS: Sixty bovine dental slabs (6x6x3 mm were obtained, sequentially polished, submitted to artificial staining (baseline and randomized into four groups (n=15, according to the bleaching agent concentration: distilled water (control, 10% (CP10, 16% (CP16 or 37% (CP37 carbamide peroxide. CP10 and CP16 were covered with 0.2 mL of the respective bleaching gels, which were applied on enamel surface for 4 h/day during two weeks. Samples of CP37 were covered with 0.2 mL of the bleaching gel for 20 min. The gel was light activated by two 40-s applications spaced by 10-min intervals. The gel was renewed and applied 3 times per clinical session. This cycle was repeated at 3 sessions with 5 days of interval between them. Tooth shade evaluations were done with a digital spectrophotometer at T0 (baseline, T1 (after 1-week of treatment and T2 (1-week post-bleaching. Tooth shade means were statistically analyzed by Kruskal-Wallis and Friedman's tests and color parameters were analyzed by two-way ANOVA and Tukey's test (p0.05. CONCLUSIONS: One week after the end of the treatment, all carbamide peroxide concentrations tested produced similar tooth color improvement.

  8. THE EFFECT OF THE APPLICATION OF 20% CARBAMIDE PEROXIDE ON THE GLASS IONOMER CEMENT TYPE II SURFACE HARDNESS

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    Ali Noerdin

    2015-06-01

    Full Text Available In dental bleaching, carbamide peroxide is usually used at concentration of 10%, 15%, to 20%. The result of our previous study showed that the application of 10% and 15% carbamide peroxide bleaching agent has increased the surface hardness of glass ionomer cement. The purpose of this study was to observe the effect of 20% carbamide peroxide bleaching to glass ionomer surface hardness. Twenty specimens of glass ionomer type II after exposed to 20% carbamide peroxide were divided into two application time groups: 4 and 8 hours per day. Glass ionomer cement surface hardness was measured by Vickers Microhardness Tester series HMV-2 with a weight of 0,025 Hv for 20 seconds. The measurement was conducted at before/no application, after a week, and after 2 weeks of application in both groups. It can be concluded that the application of 20% carbamide peroxide bleaching agent could increase the surface hardness of glass ionomer cement after 1 week and 2 weeks application period.

  9. Effect of chemical activation of 10% carbamide peroxide gel in tooth bleaching.

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    Batista, Graziela Ribeiro; Arantes, Paula Tamiao; Attin, Thomas; Wiegand, Annette; Torres, Carlos Rocha

    2013-01-01

    This study aimed to evaluate the efficacy of chemical agents to increase the bleaching effectiveness of 10% carbamide peroxide. Two hundred and ninety enamel-dentin discs were prepared from bovine incisors. The color measurement was performed by a spectrophotometer using the CIE L*a*b*system. The groups were divided according to the bleaching treatment: negative control group (NC): without bleaching; positive control group (PC): bleached with 10% carbamide peroxide gel without any chemical activator; Manganese gluconate (MG); Manganese chloride (MC); Ferrous gluconate (FG); Ferric chloride (FC); and Ferrous sulphate (FS). Three different concentrations (MG, MC, FG, FC: 0.01, 0.02 and 0.03% w/w; FS: 0.001, 0.002 and 0.003% w/w) for each agent were tested. The bleaching gel was applied on the specimens for 8 h, after which they were immersed in artificial saliva for 16 h, during 14 days. Color assessments were made after 7 and 14 days. The data were analyzed by repeated measures analysis of variance and Tukey's test (5%). Generally, the test groups were unable to increase the bleaching effect (ΔE) significantly compared to the PC group. Only for ΔL, significant higher values compared to the PC group could be seen after 7 days in groups MG (0.02%), and FS (0.002 and 0.003%). The NC group showed significantly lower values than all tested groups. It was concluded that for home bleaching procedures, the addition of chemical activators did not produce a bleaching result significantly higher than the use of 10% carbamide peroxide without activation, and that the concentration of chemical activators used did not significantly influence the effectiveness of treatment. PMID:23390623

  10. Influence of dental biofilm on release of mercury from amalgam exposed to carbamide peroxide.

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    Steinberg, Doron; Blank, Ori; Rotstein, Ilan

    2003-10-15

    Tooth bleaching is a popular procedure in modern aesthetic dentistry. Bleaching agents may affect amalgam restorations by altering the release of mercury. The aim of this study was to explore the effect of biofilm-coated amalgam restorations on the release of mercury in the presence of carbamide peroxide. Samples of SDI and Valliant amalgams were submerged for either 14 days or 7 months in buffered KCl after which they were coated with saliva, bacteria, and polysaccharides. The samples were exposed to 10% carbamide peroxide (CP) for 24 h. The amount of mercury released was examined for 120 h. Results showed that most of mercury release occurred within the first 24 h, after which the release rate decreased sharply. After 120 h the release of mercury from the tested samples was minimal and similar to the control group. The presence of biofilm coating on the amalgam samples did not induce the release of mercury but tended to reduce mercury release into the surrounding environment. CP induces the release of mercury from amalgam samples. However, the presence of biofilm did not prevent large amounts of mercury release from amalgam coated with biofilms and exposed to CP. This study indicates that dental biofilm may retard the release of mercury from amalgam restorations.

  11. The effect of space holder content and decomposition methods in fabrication of aluminum foams by powder metallurgy method using carbamide space holder

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    Amirah, A. H.; Nurulakmal, M. S.; Anasyida, A. S.

    2016-07-01

    The effect of space holder amount and decomposition methods on the morphology, density and porosity and compressive properties of aluminum foams were investigated. Aluminum foam was fabricated by powder metallurgy method using spherical carbamide as space holder using three different decomposition method of carbamide includes; dissolution process, normal sintering process and two step sintering process. Aluminum foam with 60 wt.% carbamide has the lowest density and exhibited the highest porosity for all the decomposition. The results indicated that Al foams produced by dissolution method have the highest compressive properties with acceptable density and porosity value.

  12. Effect of fluoride-free and fluoridated carbamide peroxide gels on the hardness and surface roughness of aesthetic restorative materials

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    Homayoon Alaghehmand

    2013-01-01

    Full Text Available Background: Bleaching products may show some side effects on soft and hard tissues and restorative materials in the oral cavity. This study evaluated the effect of carbamide peroxide gel with and without fluoride ions on the microhardness and surface roughness of tooth-colored restorative materials. Materials and Methods: In this in-vitro study, 76 cubic specimens (4 mm 3 × 4 mm 3 × 3 mm 3 were fabricated from 4 aesthetic A3-shade restorative materials. These materials consisted of two composite resins and two glass ionomers. The specimens made from each material were treated with the following surface treatments: 1. Control group: The specimens were not bleached and were stored in normal saline. Group 2. Fluoridated 20% carbamide peroxide gel, treated 3 h a day for 4 weeks. Group 3. Treated 1 h a day with fluoride-less 22% carbamide peroxide for two weeks. From each group, three other specimens were selected to be evaluated in terms of changes in surface roughness, under scanning electron microscopy (SEM. Results: In this study, fluoridated 20% carbamide peroxide gel increased the microhardness of the four aesthetic restorative materials. The fluoride-free carbamide peroxide 22% reduced the microhardness of the four used materials, which this change was significant for Vitremer and Amelogen. SEM analyses showed changes in surface roughness of glass ionomer specimens. Conclusion: The effect of bleaching on the microhardness of restorative materials is material dependent. Before the application of bleaching systems on the glass ionomer materials, the application of a protective barrier should be considered.

  13. Utilisation of the energy-independent underground gasification-uvea process for carbamide production; Einsatz des energieautarken Untertagevergasungs-Urea-Prozesses zur Carbamid-Herstellung

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    Nakaten, Natalie; Kempka, Thomas [Helmholtz Zentrum Potsdam, Deutsches GeoForschungszentrum (GFZ) Potsdam (Germany); Schlueter, Ralph [DMT GmbH und Co. KG, Essen (Germany). Abt. Geologie und Bohrlochvermessungen; Hamann, Joerg [EPC Industrial Engineering Deutschland GmbH, Alzenau (Germany); Islam, Rafiqul [Dhaka Univ. (Bangladesh). Dept. of Applied Chemistry and Chemical Engineering; Azzam, Rafig [RWTH Aachen (Germany). Lehrstuhl fuer Ingenieur- und Hydrogeologie

    2011-08-15

    The worldwide coal resources have an energy supply potential of several hundred years. However, great depths, thin seams and tectonic faults may greatly restrict the utilisation of the coal seams by means of conventional conveyor technologies. With the aim of production of a conveyable synthesis gas underground coal gasification (UCG) offers an environmentally friendly and economically viable possibility of utilisation of previously inaccessible coal deposits. The high-calorific UCG synthesis gas can be used, for example, for the generation of electricity in an integrated gas and steam turbine process (GaS) as well as the production of chemical starting materials. One possibility of product recovery from the UCG synthesis gas is the production of the fertiliser carbamide (CH{sub 6}N{sub 2}O{sub 2}). The aim of this study is the development of a utilisation concept for coal deposits on the basis of a combined and energy-independent UCG-GaS-urea process. To check the utilisation concept based on an independent electricity supply an economic feasibility study for a selected investigation area in the north of Bangladesh was carried out with consideration of the economic viability and potential of the UCG-GaS-urea process. (orig.)

  14. Examination of native and carbamide peroxide-bleached human tooth enamel by atomic force microscopy.

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    Mahringer, Christoph; Fureder, Monika; Kastner, Markus; Ebner, Andreas; Hinterdorfer, Peter; Vitkov, Ljubomir; Hannig, Matthias; Kienberger, Ferry; Schilcher, Kurt

    2009-10-01

    Atomic force microscopy (AFM) was used to study the effects of bleaching on the morphology of the enamel surface with nanoscale resolution. Samples of human tooth enamel with native (pumiced) or fine-polished surfaces were examined before and after bleaching with 30% carbamide peroxide. The obtained profilometric AFM data revealed significant morphological surface alterations. After 1 h of bleaching, the surface roughness increased significantly from 19 +/- 4nm to 33 +/- 5 nm. Six-hour bleaching did not produce any significant further increase in enamel surface roughness. The interrod junction depth raised more than twice after 1 h of bleaching. After 6 h of bleaching, a further and significant increase in interrod junction depth was recorded. This alteration might be a consequence of oxidation and a subsequent partial lysis of the tooth enamel matrix proteins.

  15. Ion release from a composite resin after exposure to different 10% carbamide peroxide bleaching agents

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    Renata Plá Rizzolo Bueno

    2012-06-01

    Full Text Available OBJECTIVE: This in vitro study evaluated the influence of two 10% carbamide peroxide bleaching agents - a commercial product (Opalescence PF; Ultradent Products, Inc. and a bleaching agent prepared in a compounding pharmacy - on the chemical degradation of a light-activated composite resin by determining its release of ions before and after exposure to the agents. MATERIAL AND METHODS: Thirty composite resin (Filtek Z250; 3M/ESPE samples were divided into three groups: group I (exposed to Opalescence PF commercial bleaching agent, group II (exposed to a compounded bleaching agent and group III (control - Milli-Q water. After 14 days of exposure, with a protocol of 8 h of daily exposure to the bleaching agents and 16 h of immersion in Milli-Q water, the analysis of ion release was carried out using a HP 8453 spectrophotometer. The values were analyzed statistically by ANOVA, Tukey's test and the paired t-tests. The significance level was set at 5%. RESULTS: After 14 days of the experiment, statistically significant difference was found between group II and groups I and III, with greater ion release from the composite resin in group II. CONCLUSIONS: The compounded bleaching agent had a more aggressive effect on the composite resin after 14 days of exposure than the commercial product and the control (no bleaching.

  16. At-home vital bleaching: a comparison of hydrogen peroxide and carbamide peroxide treatments.

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    Berga-Caballero, Amparo; Forner-Navarro, Leopoldo; Amengual-Lorenzo, José

    2006-01-01

    Tray bleaching of vital teeth performed at home by the patient under the dentist s supervision, whether alone or in combination with any of the in-office techniques, provides an interesting alternative to other methods employed in this type of dental treatment. This bleaching procedure applies low-concentration peroxides to the enamel by means of a custom-made mouth tray specifically designed for this purpose. The aim of this study is to examine and compare two commercially-available bleaching products, at equivalent concentrations, for use in this technique: VivaStyle (Vivadent) and FKD (Kin); the former is a 10% carbamide peroxide and the latter a 3.5% hydrogen peroxide formulation. It examines the parameters that must be monitored during the application of this type of procedure and presents 6 cases (3 treated with one of the above-mentioned products and the other 3 with the other), establishing the bleaching power of the products and the appearance and intensity of post-operatory hypersensitivity. The results obtained show that both products are effective for the purpose for which they were designed. In general, dental hypersensitivity was minimal. PMID:16388304

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

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    Sérgio Augusto Morey Ourique

    2011-10-01

    Full Text Available 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.

  18. Synthesis and structures of new uranyl malonate complexes with carbamide derivatives

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    Serezhkina, L. B., E-mail: Lserezh@samsu.ru [Samara State University (Russian Federation); Grigor’ev, M. S. [Russian Academy of Sciences, Frumkin Institute of Physical Chemistry and Electrochemistry (Russian Federation); Medvedkov, Ya. A.; Serezhkin, V. N. [Samara State University (Russian Federation)

    2015-09-15

    Crystals of new malonate-containing uranyl complexes [UO{sub 2}(C{sub 3}H{sub 2}O{sub 4})(Imon)(H{sub 2}O)] (I) and [UO{sub 2}(C{sub 3}H{sub 2}O4)(Meur){sub 3}] (II), where Imon is imidazolidin-2-one (ethylenecarbamide) and Meur is methyl-carbamide, have been synthesized and studied by X-ray diffraction. Both compounds crystallize in the monoclinic system with the following unit-cell parameters (at 100 K): a = 11.1147(10) Å, b = 6.9900(6) Å, c = 14.4934(12) Å, β = 92.042(2)°, V = 1125.30(17) Å{sup 3}, sp. gr. P2{sub 1}/n, Z = 4, R{sub 1} = 0.0398 (I); a = 16.6613(5) Å, b = 9.5635(3) Å, c = 22.9773(6) Å, β = 103.669(2)°, V = 3557.51(18) Å{sup 3}, sp. gr. C2/c, Z = 8, R{sub 1} = 0.0207 (II). The crystals are composed of electroneutral chains [UO{sub 2}(C{sub 3}H{sub 2}O{sub 4})(Imon)(H{sub 2}O)] and mononuclear groups [UO{sub 2}(C{sub 3}H{sub 2}O{sub 4})(Meur){sub 3}] as the structural units belonging to the crystal-chemical groups AT{sup 11}M{sub 2}{sup 1} and AB{sup 01}M{sub 3}{sup 1} (A =UO{sub 2}{sup 2+}, T{sup 11} and B{sup 01} = C{sub 3}H{sub 2}, M{sup 1} = Imon, H{sub 2}O, or Meur), respectively, of uranyl complexes. The packing modes of the uranyl-containing complexes were analyzed by the method of molecular Voronoi—Dirichlet polyhedra.

  19. A Clinical Study of the Effectiveness of Two Different 10% Carbamide Peroxide Bleaching Products: A 6-Month Followup

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    S. R. Grobler

    2011-01-01

    Full Text Available The purpose of this study was to evaluate the efficacy of two different 10% carbamide peroxide bleaching products just after treatment and after a 6-month follow-up period. Methods. Two 10% carbamide peroxide products (Opalescence PF and Nite White ACP were applied nightly for 14 days, according to the manufacturers' instructions. The color of teeth 11 and 21 of thirty-four subjects having A2 or darker teeth were measured with a spectrophotometer (L∗;a∗;b∗ before treatment, just after treatment (14 days and after 6 months. Results and Conclusions. Both products produced significant whitening of teeth with total color change (ΔEab∗ of approximately 5.20 units. There was a significant improvement in all 3 color coordinates (L*,a*, and b∗ for up to 6 months postbleaching (P<.05. Nite White showed a higher degree of relapse (27% than Opalescence (18% over the 6-month period. It is suggested that rebleaching after 6 months is not necessary.

  20. In vitro evaluation of human dental enamel surface roughness bleached with 35% carbamide peroxide and submitted to abrasive dentifrice brushing

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    Worschech Claudia Cia

    2003-01-01

    Full Text Available The aim of this in vitro study was to evaluate the surface roughness of human enamel bleached with 35% carbamide peroxide at different times and submitted to different superficial cleaning treatments: G1 - not brushed; G2 - brushed with fluoride abrasive dentifrice; G3 - brushed with a non-fluoride abrasive dentifrice; G4 - brushed without dentifrice. Sixty fragments of human molar teeth with 4 x 4 mm were obtained using a diamond disc. The specimens were polished with sandpaper and abrasive pastes. A perfilometer was used to measure roughness average (Ra values of the initial surface roughness and at each 7-day-interval after the beginning of treatment. The bleaching was performed on the surface of the fragments for 1 hour a week, and the surface cleaning treatment for 3 minutes daily. The samples were stored in individual receptacles with artificial saliva. Analysis of variance and the Tukey test revealed significant differences in surface roughness values for G2 and G3, which showed an increase in roughness over time; G1 and G4 showed no significant roughness differences. The bleaching with 35% carbamide peroxide did not alter the enamel surface roughness, but when the bleaching treatment was performed combined with brushing with abrasive dentifrices, there was a significant increase in roughness values.

  1. Carbamide peroxide gel stability under different temperature conditions: is manipulated formulation an option?

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    Camila de Martini Bonesi

    2011-12-01

    Full Text Available Nowadays the use of gel containing carbamide peroxide (CP prepared in Pharmacy is a normal practice in the population. However, the quality of this product is questionable concerning its stability. The aim of this study is was to synthesize and to analyze this drug alone or associated to Carbopol gel through analytical methodology compatible with the routine of the Pharmacies. The reaction between urea and hydrogen peroxide was carried out at different resting times: 24 hours (CP 24 powder and 48 hours (CP48 powder after the mixture. Both products were associated with Carbopol 940® gel 1.5% (G generating G24 and G48 samples. The stability of powders (CP24 e CP48 and the formulations (G24 and G48 were evaluated as a function of time (15, 40 and 45 days and thermal variation (refrigeration: 8 °C±1; thermal shock 32 °C±1 /8 °C±1; stove: 32 °C±1, using a standard titration method. As a result, only under refrigeration the CP24 and CP48 contents remained stable during the period of 45 days. An interesting finding was that G24 and G48 presented greater stability for at least 45-days under refrigeration and thermal shock conditions, and up to 30 days under stove conditions. The results for the G24 and G48 were slightly higher than those obtained for the control. Therefore, we were able to conclude that association with Carbopol 940® Gel 1.5 % provided greater CP stability and that manipulated formulations containing CP may be viable for use in a period of 45 days under refrigeration conditions. The titration proved to be an effective technique for the analysis of CP with or without Carbopol 940® gel 1.5%.Atualmente, a utilização de gel contendo peróxido de carbamida manipulado em Farmácia é uma prática comum na população. No entanto, a qualidade deste produto é questionada, sobretudo no que se refere à estabilidade deste fármaco. O objetivo deste trabalho consiste na avaliação da viabilidade de sintetizar e analisar

  2. Effects of 15% carbamide peroxide and 40% hydrogen peroxide on the microhardness and color change of composite resins.

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    Sedighe Sadat Hashemi Kamangar

    2014-04-01

    Full Text Available The aim of this study was to determine the effects of 40% hydrogen peroxide and 15% carbamide peroxide on microhardness and color change of a silorane-based composite resin in comparison with two methacrylate-based composites.Fifty-four disc-shaped specimens (A3 shade were fabricated of Filtek P90 (P90, Filtek Z350XT Enamel (Z350 and Filtek Z250 (Z250 (3MESPE (n=18. The samples of each composite were randomly divided into three subgroups of 6. The control subgroups were immersed in distilled water; the test groups were exposed to Opalescence Boost (OB once; and Opalescence PF (OP (Ultradent for two weeks. Vickers microhardness testing and a spectrophotometric analysis of the color of samples were performed before and after each intervention.The baseline microhardness of P90 was significantly lower than that of the other two composites (P=0.001, but no difference was found between Z250 and Z350 in this respect (P=0.293. Bleaching treatments significantly decreased the microhardness of Z250 and Z350 (P 0.05. No significant difference was detected between the two types of bleaching (P>0.05. After bleaching with OB, ΔE value was measured to be 3.12(1.97, 3.31(1.84 and 3.7(2.11 for P90, Z250 and Z350, respectively. These values were 5.98(2.42, 4.66(2.85 and 4.90(2.78 after bleaching with OP with no significant difference.Bleaching decreased the microhardness of methacrylate-based but not silorane-based composites. Although no significant differences were found in ΔE of composites, ΔE of all groups did not remain in the clinically acceptable range after bleaching except for P90 after bleaching with 40% H2O2 (ΔE < 3.3.

  3. Crystal structure of the binary complex of cobalt and zinc chlorides with carbamide [Co(OCN2H4)5(H2O)][ZnCl4

    International Nuclear Information System (INIS)

    Mixed single crystals of [Co(OCN2H4)5(H2O)][ZnCl4] were grown by the isothermal evaporation of an aqueous solution. The crystal structure of this complex was established by X-ray diffraction (R = 0.052 based on 7003 reflections). The crystals consist of [Co(OCN2H4)5(H2O)]2+ cations containing Co atoms in an octahedral coordination and [ZnCl4]2-] anions containing Zn atoms in a tetrahedral coordination. The carbamide molecules are involved in both intramolecular and interionic hydrogen bonds. The H2O molecule forms hydrogen bonds with the anions.

  4. Effect of In-Office Carbamide Peroxide-Based Tooth Bleaching System on Wear Resistance of Silorane-Based and Methacrylate-Based Dental Composites

    Science.gov (United States)

    Hasani Tabatabaei, Masoumeh; Sheikhzadeh, Sedigheh; Ghasemi Monfared Rad, Hamidreza; Beygi, Ahmad

    2015-01-01

    Objectives: Several studies have assessed the characteristics and properties of silorane-based composites and adhesive systems. Considering the extensive application of tooth-whitening agents, possible deteriorative effects of tooth bleaching agents on these restorative materials must be studied. The aim of this study was to evaluate the effect of an in-office carbamide peroxide-based tooth bleaching agent on the wear resistance of a silorane-based and a conventional microhybrid dimethyl methacrylate-based dental composite with two different application times. Materials and Methods: Thirty cylindrical specimens were made of Z250 and P90 dental composite resins (n=15 for each composite). Samples made of each composite were divided into three groups (n=5) for immersion in an in-office bleaching agent (Opalescence® Quick 45%) for either three or eight hours or saline solution (control). Wear tests were conducted after bleaching using a pin-on disk apparatus under the load of 40N at a constant sliding speed of 0.5 ms−1 for a sliding distance of 300 m. The samples were weighed before and after the wear test. Repeated measures ANOVA was used to statistically analyze the obtained data (α=0.05). Results: There was a significant decrease in the weight of samples after the wear test (P0.05). Conclusion: Bleaching for three or eight hours using 45% carbamide peroxide had no deteriorative effect on the wear resistance of Z250 and P90 composites. PMID:27123014

  5. Micromorphology and microhardness of enamel after treatment with home-use bleaching agents containing 10% carbamide peroxide and 7.5% hydrogen peroxide

    Directory of Open Access Journals (Sweden)

    Robson Tetsuo Sasaki

    2009-12-01

    Full Text Available OBJECTIVE: The purpose of this study was to assess the effect of home-use bleaching agents containing 10% carbamide peroxide and 7.5% hydrogen peroxide on enamel microhardness and surface micromorphology. MATERIAL AND METHODS: Enamel slabs (n=10 received the bleaching agents for 1 h/day and remained in artificial saliva solution for 23 h/day, during a total period of 21 days. Control group was composed of enamel slabs that were not subjected to treatment with the agents and were maintained in artificial saliva solution. Microhardness tests were performed before treatment application, 21 days of treatment and 14 days after the end of treatment. Scanning electron microscopy analyses were performed after 14 days after the end of bleaching treatment by 3 calibrated observers who attributed scores. RESULTS: The Tukey's test (α=0.05 showed no significant differences in microhardness values among bleaching agents, at 21 days of treatment and a significant increase in microhardness for different agents after 14 days from the end of treatment. Fisher's exact test showed differences in micromorphology of enamel between control and experimental groups (p=0.0342. CONCLUSIONS: Bleaching agents containing 10% carbamide peroxide and 7.5% hydrogen peroxide may change surface micromorphology of enamel, although no changes in microhardness were observed.

  6. Murine T cell activation is regulated by surfen (bis-2-methyl-4-amino-quinolyl-6-carbamide)

    Energy Technology Data Exchange (ETDEWEB)

    Warford, Jordan, E-mail: jordan.warford@dal.ca [Department of Pathology, Dalhousie University, Tupper Building, 5850 College Street, Halifax, Nova Scotia B3H 4R2 (Canada); Doucette, Carolyn D., E-mail: carolyn.doucette@dal.ca [Department of Microbiology and Immunology, Dalhousie University, Tupper Building, 5850 College Street, Halifax, Nova Scotia B3H 4R2 (Canada); Hoskin, David W., E-mail: d.w.hoskin@dal.ca [Department of Pathology, Dalhousie University, Tupper Building, 5850 College Street, Halifax, Nova Scotia B3H 4R2 (Canada); Department of Microbiology and Immunology, Dalhousie University, Tupper Building, 5850 College Street, Halifax, Nova Scotia B3H 4R2 (Canada); Easton, Alexander S., E-mail: alexander.easton@dal.ca [Department of Pathology, Dalhousie University, Tupper Building, 5850 College Street, Halifax, Nova Scotia B3H 4R2 (Canada); Department of Microbiology and Immunology, Dalhousie University, Tupper Building, 5850 College Street, Halifax, Nova Scotia B3H 4R2 (Canada); Department of Surgery (Neurosurgery), Dalhousie University, Tupper Building, 5850 College Street, Halifax, Nova Scotia B3H 4R2 (Canada)

    2014-01-10

    Highlights: •Surfen is the first inhibitor of glycosaminoglycan function to be studied in murine T cells. •Surfen reduces T cell proliferation stimulated in vitro and in vivo. •Surfen reduces CD25 expression in T cells activated in vivo but not in vitro. •Surfen increases T cell proliferation when T cell receptor activation is bypassed. •Surfen’s effects are blocked by co-administration of heparin sulfate. -- Abstract: Surfen (bis-2-methyl-4-amino-quinolyl-6-carbamide) binds to glycosaminoglycans (GAGs) and has been shown to influence their function, and the function of proteoglycans (complexes of GAGs linked to a core protein). T cells synthesize, secrete and express GAGs and proteoglycans which are involved in several aspects of T cell function. However, there are as yet no studies on the effect of GAG-binding agents such as surfen on T cell function. In this study, surfen was found to influence murine T cell activation. Doses between 2.5 and 20 μM produced a graduated reduction in the proliferation of T cells activated with anti-CD3/CD28 antibody-coated T cell expander beads. Surfen (20 mg/kg) was also administered to mice treated with anti-CD3 antibody to activate T cells in vivo. Lymphocytes from surfen-treated mice also showed reduced proliferation and lymph node cell counts were reduced. Surfen reduced labeling with a cell viability marker (7-ADD) but to a much lower extent than its effect on proliferation. Surfen also reduced CD25 (the α-subunit of the interleukin (IL)-2 receptor) expression with no effect on CD69 expression in T cells treated in vivo but not in vitro. When receptor activation was bypassed by treating T cells in vitro with phorbyl myristate acetate (10 ng/ml) and ionomycin (100 ng/ml), surfen treatment either increased proliferation (10 μM) or had no effect (2.5, 5 and 20 μM). In vitro treatment of T cells with surfen had no effect on IL-2 or interferon-γ synthesis and did not alter proliferation of the IL-2 dependent cell

  7. Evaluation of human dental loss caused by carbamide peroxide bleacher compared with phosphoric acid conditioning - radioactive method; Avaliacao da perda dental humana com o uso do clareador peroxido de carbamida comparado ao condicionamento com acido fosforico - metodo radiometrico

    Energy Technology Data Exchange (ETDEWEB)

    Adachi, Eduardo Makoto; Yousseff, Michel Nicolau [Sao Paulo Univ., SP (Brazil). Faculdade de Odontologia. Dept. de Dentistica; Saiki, Mitiko [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Lab. de Analise por Ativacao Neutronica

    2002-07-01

    The radiometric method was applied to the evaluation of dental loss caused by carbamide peroxide when it is applied on the surface layers of enamel and dentin tissues. Also the dental loss caused by the etching with 37% phosphoric acid procedure used in aesthetic restoration was assessed for comparison with those results obtained. The tooth samples irradiated with a P standard in a thermal neutron flux of the nuclear reactor were placed in contact with 10% carbamide peroxide or with 37% phosphoric acid solution. The radioactivity of {sup 32} P transferred from the radioactive teeth to the bleaching gel or to etching acid was measured using a Geiger Muller detector to calculate the mass of P removed in this treatment and losses were calculated after obtaining their P concentrations. Results obtained indicated that enamel and dentin exposed to carbamide peroxide bleaching agent lose phosphorus. The extent of enamel loss was smaller than that obtained for dentin. In the case of acid etching, there was no difference between the results obtained for enamel and dentin loss. Also the dentin loss obtained after a treatment of 30 applications of 10% carbamide peroxide was the same magnitude of that one application of 37% phosphoric acid. (author)

  8. Shear bond strength after dentin bleaching with 10% carbamide peroxide agents Resistência ao cisalhamento da dentina após clareamento com peróxido de carbamida a 10%

    OpenAIRE

    Roberta Tarkany Basting; Patrícia Moreira de Freitas; Luiz André Freire Pimenta; Mônica Campos Serra

    2004-01-01

    This in vitro study evaluated the shear bond strength (SBS) of dentin treated with two 10% carbamide peroxide bleaching agents 15 days after bleaching and storage in artificial saliva. Dentin fragments were randomly divided into 3 groups (n = 20) for the treatment with the two different bleaching agents (Rembrandt 10% or Opalescence 10%) or with a placebo agent, applied to the tooth surface for 8 hours a day. During the remaining time, the specimens were stored in artificial saliva. After 42 ...

  9. Evaluation and comparison of bond strength to 10% carbamide peroxide bleached enamel following the application of 10% and 25% sodium ascorbate and alpha-tocopherol solutions: An in vitro study

    Directory of Open Access Journals (Sweden)

    Asha Thapa

    2013-01-01

    Full Text Available Aim: To evaluate and compare composite bond strength to carbamide peroxide bleached enamel following the application of 10% and 25% sodium ascorbate and alpha-tocopherol solutions. Materials and Methods: Sixty premolars were divided into six groups. Groups I and VI served as unbleached and bleached controls respectively. Groups II, III, IV and V served as the experimental groups and were subjected to 10% carbamide peroxide bleaching followed by 10 min application of 10% and 25% sodium ascorbate and 10% and 25% alpha-tocopherol solutions, respectively. Following composite bonding, shear bond strength was determined and the results were analyzed using ANOVA and Tukey highest significant difference test. Results: Only Group IV showed significantly lower bond strength when compared to Group I (unbleached control. When compared to Group VI (bleached control, except Group IV, groups II, III and V showed significantly higher bond strength. However, there was no statistically significant difference between the experimental groups corresponding to 10% and 25% and similar concentrations of sodium ascorbate and alpha-tocopherol solutions. Conclusion: Following 10% carbamide peroxide bleaching, except 10% alpha tocopherol, 10 min application of 10% and 25% sodium ascorbate and 25% alpha-tocopherol solutions significantly improves the shear bond strength of composite resin to enamel.

  10. An in vitro study to evaluate the effect of two ethanol-based and two acetone-based dental bonding agents on the bond strength of composite to enamel treated with 10% carbamide peroxide

    Directory of Open Access Journals (Sweden)

    Deepa Basavaraj Benni

    2014-01-01

    Full Text Available Background and Objective: Carbamide peroxide bleaching has been implicated in adversely affecting the bond strength of composite to enamel. The objective of this in vitro study was to evaluate the effect of ethanol-based (Clearfil S 3 bond, Kuraray, Adper Single bond 2, 3M ESPE dental products and acetone-based (Prime and Bond NT, Dentsply, One Step, Bisco bonding agents on the shear bond strength of composite to enamel treated with 10% carbamide peroxide bleaching agent. Materials and Methods: A total of 120 extracted human noncarious permanent incisors were randomly divided into two groups (control and experimental. Experimental group specimens were subjected to a bleaching regimen with a 10% carbamide peroxide bleaching system (Opalescence; Ultradent Products Inc, South Jordan, USA. Composite resin cylinders were bonded to the specimens using four bonding agents and shear bond strength was determined with universal testing machine. Results: There was no statistically significant difference in the shear bond strength between control and experimental groups with both ethanol-based (Clearfil S 3 Bond and Adper Single Bond 2 and acetone-based bonding agent (Prime and Bond NT and One Step. Interpretation and Conclusion: The adverse effect of bleaching on bonding composite to enamel can be reduced or eliminated by using either ethanol- or acetone-based bonding agent. Clinical Significances: Immediate bonding following bleaching procedure can be done using ethanol- or acetone-based bonding agent without compromising bond strength.

  11. Influence of carbamide peroxide-based bleaching agents on the bond strength of resin-enamel/dentin interfaces Influência de agentes clareadores à base de peróxido de carbamida na resistência de união entre resina-esmalte/dentina

    OpenAIRE

    Vanessa Cavalli; Ricardo Marins Carvalho; Marcelo Giannini

    2005-01-01

    In this bond strength study, a bleaching agent containing 10% carbamide peroxide was applied over composite-teeth bonded interfaces of two adhesive systems applied to enamel and dentin. Sixteen human third molars were used for bonding procedures. Single Bond (SB) and Clearfil SE Bond (CB) were applied to enamel and dentin according to the manufacturers' instructions. A resin composite cube-like structure was incrementally built on the bonded surfaces. The restored teeth were sectioned into 0....

  12. In vitro evaluation of human dental enamel surface roughness bleached with 35% carbamide peroxide and submitted to abrasive dentifrice brushing Avaliação in vitro da rugosidade superficial do esmalte dental humano clareado com peróxido de carbamida a 35% e submetido à escovação com dentifrícios abrasivos

    OpenAIRE

    Claudia Cia Worschech; José Augusto Rodrigues; Luis Roberto Marcondes Martins; Gláucia Maria Bovi Ambrosano

    2003-01-01

    The aim of this in vitro study was to evaluate the surface roughness of human enamel bleached with 35% carbamide peroxide at different times and submitted to different superficial cleaning treatments: G1 - not brushed; G2 - brushed with fluoride abrasive dentifrice; G3 - brushed with a non-fluoride abrasive dentifrice; G4 - brushed without dentifrice. Sixty fragments of human molar teeth with 4 x 4 mm were obtained using a diamond disc. The specimens were polished with sandpaper and abrasive ...

  13. Shear bond strength after dentin bleaching with 10% carbamide peroxide agents Resistência ao cisalhamento da dentina após clareamento com peróxido de carbamida a 10%

    Directory of Open Access Journals (Sweden)

    Roberta Tarkany Basting

    2004-06-01

    Full Text Available This in vitro study evaluated the shear bond strength (SBS of dentin treated with two 10% carbamide peroxide bleaching agents 15 days after bleaching and storage in artificial saliva. Dentin fragments were randomly divided into 3 groups (n = 20 for the treatment with the two different bleaching agents (Rembrandt 10% or Opalescence 10% or with a placebo agent, applied to the tooth surface for 8 hours a day. During the remaining time, the specimens were stored in artificial saliva. After 42 days, the fragments were stored in artificial saliva for 14 days. Another group (n = 20 was exposed to distilled and deionized water for 56 days. An adhesive system and microhybrid composite resin were used to prepare specimens for the SBS test. SBS tests were performed and the fractured surfaces were visually examined using a stereoscope at 30 X magnification. The analysis of variance (ANOVA and SIDAK tests showed higher SBS values for dentin treated with Opalescence 10% than for dentin treated with Rembrandt 10% or placebo. Groups treated with Rembrandt 10%, Opalescence 10% or placebo did not differ from the group treated with distilled and deionized water. Ten percent carbamide peroxide agents or a placebo agent caused no differences in SBS of dentin after 15 days of storage in artificial saliva.Este estudo in vitro avaliou a resistência ao cisalhamento da dentina submetida ao tratamento com dois agentes clareadores contendo peróxido de carbamida a 10% depois de 15 dias de clareamento e armazenagem em saliva artificial. Fragmentos de dentina foram aleatoriamente distribuídos em 3 grupos (n = 20 para receber o tratamento com dois diferentes agentes clareadores (Rembrandt a 10% ou Opalescence a 10% ou com um agente placebo, aplicados na superfície dental por 8 horas diárias. No restante do tempo, os espécimens permaneceram imersos em saliva artificial. Após o tratamento por 42 dias, os fragmentos foram armazenados em saliva artificial por 14 dias. Outro

  14. Influence of carbamide peroxide-based bleaching agents on the bond strength of resin-enamel/dentin interfaces Influência de agentes clareadores à base de peróxido de carbamida na resistência de união entre resina-esmalte/dentina

    Directory of Open Access Journals (Sweden)

    Vanessa Cavalli

    2005-03-01

    Full Text Available In this bond strength study, a bleaching agent containing 10% carbamide peroxide was applied over composite-teeth bonded interfaces of two adhesive systems applied to enamel and dentin. Sixteen human third molars were used for bonding procedures. Single Bond (SB and Clearfil SE Bond (CB were applied to enamel and dentin according to the manufacturers' instructions. A resin composite cube-like structure was incrementally built on the bonded surfaces. The restored teeth were sectioned into 0.7 mm thick slices that were trimmed at enamel or dentin bonded interfaces to an hourglass shape with a cross-sectional area of approximately 0.5 mm². Specimens were assigned to 8 groups (n = 10 according to the following factors under study: dental substrate (enamel and dentin; adhesive system (SB and CB and treatment (10% carbamide peroxide and not bleached/control. The bleaching gel (Opalescence was applied at the bonded interfaces for 6 hours during 14 days and after daily treatment specimens were stored in artificial saliva. Unbleached specimens were stored in artificial saliva for 14 days. Specimens were tested for tension and the data were analyzed by three-way ANOVA and Tukey's test (p Este estudo avaliou a resistência de união de dois sistemas adesivos ao esmalte e à dentina após a aplicação de agente clareador sobre a união compósito-dente. Dezesseis terceiros molares humanos foram usados nos procedimentos restauradores. Single Bond (SB e Clearfil SE Bond (CB foram aplicados no esmalte e na dentina de acordo com as instruções dos fabricantes. Um bloco de compósito foi construído nas superfícies tratadas com os adesivos. Os dentes restaurados foram seccionados em fatias com espessura de 0,7 mm, que receberam constrição na interface de união num formato de ampulheta, com área de secção transversal de ± 0,5 mm². Os espécimes foram distribuídos em 8 grupos (n = 10 de acordo com os fatores em estudo: substrato dental (esmalte e

  15. Influência do agente clareador peróxido de carbamida a 10% na resistência mecânica da colagem de braquetes ortodônticos Influence of 10% carbamide peroxide gel on the shear bond strength of orthodontic brackets

    Directory of Open Access Journals (Sweden)

    Edgard Norões R. da Matta

    2005-04-01

    Full Text Available O propósito deste estudo in vitro foi determinar a influência do agente clareador peróxido de carbamida a 10% na resistência mecânica da colagem de braquetes ortodônticos. Foram estudados três grupos denominados G1 (não submetido ao clareamento, G2 (com clareamento e colagem realizada 1 semana após e G3 (com clareamento e colagem realizada 24h após. O teste de cisalhamento foi conduzido na máquina de ensaios mecânicos Emic, com a velocidade de deformação de 0,5 mm/min.A resitência ao cisalhamento em relação à área de colagem foi calculada para cada dente e expressa em MPa. Os resultados mostraram aumento estatisticamente significante (pThe purpose of this in vitro study was to determine the influence of 10% carbamide peroxide gel on the shear bond strength of orthodontic brackets. Three group were studied: G1 (without bleaching, G2 (bleaching and bonding after 1 week and G3 (bleaching and bonding after 24h. The shear test was conduced in a Emic testing machine with a crosshead speed of 0,5 mm/min. The shear bond strength was calculated for each tooth and expressed in MPa. The results show enhance statistical significant (p<0,001 on the shear bond strength after bleaching and encreased with the time interval between bleaching and bonding, significantily.

  16. Testing keratolytic effect of carbamide in various vehicles

    OpenAIRE

    Toskić-Radojičić Marija

    2002-01-01

    Background. Urea is a natural protein degradation product widely used in keratolytic preparations due to its property to promote fibrinogen decomposition and to act as a proteolytic agent dissolving and denaturing proteins. Preparations containing 20% or 40% urea in commercial ambiphylic bases are widely used to produce keratolysis. At such high concentration urea recrystallization occurs and is separated over the preparation mass, particularly if the urea content is 40%. This was the initial...

  17. Testing keratolytic effect of carbamide in various vehicles

    Directory of Open Access Journals (Sweden)

    Toskić-Radojičić Marija

    2002-01-01

    Full Text Available Background. Urea is a natural protein degradation product widely used in keratolytic preparations due to its property to promote fibrinogen decomposition and to act as a proteolytic agent dissolving and denaturing proteins. Preparations containing 20% or 40% urea in commercial ambiphylic bases are widely used to produce keratolysis. At such high concentration urea recrystallization occurs and is separated over the preparation mass, particularly if the urea content is 40%. This was the initial reason to look for a new preparation formulation that would not have the above-mentioned technological inadequacy. Considering urea's water solubility and its high content in the preparations, the most convenient form, in which recrystallisation would not occur, was gel. The aim of this work was to experimentally estimate the influence of the vehicle upon the proteolytic effect of urea on keratin in the human hair model. Methods. Hair geometrical properties, the change in longitudinal mass, and the change of disruptive force and disruptive hair elongation were measured. Results. The effect of 20% and 40% urea was estimated in three various vehicles, of which two were of organic hydrogel type, and one was an ambiphylic base of mixed type - Basiscreme. Conclusion. Keratin proteolysis effects of urea incorporated into various bases, as measured by human hair disruption forces, depended upon the base; preparations containing 20% and 40% urea in Basiscreme (ambiphylic base had no desired proteolytic effect upon keratin fibers; proteolysis was best expressed bay urea preparations in 3.5% NaCMC gel, and proteolytic effect of these preparations was best expressed in the first hour.

  18. Preparation of mechanically activated starch acetate of ester-film material for carbamide controlled release and its film performance%尿素缓释膜材料--机械活化醋酸酯淀粉的制备及其膜性能

    Institute of Scientific and Technical Information of China (English)

    陈渊; 杨家添; 韦庆敏; 何军; 黄祖强; 欧诗德; 张秀姣

    2014-01-01

    In order to improve the properties of starch-based films for carbamide controlled release, the mechanically ac-tivated starch acetate (MASA) was synthesized from mechanically activated cassava starch (MAS). The biodegradable mechani-cally activated starch acetate polyvinyl alcohol(MASA/PVA) films were produced. Fourier transform infrared spectrogram (FT-IR), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC), the microstructure, particle shape and thermal property of MASA were studied. And the film performances were compared with those made of starch acetate (SA) with variacs degrees of substitution(DS). The results revealed that the microstructure and particle shape changed greatly and thermal property of MASA increased. The properties of MASA/PVA were better than those of SA/PVA. The tensile strength of the MA-SA/PVA with MASA ( DS = 0. 2 ) was 3. 23 MPa, the breaking elongation was 206. 68% before soaking in water, the absorption of water was 115. 96% after 24 h, and the rate of biodegradation was 36. 46% in the soil after 20 d. The to-tal urea stripping rate of MASA /PVA coated urea reached 45. 69% after 9 times leaching, 18. 12 percent and 51. 49 per-cent lower than urea and coated that with SA/PVA, respec-tively. Coating film made of MASA/PVA had remarkable controlling effects on urea nitrogen release.%为了有效提高淀粉基质尿素缓释膜的性能,对机械活化1.0 h的木薯淀粉( MAS)进行酯化改性,制备了机械活化醋酸酯淀粉(MASA)、机械活化醋酸酯淀粉/聚乙烯醇的生物降解塑料膜(MASA/PVA)及MASA/PVA包膜尿素。用傅立叶红外光谱仪(FTIR)、扫描电镜(SEM)、差示扫描量热仪(DSC)分别对MASA的结构、形貌、热稳定性等进行测试,并与用不同取代度制备的原木薯醋酸酯淀粉/聚乙烯醇生物降解塑料膜( SA/PVA)进行比较。结果表明,机械活化淀粉经酯化改性后,结构和形貌都有很大的改变,热性能提高;MASA/PVA的性

  19. Fracture resistance and failure pattern of teeth submitted to internal bleaching with 37% carbamide peroxide, with application of different restorative procedures Resistência à fratura e padrão de falha de dentes submetidos ao clareamento interno com peróxido de carbamida a 37%, com aplicação de diferentes procedimentos restauradores

    Directory of Open Access Journals (Sweden)

    Gerson Bonfante

    2006-08-01

    Full Text Available OBJECTIVE: This study investigated the compressive fracture strength and failure pattern in premolars submitted to endodontic treatment and internal bleaching with 37% carbamide peroxide for 21 days, with application of different restorative procedures. MATERIAL AND METHODS: Six groups were employed (n = 10: 1 non-bleached teeth and pulp chamber sealed with IRM; 2 bleached teeth and pulp chamber sealed with IRM; 3 bleached teeth and pulp chamber filled with light cured composite resin; 4 bleached teeth, root canals prepared at 10mm, filling of the root canal and pulp chamber with IRM; 5 bleached teeth, root canals prepared at 10mm, luting of prefabricated metallic post with zinc phosphate and pulp chamber sealed with composite resin; 6 bleached teeth, root canals prepared at 10mm, luting of glass fiber post with resin cement and pulp chamber sealed with composite resin. After 24-hour storage in distilled water, the specimens were submitted to compressive fracture strength testing in a universal testing machine. RESULTS: The following values were found: Group 1 - 56.23kgf; Group 2 - 48.96kgf; Group 3 - 53.99kgf; Group 4 - 45.72kgf; Group 5 - 54.22kgf; Group 6 - 60.12kgf. The analysis of variance did not reveal statistically significant difference between groups (pOBJETIVO: O objetivo do estudo foi investigar a resistência à fratura sob compressão e padrão de falha de pré-molares tratados endodonticamente e clareados internamente por 21 dias com peróxido de carbamida a 37%, aplicando-se diferentes procedimentos restauradores. MATERIAL E MÉTODOS: O objetivo deste estudo foi investigar a resistência à fratura sob compressão e padrão de falha de pré-molares unirradiculares tratados endodonticamente e clareados internamente com peróxido de carbamida a 37%. Foram constituídos 6 grupos (n = 10: 1 dentes sem clareamento e câmara pulpar vedada com IRM; 2 dentes clareados e câmara pulpar vedada com IRM; 3 dentes clareados e câmara pulpar

  20. Effect of carbamide peroxide-based bleaching agents containing fluoride or calcium on tensile strength of human enamel Efeito de agentes clareadores à base de peróxido de carbamida contendo fluoreto e cálcio na resistência à tração do esmalte humano

    Directory of Open Access Journals (Sweden)

    Marcelo Giannini

    2006-04-01

    Full Text Available OBJECTIVE: The aim of this study was to evaluate the effects of carbamide peroxide-based bleaching agents (CPG containing fluoride (CF or calcium (CCa on the ultimate tensile strength of enamel (UTS. METHOD: A "cube-like" resin composite structure was built-up on the occlusal surface of twenty-two sound third molars to facilitate specimen preparation for the micro-tensile test. The restored teeth were serially sectioned in buccal-lingual direction in slices with approximate 0.7 mm thickness. Each slice was trimmed with a fine diamond bur to reduce the buccal, internal slope enamel of the cusps to a dumb-bell shape with a cross-sectional area at the "neck" of less than 0.5 mm². The samples were randomly divided into 12 groups (n=11. The control groups were not submitted to the bleaching regimen. Specimens were treated with 10% CPG gel or with 10% CPG formulations containing CF (0.2% and 0.5% or CCa (0.05% and 0.2%. Bleached groups received the application of the 10% CPGs for 6 hours/day at 37º C, during 14 consecutive days and were stored in artificial saliva (AS or 100% relative humidity (RH among each application. After bleaching, specimens were tested with the microtensile method at 0.5 mm/min. Data were analyzed by two-way ANOVA and Tukey test (5%. RESULTS: No significant difference was observed between groups stored in AS or RH. Specimens treated with CF or CCa presented similar UTS as unbleached control groups. CONCLUSION: Either 10% CPG formulations containing CF or CCa can preserve the UTS after bleaching regimen.OBJETIVO: O propósito deste estudo foi avaliar os efeitos de agents clareadores à base de peróxido de carbamida (CPG contendo fluoreto (CF e cálcio (CCa na resistência à tração do esmalte (UTS. MÉTODO: Um bloco de resina composta foi confeccionada na superfície oclusal de vinte e dois terceiros molars hígidos para facilitar a preparação dos espécimes para o teste de micro-tração. Os dentes restaurados foram

  1. 过氧化脲漂白剂对树脂修复体边缘微渗漏影响的实验研究%Effect of carbamide peroxide bleaching agents on micro-leakage of composite resin interface in vitro

    Institute of Scientific and Technical Information of China (English)

    王晓玲; 徐娟; 赵信义; 何惠明

    2011-01-01

    Objective To evaluate the effect of carbamide peroxide (CP) bleaching agents at different concentrations and with different carriers on the micro-leakage of composite resin interface. Methods Class V cavity (2 mm in diameter and 2 mm in depth) preparations were made at the enamelo-cemental junction on the buccal and lingual surfaces of 35 extracted human premolars. The cavities were filled with hybrid composite resin. The teeth were stored for 24 h in distilled water at 37°C before thermocyling for 500 times between 5 and 55 °C. The teeth were then randomly assigned into 7 groups, and in groups 1-6, the bleaching gels containing 10% or 20% of CP were applied on the buccal and lingual surface of the teeth for two weeks (6-8 h/day, 37 °C, 100% relative humidity) using Carbopol, PVP or Poloxamer as the thickening carriers, respectively. The seventh group served as the control without bleaching treatment. Nail polish was applied to the surface of the tooth, and all the teeth were immersed in ammoniacal silver nitrate solution followed by developing solution. The teeth were finally sectioned through the midline of the restoration and observed under stereomicroscope. SEM micrographs were also made to observe the interface. Results With the same bleaching agent, the micro-leakage in the gingival wall was slightly greater than in the occlusive wall, but the difference was not significant. Only 20% CP with Poloxamer as the thickening agent significantly increased the leakage of dentine-resin composite interface, and 10% and 20% CP with Carbopol or PVP as the thickening agents and 10% CP with Poloxamer produced minimal effects on filling the micro-leakage. Conclusion Thickening carriers and the concentration of CP (20% or below) have no significant effect on micro-leakage of composite resin.%目的 评价以不同载体配制的不同浓度过氧化脲(CP)漂白剂对复合树脂边缘微渗漏的影响.方法 在35颗离体前磨牙颊舌面牙颈部制备V类洞(直径2

  2. Study on the Carbamide in Washing Powder%碳酰胺在洗衣粉中的研究及应用

    Institute of Scientific and Technical Information of China (English)

    郭俊华

    2016-01-01

    分析了碳酰胺的功能用途,并通过实验测试,解决了由于洗衣粉所含的碳酸钠及部分原料对皮肤的刺激损害问题,提高了产品的抗冻效果和增溶、去污能力,使洗涤产品具有洗涤、去污、护肤的功能。%The function of carbamideis is introduced. The skin irritation as a result of sodium carbonate and other material in washing powder is decreased, and the freeze resistance and soil-releasing is increased.

  3. Side-effects of weeding carbamide on non-target organisms in paddy fields%高效除草尿素(药肥)对稻区非目标生物影响研究

    Institute of Scientific and Technical Information of China (English)

    李少南; 顾晓军; 吴加伦; 樊德方; 李增增; 蒋建华

    2000-01-01

    研究了高效除草尿素(药肥)对稻区水生生物的影响.结果表明,药肥对蟾蜍Bufo bufo gargarizans蝌蚪、棘胸蛙Rana spinosa蝌蚪、食蚊鱼Gambusia affinis、虹鳟Salmo gairdneri、湖螺Ballamya sp和蚤状CF6DDaphnia pulex的96 h LC50分别为5436、1579、4073、568、4139和9781 mg/L.按照用量和目前国内外普遍采用的评价标准,药肥对蟾蜍、食蚊鱼、湖螺和蚤状CF6D低毒,对棘胸蛙和虹鳟具有中等毒性.生长潜力试验表明,小球藻Chlorella sp.和删藻Scenedesmus sp.对药肥敏感性不同,但是在mg/L的药肥模拟田间浓度下两种藻的生物量均有所增加.

  4. 高粘度、多功能过氧化脲洁牙凝胶的制备研究%Research on Preparation of High-viscosity and Multifunction Carbamide Peroxide Dental-bleaching Gel

    Institute of Scientific and Technical Information of China (English)

    窦宏仪; 陈枚; 王磊; 徐士清

    2003-01-01

    制备了具有洁牙、护牙、抗菌消炎作用的高粘度、多功能过氧化脲洁牙凝胶.该凝胶无毒、无副作用,在口腔应用中粘度稳定,避免唾液溶解,使洁牙成分持久释放,提高洁牙效率.研究了过氧化脲的制备方法,所制备的过氧化脲质量分数大于98%.所制备的齿科材料为粘度300~450Pa.s,pH值5~7的无色透明凝胶,含过氧化脲质量分数6%~20%,稀释剂40%~80%,增稠剂4%~10%,pH调节剂2%~10%及稳定剂、抗过敏剂、护牙剂、调味剂等成分.

  5. Evaluation of the bleached human enamel by Scanning Electron Microscopy

    DEFF Research Database (Denmark)

    Miranda, Carolina Baptista; Pagani, Clovis; Benetti, Ana Raquel;

    2005-01-01

    Electron Microscopy (SEM). Materials and Methods: Twenty intact human third molars extracted for orthodontic reasons were randomly divided into four groups (n=5) treated as follows: G1- storage in artificial saliva (control group); G2- four 30-minute applications of 35% carbamide peroxide (total exposure...... analysis performing gold sputter coating under vacuum and were examined using 15kV at 500x and 2000x magnification. Results: Morphological alterations on the enamel surface were similarly detected after bleaching with either 35% carbamide peroxide or 35% hydrogen peroxide. Surface porosities were...

  6. Drug: D00023 [KEGG MEDICUS

    Lifescience Database Archive (English)

    Full Text Available utions producing osmotic diuresis B05BC02 Carbamide D00023 Urea (JP16/USP) D DERMAT...ssification [BR:br08303] B BLOOD AND BLOOD FORMING ORGANS B05 BLOOD SUBSTITUTES AND PERFUSION SOLUTIONS B05B I.V. SOLUTIONS B05BC Sol

  7. Colour Change of Enamel after Application of Averrhoa bilimbi

    Directory of Open Access Journals (Sweden)

    Cut Fauziah

    2013-07-01

    Full Text Available Normal 0 false false false MicrosoftInternetExplorer4 Teeth discoloration is mainly treated with dental bleaching. Use of chemical bleaching has side effects, so it is important to find an alternative natural dental bleaching agent. Averrhoa bilimbi contains peroxide and oxalate acid that possess tooth whitening properties. Objective: To determine the change in color of dental enamel after the application of Averrhoa bilimbi and 10% carbamide peroxide. Methods: Samples were 20 post-extracted of the two tested materials premolars (10 specimens each for Averrhoa bilimbi and carbamide peroxide application. After the application, the specimens were incubated at 37ºC for 2 hours, washed and soaked in aquadest before further incubated for another 14 days. The colour changed was observed by 5 independent observers using shade guide. Results: Quantitative and qualitative analyzes were performed. Qualitatively, A3 color has changed into C1, A2, D2, B2 and B1 in the Averrhoa bilimbi group. A more significant color change in the 10% carbamide peroxide group (p=0.005 compared to Averrhoa bilimbi group (p=0.005 were observed. The difference of resulted enamel colour change was statistically significant (p=0.002. Conclusion: Averrhoa bilimbi had a good prospect as dental bleaching agent since its application effectively resulted in a slight enamel colour change although its whitening properties was still lower than 10% carbamide peroxide.DOI: 10.14693/jdi.v19i3.134

  8. New semisynthetic antimicrobial labdane-type diterpenoids derived from the resin "ladano" of Cistus creticus.

    Science.gov (United States)

    Kalpoutzakis, E; Aligiannis, N; Mitaku, S; Chinou, I; Harvala, C; Skaltsounis, A L

    2001-01-01

    The antimicrobial activity of fifteen semisynthetic labdane-type diterpenes derived from the two major natural compounds 3 and 4 of the resin "ladano" of Cistus creticus is reported. The chloroethyl carbamidic esters 15 and 20 showed the strongest antimicrobial activity against Gram(+), Gram(-) bacteria and pathogenic fungi. PMID:11302213

  9. Вивчення процесу мікрокапсулювання диоксиду титану карбамідоформальдегідними олігомерами

    OpenAIRE

    Маслош, Володимир Зіновійович; Островерхова, Інна Олександрівна; Маслош, Ольга Володимирівна

    2010-01-01

    The possibility of titanium dioxide microcapsulation by water-soluble urea-formaldehyde oligomer is studied. It is established that in process of microcapsulation occurs the carbamide sorption on titanium dioxide surface with subsequent formation of polymetileurea on titanium dioxide surface. Injection of polymetileurea to 30 % from weight titanium dioxide weight doesn't impact on properties of the received product.

  10. The effect of two in-office and home bleaching gels on microhardness of composite resin

    Directory of Open Access Journals (Sweden)

    Alizadeh Oskoee P.

    2007-07-01

    Full Text Available Background and Aim: Bleaching products as chemical materials can exert side effects on soft and hard tissues and existing restorative materials with oxidizing mechanism. The aim of this study was to evaluate the effect of 15% and 35% carbamide peroxide gels as home and in-office bleaching agents respectively, on microhardness and surface topography of composite resin.Materials and Methods: In this in vitro study, a total of 75 disc shaped specimens were prepared from Z100  composite resin (3M and randomly divided into three groups with following treatment designs: group 1, 370C distilled water, group 2, 15% carbamide peroxide, 6 hours/day for 3 weeks, group 3, 35% carbamide peroxide 30 minutes/week for 3 weeks. The microhardness (Vickers hardness of samples was measured using Shimadzu set on three different points of each sample. 8 samples of each group were selected randomly to be assessed by scanning electron microscopy (SEM for probable changes in surface topography. Data were analyzed using one way ANOVA and Duncan tests with p<0.05 as the level of significance. Results: 15% carbamide peroxide group had the maximum amount of microhardness (84.59±1.87 and 35% carbamide peroxide group had the minimum (76. 14±1.77. Only the difference between home bleaching and control group was not statistically significant (P=0.24. The SEM assessing revealed no changes in surface topography.Conclusion: Based on the results of this study, in-office bleaching may decrease the microhardness of composite resin.

  11. Production and characterization of high porosity porous FeCrC alloys by the space holder leaching technique

    Institute of Scientific and Technical Information of China (English)

    Da-rong Tian; Yu-hua Pang; Liang Yu; Li Sun

    2016-01-01

    Spherical carbamide particles were employed to produce porous Fe–Cr–C alloy with high porosity and large aperture via the space-holder leaching technique. A series of porous samples were prepared by regulating the processing parameters, which included the car-bamide content and the compaction pressure. The pore characteristics and compression properties of the produced samples were investigated. The samples were characterized by scanning electron microscopy, image analysis, and compression tests. The results showed that the macro-porosity and the mean pore size were in the ranges 40.4%–82.4% and 0.6–1.5 mm, respectively. The compressive strength varied be-tween 25.38 MPa and 127.9 MPa, and was observed to decrease with increasing total porosity.

  12. Comparison of the bleaching efficacy of three different agents used for intracoronal bleaching of discolored primary teeth: An in vitro study

    Directory of Open Access Journals (Sweden)

    R Ganesh

    2013-01-01

    Full Text Available Everyone wants whiter teeth to make them feel younger and to provide beautiful smiles with the accompanying increase in self-esteem. Bleaching is an established, simple, cost-effective and conservative method for improving the color of the discolored teeth. Aim: The aim of this in vitro study was to compare the bleaching efficacy of 10% carbamide peroxide, 10% hydrogen peroxide and 2g sodium perborate as bleaching agents on the artificially discolored human primary maxillary central incisors. Materials and Methods: Forty extracted human primary central incisors with intact crowns were selected for the study. Pulpectomy was performed and each tooth was artificially stained with 2 ml of fresh human blood and centrifuged. --The teeth were randomly divided into four experimental groups of 10 teeth each and the baseline color evaluation was performed. 0.04 ml of the bleaching agent is syringed into the access cavity of the tooth and, in the control group, 0.04 ml of distilled water was syringed into the access cavity and it was sealed with IRM and placed at 37°C in an incubator throughout the experiment. The color of the bleached teeth was determined at 0, 7 and 14 days. The data obtained were analyzed using ANOVA and Turkey′s test. Results: There was statistical significance (P = 0.00 among the carbamide peroxide, sodium perborate, hydrogen peroxide and control groups after 7 and 14 days and a significance of P = 0.013 among the carbamide peroxide, sodium perborate and hydrogen peroxide after two bleaching sessions (day 14 was seen. Conclusions: The bleaching efficacy of 10% hydrogen peroxide gel was more effective than 10% carbamide peroxide and sodium perborate in bleaching the artificially discolored primary teeth.

  13. THE EFFECTS OF HOME BLEACHING ON THE HARDNESS OF AMALGAM FILLING

    OpenAIRE

    Andi Soufyan; Niti Matram

    2015-01-01

    Dental bleaching has been considered as a feasible approach for dental esthetic, and many dental bleaching products can be seen in the market. Therefore, the side effect of such dental product should be studied. This study was aimed to determine the effect of carbamide peroxide-containing home bleaching agent on the hardness of dental amalgam surface structure. Forty amalgam filling specimens were divided into 4 groups, which consist of 3 treatment groups and 1 controu group. Each group was e...

  14. Effect of at-home bleaching with different thickeners and aging on physical properties of a nanocomposite

    OpenAIRE

    Gouveia, Thayla Hellen Nunes; Públio, Juliana do Carmo; Ambrosano, Glaucia Maria Bovi; Paulillo, Luís Alexandre Maffei Sartini; Aguiar, Flávio Henrique Baggio; Lima, Débora Alves Nunes Leite

    2016-01-01

    Objective: To evaluate the influence of 16% carbamide peroxide (CP) containing different thickeners on the physical characteristics of a nanocomposite resin submitted or not to accelerated artificial aging (AAA). Materials and Methods: One hundred samples were randomly distributed into two groups (n = 50) according to AAA. Each group was divided into 5 subgroups (n = 10) depending on the bleaching/thickener treatment: CP + carbopol, CP + natrosol, carbopol, natrosol, and no treatment (control...

  15. Avaliação clínica da eficácia do clareamento dental pela técnica caseira utilizando moldeiras com e sem alívio

    OpenAIRE

    Fábio Herrmann Coelho-de-Souza; Celso Afonso Klein-Júnior; Leandro Azambuja Reichert; Renata Zago; Gabriela Figueiredo Braga; Michele Souza Pontes

    2010-01-01

    The aim of this study was to evaluate the clinical performance of 16% carbamide peroxide home vital bleaching, using trays constructed with or without reservoirs, and analyze the postoperative hypersensitivity. This was a randomized, double-blind and split-mouth study. Two examinators evaluated 11 and 21 teeth from eleven patients (Kappa 0,75). Right side of upper stone models received reservoirs before trays were constructed, left side didn't. Home bleaching was performed through two weeks, ...

  16. Peroxide bleaching agent effects on enamel surface microhardness, roughness and morphology Efeitos de agentes clareadores à base de peróxidos na microdureza, rugosidade e morfologia superficial do esmalte

    OpenAIRE

    Cristiane Franco Pinto; Rogério de Oliveira; Vanessa Cavalli; Marcelo Giannini

    2004-01-01

    The aim of this study was to evaluate the surface roughness, microhardness and morphology of human enamel exposed to six bleaching agents (at baseline and post-treatment). Human dental enamel samples were obtained from human third molars and randomly divided into seven groups (n = 11): control, Whiteness Perfect - 10% carbamide peroxide (10% CP), Colgate Platinum - 10% CP, Day White 2Z - 7.5% hydrogen peroxide (7.5% HP), Whiteness Super - 37% CP, Opalescence Quick - 35% CP and Whiteness HP - ...

  17. Influence of fluoride-containing adhesives and bleaching agents on enamel bond strength

    OpenAIRE

    Vanessa Cavalli; Priscila Cristiane Suzy Liporoni; Marcos Augusto do Rego; Sandrine Bittencourt Berger; Marcelo Giannini

    2012-01-01

    This study evaluated the influence of fluoride-containing carbamide peroxide (CP) bleaching agents and adhesive systems on bonded enamel interfaces that are part of the dynamic pH cycling and thermal cycling models. The buccal surfaces of 60 bovine incisors were restored with a composite resin and bonded with three- and two-step, etch-and-rinse, fluoride-containing adhesives, Optibond FL (FL) and Optibond Solo Plus (SP), respectively. Restored teeth were subjected to thermal cycling to age th...

  18. Electrochemical behavior of non-precious dental alloys in bleaching agents

    Energy Technology Data Exchange (ETDEWEB)

    Ameer, M.A. [Cairo University, Giza (Egypt). Chemistry Department; Khamis, E. [Alexandria University (Egypt). Chemistry Department; Al-Motlaq, M. [King Saudi University (Saudi Arabia). College of Science, Chemistry Department

    2004-11-15

    Corrosion behavior of dental alloys in artificial saliva containing different concentrations of hydrogen peroxide, carbamide peroxide and fluoride ions was studied using electrochemical technique. The alloys have been arranged according to its corrosion resistance in the hydrogen peroxide and carbamide peroxide as follows: wiron99 > wirolloy > wironit. Alloys suffer less corrosion rates in presence of carbamide peroxide than hydrogen peroxide. The effect of CH{sub 6}N{sub 2}O{sub 3} on the corrosion is less than the effect of H{sub 2}O{sub 2} and this is due to the presence of centers rich by electrons such as nitrogen and oxygen in CH{sub 6}N{sub 2}O{sub 3}. Nitrogen and oxygen adsorbed on the alloy surface forming protective layer isolate it relatively from the corrosive medium. The order of increasing resistivity of the alloys in fluoride solution is as follows: wironit > wiron99 > wirolloy. SEM for the three alloys in artificial saliva containing 0.015 M F{sup -} shows that wironit has less corrosion compared to the two other alloys and this agrees with the results obtained from potentiodynamic polarization curves and Nyquist impedance diagrams. (author)

  19. The effect of combined bleaching techniques on oral microbiota

    Directory of Open Access Journals (Sweden)

    Franz-Montan Michelle

    2009-01-01

    Full Text Available Aims : To evaluate the antimicrobial activity of 10% and 37% carbamide peroxide during dental bleaching in three different modes. Materials and Methods : This five-week double-blind randomized controlled trial included 32 volunteers assigned to four groups (n = 8. Each group received bleaching agents or placebo as an in-office and at-home treatment. The dental bleaching techniques were: In-office bleaching (37% carbamide peroxide: CP37; at-home bleaching (10% carbamide peroxide: CP10 and the association of both (CP37 and CP10. Saliva samples were collected right before (baseline, right after, 12 hours after, and seven days after the treatment. Counts of total microorganisms, Streptococci, and Mutans streptococci were carried out. Friedman test (α = 0.05 was used to compare the microorganism counts. Results : The number of the all oral microorganisms remained stable during all experiment. Conclusions : No bleaching agent (CP37, CP10 or the combination of both was able to reduce the oral microorganisms tested.

  20. 硅钙包裹尿素对温室大棚菜地土壤养分的影响%Effect of Si-Ca Coated Urea on Vegetable Soil Nutrient in the Greenhouse

    Institute of Scientific and Technical Information of China (English)

    戚新革; 王曰鑫; 吴迪

    2014-01-01

    通过不同用量硅钙包裹尿素与普通尿素对土壤养分的对比试验,研究了硅钙包裹尿素对温室大棚西葫芦菜地土壤养分的影响。试验结果表明:相同施肥条件下,硅钙包裹尿素处理的土壤速效钾、有效硅、水溶性钙和镁、有机质含量高于普通尿素处理,且随着硅钙包裹尿素施入量的增加而提高,最高值出现在施入量为0.224 kg/m2时;硅钙包裹尿素处理的速效磷含量优于普通尿素处理,其含量随硅钙包裹尿素施入量增加而降低;硅钙包裹肥对碱解氮起到了缓释效果,在生长后期含量较高,且随施肥量增加而提高。%The effect of different amount of Si-Ca coated carbamide fertilizer and carbamide on soil fertility were stud-ied with contrast Experiment. The results showed that under the same fertilization conditions, the contents of available potassium, available silicon, water soluble calcium and magnesium, organic matter were higher in wrapped fertilizer treatment than those in the carbamide treatment. These indice increased with the enhancing of fertilizer. The maximum vaule appeared in the application of 0.224 kg/m2 coated fertilizer. The wrapped fertilizer increased with the enhancing of fertilizer that caused by slow-releasing on available nitrogen.

  1. Effectiveness of home bleaching agents in discolored teeth and influence on enamel microhardness

    Directory of Open Access Journals (Sweden)

    Carina Sinclér Delfino

    2009-08-01

    Full Text Available OBJECTIVES: This study evaluated the effectiveness of different home bleaching agents on color alteration and their influence on surface and subsurface microhardness of discolored bovine enamel. MATERIAL AND METHODS: Forty-five fragments of bovine incisors were randomly allocated into 3 groups (n=15 according to the bleaching agent: 10% carbamide peroxide gel (CP10, 16% carbamide peroxide gel (CP16 and 6.5%-hydrogen-peroxide-based strip (HP6.5. Before bleaching treatment, initial values of Knoop surface microhardness and color (CIEL*a*b* were obtained and the fragments were artificially stained in hemolyzed rat blood. Then, bleaching treatments were performed over a 21-day period. Color changes (ΔE were assessed at 7, 14 and 21 days, and final surface microhardness reading was done after 21 days. Thereafter, the fragments were bisected to obtain subsurface microhardness. Data were subjected to ANOVA and Tukey's tests (α=5%. RESULTS: Color changes produced by CP16 were similar to those of CP10, and the color changes produced by these materials were significantly superior to those produced by HP6.5. Color changes at 21 days were superior to 7 days and similar to 14 days. The time did not influence color changes for CP16, which showed similarity between the 14- and 21-day results. No statistically significant differences were found among the home bleaching agents for surface and subsurface microhardness. CONCLUSIONS: Microhardness of bovine enamel was not affected by the bleaching agents. The 16% carbamide peroxide gel was the most effective for bleaching the stained substrate.

  2. AC electrokinetic drug delivery in dentistry using an interdigitated electrode assembly powered by inductive coupling.

    Science.gov (United States)

    Ivanoff, Chris S; Wu, Jie Jayne; Mirzajani, Hadi; Cheng, Cheng; Yuan, Quan; Kevorkyan, Stepan; Gaydarova, Radostina; Tomlekova, Desislava

    2016-10-01

    AC electrokinetics (ACEK) has been shown to deliver certain drugs into human teeth more effectively than diffusion. However, using electrical wires to power intraoral ACEK devices poses risks to patients. The study demonstrates a novel interdigitated electrode arrays (IDE) assembly powered by inductive coupling to induce ACEK effects at appropriate frequencies to motivate drugs wirelessly. A signal generator produces the modulating signal, which multiplies with the carrier signal to produce the amplitude modulated (AM) signal. The AM signal goes through the inductive link to appear on the secondary coil, then rectified and filtered to dispose of its carrier signal, and the positive half of the modulating signal appears on the load. After characterizing the device, the device is validated under light microscopy by motivating carboxylate-modified microspheres, tetracycline, acetaminophen, benzocaine, lidocaine and carbamide peroxide particles with induced ACEK effects. The assembly is finally tested in a common dental bleaching application. After applying 35 % carbamide peroxide to human teeth topically or with the IDE at 1200 Hz, 5 Vpp for 20 min, spectrophotometric analysis showed that compared to diffusion, the IDE enhanced whitening in specular optic and specular optic excluded modes by 215 % and 194 % respectively. Carbamide peroxide absorbance by the ACEK group was two times greater than diffusion as measured by colorimetric oxidation-reduction and UV-Vis spectroscopy at 550 nm. The device motivates drugs of variable molecular weight and structure wirelessly. Wireless transport of drugs to intraoral targets under ACEK effects may potentially improve the efficacy and safety of drug delivery in dentistry. PMID:27565821

  3. Effect of casein phosphopeptide-amorphous calcium phosphate on the flexural strength of enamel-dentin complex following extracoronal bleaching

    Directory of Open Access Journals (Sweden)

    Diatri Nari Ratih

    2015-03-01

    Full Text Available Background: Bleaching can affect the mechanical properties of enamel-dentin complex, such as flexural strength. Casein phosphopeptide-amorphus calcium phosphate (CPP-ACP is often used following bleaching treatment to reduce hypersensitivity and to increase demineralization of tooth. Purpose: The purpose of the study was to investigate the effect of CPP-ACP on the flexural strength of enamel-dentin complex following extracoronal bleaching. Methods: Forty-eight enamel-dentin plates (size 8 x 2 x 3 mm were randomly assigned into 6 groups, each consisted of 8 samples. Group 1, no bleaching and immersed in artificial saliva. Group 2, no bleaching, CPP-ACP application only. Group 3, bleaching using 15% carbamide peroxide. Group 4, similar to group 3, except application of CPP-ACP for the times between bleaching. Group 5, bleaching with 40% hydrogen peroxide. Group 6, similar to group 5, except application of CPP-ACP for the times between bleaching. Flexural strength of each enamel-dentin plate was tested by threepoint bending test using universal testing machine. Results: The results showed that 15% carbamide peroxide and 40% hydrogen peroxide significantly reduced flexural strength of enamel-dentin (216.25±26.44 MPa and 206.67±32.07 MPa respectively. Conversely, application of CPP-ACP following both bleachings increased flexural strength (266.75± 28.27MPa and 254.58±36.59 MPa respectively. A two-way Anova revealed that extracoronal bleaching agents significantly reduced flexural strength (p<0.05. Conclusion: Extracoronal bleaching agents reduce flexural strength, whereas application of CPP-ACP following bleaching either with 15% carbamide peroxide or 40% hydrogen peroxide can increase the flexural strength of enamel-dentin complex.

  4. Effect of postoperative bleaching on microleakage of etch-and-rinse and self-etch adhesives

    Directory of Open Access Journals (Sweden)

    Vajihesadat Mortazavi

    2011-01-01

    Full Text Available Background: Bleaching the discoloured teeth may affect the tooth/composite interface. The aim of this in vitro experimental study was to evaluate the effect of vital tooth bleaching on microleakage of existent class V composite resin restorations bonded with three dental bonding agents. Methods : Class V cavities were prepared on buccal surfaces of 72 intact, extracted human anterior teeth with gingival margins in dentin and occlusal margins in enamel, and randomly divided into 3 groups. Cavities in the three groups were treated with Scotch bond Multi-Purpose, a total etch system and Prompt L-Pop and iBond, two self-etch adhesives. All teeth were restored with Z250 resin composite material and thermo-cycled. Each group was equally divided into the control and the bleached subgroups (n = 12. The bleached subgroups were bleached with 15% carbamide peroxide gel for 8 hours a day for 15 days. Microleakage scores were evaluated on the incisal and cervical walls. Data were analyzed using Kruskal-Wallis, Mann-Whitney and Bonferroni post-hoc tests (α = 0.05. Results: Bleaching with carbamide peroxide gel significantly increased the microleakage of composite restorations in Prompt L-Pop group at dentinal walls (P = 0.001. Bleaching had no effect on microleakage of restorations in the Scotch bond Multi-Purpose and iBond groups. Conclusion: Vital tooth bleaching with carbamide peroxide gel has an adverse effect on marginal seal of dentinal walls of existent composite resin restorations bonded with prompt L-Pop self-etch adhesive.

  5. Mercury release of amalgams with various silver contents after exposure to bleaching agent

    OpenAIRE

    Bahari, Mahmoud; Alizadeh Oskoee, Parnian; Savadi Oskoee, Siavash; Pouralibaba, Firoz; Morsali Ahari, Ali

    2016-01-01

    Background. Since it is possible for carbamide peroxide (CP) bleaching agent to contact old amalgam restorations, the present in vitro study evaluated the amount of dissolved mercury released from amalgam restorations with various percent-ages of silver content subsequent to the use of 15% CP. Methods. Thirty ANA 2000 amalgam disks with 43.1% silver content and thirty ANA 70 amalgam disks with 69.3% silver content were prepared. In each group, 15 samples were randomly placed in glass tubes co...

  6. Intracoronal bleaching of discolored non-vital teeth using laser irradiation: a case report

    Science.gov (United States)

    Marchesan, Melissa A.; de Castro, Fabiana C.; Matarazzo, Alexandre T.; Pecora, Jesus D.; Zanin, Fatima A.; Brugnera, Aldo, Jr.

    2004-09-01

    Dissemination of blood into the dentinal tubules caused by pulp extirpation or traumatically induced internal pulp bleeding is a possible cause of discoloration of non-vital teeth. Discolored teeth, especially in the anterior region, can result in considerable cosmetic impairment. The whitening of these teeth is an alternative therapeutic method that is relatively non-invasive and conserves dental hard tissue. Recently, intracoronal bleaching of pulpless discolored teeth can be performed with the association of laser irradiation to hydrogen and carbamide peroxide and can even be accomplished in one session. This report shows a clinical case of an endodontically treated tooth submitted to bleaching using LED light and infrared LLLT therapy.

  7. Effect of bleaching on the shear bond strength of the enamel

    Directory of Open Access Journals (Sweden)

    Thiago Arruda

    2008-01-01

    Full Text Available Objective: To evaluate the effect of dental bleaching on the shear bond strength of enamel. Methods: Fifty molars were selected and divided into five groups (n=10; G1-without bleaching (control; G2-bleached with 10% carbamide peroxide and restored 24h later; G3-bleached with 10% carbamide peroxide and restored seven days later; G4-bleached with 35% hydrogen peroxide and restored a 35% and restored 24h later; G5-bleached with 35% hydrogen peroxide and restored a 35% and restored seven days later. During the 24h and 7-day intervals the test specimens remained stored in artificial saliva, after which the restorative procedures were performed on the enamel. Results: The microshear bond strength test indicated the following results in MPa (ANOVA and Tukey post-hoc: G1-43.15 a (±5.19; G2-31.34 ab (± 4.41; G3-36.66 ab (± 3.11; G4-22.87 c (±3.76 and G5-35.67 ab (± 4.64. Conclusion: Groups G1, G2, G3 and G5 showed no statistical difference and Group G4 (bleached with 35% hydrogen peroxide and restored 24h later showed diminished bond strength between the bleached enamel and resin composite.

  8. Susceptibility of Enamel Treated with Bleaching Agents to Mineral Loss after Cariogenic Challenge

    Directory of Open Access Journals (Sweden)

    Hüseyin Tezel

    2011-01-01

    Full Text Available Objectives. Controversial reports exist whether bleaching agents cause a susceptibility to demineralization. The aim of this study was to compare the calcium loss of enamel treated with different bleaching agents and activation methods. Method and Materials. The specimens obtained from human premolars were treated in accordance with manufacturer protocols; 10% carbamide peroxide, 38% hydrogen peroxide light-activated, 38% hydrogen peroxide laser-activated, and no treatment (control. After cariogenic challenge calcium concentrations were determined by Inductively Coupled Plasma Mass Spectrometry. Results. No differences were found between the calcium loss of the laser-activated group and 10% carbamide peroxide group (>0.05. However, the differences between laser-activated and control groups were statistically significant (0.05. On the other hand, the light-activated group showed a significantly higher calcium loss compared with the other groups (<0.05. Conclusions. The results show that bleaching agents may cause calcium loss but it seems to be a negligible quantity for clinical aspects.

  9. Erosion and abrasion on dental structures undergoing at-home bleaching

    Directory of Open Access Journals (Sweden)

    Tarquinio SBC

    2011-07-01

    Full Text Available Flávio Fernando Demarco1, Sônia Saeger Meireles2, Hugo Ramalho Sarmento1, Raquel Venâncio Fernandes Dantas1, Tatiana Botero3, Sandra Beatriz Chaves Tarquinio11Graduate Program in Dentistry, School of Dentistry, Federal University of Pelotas, Brazil; 2Department of Operative Dentistry, Federal University of Paraíba, Brazil; 3Cariology, Restorative Science, and Endodontics Department, School of Dentistry, University of Michigan, MI, USAAbstract: This review investigates erosion and abrasion in dental structures undergoing at-home bleaching. Dental erosion is a multifactorial condition that may be idiopathic or caused by a known acid source. Some bleaching agents have a pH lower than the critical level, which can cause changes in the enamel mineral content. Investigations have shown that at-home tooth bleaching with low concentrations of hydrogen or carbamide peroxide have no significant damaging effects on enamel and dentin surface properties. Most studies where erosion was observed were in vitro. Even though the treatment may cause side effects like sensitivity and gingival irritation, these usually disappear at the end of treatment. Considering the literature reviewed, we conclude that tooth bleaching agents based on hydrogen or carbamide peroxide have no clinically significant influence on enamel/dentin mineral loss caused by erosion or abrasion. Furthermore, the treatment is tolerable and safe, and any adverse effects can be easily reversed and controlled.Keywords: peroxide, tooth bleaching, enamel, dentin, erosion, abrasion

  10. X-ray diffraction study of uranyl sulfate complexes with acetamide

    International Nuclear Information System (INIS)

    X-ray diffraction study of UO2SO4xLx2H2O (1), UO2SO4x2Lx2H2O (2) and UO2SO4x3LxH2O (3) (L-acetamide) complexes, which crystals were prepared by slow evaporation at room temperature uranyl sulfate and acetamide aqueous solutions with a definite molar ratio, is carried out. The lattice parameters for (1) are: a=17.520; b=6.917; c=8.759 A; β=104.40 deg sp.gr. s2/mC2 or Cm; for (2): a=7.248; b=9.451; c=10.623 A; α=109.15; β=107.79; γ=74.55 deg; sp.gr. P1-bar; for (3): a=8.494; b=10.170; c=10.606 A; α=118.81; β=102.92; γ=90.10 deg; sp.gr. P1-bar. Peculiarities of crystal-structure transformations in acetamide and carbamide uranyl sulfate complexes with change of UO2SO4:L ratio (L-acetamide or carbamide) are discussed

  11. Evaluation of Extraradicular Diffusion of Hydrogen Peroxide during Intracoronal Bleaching Using Different Bleaching Agents

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    Mohammad E. Rokaya

    2015-01-01

    Full Text Available Objectives. Extra radicular diffusion of hydrogen peroxide associated with intracoronal teeth bleaching was evaluated. Methods. 108 intact single rooted extracted mandibular first premolars teeth were selected. The teeth were instrumented with WaveOne system and obturated with gutta percha and divided into four groups (n=27 according to the bleaching materials used. Each main group was divided into three subgroups (n=9 according to the time of extra radicular hydrogen peroxide diffusion measurements at 1, 7, and 14 days: group 1 (35% hydrogen peroxide, group 2 (35% carbamide peroxide, group 3 (sodium perborate-30% hydrogen peroxide mixture, and group 4 (sodium perborate-water mixture. Four cemental dentinal defects were prepared just below the CEJ on each root surface. The amount of hydrogen peroxide that leached out was evaluated after 1, 7, and 14 days by spectrophotometer analysis. The results were analyzed using the ANOVA and Tukey’s test. Results. Group 1 showed highest extra radicular diffusion, followed by group 3 and group 2, while group 4 showed the lowest mean extra radicular diffusion. Conclusion. Carbamide peroxide and sodium perborate-water mixture are the most suitable bleaching materials used for internal bleaching due to their low extra radicular diffusion of hydrogen peroxide.

  12. Effect of Four Bleaching Regimens on Color Changes and Microhardness of Dental Nanofilled Composite

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    Vanderlei Salvador Bagnato

    2009-01-01

    Full Text Available Objective. The purpose of this study was to compare the color changes and microhardness of a nanocomposite after four bleaching regimens. Materials. Twenty-five specimens (n=25 were made with a nanocomposite resin (Filtek Supreme XT. The specimens were divided into five groups equally (n=5: bleaching groups and control group, as follows: G1: artificial saliva at 37∘C; (control G2: hydrogen peroxide (HP at 7%; G3: hydrogen peroxide (HP at 35%; G4: carbamide peroxide (CP at 10%; G5: carbamide peroxide (CP 35%. Color measurements were made with spectrophotometer using CIELAB color scale. The Vickers hardness (VHN measurements were performed at the top surface. The data were analyzed with two-way Analysis of Variance. Results. ΔE and VHN mean values into the groups were not statistically different, however, the VHN mean values before and after storage and bleaching showed statistically significant differences. Conclusion. Nanocomposite samples showed no significant alteration (color and microhardness after bleaching. Thus, no replacement of restorations is required after bleaching.

  13. THE EFFECTS OF HOME BLEACHING ON THE HARDNESS OF AMALGAM FILLING

    Directory of Open Access Journals (Sweden)

    Andi Soufyan

    2015-06-01

    Full Text Available Dental bleaching has been considered as a feasible approach for dental esthetic, and many dental bleaching products can be seen in the market. Therefore, the side effect of such dental product should be studied. This study was aimed to determine the effect of carbamide peroxide-containing home bleaching agent on the hardness of dental amalgam surface structure. Forty amalgam filling specimens were divided into 4 groups, which consist of 3 treatment groups and 1 controu group. Each group was exposed to the bleaching agent daily for 2, 4 and 8 hours within 7 days. The Vickers Microhardness Tester, with loads 98.07 mN for 20 seconds, was used to measure the hardness of amalgam surface. It was revealed that, there was a significant difference between the treatment and the control group on 8 hours period. It was concluded that there was a decrease in hardness of dental amalgam surface after having a contact with carbamide peroxide bleaching agent.

  14. 3种浓度过氧化脲漂白剂对牙科陶瓷表面粗糙度的影响%Effects of three different concentrations of bleaching gels on the surface roughness of dental porcelain

    Institute of Scientific and Technical Information of China (English)

    刘金萍; 谢瑜侠

    2012-01-01

    目的 评估3种浓度过氧化脲漂白剂对牙科陶瓷表面粗糙度的影响.方法 80个瓷块按随机数字表法分成4组.A、B、C组所有瓷块进行为期3周,每天8h的漂白,A组漂白剂为质量分数10%的过氧化脲,B组为质量分数15%的过氧化脲,C组为质量分数20%的过氧化脲;D组为空白对照组,浸泡于人工唾液里.表面粗糙度仪测量所有样本初始时和漂白1d、2d、3d、1周、2周、3周后的瓷块表面粗糙度,并进行统计学分析.结果 A、B、C、D 4组瓷块的初始表面粗糙度分别为(0.073±0.003)μm、(0.073±0.002)μm、(0.072±0,003)μm、(0.074±0.003)μm,3周后的粗糙度分别为(0.073±0.004)μm、(0.073±0.005)μm、(0.074±0.006)μm、(0.074±0.005)μm.7个时间点,4组组间和组内表面粗糙度差异均无统计学意义(P>0.05).结论 3种浓度过氧化脲漂白剂对牙科陶瓷表面无明显不良影响.%Objective To assess effects of three different concentrations of carbamide peroxide on the surface roughness of dental porcelain. Methods Surface roughness of 80 ceramic blocks were measured by a surface roughness tester, and then were randomly divided into four groups; group A were bleached with 10% carbamide peroxide eight hours per day; group B were bleached with 15% carbamide peroxide eight hours per day; group C were bleached with 20% carbamide peroxide eight hours per day; group D were soaked in artificial saliva as a blank control group. The first three groups were bleached for 3 weeks. Ceramic blocks surface roughness were measured at time points of 1 d,2d,3d, 1 w, 2 w, 3 w. Results There were no significant difference (P >0.05) of ceramic blocks surface roughness among the four groups. Conclusion Bleaching with 10% , 15% or 20% carbamide peroxide for three weeks have no obvious adverse effects on dental porcelain surface.

  15. Pyrite surface interaction with selected organic aqueous species under anoxic conditions

    Directory of Open Access Journals (Sweden)

    Bebié Joakim

    2000-10-01

    Full Text Available The interaction between low-molecular weight organic compounds and pyrite under anoxic conditions has been studied using a combination of electrophoresis and batch sorption experiments. The results suggest that acetate, carbamide, ethylamine, formamide, purine, D-ribose, and adenine, as well as the amino acids alanine, cysteine and glycine, interact within the electrophoretic shearplane of the pyrite surface. The observed surface interaction between the negatively charged surface of pyrite and the organic aqueous species takes place regardless of the formal charge of the aqueous species of interest. This indicates that the interaction of organic molecules with pyrite surfaces under anoxic conditions is dictated by interactions with specific surface sites (thiol or iron surface sites rather than electrostatic forces. Dissolved metals typically enhance the interaction of the organics species. This enhancement is either due to an alteration in the distribution of thiol and iron groups on the pyrite surface or by the formation of ternary surface complexes.

  16. Cation Tuning toward the Inference of the Gelation Behavior of Supramolecular Gels

    Science.gov (United States)

    Xue, Peng; Wu, Huiqiong; Wang, Xiaojuan; He, Ting; Shen, Rujuan; Yue, Fan; Wang, Jide; Zhang, Yi

    2016-05-01

    We serendipitously discovered that the tripeptide Asp–Phe–Phe trifluoroacetic acid salt (hereafter abbreviated as β-AspFF) formed a reversible thermotropic gel in chloroform solution (at temperatures higher than the boiling point of chloroform), and a stable gel in toluene solution (at equal to or lower than the room temperature). Experimental results indicate that doping metal ions into β-AspFF toluene gels can trigger morphological variations in the gel skeleton, thereby increasing gel volume and inducing the collapse of organogels. Investigation on the cation-tuned gelation behavior of β-AspFF can be used to elucidate heating-induced gel collapse (of normal gel) or reverse thermotropic gelation as well as select carbamide and acetamide as activators of β-AspFF gels in chloroform solution at room temperature.

  17. Bleaching in vital teeth: a literary review

    Directory of Open Access Journals (Sweden)

    Felipe Fagundes Soares

    2008-01-01

    Full Text Available Tooth bleaching technique has presented a significant evolution, promoting higher satisfaction and comfort to the patients. Therefore, the aim of this study was to present the bleaching agents and the techniques, discussing advantages and disadvantages of each one, and the effect of these agents in the oral environment. The main agents used in the bleaching technique are the hydrogen peroxide and the carbamide peroxide, promoting the bleaching effect through oxidation of organic compounds. The application of these agents can be made at home or at a doctor office. During treatment, it may occur some adverse effects, such as tooth sensibility, increasing of dental porosity, and some interactions with the restorative material. However, these adverse effects can be eliminated or controlled when the treatment is executed under professional orientation. When the bleaching technique is well indicated and correctly conducted, it is associated with significantly positive results.

  18. Synthesis of fungicide bis-(8-guanidino-octyl)amine acetate and its intermediates and bioactivity%双胍辛醋酸盐杀菌剂及其两种中间体的合成与生物活性

    Institute of Scientific and Technical Information of China (English)

    邹曲辉; 于世涛; 刘福胜; 解从霞

    2003-01-01

    O-methylisourea acetate was synthesized by two procedures from the main raw materials including carbamide, dimethyl sulfate, acetic acid and concentrated sulfuric acid. Its content reaches 98 % and the total yield attains to 70%. 1, 17-Diamino-9-azaheptadecane was first synthesized by two procedures using sebcic acid, 1,8-octanediamine, sodium azide and concentrated sulfuric acid as the main raw materials. Its content reaches 98% and the total yield is 65%. The structure of both were confirmed by FT-IR, 1H NMR and their available analysis method was established. Fungicide bis-(8-guanidino-octyl )amine acetate was synthesized from these two intermediates and its structure was confirmed by FT-IR and 1HNMR. Fungicidal activity test showed that it is a kind of broad-spectrum fungicide with notably effect.

  19. Effect of intracoronal bleaching agents on ultrastructure and mineral content of dentin

    Directory of Open Access Journals (Sweden)

    Fatemeh Maleknejad

    2012-01-01

    Full Text Available Aim: The purpose of this in vitro study was to evaluate the ultrastructural changes of dentin induced after exposure to different intracoronal tooth bleaching agents. Materials and Methods: Dental discs of 1 mm thickness were prepared from coronal dentin of sixty-four human maxillary premolars. Experimental specimens were divided into four subgroups: 45% carbamide peroxide, 35% hydrogen peroxide, sodium perborate + 30% hydrogen peroxide, sodium perborate + water. The specimens were then evaluated under scanning electron microscope to determine diameter of dentinal tubules and chemical analysis. Results: There was significant difference between dentinal tubule diameter of all test and control groups with the exception of sodium perborate + water. Chemical analysis revealed that there was no significant difference between experimental subgroups regarding calcium and sulfur wt%. Conclusions: All bleaching agents increased dentinal tubule diameter and promote alterations in mineral content of dentin with the exception of Sodium perborate mixed with water.

  20. Comparative study of the effects of two bleaching agents on oral microbiota.

    Science.gov (United States)

    Alkmin, Yara Tardelli; Sartorelli, Renata; Flório, Flávia Martão; Basting, Roberta Tarkany

    2005-01-01

    This study evaluated the in vivo effects of bleaching agents containing 10% carbamide peroxide (Platinum/Colgate) or 7.5% hydrogen peroxide (Day White 2Z/Discus Dental) on mutans Streptococcus during dental bleaching. The products were applied on 30 volunteers who needed dental bleaching. In each volunteer, one of the two bleaching agents was used on both dental arches one hour a day for three weeks. Analysis of the bacterial counts was made by collecting saliva before (baseline values), during (7 and 21 days) bleaching treatments and 14 days posttreatment. The Friedman non-parametric analysis (alpha=0.05) found no differences in microorganism counts at different times for each group for both agents (p>0.05). The Mann Whitney nonparametric test (alpha=0.05) showed no differences in micro-organism counts for both agents (p>0.05). Different bleaching agents did not change the oral cavity mutans Streptococcus counts. PMID:16130860

  1. Optimizing the Esthetics of peg-shaped teeth

    Directory of Open Access Journals (Sweden)

    Fabia Danielle Sales da Cunha Medeiros e Silva

    2008-01-01

    Full Text Available In modern esthetic dentistry, recontouring peg-shaped teeth present the option of a technique for obtaining a harmonious smile. In thiscontext, the advancement of direct dental materials, such as resin composites and adhesive systems, allows this procedure to be performedsimply and efficiently, when compared with other available techniques. Thus, the aim of this report is to present a clinical case with an esthetic solution in peg-shaped lateral incisors (12 and 22. Initially, it was opted first to perform dental bleaching with a home bleaching gel (16% carbamide peroxide associated with an acetate mold duly made for this purpose. The peg-shaped teeth were recontoured with a microhybrid resin composite (shade EA1 and DA1 with the aid of a platinum guide in silicone, obtained after diagnostic waxing on the plaster model. It was concluded that the association of esthetic procedures is of the utmost importance for obtaining good looking, aligned and harmonious teeth.

  2. Cation Tuning toward the Inference of the Gelation Behavior of Supramolecular Gels.

    Science.gov (United States)

    Xue, Peng; Wu, Huiqiong; Wang, Xiaojuan; He, Ting; Shen, Rujuan; Yue, Fan; Wang, Jide; Zhang, Yi

    2016-01-01

    We serendipitously discovered that the tripeptide Asp-Phe-Phe trifluoroacetic acid salt (hereafter abbreviated as β-AspFF) formed a reversible thermotropic gel in chloroform solution (at temperatures higher than the boiling point of chloroform), and a stable gel in toluene solution (at equal to or lower than the room temperature). Experimental results indicate that doping metal ions into β-AspFF toluene gels can trigger morphological variations in the gel skeleton, thereby increasing gel volume and inducing the collapse of organogels. Investigation on the cation-tuned gelation behavior of β-AspFF can be used to elucidate heating-induced gel collapse (of normal gel) or reverse thermotropic gelation as well as select carbamide and acetamide as activators of β-AspFF gels in chloroform solution at room temperature. PMID:27138527

  3. Comparative study of the effects of two bleaching agents on oral microbiota.

    Science.gov (United States)

    Alkmin, Yara Tardelli; Sartorelli, Renata; Flório, Flávia Martão; Basting, Roberta Tarkany

    2005-01-01

    This study evaluated the in vivo effects of bleaching agents containing 10% carbamide peroxide (Platinum/Colgate) or 7.5% hydrogen peroxide (Day White 2Z/Discus Dental) on mutans Streptococcus during dental bleaching. The products were applied on 30 volunteers who needed dental bleaching. In each volunteer, one of the two bleaching agents was used on both dental arches one hour a day for three weeks. Analysis of the bacterial counts was made by collecting saliva before (baseline values), during (7 and 21 days) bleaching treatments and 14 days posttreatment. The Friedman non-parametric analysis (alpha=0.05) found no differences in microorganism counts at different times for each group for both agents (p>0.05). The Mann Whitney nonparametric test (alpha=0.05) showed no differences in micro-organism counts for both agents (p>0.05). Different bleaching agents did not change the oral cavity mutans Streptococcus counts.

  4. [The refractory susceptibility in determination of sulfur in organic drugs using the Schoniger method].

    Science.gov (United States)

    Listov, S A; Arsamastsev, A P; Gamanina, G J

    1988-10-01

    Conventional methods of the determination of sulphur in organic drugs were studied (Schöniger method) and new methods developed. Emphasis was put on the disturbance effect of 5 elements, which often occur in the structure of organic drug compounds. It could be shown, that the disturbance effect of nitrogen and chlorine was overcome by the use of carbamide and ammonium carbonate in the absorption solution. The effect of fluorine was abolished by the use of boric acid and a special two-spiral technique of the analysis. Based on these studies concrete recommendations for the Schöniger method of sulphur determination in drugs of various composition of elements were given.

  5. [Effect of tricarboxylic acid cycle intermediates on nitric oxide system during acute hypoxia].

    Science.gov (United States)

    Kurhaliuk, N M

    2002-01-01

    Effects Crebs Cycle of exogenous intermediates sodium succinate (50 mg/kg) and sodium alpha-ketoglutarate (200 mg/kg) on processes of mitochondrial ADP-stimulated respiration (using as substrates of oxidation 0.35 mM succinate, 1 mM alpha-ketoglutarate), production of nitric oxide under NO2-, NO3-, as well as carbamide, putrescyne content and processes of lipid peroxidation in the rats liver under acute hypoxia (7% O2 in N2, 30 min) have been studied. It was shown, that the exogenous sodium alpha-ketoglutarate increases nitric oxide content, aminotransferase activation, inhibition of succinatedehydrogenase simultaneously more than exogenous sodium succinate. It correlates with decreasing of processes lipid peroxidation in liver. PMID:14964867

  6. Preparation and characterization of porous magnesium materials

    Institute of Scientific and Technical Information of China (English)

    LIU Xi-qin; LIU Zi-li; ZHANG Xiao-hong; FENG Jun-dong; YU Ta-xi

    2006-01-01

    The proper spacer material and the preparation technology for biological compatible porous magnesium materials were explored by the powder metallurgy method, and microstructures, porosity and mechanical properties of sintered porous magnesium were investigated. The results show that compared with spacer materials of NH4CO3, NH3Cl and carbamide, NH4CO3 is the best one for preparation of sintered porous magnesium, and the worst one is NH3Cl. The isolated blind pores are formed mainly by the particle interval of the magnesium powders. Adding spacer material favors the formation of open pores, while has little contribution to the formation of blind pores. The overall porosity and porosity of open pore of the sintered porous magnesium increase with the increase of added spacer material, while decrease with the increase of the molding stress. The mechanical properties of sintered porous magnesium increase with decreasing addition of spacer material and increasing molding stress.

  7. Chemical gas analyzers for proximate analysis of mine atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Pochenkova, T.K.; Klassovskaya, N.A.; Zlenko, A.G.; Gus' kova, A.N. (Vsesoyuznyi Nauchno-Issledovatel' skii Institut Gornogo Dela, Donetsk (Ukraine))

    1992-09-01

    Describes a series of chemical gas analyzers developed by the VNIIGD institute for proximate analysis of mine atmosphere in coal mines. The new GKh-4, GKh-5, GKh-6, GKh CO-5 use detector tubes for carbon monoxide and dioxide, nitrogen oxides, sulfur dioxide, oxygen and hydrogen sulfide. These devices allow miners to determine gas concentrations in the mine atmosphere in less than 4 minutes with an accuracy of +/-25%. The series is now complemented by the GKh-M CH[sub 2]O-0.004 gas analyzer for measuring formaldehyde content in mine air during mine rescue operations conducted with the use of carbamide-formaldehyde resins. Key technical data on the gas analyzers are given.

  8. Experimental investigation of the input section structure elements of the paste-cooled channel of a reusable pulsed MHD generator

    International Nuclear Information System (INIS)

    The results of experimental study on thermal stability of the input section structure elements of the paste-cooled channel of the MHD multi-action pulse generator are presented. The test rocket fuel engine with addition of powder-like aluminium was used as a gas generator. The engine nozzle with a critical cross section of a rectangular shape is accomplished from upper paste-cooled walls. Two paste-coolants: the melting one on the basis of carbamide and sublimation one on the basis of ammonium oxalate are tested. The fire tests confirmed the efficiency of copper walls by cooling through the paste-like coolants of two types by multiple thermal loadings. It is proved that the gas generator is a comfortable instrument for working off the MHD channel design on thermal stability through multicycle operation

  9. Application of quantitative light-induced fluorescence to determine the depth of demineralization of dental fluorosis in enamel microabrasion: a case report.

    Science.gov (United States)

    Park, Tae-Young; Choi, Han-Sol; Ku, Hee-Won; Kim, Hyun-Su; Lee, Yoo-Jin; Min, Jeong-Bum

    2016-08-01

    Enamel microabrasion has become accepted as a conservative, nonrestorative method of removing intrinsic and superficial dysmineralization defects from dental fluorosis, restoring esthetics with minimal loss of enamel. However, it can be difficult to determine if restoration is necessary in dental fluorosis, because the lesion depth is often not easily recognized. This case report presents a method for analysis of enamel hypoplasia that uses quantitative light-induced fluorescence (QLF) followed by a combination of enamel microabrasion with carbamide peroxide home bleaching. We describe the utility of QLF when selecting a conservative treatment plan and confirming treatment efficacy. In this case, the treatment plan was based on QLF analysis, and the selected combination treatment of microabrasion and bleaching had good results. PMID:27508165

  10. Synthesis and Characterization of Nickel Nanorods Transferred from Hydrotherally Decomposed Rod-like NiS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Powders of hexagonal-structured single-crystalline nickel sulfide nanorods have been synthesized in cetyltrimethyl ammonium bromide (CTAB)/water/hexane/n-pentanol quaternary microemulsion under hydrothermal conditions by using the reaction of carbamide and carbon disulfide as a sulfide source. Single-crystalline nickel nanorods have been synthesized via thermal decomposition by using single-crystalline nickel sulfide nanorods as precursor. The influence of different reaction parameters on the morphology of the products has been investigated. The structure, morphology and magnetic properties of the products were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), thermogravimetric analysis-differential scanning calorimeter (TGA-DSC) and vibrating sample magnetometer (VSM). The results of magnetic measurements showed that the specific saturation magnetization (σs) and coercivity values (Hc) of nickel nanorods were 37.5 emu/g and 68.5 Oe, respectively.

  11. Application of quantitative light-induced fluorescence to determine the depth of demineralization of dental fluorosis in enamel microabrasion: a case report

    Science.gov (United States)

    Park, Tae-Young; Choi, Han-Sol; Ku, Hee-Won; Kim, Hyun-Su; Lee, Yoo-Jin

    2016-01-01

    Enamel microabrasion has become accepted as a conservative, nonrestorative method of removing intrinsic and superficial dysmineralization defects from dental fluorosis, restoring esthetics with minimal loss of enamel. However, it can be difficult to determine if restoration is necessary in dental fluorosis, because the lesion depth is often not easily recognized. This case report presents a method for analysis of enamel hypoplasia that uses quantitative light-induced fluorescence (QLF) followed by a combination of enamel microabrasion with carbamide peroxide home bleaching. We describe the utility of QLF when selecting a conservative treatment plan and confirming treatment efficacy. In this case, the treatment plan was based on QLF analysis, and the selected combination treatment of microabrasion and bleaching had good results. PMID:27508165

  12. Comparação da superfície do esmalte antes e após clareamento com dois diferentes agentes: estudo clínico

    Directory of Open Access Journals (Sweden)

    Virgínia Teichmann Espina

    2008-01-01

    Full Text Available The purpose of this study was to compare of enamel surface before and after bleaching with two different agents. Twenty subjects were selected and divided in two groups: Group 1- treated with the night guard vital bleaching using 10% carbamide peroxide (Whiteness Perfect and Group 2- treated with the in-offi ce technique using 35% hydrogen peroxide (Whiteness HP. Epoxi resin replicas obtained from the maxillary central incisors, before, immediately after and thirty days after the bleaching procedure. All replicas were photography in scanning electron microscopy and examined for one expert and blind examiner taken in scores: 1- surface without alteration 2- surface with alteration. This study demonstrated that bleaching treatment using both agents causes effect on namel surface, but these are partially reverted in thirty days.

  13. City sewer collectors biocorrosion

    Science.gov (United States)

    Ksiażek, Mariusz

    2014-12-01

    This paper presents the biocorrosion of city sewer collectors impregnated with special polymer sulphur binders, polymerized sulphur, which is applied as the industrial waste material. The city sewer collectors are settled with a colony of soil bacteria which have corrosive effects on its structure. Chemoautotrophic nitrifying bacteria utilize the residues of halites (carbamide) which migrate in the city sewer collectors, due to the damaged dampproofing of the roadway and produce nitrogen salts. Chemoorganotrophic bacteria utilize the traces of organic substrates and produce a number of organic acids (formic, acetic, propionic, citric, oxalic and other). The activity of microorganisms so enables the origination of primary and secondary salts which affect physical properties of concretes in city sewer collectors unfavourably.

  14. Optimization of synthesis of upconversion luminescence material NaYF4:Er3+,Yb3+ nanometer-phosphor by low-temperature combustion synthesis method

    Institute of Scientific and Technical Information of China (English)

    LU Liping; ZHANG Xiyan

    2013-01-01

    A kind of Er3+-yb3+ co-doped natrium yttrium fluoride nanometer-phosphor sensitive to 980 nm was synthesized by the low-temperature combustion synthesis method,which expanded the application range of the low-temperature combustion synthesis (LCS) method which is always used in the synthesis of oxides and compound oxides.The synthesis conditions were optimized with orthogonal experiments and the optimum technological parameters were obtaincd.Intense upconversion emissions at 522,540 and 653 nm corresponding to the 2H11/2,4S3/2,and 4F9/2 transitions to the 4I15/2 ground state were observed when excited by continuous wavclength (CW) laser radiation at 980 nm.The effect of the carbamide amount on the phase formation and the luminescence intensity was analyzed.The average particle size of the sample was 30-40 nm.

  15. 基于环境友好的可替代煤及石油中有机碳源的CO2合成利用途径与技术探析%Utilization and Technology Exploration of Organic Carbon Source CO2 in Environmental Friendly and Replaceable Coal and Oil

    Institute of Scientific and Technical Information of China (English)

    沈发治

    2012-01-01

    The ways and technology of synthesis of alcghol, ether, ester, amine ester, lactone, polyester, carbamide and diamond based on CO2 were explored. Using CO2 as potential organic carbon resources not only solves environmental problem, but also eases shortage of resources.%对以CO2为原料合成醇、醚、酯、胺酯、内酯、聚酯、尿素及金钢石等物质的途径与技术进行了探析,指出二氧化碳作为潜在的有机碳资源,充分利用,变废为宝,不仅解决了环境问题,也能缓解资源短缺.

  16. 一锅法合成5,6-二苯基-4-对甲苯基-3,4-二氢嘧啶-2-酮工艺研究%Study of synthesis technology of 5,6-diphenyl-4-p-tolyl-3,4-dihydropyrimidin-2 (1H)-ketone by one-pot method

    Institute of Scientific and Technical Information of China (English)

    闫杏丽; 陈天云

    2013-01-01

    In the presence of a catalyst,5,6-diphenyl-4-p-tolyl-3,4-dihydropyrimidin-2 (1H)-ketone were synthetized by acetophenone,p-methylbenzaldehyde and carbamide which were used as raw materials.The experimental results showed that when the molar ratio of acetophenone,p-methylbenzaldehyde and carbamide was 1 ∶ 1.15 ∶ 1.1,the reaction temperture was 80 ℃,the reaction time was 2.0 h,and the amount of substance of NaOC2H5 used as the catalyst is 0.001 mol,the product yield could reach 96%.The structure of the product was confirmed by FT-IR and 1HNMR.%文章以二苯乙酮、对甲基苯甲醛和尿素为原料,在催化剂的作用下合成了5,6-二苯基-4-对甲苯基-3,4-二氢嘧啶-2-酮.通过实验确定了反应的较佳工艺参数如下:二苯乙酮、对甲基苯甲醛、尿素的摩尔比为1∶1.15∶1.1,反应温度为80℃,反应时间为2.0h,催化剂选用NaOC2 H5,其用量为0.001 mol,在该工艺条件下,产物的收率达到了96%.采用FT-IR和1HNMR对目标化合物的结构进行了表征.

  17. Influence of bleaching agents on the microhardness of nanoparticle resin composite

    Directory of Open Access Journals (Sweden)

    Vanderlei Salvador Bagnato

    2009-01-01

    Full Text Available Objective: To assess the effect of bleaching agents on the microhardness of nanoparticle resin composite. Methods: Twenty-eight cylindrical test specimens (8x1mm of FiltekTM Supreme XT resin (3M/ESPE were prepared and divided into 5 groups. The initial Vickers microhardness was measured (load of 50 grams force for 30 seconds on the top surface of the test specimens. The groupswere treated and divided as follows: G1 – artificial saliva (21 days - control; G2 - 7% hydrogen peroxide gel applied for 4h/day, for 14 days; G3 - 10% carbamide peroxide for 4h/day, for 14 days: G4 – 35% hydrogen peroxide gel applied in three sessions of 30 minutes each, with an interval of one week (21 days between the sessions; G5 - 35% carbamide peroxide, three sessions of 30 minutes each, with an interval of one week (21 days between the sessions. The top surfaces of the test specimens received treatment and were submitted to the Vickers microhardness test. Results: The results obtained were submitted to the Analysis of Variance at a fixed criterion, at a level of significance of p=0.05. No significant differences were observed among the treatments tested (p=0.42 when compared with G1. Significant differences (Tukey test were found when the initial microhardness values were compared with the values after experimental treatments (p<0.01. Conclusion: The application of bleaching agents did not alter the microhardness of resin composites. Therefore, there is no need to change restorations after bleaching.

  18. Effect of dental bleaching after bracket bonding and debonding using three different adhesive systems

    Directory of Open Access Journals (Sweden)

    Lucianna de Oliveira Gomes

    2013-04-01

    Full Text Available OBJECTIVE: To evaluate the influence of bonding and debonding of orthodontic brackets on dental in-home bleaching, taking into account three different adhesive systems. METHODS: Forty-four bovine incisors were divided into four groups according to the primer system used for orthodontic bracket bonding. Following the debonding of orthodontic brackets, the teeth were stored in staining solution for 96 hours. Then, teeth were whitened using 10% carbamide peroxide for two weeks at a 6-hour-a-day regime. Standardized digital photographs were taken at the following intervals: T0 (initial; T1 (after debonding; T2 (after pigmentation; T3, T4 and T5 representing 1, 7, and 14 days of bleaching. Repeatability and stability tests were carried out to check the method accuracy. Images were analyzed using Adobe Photoshop 7.0 software considering (L*a*b*color coordinate values and a modified color difference total (Δ;E'. RESULTS: The results of this study (ANOVA and Tukey; p < 0.01 demonstrated that after 7 days of bleaching, experimental groups showed significantly less teeth whitening compared to the control group. However, there were no significant color differences between the groups after 14 days, according to values of lightness (L*. CONCLUSIONS: Regardless of the adhesive primer system applied, bonding and debonding of orthodontic brackets alters the outcome of tooth whitening in the first 7 days of bleaching, however it has no influence on the whitening of the dental structure after 14 days of in-home dental bleaching with 10% carbamide peroxide.

  19. Effects of 10%sodium ascorbate on microleakage of composite resin restorations after external bleaching%10%抗坏血酸钠对外漂白后复合树脂充填体微渗漏的影响

    Institute of Scientific and Technical Information of China (English)

    韩艳彦; 杜嵘; 朱亚琴

    2015-01-01

    Objective To investigate the effects of 10%sodium ascorbate, 10%sodium ascorbate com-bined with a surfactan(Tween,0.2%) on the microleakage of composite resin restorations after external tooth bleaching with 10% carbamide peroxide. Methods Fifty extracted human premolars, intact and health, were randomly divided into five groups:group 1, direct composite resin filling without bleaching;group 2, composite resin filling immediately after bleaching with 10%carbamide peroxide;group 3, immersed in artificial saliva for three weeks after bleaching, then filled by composite resin;group 4, cavity treated with 10%sodium ascorbate after bleaching and then filled by composite resin;group 5, cavity treated with 10%sodium ascorbate combined with 0.2%Tween after bleaching and then filled by composite resin. After 2000 thermal cycles, teeth were immersed in 2%methylene blue for 24 hours, then the microleakage at resin/deatin interface was observed under stereomicro-scope. Results Group 1 displayed the least amount of microleakage, while group 2 showed the greatest amount of microleakage, group 3 and group 4 behaved similarly to group 2, having great amount of microleakage, show-ing no significant difference (P>0.05);the microleakage of group 5 decreased significantly (P0.05);第5组渗漏值较第2组及第4组显著下降(P<0.05)。结论10%过氧化脲外漂白致复合树脂充填体边缘微渗漏明显增加,含0.2%Tween的10%抗坏血酸钠处理窝洞可以有效减少该微渗漏的增加,延迟充填和单纯使用抗坏血酸钠均不能有效减少微渗漏。

  20. Molecular analysis of tooth enamel by Raman spectroscopy after treatment with bleaching agents at different concentrations

    International Nuclear Information System (INIS)

    The changes in the concentration of the v1 phosphate molecule of the surface of dentin enamel are treated and researched with bleaching agents of chemical activation to basis of hydrogen peroxide than 9,5% and 14% and carbamide peroxide than 38%, for a period of 28 days. Raman spectroscopy was used and 30 dental pieces extracted, of which, were to be free of blemishes and pigmentations, without possessing fractures of the enamel, decay nor any other type of defect. The Raman spectrum was obtained of each dental piece prior to the application of bleaching agents. The specimens were separated into three experimental groups according to the concentration of whitening. The concentration of the v1 phosphate molecule was measured in the tooth enamel to the second and fourth week of treatment. In addition, ANOVA was performed for respective measurements (p≤0.05). A reduction of the v1 phosphate molecule were observed during and after the bleaching process in the experimental groups that have used of hydrogen peroxide to 14% and carbamide peroxide 38%. In the group of hydrogen peroxide to 9,5% has remained unproven a significant reduction. Within the limitations of this study is concluded that the bleaching agent causes a loss of v1 phosphate. This loss has been greater in the whitening of higher concentration. In spite, that the possible effect remineralizing of the saliva on a teeth whitening process has been unevaluated, it is recommended using during and after the treatment, toothpastes, mouthwashes, chewing gums, dental floss, among others, that contain ACP to help to cushion the potential loss of phosphate from tooth enamel. (author)

  1. Effects of Nitrogen Source on Photosynthesis and Pigment Accumulation of Chlorella sp.TCCC45058%氮源对小球藻光合作用和色素积累的影响

    Institute of Scientific and Technical Information of China (English)

    赵华; 董晓宇; 夏媛媛; 牛堃

    2012-01-01

    In the study, effects of four kinds of nitrogen source (carbamide, NH4NO3, (NH4)2SO4 and NaNO3) on biomass, photosynthesis and Chlorophyll A productivity of Chlorella sp. TCCC45058 under autotrophy condition was investigated. The highest cell density (4.1 × 107/mL) of Chlorella sp. TCCC45058 was acquired when NaNO3 was used as nitrogen source. The optimal nitrogen source for pigment accumulation of Chlorella sp. TCCC45058 was carbamide, with which the highest Chlorophyll A productivity of cell was found as 21 mg/g. Different nitrogen source showed varied influences on medium pH. When NaNO3 was used as nitrogen source, medium pH rose significantly with consuming of NO3'. Use of (NH4)2SO4 as nitrogen source resulted in reduced medium pH. Carbamide and NH4NO3 had little effect on it When medium pH was controlled at neutral, the result of culture has not improved. Therefore, it was unnecessary to adjust medium pH throughout the cultivation.%本文研究了自养培养条件下尿素、NH4NO3、(NH4)2SO4和NaNO3四种氮源对小球藻(Chlorella sp.TCCC45058)生长、光合作用以及叶绿素a产率的影响.实验结果显示,NaNO3是Chlorella sp.TCCC45058生长的最佳氮源,以NaNO3为氮源时得到最高细胞密度4.1×107个/mL;而尿素对藻细胞色素积累最有利,最高叶绿素a产率达到21 mg/g.培养过程中,不同氮源会对培养液pH造成不同影响,以NaNO3为氮源时,随着NO3的消耗培养液pH会出现显著的上升;以(NI4)2SO4为氮源时pH呈下降趋势;而尿素和NH4NO3则不会对其产生明显影响.将pH维持在中性不会对各组氮源培养效果产生显著影响,因此实际生产中无需对培养基pH做全程控制.

  2. Penggunaan Karbamid Peroksida Sebagai Bahan Pemutih Gigi

    Directory of Open Access Journals (Sweden)

    Endang Suprastiwi

    2015-10-01

    Full Text Available Carbamide peroxide as a whitening agent for teeth is very popular because the use of this agent is easy and inexpensive. There are two kinds of concentrations, i.e. 10%-15% and 35%. The methods are home bleaching and in office bleaching. For home bleaching, the duration of whitening application is 2-6 weeks, each day for 8 hours, whilst for in office bleaching, two hour application will be required. Whitening efficacy might be increased up to 2-5 levels and the color may sustain for 1-3 years, and this treatment could be reapplied. There is an effect on pulp system, but the effect is reversible, i.e. sensitivity which could be treated with fluoridation or application of potassium nitrate. The side effects on gingiva include inflammation which is caused by the buffer and is only temporary. Bleaching is safe to be use and the result will be satisfying if proper procedure is followed.

  3. Effect of Bleaching on Color Change and Surface Topography of Composite Restorations

    Directory of Open Access Journals (Sweden)

    Gunjan Pruthi

    2010-01-01

    Full Text Available This study was conducted to determine the effect of 15% carbamide peroxide bleaching agent on color change and surface topography of different composite veneering materials (Filtek Z350 (3M ESPE, Esthet X (Dentsply India, and Admira (Voco, Germany. Methods. 30 samples were fabricated for evaluation of color change using CIELAB color system and Gonioreflectometer (GK 311/M, ZEISS. 45 disc-shaped specimens were made for evaluation of surface topography after bleaching (Nupro White Gold; Dentsply using SEM. Statistical analysis. One way ANOVA and Multiple comparison tests were used to analyze the data. Statistical significance was declared if the P value was .05 or less. Results and conclusion. All the specimens showed significant discoloration (ΔE>3.3 after their immersion in solutions representing food and beverages. The total color change after bleaching as compared to baseline color was significant in Filtek Z350 (P=.000 and Esthet X (P=.002, while it was insignificant for Admira (P=.18. Esthet X showed maximum surface roughness followed by Admira and Filtek Z350. Bleaching was effective in reducing the discoloration to a clinically acceptable value in all the three groups (ΔE<3.3.

  4. Application of biological markers for the identification of oil-type pollutants in recent sediments: Alluvial formation of the Danube river, Oil refinery Pančevo

    Directory of Open Access Journals (Sweden)

    Rašović Aleksandar S.

    2002-01-01

    Full Text Available The purpose of this paper was to examine to which extent the abundance and distribution of certain biological markers may be used for the identification of oil-type pollutants in recent sediments and ground waters. The samples were taken from the area of the Oil Refinery Pančevo (alluvial formation of the Danube River. The organic matter of the investigated samples was isolated using an extraction method with chloroform. The group composition and usual biological markers were analyzed in the obtained extracts. n-Alkanes and acyclic isoprenoids, pristane and phytane were analyzed using gas chromatographie (GC analysis of saturated hydrocarbons. Polycyclic alkanes of the sterane and terpane type were analyzed using gas chromatography-mass spectrometry (GC-MS, i.e. by analyzing the carbamide non-adduct of the total alkane fraction (Single Ion Monitoring SIM-technique. The obtained results indicate that n-alkanes can be used for the identification of oil-type pollutants (for example, if the oil-pollutant is biodegraded or present in very low concentrations, and steranes and triterpanes can be used as very reliable indicators of oil-type pollution in recent sediments and ground waters.

  5. Evaluation of the bleached human enamel by Scanning Electron Microscopy Avaliação do esmalte dental humano submetido ao tratamento clareador por meio de Microscopia Eletrônica de Varredura

    Directory of Open Access Journals (Sweden)

    Carolina Baptista Miranda

    2005-06-01

    Full Text Available Since bleaching has become a popular procedure, the effect of peroxides on dental hard tissues is of great interest in research. Purpose: The aim of this in vitro study was to perform a qualitative analysis of the human enamel after the application of in-office bleaching agents, using Scanning Electron Microscopy (SEM. Materials and Methods: Twenty intact human third molars extracted for orthodontic reasons were randomly divided into four groups (n=5 treated as follows: G1- storage in artificial saliva (control group; G2- four 30-minute applications of 35% carbamide peroxide (total exposure: 2h; G3- four 2-hour exposures to 35% carbamide peroxide (total exposure: 8h; G4- two applications of 35% hydrogen peroxide, which was light-activated with halogen lamp at 700mW/cm² during 7min and remained in contact with enamel for 20min (total exposure: 40min. All bleaching treatments adopted in this study followed the application protocols advised by manufacturers. Evaluation of groups submitted to 35% carbamide peroxide was carried out after two time intervals (30 minutes and 2 hours per session, following the extreme situations recommended by the manufacturer. Specimens were prepared for SEM analysis performing gold sputter coating under vacuum and were examined using 15kV at 500x and 2000x magnification. Results: Morphological alterations on the enamel surface were similarly detected after bleaching with either 35% carbamide peroxide or 35% hydrogen peroxide. Surface porosities were characteristic of an erosive process that took place on human enamel. Depression areas, including the formation of craters, and exposure of enamel rods could also be detected. Conclusion: Bleaching effects on enamel morphology were randomly distributed throughout enamel surface and various degrees of enamel damage could be noticed. Clinical significance: In-office bleaching materials may adversely affect enamel morphology and therefore should be used with caution.Desde o

  6. In vitro evaluation of the chemical and morphological changes of the enamel surface using different bleaching techniques

    International Nuclear Information System (INIS)

    'In vitro' evaluation through MEV and EDS of the morphological and chemical changes, respectively, of the bovine enamel, submitted to different bleaching techniques. For the MEV evaluation eighteen apical thirds were pigmented and divided into two parts. One half of each sample was the control and the other half was bleached according to the protocol of each test group (n= 6). Group I - home bleaching with a 10% carbamide peroxide; group II bleaching with 35% hydrogen peroxide and LED; group III - bleaching with 35% hydrogen peroxide with diode laser bleaching. The same procedure was done with the eighteen samples which were analyzed through EDS and which had their buccal surface grinded and polished before the bleaching procedure in order to obtain more precise values of the fraction of calcium and phosphorus. The results showed no morphological changes among the analyzed control halves and the bleached halves. There was not a statistical significant difference about Ca and P values, among the control halves and the bleached halves regarding the chemical components (p< 0,05). (author)

  7. 葛林美腐植酸有机复合液肥对苦瓜产量和品质的影响%Effects of Greentech Humic Acid Organic Compound Fertilizer on the Yield and Quality of Momordica charantia

    Institute of Scientific and Technical Information of China (English)

    游勇; 张志元

    2011-01-01

    The field experiment and instrument analytical method was conducted to study the effects of the Greentech humic acid organic compound fertilizer on the yield and quality of Momordica charantia L.. The results showed that the yield of cucumber was increased drastically through applying Greentech humic acid organic compound fertilizer, the yield was 19.3%higher than the contrast, and 11.8% higher compared with the treatment of carbamide. The economic benefits increased RMB 8 340 per hectare.%采用田间试验和仪器分析方法,研究了葛林美腐植酸有机复合液肥对苦瓜(Momordica charantia L.)产量和品质的影响.结果表明,葛林美腐植酸有机复合液肥处理的产量显著高于不施肥和尿素处理,比不施肥增产19.3%,比尿素处理增产11.8%,每公顷增加经济效益8340元以上.

  8. Effect of various antioxidants on the shear bond strength of composite resin to bleached enamel: An in vitro study

    Directory of Open Access Journals (Sweden)

    Mageshwaran Thandalam Arumugam

    2014-01-01

    Full Text Available Objective: The aim of this in vitro study was to evaluate and compare the effect of 10% sodium ascorbate, 6.5% proanthocyanidin, and 5% lycopene on the bond strength of composite resin to bleached enamel. Materials and Methods: Labial enamel surfaces of 100 extracted human maxillary central incisors were used in this study. Twenty teeth served as group I (control and received no bleaching treatment. The remaining 80 teeth were randomly divided into four groups of 20 teeth each, based on the antioxidant used as follows: group II- bleaching with 35% carbamide peroxide gel for 30 min without the use of an antioxidant, group III- bleaching followed by use of 10% sodium ascorbate solution, group IV- bleaching followed by use of 6.5% proanthocyanidin, and group V- bleaching followed by use of 5% lycopene. These groups were further subdivided into two subgroups of 10 teeth each, based on whether composite buildup was done immediately (subgroup A or after a delay of 2 weeks (subgroup B post bleaching. Shear bond strength of the specimens was tested under universal testing machine. The data were tabulated and statistically analyzed. Results: Significantly higher shear bond strength values were observed in teeth treated with control group prior to bonding, followed by sodium ascorbate group. Conclusion: Within the limitations of this study, it can be concluded all the antioxidants used in this study increased the bond strength of bleached enamel. Among the antioxidant groups, sodium ascorbate showed significantly higher bond strength compared to proanthocyanidin and lycopene.

  9. An overview of Gly-Oxide liquid in control and prevention of dental disease.

    Science.gov (United States)

    Stindt, D J; Quenette, L

    1989-09-01

    Removal of dental plaque is the generally accepted method of preventing and controlling periodontal disease. Several studies have identified bacterial plaque as the primary etiologic factor in periodontal disease. However, many individuals have difficulty in mechanically removing plaque or may have physical limitations that hinder their ability to effectively brush and floss. Consequently, in recent years, the search for an agent to remove or inhibit dental plaque has intensified. Numerous studies have been conducted to investigate the effectiveness of various agents in removing or inhibiting plaque. In its Technical Report No. 26, the Federation Dentair Internationale provides a comprehensive overview of the efficacy of antibiotics, antiseptics, chemical agents, irrigation, pastes, and slow release devices in plaque removal and inhibition. Addy has suggested that investigation of oxygenating mouthrinses as antiplaque agents deserves attention because of their potential ability to affect the anaerobes responsible for periodontal disease. The purpose of this article is to provide an overview of the role of one oxygenating agent, carbamide peroxide in glycerol solution, in the prevention and control of periodontal disease. PMID:2637067

  10. Effect of tooth bleaching agents on protein content and mechanical properties of dental enamel.

    Science.gov (United States)

    Elfallah, Hunida M; Bertassoni, Luiz E; Charadram, Nattida; Rathsam, Catherine; Swain, Michael V

    2015-07-01

    This study investigated the effect of two bleaching agents, 16% carbamide peroxide (CP) and 35% hydrogen peroxide (HP), on the mechanical properties and protein content of human enamel from freshly extracted teeth. The protein components of control and treated enamel were extracted and examined on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Marked reduction of the protein matrix and random fragmentation of the enamel proteins after bleaching treatments was found. The mechanical properties were analyzed with Vickers indentations to characterize fracture toughness, and nanoindentation to establish enamel hardness, elastic modulus and creep deformation. Results indicate that the hardness and elastic modulus of enamel were significantly reduced after treatment with CP and HP. After bleaching, the creep deformation at maximum load increased and the recovery upon unloading reduced. Crack lengths of CP and HP treated enamel were increased, while fracture toughness decreased. Additionally, the microstructures of fractured and indented samples were examined with field emission gun scanning electron microscopy (FEG-SEM) showing distinct differences in the fracture surface morphology between pre- and post-bleached enamel. In conclusion, tooth bleaching agents can produce detrimental effects on the mechanical properties of enamel, possibly as a consequence of damaging or denaturing of its protein components.

  11. The effect of enamel bleaching on the shear bond strengths of metal and ceramic brackets.

    Science.gov (United States)

    Oztaş, E; Bağdelen, G; Kiliçoğlu, H; Ulukapi, H; Aydin, I

    2012-04-01

    The aim of this study was to evaluate the effects of bleaching and delayed bonding on the shear bond strengths of metal and ceramic brackets bonded with light and chemically cure composite resin to human enamel. One hundred and twenty extracted human premolar teeth were randomly divided into three groups of 40 each. The first two groups were bleached with 20 per cent carbamide peroxide (CP) at-home bleaching agent. No bleaching procedures were applied to the third group and served as control. The first two and control groups were divided into equal subgroups according to different adhesive-bracket combinations. Specimens in group 1 (n = 40) were bonded 24 hours after bleaching process was completed while the specimens in group 2 (n = 40) were bonded 14 days after. The specimens in all groups were debonded with a Universal testing machine while the modified adhesive remnant index was used to evaluate fracture properties. No statistically significant differences were found between the shear bond strengths of metal and ceramic brackets bonded to bleached enamel after 24 hours, 14 days, and unbleached enamel with light or chemical cure adhesives (P > 0.05). The mode of failure was mostly at the bracket/adhesive interface and cohesive failures within the resin were also observed. Our findings indicated that at-home bleaching agents that contain 20 per cent CP did not significantly affect the shear bond strength of metal and ceramic orthodontic brackets to enamel when bonding is performed 24 hours or 14 days after bleaching.

  12. A caged substrate peptide for matrix metalloproteinases.

    Science.gov (United States)

    Decaneto, Elena; Abbruzzetti, Stefania; Heise, Inge; Lubitz, Wolfgang; Viappiani, Cristiano; Knipp, Markus

    2015-02-01

    Based on the widely applied fluorogenic peptide FS-6 (Mca-Lys-Pro-Leu-Gly-Leu-Dpa-Ala-Arg-NH2; Mca = methoxycoumarin-4-acetyl; Dpa = N-3-(2,4-dinitrophenyl)l-α,β-diaminopropionyl) a caged substrate peptide Ac-Lys-Pro-Leu-Gly-Lys*-Lys-Ala-Arg-NH2 (*, position of the cage group) for matrix metalloproteinases was synthesized and characterized. The synthesis implies the modification of a carbamidated lysine side-chain amine with a photocleavable 2-nitrobenzyl group. Mass spectrometry upon UV irradiation demonstrated the complete photolytic cleavage of the protecting group. Time-resolved laser-flash photolysis at 355 nm in combination with transient absorption spectroscopy determined the biphasic decomposition with τa = 171 ± 3 ms (79%) and τb = 2.9 ± 0.2 ms (21%) at pH 6.0 of the photo induced release of the 2-nitrobenzyl group. The recombinantly expressed catalytic domain of human membrane type I matrix metalloproteinase (MT1-MMP or MMP-14) was used to determine the hydrolysis efficiency of the caged peptide before and after photolysis. It turned out that the cage group sufficiently shields the peptide from peptidase activity, which can be thus controlled by UV light.

  13. A New Approach for Manufacturing a High Porosity Ti-6Al-4V Scaffolds for Biomedical Applications

    Institute of Scientific and Technical Information of China (English)

    Montasser DEWIDAR; H.Fouad MOHAMED; Jae-Kyoo LIM

    2008-01-01

    Titanivm and its alloys are currently considered as one of the most important metallic materials used in the biomedical applications,due to their excellent mechanical properties and superior biocompatibility.In the present study,a new effective method for fabricating high porosity titanium alloy scaffolds was developed.Porous Ti-6Al-4V scaffolds are successfully fabricated with porosities ranging from 30% to 70% using space-holder and powder sintering technique.Based on its acceptable properties,spherical carbamide particles with different diameters (0.56,0.8,and 1 mm) were used as the space-holder material in the present investigation.The Ti-6Al-4V scaffolds porosity is characterized by using scanning electron microscopy.The results show that the scaffolds spherical-shaped pores are depending on the shape,size and distribution of the space-holder particles.This investigation shows that the present new manufacturing technique is promising to fabricate a controlled high porosity and high purity Ti-6Al-4V scaffolds for hard tissue replacement.

  14. Results of research in the area of nanotechnologies and nanomaterials. Part 4

    Directory of Open Access Journals (Sweden)

    KARPOV Alexey Ivanovich

    2014-08-01

    Full Text Available To popularize scientific achievements in construction the main results of Russian and foreign scientists’ research are published in the form of abstract. Within the frame of the research «Nanocomposite cabel elastrons based on polyvinylchloride and aluminum silicate» new nanocomposite materials based on polyvinylchloride elastron with organomodified montmorillonite and combinations of it with non-halogen fire flame retardant have been developed. The experiment shows that carbamide-containing organoclay is the efficient filler of polyvinylchloride elastron. The receipts and production method for new polymer nanocomposites based on PVC elastron and organomodified montmorillonite have been designed. The paper provides information on the methods to obtain nanodimensional natural fillers; principles for choosing organomodifiers and their influence on the quality of nanodimensional flaked silicate fillers; application efficiency of organoclays when modifying properties of polymer materials. All that makes the results of the research to be very useful for specialists engaged into the area of filler manufacture, creation and processing of polymer composite material and designing products of them. Specialists can use published materials in their scientific and practical activities.

  15. Effect of sodium ascorbate on the bond strength of silorane and methacrylate composites after vital bleaching

    Directory of Open Access Journals (Sweden)

    Eda Guler

    2013-07-01

    Full Text Available We investigated the effect of sodium ascorbate (SA on the microtensile bond strengths (MTBSs of different composites to bovine enamel after vital bleaching with hydrogen peroxide (HP or carbamide peroxide (CP. Thirty bovine incisors were randomly divided into five groups and treated with no bleaching application (control, 35% HP alone, 35% HP + 10% SA for 10 minutes (HP + SA, 16% CP alone, or 16% CP + 10% SA for 10 minutes (CP + SA. Specimens were restored with Silorane adhesive and Filtek Silorane composite (designated as S / group or with Clearfil SE bond and Filtek Supreme XT (designated as F / group. Composite build-up was created on the enamel. Sectioned specimens (n = 10 per group; 1 mm2; cross-sectional area were created and stressed in a universal testing machine at 1 mm/min crosshead speed. The application of 10% SA immediately after bleaching with 16% CP or 35% HP increased the enamel MTBS, regardless of the adhesive / composite resin used. The resulting MTBS values were similar to those of the control groups. Use of 16% CP and 35% HP alone decreased the enamel MTBS, regardless of the adhesive / composite resin used, with F / CP + SA = F / HP + SA = F / CP = S / CP + SA = S / HP + SA = S / C > S / CP = S / HP = F / CP = F / HP (p < 0.05. We concluded that the application of SA for 10 minutes immediately after vital bleaching increases the enamel BS for dimethacrylate- and silorane-based composites

  16. Esthetic rehabilitation with tooth bleaching, enamel microabrasion, and direct adhesive restorations.

    Science.gov (United States)

    Bezerra-Júnior, Douglas Machado; Silva, Luciana Mendonça; Martins, Leandro de Moura; Cohen-Carneiro, Flávia; Pontes, Danielson Guedes

    2016-01-01

    The aim of this case report is to report esthetic rehabilitation with combined tooth bleaching, enamel microabrasion, and anterior restoration replacement in a 26-year-old man. Clinical examination showed deficient restorations in the maxillary anterior teeth, significant discoloration of the maxillary left central incisor, and hypoplastic stains affecting the maxillary right lateral incisor. A radiograph of the left central incisor showed satisfactory endodontic treatment, allowing preparation for the walking bleach technique. For 3 weeks, 37% carbamide peroxide in the pulp chamber was renewed every week. In-office bleaching with 35% hydrogen peroxide was also performed on the maxillary teeth. After 21 days, all teeth had been bleached to shade A1. After bleaching was completed, enamel microabrasion of the maxillary right lateral incisor was conducted with 6% hydrochloric acid. In later sessions, microhybrid composite resin restorations were placed in all 4 maxillary incisors. A combination of dental bleaching techniques, enamel microabrasion, and resin restorations was a successful and conservative choice for reestablishing the natural appearance of discolored teeth, improving the self-esteem of the patient. PMID:26943091

  17. Physical-chemical characteristics of whitening toothpaste and evaluation of its effects on enamel roughness

    Directory of Open Access Journals (Sweden)

    Sérgio Paulo Hilgenberg

    2011-08-01

    Full Text Available This in vitro study evaluated the physical-chemical characteristics of whitening toothpastes and their effect on bovine enamel after application of a bleaching agent (16% carbamide peroxide. Physical-chemical analysis was made considering mass loss by desiccation, ash content and pH of the toothpastes. Thirty bovine dental enamel fragments were prepared for roughness measurements. The samples were subjected to bleaching treatments and simulated brushing: G1. Sorriso Dentes Brancos (Conventional toothpaste, G2. Close-UP Whitening (Whitening toothpaste, and G3. Sensodyne Branqueador (Whitening toothpaste. The average roughness (Ra was evaluated prior to the bleaching treatment and after brushing. The results revealed differences in the physical-chemical characteristics of the toothpastes (p < 0.0001. The final Ra had higher values (p < 0.05 following the procedures. The mean of the Ra did not show significant differences, considering toothpaste groups and bleaching treatment. Interaction (toothpaste and bleaching treatment showed significant difference (p < 0.0001. The whitening toothpastes showed differences in their physical-chemical properties. All toothpastes promoted changes to the enamel surface, probably by the use of a bleaching agent.

  18. Optical properties and surface structure comparison of tooth whitening using four laser systems and chemical action agents

    Science.gov (United States)

    Dostalova, Tatjana; Jelinkova, Helena; Koranda, Pavel; Nemec, Michal; Sulc, Jan; Housova, Devana; Miyagi, Mitsunobu; Kokta, Milan R.

    2003-06-01

    The purpose of the study is to evaluate the effect of various laser techniques for bleaching teeth in office vital whitening. Hydrogen peroxide (30% concentration) and carbamide peroxide (10% solution) were used for chemical activation of bleaching process. Extracted non-carcious upper central incisors were exposed to laser radiation. Four different laser systems (Nd:YAG laser SHG, wavelength 0.53 μm, CTE:YAG laser, wavelength 2.7 μm, Nd:YAG laser, wavelength 1.06 μm, and alexandrite laser, wavelength 0.75 μm) were applied to accelerate the speed of the process. The end of chemical exposition was verified by the change of bleaching agent color. The color change was determined by stereomicroscope (Nikon SMZ 2T, Japan), the quality of surface structure was checked by scanning electron microscope Joel, Japan). The speed of bleaching rnaged from 630 s (chemical methods only) to 250-340 s (chemicals + alexandrite laser radiation). The Alexandrite laser application was considered an elective process to decrease the time of bleaching without modifying the surface.

  19. Can a bleaching toothpaste containing Blue Covarine demonstrate the same bleaching as conventional techniques? An in vitro, randomized and blinded study

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    Andréa Abi Rached DANTAS

    2015-12-01

    Full Text Available ABSTRACT Objective The purpose of this in vitro study was to compare the efficacy of a bleaching toothpaste containing Blue Covarine vs. conventional tooth bleaching techniques using peroxides (both in-office and at-home. Material and Methods Samples were randomly distributed into five experimental groups (n=15: C - Control; BC – Bleaching toothpaste containing Blue Covarine; WBC – Bleaching toothpaste without Blue Covarine; HP35 - In-office bleaching using 35% hydrogen peroxide; and CP10 – At-home bleaching with 10% carbamide peroxide. The dental bleaching efficacy was determined by the color difference (ΔE, luminosity (ΔL, green-red axis (Δa, and blue-yellow axis (Δb. The CIELab coordinates were recorded with reflectance spectroscopy at different times: T0 - baseline, T1 – immediately after bleaching, T2 - 7 days, T3 - 14 days, and T4 - 21 days after the end of treatments. Data were analyzed by a repeated measures mixed ANOVA and post hoc Bonferroni test, with a significance level of 5%. Results No significant differences were found between the treatment groups C, BC, and WBC. The groups HP35 and CP10 showed significantly higher whitening efficacy than groups C, BC, and WBC. Conclusions There were no significant differences in the whitening efficacy between a Blue Covarine containing toothpaste, a standard whitening toothpaste, and a control. Neither of the whitening toothpastes tested were as effective as in-office or at-home bleaching treatments.

  20. 3D Surface Profile and Color Stability of Tooth Colored Filling Materials after Bleaching.

    Science.gov (United States)

    Irawan, Bryant Anthony; Irawan, Stacey Natalie; Masudi, Sam'an Malik; Sukminingrum, Ninin; Alam, Mohammad Khursheed

    2015-01-01

    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 Estelite Σ Quick, 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 (CIE L(*), 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 a P value of ≤ 0.05. The three restorative materials showed significant color changes (ΔE); P ≤ 0.05. In diminishing order, the mean color changes recorded were Estelite Σ (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. PMID:26558267

  1. Mercury release of amalgams with various silver contents after exposure to bleaching agent.

    Science.gov (United States)

    Bahari, Mahmoud; Alizadeh Oskoee, Parnian; Savadi Oskoee, Siavash; Pouralibaba, Firoz; Morsali Ahari, Ali

    2016-01-01

    Background. Since it is possible for carbamide peroxide (CP) bleaching agent to contact old amalgam restorations, the present in vitro study evaluated the amount of dissolved mercury released from amalgam restorations with various percent-ages of silver content subsequent to the use of 15% CP. Methods. Thirty ANA 2000 amalgam disks with 43.1% silver content and thirty ANA 70 amalgam disks with 69.3% silver content were prepared. In each group, 15 samples were randomly placed in glass tubes containing 15% CP (as experimental groups) and the remaining 15 samples were placed in buffered phosphate solution (as control groups) with the same 3-mL volume for 48 hours. Subsequently, the amount of mercury dissolved in each test tube was measured using Mercury Analyzing System (Cold Vapor Atomic Absorption, MASLO, Shimadzu, Japan). Data was analyzed with two-way ANOVA and a post hoc Tukey test. (α = 0.05). Results. The amount of mercury released after exposure to CP was significantly higher than that released after exposure to buffered phosphate (P dental amalgam with a silver content of 43% was significantly higher than that released from dental amalgam with a silver content of 69% (P dental amalgam. PMID:27429729

  2. Avaliação clínica da eficácia do clareamento dental pela técnica caseira utilizando moldeiras com e sem alívio

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    Fábio Herrmann Coelho-de-Souza

    2010-01-01

    Full Text Available The aim of this study was to evaluate the clinical performance of 16% carbamide peroxide home vital bleaching, using trays constructed with or without reservoirs, and analyze the postoperative hypersensitivity. This was a randomized, double-blind and split-mouth study. Two examinators evaluated 11 and 21 teeth from eleven patients (Kappa 0,75. Right side of upper stone models received reservoirs before trays were constructed, left side didn't. Home bleaching was performed through two weeks, 6 hours-day. After this time, 11 and 21 teeth was evaluated again by the same examinators. Patients were asked about postoperative hypersensitivity. Data were statistically analyzed by Fisher¿s exact test (p>0,05, and didn't show any statistically significant difference between trays with or without reservoirs. All patients related postoperative hypersensitivity during bleaching time. Home bleaching technique was effective on dental bleaching, with or without reservoirs on the trays. Home bleaching promoted postoperative hypersensitivity in all cases.

  3. A conservative approach to esthetically treat stained arrested caries lesions.

    Science.gov (United States)

    Al-Angari, Sarah S; Hara, Anderson T

    2016-01-01

    Esthetic treatment of stained arrested caries lesions (ACLs) has mostly been done using invasive restorative techniques. The aim of this paper was to propose and report the efficacy of a conservative approach based on dental bleaching to esthetically treat these lesions, both experimentally (extracted teeth) and clinically. In a laboratory experiment, ten extracted human teeth with stained ACLs in either pit and fissure or smooth surface were selected and treated with 15% carbamide peroxide gel, 4 h per day, for a total of 6 days. The second part of the paper reports a clinical case of pit and fissure-stained ACLs in four posterior teeth, which were treated with 40% hydrogen peroxide in-office bleaching. Digital photographs were taken in both parts to document the efficacy of the treatment. The lesions showed noticeable increase in color lightness indicating the efficacy and suitability of the proposed approach. By using the conservative clinical technique presented, the esthetics of most stained ACLs could be improved, eliminating the need for invasive restorative treatments. PMID:27092359

  4. Effect of hydrazine and hydroxylaminophosphate on chrome plating from trivalent electrolytes

    Science.gov (United States)

    Survilienė, S.; Jasulaitienė, V.; Nivinskienė, O.; Češūnienė, A.

    2007-06-01

    The influence of hydrazine and hydroxylaminophosphate on solution chemistry and quality of chromium coatings deposited from Cr(III) formate-urea baths has been studied by FT-IR, XPS and AFM. The results have shown that hydrazine and hydroxylaminophosphate differently affect Cr plating. The morphology of Cr deposits obtained in the formate-urea electrolytes is a typical nodular structure with a less nodular and smoother fine-grained structure of Cr obtained in the presence of hydroxylaminophosphate. Hydrazine, in contrast, worsened the quality and lowered the hardness of the deposits. The current efficiency of chromium increases in the presence of both hydrazine and hydroxylaminophosphate. This may be related with the ability of these ligands to reduce the CrH content in the growing Cr deposit. The data obtained suggest that hydroxylaminophosphate improves the stability of the active [Cr(carbamide) n(H 2O) 6- n] 3 complexes providing good quality of the deposits and prolonged working lifetime in the formate-urea bath.

  5. Kinetic release of hydrogen peroxide from different whitening products.

    Science.gov (United States)

    da Silva Marques, Duarte Nuno; Silveira, Joao Miguel; Marques, Joana Rita; Amaral, Joao Almeida; Guilherme, Nuno Marques; da Mata, António Duarte

    2012-01-01

    The objective of this in vitro study was to evaluate the kinetics of hydrogen peroxide (HP) release from five different bleaching products: VivaStyle® 10% fitted tray gel, VivaStyle® 30% in-office bleaching gel, VivaStyle® Paint-On Plus paint-on bleaching varnish, Opalescence PF® 10% carbamide peroxide gel and Trèswhite Supreme™ 10% HP gel. Each product was firstly titrated for its HP content by a described method. HP release kinetics was assessed by a modified spectrophotometric technique. One sample t test was performed to test for differences between the manufacturers' claimed HP concentrations and the titrated HP content in the whitening products. Analysis of variance plus Tamhane's post hoc tests and Pearson correlation analysis were used as appropriate. Values of P tested (P tested. These results are consistent with manufacturers' reduced recommended application times. The results of this study suggest that modifying the matrix composition may be a viable alternative to HP concentration increase, since this may result in faster release kinetics without exposure to high HP concentrations. PMID:22908081

  6. In vitro evaluation of the chemical and morphological changes of the enamel surface using different bleaching techniques; Avaliacao in vitro das alteracoes quimica e morfologica da superficie do esmalte utilizando diferentes tecnicas de clareamento dental

    Energy Technology Data Exchange (ETDEWEB)

    Mattos, Alessandra de Siervi

    2003-07-01

    'In vitro' evaluation through MEV and EDS of the morphological and chemical changes, respectively, of the bovine enamel, submitted to different bleaching techniques. For the MEV evaluation eighteen apical thirds were pigmented and divided into two parts. One half of each sample was the control and the other half was bleached according to the protocol of each test group (n= 6). Group I - home bleaching with a 10% carbamide peroxide; group II bleaching with 35% hydrogen peroxide and LED; group III - bleaching with 35% hydrogen peroxide with diode laser bleaching. The same procedure was done with the eighteen samples which were analyzed through EDS and which had their buccal surface grinded and polished before the bleaching procedure in order to obtain more precise values of the fraction of calcium and phosphorus. The results showed no morphological changes among the analyzed control halves and the bleached halves. There was not a statistical significant difference about Ca and P values, among the control halves and the bleached halves regarding the chemical components (p< 0,05). (author)

  7. Effect of bleaching agents having a neutral pH on the surface of mineral trioxide aggregate using electron microscopy and energy dispersive X-ray microanalysis

    Science.gov (United States)

    Kazia, Nooh; Suvarna, Nithin; Shetty, Harish Kumar; Kumar, Pradeep

    2016-01-01

    Aim: To investigate the effect of bleaching agents having a neutral pH on the surface of mineral trioxide aggregate (MTA) used as a coronal seal material for nonvital bleaching, beneath the bleaching agent, with the help of energy dispersive X-ray microanalysis and scanning electron microscopy (SEM). Materials and Methods: Six samples of plastic tubes filled with white MTA (Angelus white) were kept in 100% humidity for 21 days. Each sample was divided into 2 and made into 12 samples. These were then divided into three groups. Group A was exposed to Opalescence Boost 40% hydrogen peroxide (HP) (Ultradent). Group B to Opalescence 10% carbamide peroxide (Ultradent) and Group C (control group) not exposed to any bleaching agent. After recommended period of exposure to bleaching agents according to manufacturers’ instructions, the samples were observed under SEM with an energy dispersive X-ray microanalysis system (JSM-6380 LA). Results: There were no relevant changes in color and no statistically significant surface structure changes of the MTA in both the experimental groups. Conclusion: The present findings suggest that even high concentration HP containing bleaching agents with neutral pH can be used on the surface of MTA without causing structural changes. The superior sealing ability of MTA and the high alkalinity would prevent cervical resorption postbleaching. PMID:27656061

  8. USE OF NEUTRALIZED PHOSPHOGYPSUM AS MULTICOMPONENT FERTILIZER FOR RICE CROPS. MESSAGE II

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    Sheudghen A. H.

    2015-11-01

    Full Text Available The article shows a possibility of using neutralized phosphogypsum as multicomponent fertilizer for rice crops. In the system of rice fertilization replace of 150kg/ha of ammophos during main application with 40 kg/ha of carbamide and 4 tons/ha of phosphogypsum applied in spring provides the same content of available forms of nitrogen, phosphorus and potassium in soil and plants as with application of N120P80K60. Application of phosphogypsum in spring before sowing is less effective than application in autumn before plowing. When applicating phosphogypsum in spring 2013 with a rate of 4 t / ha the obtained yield was 0.57 t / ha or 8.98% higher than in the control, and in 2014 it was not different from that obtained with the application of solid mineral fertilizers with a rate of N120P80K60. With autumn application of phosphogypsum increase in yield in 2014 was 0.98 t / ha or 12.6%. Yield growth is the result of increasing the survival of plants, grain content in panicle and grain weight per plant. Use of neutralized phosphogypsum is economically feasible. Relative benefits of using phosphogypsum instead of phosphorus fertilizer (ammonium phosphate on rice crops in the Federal State Unitary Enterprise SRSF "Krasnoarmeyskiy" named after A.I.Maystrenko, Krasnoarmeyskiy district of Krasnodar region at the optimal rate amounted to 13139.7 rubles per 1 ha

  9. Can a bleaching toothpaste containing Blue Covarine demonstrate the same bleaching as conventional techniques? An in vitro, randomized and blinded study

    Science.gov (United States)

    DANTAS, Andréa Abi Rached; BORTOLATTO, Janaina Freitas; RONCOLATO, Ávery; MERCHAN, Hugo; FLOROS, Michael Christopher; KUGA, Milton Carlos; de OLIVEIRA, Osmir Batista

    2015-01-01

    ABSTRACT Objective The purpose of this in vitro study was to compare the efficacy of a bleaching toothpaste containing Blue Covarine vs. conventional tooth bleaching techniques using peroxides (both in-office and at-home). Material and Methods Samples were randomly distributed into five experimental groups (n=15): C - Control; BC – Bleaching toothpaste containing Blue Covarine; WBC – Bleaching toothpaste without Blue Covarine; HP35 - In-office bleaching using 35% hydrogen peroxide; and CP10 – At-home bleaching with 10% carbamide peroxide. The dental bleaching efficacy was determined by the color difference (ΔE), luminosity (ΔL), green-red axis (Δa), and blue-yellow axis (Δb). The CIELab coordinates were recorded with reflectance spectroscopy at different times: T0 - baseline, T1 – immediately after bleaching, T2 - 7 days, T3 - 14 days, and T4 - 21 days after the end of treatments. Data were analyzed by a repeated measures mixed ANOVA and post hoc Bonferroni test, with a significance level of 5%. Results No significant differences were found between the treatment groups C, BC, and WBC. The groups HP35 and CP10 showed significantly higher whitening efficacy than groups C, BC, and WBC. Conclusions There were no significant differences in the whitening efficacy between a Blue Covarine containing toothpaste, a standard whitening toothpaste, and a control. Neither of the whitening toothpastes tested were as effective as in-office or at-home bleaching treatments. PMID:26814462

  10. Mercury release of amalgams with various silver contents after exposure to bleaching agent

    Science.gov (United States)

    Bahari, Mahmoud; Alizadeh Oskoee, Parnian; Savadi Oskoee, Siavash; Pouralibaba, Firoz; Morsali Ahari, Ali

    2016-01-01

    Background. Since it is possible for carbamide peroxide (CP) bleaching agent to contact old amalgam restorations, the present in vitro study evaluated the amount of dissolved mercury released from amalgam restorations with various percent-ages of silver content subsequent to the use of 15% CP. Methods. Thirty ANA 2000 amalgam disks with 43.1% silver content and thirty ANA 70 amalgam disks with 69.3% silver content were prepared. In each group, 15 samples were randomly placed in glass tubes containing 15% CP (as experimental groups) and the remaining 15 samples were placed in buffered phosphate solution (as control groups) with the same 3-mL volume for 48 hours. Subsequently, the amount of mercury dissolved in each test tube was measured using Mercury Analyzing System (Cold Vapor Atomic Absorption, MASLO, Shimadzu, Japan). Data was analyzed with two-way ANOVA and a post hoc Tukey test. (α = 0.05). Results. The amount of mercury released after exposure to CP was significantly higher than that released after exposure to buffered phosphate (P < 0.001). In addition, the amount of mercury released from dental amalgam with a silver content of 43% was significantly higher than that released from dental amalgam with a silver content of 69% (P < 0.001). Conclusion. The amount of mercury release is inversely proportional to the silver content of dental amalgam. PMID:27429729

  11. Mercury release of amalgams with various silver contents after exposure to bleaching agent

    Science.gov (United States)

    Bahari, Mahmoud; Alizadeh Oskoee, Parnian; Savadi Oskoee, Siavash; Pouralibaba, Firoz; Morsali Ahari, Ali

    2016-01-01

    Background. Since it is possible for carbamide peroxide (CP) bleaching agent to contact old amalgam restorations, the present in vitro study evaluated the amount of dissolved mercury released from amalgam restorations with various percent-ages of silver content subsequent to the use of 15% CP. Methods. Thirty ANA 2000 amalgam disks with 43.1% silver content and thirty ANA 70 amalgam disks with 69.3% silver content were prepared. In each group, 15 samples were randomly placed in glass tubes containing 15% CP (as experimental groups) and the remaining 15 samples were placed in buffered phosphate solution (as control groups) with the same 3-mL volume for 48 hours. Subsequently, the amount of mercury dissolved in each test tube was measured using Mercury Analyzing System (Cold Vapor Atomic Absorption, MASLO, Shimadzu, Japan). Data was analyzed with two-way ANOVA and a post hoc Tukey test. (α = 0.05). Results. The amount of mercury released after exposure to CP was significantly higher than that released after exposure to buffered phosphate (P dental amalgam with a silver content of 43% was significantly higher than that released from dental amalgam with a silver content of 69% (P dental amalgam. PMID:27429729

  12. Influence of fluoride-containing adhesives and bleaching agents on enamel bond strength

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    Vanessa Cavalli

    2012-12-01

    Full Text Available This study evaluated the influence of fluoride-containing carbamide peroxide (CP bleaching agents and adhesive systems on bonded enamel interfaces that are part of the dynamic pH cycling and thermal cycling models. The buccal surfaces of 60 bovine incisors were restored with a composite resin and bonded with three- and two-step, etch-and-rinse, fluoride-containing adhesives, Optibond FL (FL and Optibond Solo Plus (SP, respectively. Restored teeth were subjected to thermal cycling to age the interface. Both SP and FL adhesive-restored teeth were bleached (n = 10 with 10% CP (CP and 10% CP + fluoride (CPF or were left unbleached (control. Bleaching was performed for 14 days simultaneously with pH cycling, which comprised of 14 h of remineralization, 2 h of demineralization and 8 h of bleaching. The control groups (FL and SP were stored in remineralizing solution during their bleaching periods and were also subjected to carious lesion formation. Parallelepiped-shaped samples were obtained from the bonded interface for microtensile bond strength (∝TBS testing. The enamel ∝TBS of the FL and SP groups (control, not bleached were higher (p FL + CPF = FL + CP and SP > SP + CPF = SP + CP. The groups subjected to treatment with the fluoride-containing bleaching agents exhibited similar ∝TBS compared to regular bleaching agents. Bleaching agents, regardless of whether they contained fluoride, decreased enamel bond strength.

  13. Influence of fluoride-containing adhesives and bleaching agents on enamel bond strength.

    Science.gov (United States)

    Cavalli, Vanessa; Liporoni, Priscila Cristiane Suzy; Rego, Marcos Augusto do; Berger, Sandrine Bittencourt; Giannini, Marcelo

    2012-01-01

    This study evaluated the influence of fluoride-containing carbamide peroxide (CP) bleaching agents and adhesive systems on bonded enamel interfaces that are part of the dynamic pH cycling and thermal cycling models. The buccal surfaces of 60 bovine incisors were restored with a composite resin and bonded with three- and two-step, etch-and-rinse, fluoride-containing adhesives, Optibond FL (FL) and Optibond Solo Plus (SP), respectively. Restored teeth were subjected to thermal cycling to age the interface. Both SP and FL adhesive-restored teeth were bleached (n = 10) with 10% CP (CP) and 10% CP + fluoride (CPF) or were left unbleached (control). Bleaching was performed for 14 days simultaneously with pH cycling, which comprised of 14 h of remineralization, 2 h of demineralization and 8 h of bleaching. The control groups (FL and SP) were stored in remineralizing solution during their bleaching periods and were also subjected to carious lesion formation. Parallelepiped-shaped samples were obtained from the bonded interface for microtensile bond strength (μTBS) testing. The enamel μTBS of the FL and SP groups (control, not bleached) were higher (p FL > FL + CPF = FL + CP and SP > SP + CPF = SP + CP). The groups subjected to treatment with the fluoride-containing bleaching agents exhibited similar μTBS compared to regular bleaching agents. Bleaching agents, regardless of whether they contained fluoride, decreased enamel bond strength. PMID:23184165

  14. 再矿化疗法对新型漂白术后釉质显微硬度影响及牙齿增白的效果%Effect of fluoride therapy on remineralization and whiting of bleached enamel

    Institute of Scientific and Technical Information of China (English)

    曹立群; 赵蕾; 沈志英

    2010-01-01

    Objective To evaluate the effect of fluorin dentifrice on the microhardness and whiting of dental enamel bleached with different concentration bleachers.Methods 6%carbamide peroxide(CP)and 30%CP were selected as bleachers.Twenty undefected molars were subjected to 3 groups.Groups A and B.which composed of 8 teeth each,were tested and group C was the control one.Group A(buccal surface)and group B(buccal surface)were treated with 6%CP.Group A (lingual surface)and group B(lingual surface)were treated with 30%CP.They were bleached 30 min every day for two weeks.The teeth in group B were brushed with fluorin dentifrice for 15 min after bleached every time and then all tested samples were kept in the artificial saliva at 37℃.Vickers microhardness of all teeth and color measurement of groups A and B were made before and at the end of bleaching procedure.Results The difference of microhardness values between the bleached and control samples were not statistically significant(P>0.05).Brushed with fluorin agent significantly increased the hardness of enamelin group B(P<0.05).The color change was not significant between bleached samples.Conclusion Using fluoride in the interphase of bleaching makes this therapy safer,and does not affect the whitening effect.%目的 探讨低浓度漂白剂配合使用含氟牙膏与否,对漂白后的牙釉质显微硬度和增白效果的影响.方法 将20颗无缺损的离体磨牙随机分成A、B、C 3组,A、B两组各8颗,C组4颗作为对照组,A、B两组的颊面采用6%过氧化脲(carbamide peroxide,CP)漂白,舌面采用30%CP漂白,每天漂白30 min,持续2周,在此期间对B组牙用含氟牙膏刷牙,每天15 min,随后将所有牙齿浸泡于37℃的人工唾液中,测定漂白前、后的牙齿的亮度值及釉质显微硬度,并进行统计学分析.结果 两种漂白剂使用2周后对牙釉质的脱矿作用不明显(P>0.05),含氟牙膏刷牙可增加漂白后牙釉质显微硬度(P<0.05),但对漂白

  15. Bond strength of dentin submitted to bleaching and restored with different materials

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    Nelize Marcelino Pessarello

    2012-09-01

    Full Text Available Introduction: The use of adhesive composite resin with fluoride and with greater fluidity can be favorable to the restoration of the palatal/lingual face of teeth submitted to internal bleaching. Objective: This study evaluated the bond strength of adhesive systems and composite resins to bleached dentin. Material and methods: Forty maxillary canines were sectioned to obtain 40 blocks (5 x 5 mm of intracoronary dentin. The fragments were included and bleached with 37% carbamide peroxide. After 7 days, the specimens were divided into two groups according to the adhesive system: with (Optibond Solo Plus and without (Single Bond fluoride and subdivided into 2 subgroups (n = 10 according to the composite resin: microhybrid (Z250 and flowable (Z350. The restoration was carried out through a bipartite matrix. After 24 hours, the specimens were subjected to shear bond strength test. The data (MPa were analyzed by ANOVA and Tukey test (α = 0.05. Results: The best results (p < 0.05 were obtained for fluoridated adhesive (7.44 ± 2.35 compared with that without fluoride (5.36 ± 2.01; flowable resin (7.76 ± 2.23 performed better than microhybrid resin (5.03 ± 1.72. When the two variables were associated, the highest results were obtained for the specimens restored with fluoridated adhesive and flowable resin(9.04 ± 1.92. Lower results were observed for non-fluoridated adhesive + microhybrid resin – control (4.24 ± 1.59, without statistically

  16. High-efficiency tooth bleaching using non-thermal atmospheric pressure plasma with low concentration of hydrogen peroxide

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    Seoul Hee NAM

    2013-06-01

    Full Text Available Light-activated tooth bleaching with a high hydrogen peroxide (HP; H2O2 concentration has risks and the actual role of the light source is doubtful. The use of conventional light might result in an increase in the temperature and cause thermal damage to the health of the tooth tissue. Objective This study investigated the efficacy of tooth bleaching using non-thermal atmospheric pressure plasma (NAPP with 15% carbamide peroxide (CP; CH6N2O3 including 5.4% HP, as compared with conventional light sources. Material and Methods Forty human teeth were randomly divided into four groups: Group I (CP+NAPP, Group II (CP+plasma arc lamp; PAC, Group III (CP+diode laser, and Group IV (CP alone. Color changes (∆E of the tooth and tooth surface temperatures were measured. Data were evaluated by one-way analysis of variance (ANOVA and post-hoc Tukey's tests. Results Group I showed the highest bleaching efficacy, with a ∆E value of 1.92-, 2.61 and 2.97-fold greater than those of Groups II, III and IV, respectively (P<0.05. The tooth surface temperature was maintained around 37°C in Group I, but it reached 43°C in Groups II and III. Conclusions The NAPP has a greater capability for effective tooth bleaching than conventional light sources with a low concentration of HP without causing thermal damage. Tooth bleaching using NAPP can become a major technique for in-office bleaching in the near future.

  17. Over-the-counter whitening agents: a concise review

    Directory of Open Access Journals (Sweden)

    Flávio Fernando Demarco

    2009-06-01

    Full Text Available Tooth discoloration is commonly found in the dental clinic and tooth bleaching has been considered the preferred esthetic alternative, being more conservative, safe and with predictable results. Supervised home-use of 10% Carbamide Peroxide (CP bleaching with custom-trays is the most common bleaching procedure dispensed by dentists to their patients. The good results obtained with this technique stimulated the flourishing of new products and techniques. Over-the-counter (OTC bleaching products appeared as a low-cost alternative to bleach discolored teeth without dentist supervision. Different OTC products are available in supermarkets, drug stores or on the Internet, including rinses, paint-on brushes, toothpastes, chewing guns, dental floss, and whitening strips. There is lack of clinical evidence regarding the safety and effectiveness of these products, being most of the studies supported by the manufacturers'. Basically, toothpastes, chewing gums, and dental floss are removal agents of superficial stains. Rinses and paint-on brushes with low levels of hydrogen peroxide have some whitening effect, but without clinical relevance. Strips present similar esthetic results and side-effects, compared to bleaching with 10% CP using trays; however, the studies have financial support from the manufacturers and were based on short term evaluations. Legislation varies widely in different countries regarding OTC dental bleaching. Concerns have appeared due to the potential abusive use of these self-medication agents, especially in young patients, with potential harmful results. Dentists should be acquainted with this kind of products to be able to inform their patients. In conclusion, there is a need for independent clinical trials to provide sufficient evidence regarding the use of OTC bleaching products.

  18. 3D Surface Profile and Color Stability of Tooth Colored Filling Materials after Bleaching

    Directory of Open Access Journals (Sweden)

    Bryant Anthony Irawan

    2015-01-01

    Full Text Available 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 Estelite Σ Quick, 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 (CIE L*, 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 a P value of ≤0.05. The three restorative materials showed significant color changes (ΔE; P≤0.05. In diminishing order, the mean color changes recorded were Estelite Σ (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.

  19. Acid demineralization susceptibility of dental enamel submitted to different bleaching techniques and fluoridation regimens.

    Science.gov (United States)

    Salomão, Dlf; Santos, Dm; Nogueira, Rd; Palma-Dibb, Rg; Geraldo-Martins, Vr

    2014-01-01

    The aim of the current study was to assess the acid demineralization susceptibility of bleached dental enamel submitted to different fluoride regimens. One hundred bovine enamel blocks (6×6×3 mm) were randomly divided into 10 groups (n=10). Groups 1 and 2 received no bleaching. Groups 3 to 6 were submitted to an at-home bleaching technique using 6% hydrogen peroxide (HP; G3 and G4) or 10% carbamide peroxide (CP; G5 and G6). Groups 7 to 10 were submitted to an in-office bleaching technique using 35% HP (G7 and G8) or 35% CP (G9 and G10). During bleaching, a daily fluoridation regimen of 0.05% sodium fluoride (NaF) solution was performed on groups 3, 5, 7, and 9, while weekly fluoridation with a 2% NaF gel was performed on groups 4, 6, 8, and 10. The samples in groups 2 to 10 were pH cycled for 14 consecutive days. The samples from all groups were then assessed by cross-sectional Knoop microhardness at different depths from the outer enamel surface. The average Knoop hardness numbers (KHNs) were compared using one-way analysis of variance and Tukey tests (α=0.05). The comparison between groups 1 and 2 showed that the demineralization method was effective. The comparison among groups 2 to 6 showed the same susceptibility to acid demineralization, regardless of the fluoridation method used. However, the samples from groups 8 and 10 showed more susceptibility to acid demineralization when compared with group 2 (penamel to acid demineralization. However, the use of 35% HP and 35% CP must be associated with a daily fluoridation regimen, otherwise the in-office bleaching makes the bleached enamel more susceptible to acid demineralization.

  20. Influence of Enamel Thickness on Bleaching Efficacy: An In-Depth Color Analysis

    Science.gov (United States)

    Públio, Juliana do Carmo; D’Arce, Maria Beatriz Freitas; Catelan, Anderson; Ambrosano, Gláucia Maria Bovi; Aguiar, Flávio Henrique Baggio; Lovadino, José Roberto; Lima, Débora Alves Nunes Leite

    2016-01-01

    This study evaluated the influence of different enamel thicknesses and bleaching agents on treatment efficacy in-depth by spectrophotometry color analysis. Eighty bovine dental fragments were previously stained in black tea solution and randomly assigned into eight groups (n=10), 1.75mm dentin thickness and different enamel thicknesses as follows: 0.5mm, 1.0mm planned, 1.0mm unplanned (aprismatic enamel), and absence of enamel. The 10% carbamide peroxide (CP) and 35% hydrogen peroxide (HP) bleaching gels were applied on the enamel surface following the manufacturer's recommendations. Color of underlying dentin was evaluated at four times: after staining with tea (baseline) and after each one of the three weeks of bleaching treatment, by CIE L*a*b* system using reflectance spectrophotometer (CM 700d, Konica Minolta). The ΔE, ΔL, Δa, and Δb values were recorded and subjected to repeated measures ANOVA and Tukey’s test (α=0.05). The results showed an increase on lightness (L*), with decreased redness (a*) and yellowness (b*). At first and second week, bleaching with CP showed higher whitening effectiveness compared to bleaching with HP and the presence of aprismatic enamel significantly reduced ΔE for bleaching with CP. After three weeks of bleaching, few differences were observed between CP and HP groups, and outer enamel layer caused no influence on bleaching effectiveness. Overall, both at-home and in-office bleaching treatments were effective and the presence of aprismatic enamel did not interfere on the whitening efficacy. PMID:27708725

  1. The effect of home bleaching agents on the surface roughness of five different composite resins: A SEM evaluation.

    Science.gov (United States)

    Cengiz, Esra; Kurtulmus-Yilmaz, Sevcan; Ulusoy, Nuran; Deniz, Sule Tugba; Yuksel-Devrim, Ece

    2016-05-01

    The aim of this study was to investigate the effect of hydrogen peroxide (HP) and carbamide peroxide (CP) on the surface roughness of five different composite resins using profilometer and scanning electron microscope (SEM). Thirty-six specimens (1 mm thick, 10 mm in diameter) of five composite resins were fabricated. Each composite group was equally divided into three subgroups as control, CP and HP. In control group, specimens were stored in daily refreshed distilled water during the 14-day testing period. In other groups, 10% HP (Opalescence Treswhite) and 10% CP (Opalescence PF) were applied and surface roughness values (Ra) of each specimen were measured with a profilometer at the end of 14 days. Additionally, SEM analysis was performed to evaluate the surface deformations of composite resins. Data were analyzed with Kruskal-Wallis and Mann-Whitney U tests. Ra values of composite groups exposed to bleaching agents were statistically higher than control group (p SEM micrographs showed higher surface alterations at HP group compared to CP. Among the composite resins tested, Ceram-X Mono revealed the lowest Ra values after CP and HP applications as seen at SEM images. Home bleaching agents increased the surface roughness of all composites. Except CP applied Ceram-X mono specimens, Ra values of all composite resins evaluated in this study exceeded the critical limit of 0.2 μm. Ceram-X mono was the least affected composite material after bleaching application. SCANNING 38:277-283, 2016. © 2016 Wiley Periodicals, Inc.

  2. Aircraft measurements of polar organic tracer compounds in tropospheric particles (PM10 over Central China

    Directory of Open Access Journals (Sweden)

    P. Q. Fu

    2013-09-01

    Full Text Available Atmospheric aerosol samples were collected by aircraft at low to middle altitudes (0.8–3.5 km a.g.l. over Central East to West China during summer 2003 and spring 2004. The samples were analyzed for polar organic compounds using a technique of solvent extraction/BSTFA derivatization/gas chromatography-mass spectrometry. Biogenic secondary organic aerosol (SOA tracers from the oxidation of isoprene were found to be more abundant in summer (3.3–138 ng m−3, mean 39 ng m−3 than in spring (3.2–42 ng m−3, 15 ng m−3, while α/β-pinene and β-caryophyllene SOA tracers showed similar abundance between these two seasons. A strong positive correlation (R2=0.83 between levoglucosan and β-caryophyllinic acid was found in the spring samples versus a weak correlation (R2=0.17 in the summer samples, implying substantial contributions from biomass burning to the β-caryophyllinic acid production in spring. Two organic nitrogen species (oxamic acid and carbamide were detected in the aircraft aerosol samples and their concentrations were comparable to those of biogenic SOA tracers. Most of the POA and SOA tracers were less abundant at higher altitudes, suggesting they are of ground surface origin, either being directly emitted from anthropogenic/natural sources on the ground surface, or rapidly formed through photooxidation of their precursors emitted from the ground surface and then diluted during uplifting into the troposphere. This study demonstrates that primary biological aerosols, biogenic SOA, and organic nitrogen species are important components of organic aerosols in the troposphere over Central China.

  3. The Effect of Aloe Vera, Pomegranate Peel, Grape Seed Extract, Green Tea, and Sodium Ascorbate as Antioxidants on the Shear Bond Strength of Composite Resin to Home-bleached Enamel

    Directory of Open Access Journals (Sweden)

    Farahnaz Sharafeddin

    2015-12-01

    Full Text Available Statement of the Problem: Immediate application of bonding agent to home- bleached enamel leads to significant reduction in the shear bond strength of composite resin due to the residual oxygen. Different antioxidant agents may overcome this problem. Purpose: This study aimed to assess the effect of different antioxidants on the shear bond strength of composite resin to home-bleached. Materials and Method: Sixty extracted intact human incisors were embedded in cylindrical acrylic resin blocks (2.5×1.5 cm, with the coronal portion left out of the block. After bleaching the labial enamel surface with 15% carbamide peroxide, they were randomly divided into 6 groups (n=10. Before performing composite resin restoration by using a cylindrical Teflon mold (5×2 mm, each group was treated with one of the following antioxidants: 10% sodium ascorbate solution, 10% pomegranate peel solution, 10% grape seed extract, 5% green tea extract, and aloe vera leaf gel. One group was left untreated as the control. The shear bond strength of samples was tested under a universal testing machine (ZwickRoell Z020. The shear bond strength data were analyzed by one-way ANOVA and post hoc Tukey tests (p< 0.05. Results: No significant difference existed between the control and experimental groups. Moreover, there was no statistically significant difference between the effects of different antioxidants on the shear bond strength of bleached enamel. Conclusion: Different antioxidants used in this study had the same effect on the shear bond strength of home-bleached enamel, and none of them caused a statistically significant increase in its value.

  4. Effect of at-home bleaching with different thickeners and aging on physical properties of a nanocomposite

    Science.gov (United States)

    Gouveia, Thayla Hellen Nunes; Públio, Juliana do Carmo; Ambrosano, Glaucia Maria Bovi; Paulillo, Luís Alexandre Maffei Sartini; Aguiar, Flávio Henrique Baggio; Lima, Débora Alves Nunes Leite

    2016-01-01

    Objective: To evaluate the influence of 16% carbamide peroxide (CP) containing different thickeners on the physical characteristics of a nanocomposite resin submitted or not to accelerated artificial aging (AAA). Materials and Methods: One hundred samples were randomly distributed into two groups (n = 50) according to AAA. Each group was divided into 5 subgroups (n = 10) depending on the bleaching/thickener treatment: CP + carbopol, CP + natrosol, carbopol, natrosol, and no treatment (control). The physical properties tested were color (ΔE), gloss (GU), mean roughness (Ra), and Knoop microhardness (KHN). The resin surface was performed with atomic force microscopy (AFM). Statistical Analysis: The color (variable Δ E) was assessed with two-way analysis of variance (ANOVA) and additionally with Tukey's and Dunnett's tests, the roughness values were submitted to Kruskal–Wallis, Dunn's, and Mann–Whitney's tests. Data on gloss and KHN were submitted to two-way ANOVA and Tukey's test (α = 0.05). Results: Among the physical properties evaluated, CP + carbopol promoted a reduction in composite microhardness only, thus differing statistically from the controls. As for CP + natrosol, such a change was not observed. The aging process reduced all the physical properties, thus differing statistically from the nonaging group. CP + carbopol increased the roughness and decreased the gloss of aged resins, whereas natrosol reduced gloss only, which differed statistically from the controls. Conclusions: AFM showed evidence of the loss of organic matrix and exposure to load particles in the aged samples. Therefore, the replacement of carbopol with natrosol provided maintenance of the composite microhardness following bleaching. The aging process reduced the physical properties evaluated, and some changes were enhanced by the application of bleaching. PMID:27011745

  5. Comparative clinical study of the effectiveness of different dental bleaching methods - two year follow-up

    Directory of Open Access Journals (Sweden)

    Rafael Francisco Lia Mondelli

    2012-08-01

    Full Text Available This study evaluated color change, stability, and tooth sensitivity in patients submitted to different bleaching techniques. MATERIAL AND METHODS: In this study, 48 patients were divided into five groups. A half-mouth design was conducted to compare two in-office bleaching techniques (with and without light activation: G1: 35% hydrogen peroxide (HP (Lase Peroxide - DMC Equipments, São Carlos, SP, Brazil + hybrid light (HL (LED/Diode Laser, Whitening Lase II DMC Equipments, São Carlos, SP, Brazil; G2: 35% HP; G3: 38% HP (X-traBoost - Ultradent, South Jordan UT, USA + HL; G4: 38% HP; and G5: 15% carbamide peroxide (CP (Opalescence PF - Ultradent, South Jordan UT, USA. For G1 and G3, HP was applied on the enamel surface for 3 consecutive applications activated by HL. Each application included 3x3' HL activations with 1' between each interval; for G2 and G4, HP was applied 3x15' with 15' between intervals; and for G5, 15% CP was applied for 120'/10 days at home. A spectrophotometer was used to measure color change before the treatment and after 24 h, 1 week, 1, 6, 12, 18 and 24 months. A VAS questionnaire was used to evaluate tooth sensitivity before the treatment, immediately following treatment, 24 h after and finally 1 week after. RESULTS: Statistical analysis did not reveal any significant differences between in-office bleaching with or without HL activation related to effectiveness; nevertheless the time required was less with HL. Statistical differences were observed between the results after 24 h, 1 week and 1, 6, 12, 18 and 24 months (intergroup. Immediately, in-office bleaching increased tooth sensitivity. The groups activated with HL required less application time with gel. CONCLUSION: All techniques and bleaching agents used were effective and demonstrated similar behaviors.

  6. The effect of remin pro and MI paste plus on bleached enamel surface roughness.

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    Haleh Heshmat

    2014-04-01

    Full Text Available The growing demand for enhanced esthetic appearance has led to great developments in bleaching products. The exposure of hard tissues of the tooth to bleaching agents can affect the roughness of the enamel surface. The freshly bleached enamel surface exposed to various surface treatments such as fluoride and other remineralizing agents have been assessed in this study. The aim of this experimental study was to compare the effect of Casein Phosphopeptide-Amorphous Calcium Phosphate with Fluoride (MI Paste Plus and Remin Pro on the enamel surface roughness after bleaching.Thirty enamel samples of sound human permanent molars were prepared for this study. After initial roughness measurement with profilometer, the samples were exposed to 37% carbamide peroxide bleaching agent 20 minutes twice, and randomly divided into three groups of ten. In group 1, a CPP-ACPF containing paste (MI Paste Plus and in group 2, Remin Pro were applied to the teeth during a 15 day period for 5 minutes, twice a day. Samples of group 3 (control were immersed in artificial saliva for 15 days. The roughness of all samples were measured at the beginning, after bleaching and after the study intervention and statistically analyzed.The surface roughness significantly increased in all groups following bleaching, and then it showed a decrease after application of both Remin Pro and CPP-ACPF in comparison to using bleaching agent (P0.05.There was no difference between surface roughness of MI Paste Plus and Remin Pro groups. Also the surface roughness was decreased compared to the initial enamel surface roughness.

  7. Clinical Comparison of At-Home and In-Office Dental Bleaching Procedures: A Randomized Trial of a Split-Mouth Design.

    Science.gov (United States)

    Machado, Lucas Silveira; Anchieta, Rodolfo Bruniera; dos Santos, Paulo Henrique; Briso, André Luiz; Tovar, Nick; Janal, Malvin N; Coelho, Paulo Guilherme; Sundfeld, Renato Herman

    2016-01-01

    The objective of this split-mouth clinical study was to compare a combination of in-office and at-home dental bleaching with at-home bleaching alone. Two applications of in-office bleaching were performed, with one appointment per week, using 38% hydrogen peroxide. At-home bleaching was performed with or without in-office bleaching using 10% carbamide peroxide in a custom-made tray every night for 2 weeks. The factor studied was the bleaching technique on two levels: Technique 1 (in-office bleaching combined with home bleaching) and Technique 2 (home bleaching only). The response variables were color change, dental sensitivity, morphology, and surface roughness. The maxillary right and left hemiarches of the participants were submitted to in-office placebo treatment and in-office bleaching, respectively (Phase 1), and at-home bleaching (Phase 2) treatment was performed on both hemiarches, characterizing a split-mouth design. Enamel surface changes and roughness were analyzed with scanning electron microscopy and optical interferometry using epoxy replicas. No statistically significant differences were observed between the bleaching techniques for either the visual or the digital analyses. There was a significant difference in dental sensitivity when both dental bleaching techniques were used, with in-office bleaching producing the highest levels of dental sensitivity after the baseline. Microscopic analysis of the morphology and roughness of the enamel surface showed no significant changes between the bleaching techniques. The two techniques produced similar results in color change, and the combination technique produced the highest levels of sensitivity. Neither technique promoted changes in morphology or surface roughness of enamel. PMID:26901303

  8. Nanotribological and Nanomechanical Properties Changes of Tooth After Bleaching and Remineralization in Wet Environment

    Science.gov (United States)

    Yu, Dandan; Gao, Shanshan; Min, Jie; Zhang, Qianqian; Gao, Shuai; Yu, Haiyang

    2015-12-01

    Teeth bleaching cases had increased with people's desire for oral aesthetic; however, bleached teeth would still undertake chewing actions and remineralizing process in saliva. Nanotribological and nanomechanical properties are proper displays for dental performance of bleached teeth. The purpose of the research was to reveal the effect of bleaching and remineralization on the nanotribological and nanomechanical properties of teeth in wet environment. The specimens were divided into four groups according to the bleaching products used: 12 % hydrogen peroxide (HP) (12HP group); 15 % carbamide peroxide (CP) (15CP group); 35 % CP (35CP group); and artificial saliva (control group). The nanotribological and nanomechanical property changes of tooth enamel after bleaching and remineralization were evaluated respectively by nanoscratch and nanoindentation tests in wet environment, imitating the wet oral environment. The morphology changes were evaluated by statistical parametric mapping (SPM) and scanning electron microscopy (SEM). After bleaching, 12HP group and 15CP group showed increased scratch depth with more pile ups on the scratch edges, decreased nanohardness, and corroded surface appearance. While the 35CP group showed an increase in nanoscratch depth, no change in nanohardness and surface appearance was observed. The control group showed no change in these measurements. After remineralization, the three bleaching groups showed decreased nanoscratch depth and no change of nanohardness compared with the bleached teeth. And the control group showed no changes in nanotribological and nanomechanical properties. The nanotribological and nanomechanical properties of the 12HP group and 15CP group were affected by bleaching, but the nanotribological properties recovered partly and the nanomechanical properties got no change after 1 week of remineralization. As for the 35CP group, the nanotribological properties were influenced and the nanomechanical properties were not

  9. Comparison of the effect of hydrogel and solution forms of sodium ascorbate on orthodontic bracket-enamel shear bond strength immediately after bleaching: An in vitro study

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    Kimyai Soodabeh

    2010-01-01

    Full Text Available Aim: This study compared the effects of hydrogel and solution forms of sodium ascorbate (SA with two different application times on bracket bond strength subsequent to bleaching. Materials and Methods: A total of 72 sound premolars were randomly divided into six groups (n = 12: An unbleached control group (group one and five experimental groups of carbamide peroxide. Specimens in group two were bonded immediately after bleaching; specimens in groups three and four were bleached, then treated with SA solution for ten minutes and three hours, respectively, and then bonded. In groups five and six, SA hydrogel was used and the specimens were prepared similar to groups three and four, respectively. Following debonding, bond strengths were recorded in MPa. To evaluate the amount of resin left on the enamel surfaces, adhesive remnant index (ARI scores were used. Statistical Analysis: The bond strength data were analyzed with ANOVA and pairwise comparisons were made by Tukey test. The ARI data were subjected to Kruskal-Wallis test and two-by-two comparisons were made by the Mann-Whitney U test. Results: There were significant differences in bond strengths between the groups ( P < 0.0005. However, the differences between groups three, four, five and six were not significant. Furthermore, there were no significant differences between group one and groups four and six, whereas the differences between the other groups were significant ( P < 0.05. Regarding ARI, there were significant differences among the groups ( P = 0.004. Conclusion: Bleaching significantly decreased the bracket bond strength. Compromised bonding was reversed with a three-hour application of both forms of SA.

  10. Effect of Green Tea Extract as Antioxidant on Shear Bond Strength of Resin Composite to in-Office and Home-Bleached Enamel

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    Sharafeddin F

    2016-09-01

    Full Text Available Statement of Problem: Shear bond strength (SBS of home and office bleached enamel will be compromised by immediate application of composite restoration. Antioxidant agent may overcome this problem. Objectives: This in vitro study assessed the effect of green tea extract on shear bond strength of resin composite to in-office and home-bleached enamel. Materials and Methods: In this experimental study, 40 extracted intact human incisors were embedded in cylindrical acrylic resin blocks (2.5 ×1.5 cm, with the coronal portion above the cemento enamel junction out of the block. Then, after bleaching labial enamel surfaces of 20 teeth with 15% carbamide peroxide 6 hours a day for 5 days, they were randomly divided into two groups: A1 and A2 (n = 10, depending upon whether or not they are treated with antioxidant. Labial enamel surfaces of the remaining 20 teeth were bleached with 38% hydrogen peroxide before being randomly divided into groups B1 and B2 (n = 10, again depending on whether or not the antioxidant was used in their treatment . The experimental groups (A2,B2 were treated with 5% solution of green tea extract before resin composite restoration was done by a cylindrical Teflon mould (5×2 mm. Shear bond strength of the specimens was tested under a universal testing machine (Zwick/Roell Z020. The SBS data were analyzed by using One-way ANOVA and Tukey HSD tests (p < 0.05. Results: There were no statistically significant differences between shear bond strength of the control group (A1 and treated group (A2 but there were statistically significant differences between the groups B1 and B2 (p < 0.05. Conclusions: Application of antioxidant did not increase the shear bond strength of home-bleached enamel to resin composite but its application increased the shear bond strength of in-office bleached enamel to resin composite.

  11. Porous materials with gradient and biporous structure, methods of their production

    International Nuclear Information System (INIS)

    We have worked out the technology of production porous powder materials (PPMs) of bronze, nickel, corrosion resistant steel and titanium powders with gradient and (or) biporous structure: vibrating forming of metal powders (including in electromagnetic field); layer-by-layer forming of metal powders with pore-maker while different proportion of the latter in the layer; forming of powder polymer layer on the preliminary sintered metal PPM surface. We have worked out the technology of production biporous structure by the following methods: metal granules forming and sintering; forming and sintering of metal powder with granules (2-3 mm) and pores-forming powder (size of particles is 0,4-0,63 mm). The novelty is in creation of technological bases of pores sizes regulation from 5 mkm on one PPM surface to 120 mkm on the opposite PPM surface which thickness can be 2-6 mm. PPM porosity can be constant within 0,3-0,6 relative units. More effective are those PPM which pores sizes are changeable and also porosity (from 0,35 to 0,60) from one surface o the opposite one. Two-layer metal-polymer PPM have pores sizes of 20-40 mkm in polymer layer and porosity 0,4-0,5 and, correspondingly, in metal layer 80-100 mkm and 0,45-0,55. In biporous structures made of 2-3 mm metal granules the distance between granules is 300-600 mkm and in granules - 14-30 mkm. The integral porosity of such PPM is 0,55-0,70. The technology of forming and sintering metal powder with granules and pores-making powder (carbamide) enables to regulate the integral porosity within 0,7-0,8 and average pores sizes within 100-1000 mkm with average size of metal powder particles of 0,63-1,0 mm. (author)

  12. 沙床栽培中施肥对忽地笑生长量及净光合速率的影响%Effect of fertilization in sand bed on growth and photosynthesis of Lycoris aurea

    Institute of Scientific and Technical Information of China (English)

    鲍淳松; 张鹏翀; 张海珍; 徐芸茜; 江燕

    2012-01-01

    以尿素和磷酸二氢钾在沙床上对忽地笑(Lycoris aurea)进行施肥试验,分析施肥对忽地笑叶生长量、净光合速率及鳞茎生物量的影响,并且就忽地笑净光合速率对光有效辐射的响应、净光合速率的日变化进行了探讨.结果表明:沙土栽培施肥未明显增加忽地笑叶生长量和鳞茎生物量,也未显著提高净光合速率;忽地笑为耐阳植物,其光响应有“单峰型”和“抛物线型”两种类型,净光合速率日变化为“单峰型”.%Carbamide and KH2PO4 were set for topdressing fertilization to study the fertilization effects on leaf growth, bulb biomass and the net photosynthetic rate (Pn) of Lycoris aurea. The light-response to photosynthesis and a diurnal change of Pn were also studied. Results showed that the fertilization couldn't increase the leaf growth, bulb biomass and Pn significantly. L. aurea showed light-tolerance with two types of the light-response curve, single-peak and parabola, and the diurnal change of Pn had a single peak. Finally a suggestion was given for the cultivation of L. aurea.

  13. Mineral loss and color change of enamel after bleaching and staining solutions combination.

    Science.gov (United States)

    de Araújo, Larissa Sgarbosa Napoleão; dos Santos, Paulo Henrique; Anchieta, Rodolfo Bruniera; Catelan, Anderson; Fraga Briso, André Luiz; Fraga Zaze, Ana Carolina Soares; Sundfeld, Renato Herman

    2013-10-01

    Pigments of food and beverages could affect dental bleaching efficacy. The aim of this investigation was to evaluate color change and mineral loss of tooth enamel as well as the influence of staining solutions normally used by adolescent patients undergoing home bleaching. Initial hardness and baseline color were measured on enamel blocks. Specimens were divided into five groups (n=5): G1 (control) specimens were kept in artificial saliva throughout the experiment (3 weeks); G2 enamel was exposed to 10% carbamide peroxide for 6 h daily, and after this period, the teeth were cleaned and stored in artificial saliva until the next bleaching session; and G3, G4, and G5 received the same treatments as G2, but after bleaching, they were stored for 1 h in cola soft drink, melted chocolate, or red wine, respectively. Mineral loss was obtained by the percentage of hardness reduction, and color change was determined by the difference between the data obtained before and after treatments. Data were subjected to analysis of variance and Fisher's test (α=0.05). G3 and G5 showed higher mineral loss (92.96 ± 5.50 and 94.46 ± 1.00, respectively) compared to the other groups (p ≤ 0.05). G5 showed high-color change (9.34 ± 2.90), whereas G1 presented lower color change (2.22 ± 0.44) (p ≤ 0.05). Acidic drinks cause mineral loss of the enamel, which could modify the surface and reduce staining resistance after bleaching. PMID:24165745

  14. 不同施肥水平对日光温室番茄产量和品质的影响%Effects of different fertilization levels on yield and quality of greenhouse tomato

    Institute of Scientific and Technical Information of China (English)

    贺会强; 陈凯利; 邹志荣; 李丽霞

    2012-01-01

    【目的】研究不同施肥水平对日光温室春茬番茄果实产量和品质的影响,为日光温室番茄的高产优质栽培确定合理的施肥指标。【方法】以"金棚一号"番茄为试材,以当地常规施肥为对照,设定3个不同的施肥水平(T1.每小区的施肥量为尿素711.1g、过磷酸钙1 511.1g、硫酸钾462.2g、牛粪46.67kg;T2.每小区的施肥量为尿素1 066.7g、过磷酸钙2 266.7g、硫酸钾693.3g、牛粪70.00kg;T3.每小区的施肥量尿素1 422.2g、过磷酸钙3 022.2g、硫酸钾924.3g、牛粪93.33kg,小区面积4.68m2)处理,测定番茄果实产量及果实中NO3--N、可溶性固形物、可溶性糖、有机酸、VC、番茄红素的含量。【结果】与对照相比,T1、T2、T3处理的番茄产量分别提高了11.5%,43.4%和25.5%,其中T2处理的单果质量、小区果数、产量均高于T1和T3处理。随着施肥量的增加,NO3--N、可溶性糖、可溶性固形物含量和糖酸比减小,番茄红素和有机酸含量呈上升趋势,VC含量呈先上升后下降趋势。【结论】综合考虑产量和品质因素,T2处理的施肥量最佳。推荐的施肥量为:每hm2施N 1 182.0kg、P2O5655.5kg、K2O835.5kg、牛粪168.75t,在此施肥条件下,番茄可得到较高的产量和较好的品质。%【Objective】 Under different fertilizer levels,the yield and quality of tomato in solar greenhouse in spring were explored,which can provide a theoretical evidence for the reasonable fertilization index to ensure the high quality and high yield of tomato in greenhouse cultivation.【Method】 With tomato "Jinpeng No.1" as experimental materials,taking local conventional fertilization as control treatment,setting 3 different fertilization levels(The fertilization amount T1 was carbamide 711.1 g,calcium superphosphate 1 511.1 g,potassium sulphate 462.2 g,cow dung 46.67 kg.The fertilization amount T2 was carbamide 1 066.7 g,calcium superphosphate 2 266.7 g,potassium sulphate

  15. 腐烂柑橘与猪粪混合厌氧发酵产沼气试验研究%Study on Biogas Yield of Rotten Citrus Fruits Mixed with Swine Manure in Anaerobic Fermentation

    Institute of Scientific and Technical Information of China (English)

    赵红; 张衍林

    2011-01-01

    The secondary pH regulation were tested to reactivate the soured anaerobic system treating mixture of rotten citrus fruits and swine manure.Various indexes of biogas and effluent in anaerobic fermentation system were determined.The result showed that the soured anaerobic system treating rotten citrus fruits and swine manure mixture could be reactivated by secondary pH regulation with limewater and C: N regulation with carbamide.The best ratio for rotten citrus fruits and swine manure was 2:1 ,and the optimum inoculum rates was 30%, under which the gas production could last 30 days with TS gas yield of 480.69 mL · g-1.The average methane content of biogas was 51.5% ,and COD removal rate was 75.14%.%文章以腐烂柑橘果实和猪粪为原料,通过测定厌氧发酵过程中发酵液和沼气的各项指标,探讨二次调节pH值是否可启动橘类比高的厌氧发酵系统及在此条件下腐烂柑橘与猪粪混合厌氧发酵产沼气的最佳配比和最优接种率.研究表明:用石灰水调节pH值,尿素调节其C∶N,二次调节pH值可以重新启动橘粪比高的厌氧发酵系统.在二次调解pH值情况下,腐烂柑橘与猪粪混合厌氧发酵最佳配比为2∶1,接种率30%最为适宜.该组合条件下产气可维持30天,TS产气率为480.69 mL·g-1,平均甲烷含量为51.5%,COD去除率为75.14%.

  16. Exogenous bleaching evaluation on dentin using chemical activated technique compared with diode laser technique

    International Nuclear Information System (INIS)

    This in vitro study compared the results of different exogenous bleaching proceedings on dentin after treatment of enamel surface. Thirty human canine were hewn preserving the vestibular half of the crown and 3 mm of root, showing a vestibular-lingual thickness average of 3,5 mm, measuring in the third middle of the crown. Ali teeth were maintained in wet chamber during the experiment. Digital photographs were taken of the dentin surface at 3 experimental times (LI: initial record, L0: immediate pos-bleaching record and L 15: 15 days after bleaching). The teeth were divided into 3 experimental groups of 10 teeth in each. The Control Group did not receive any kind of treatment. The Laser Group received 2 session of laser bleaching, with 3 applications each, using 35% hydrogen peroxide, activated by diode laser during 30 seconds, by scanning the enamel surface from incisal edge to the top of the crown, from mesial to distal portion of the crown and circularly, each movement during 10 seconds. The following parameters being adopted: wavelength of 808 nm, power of 1,5 W and optic fiber with 600 μm (core). The Peroxide Group received 28 daily applications, during 4 hours each application, using 16% carbamide peroxide. The bleaching records were analysed using a computer, through RGBK (red, green , blue and black). The K averages (K=100% for black and K=0% for white) of the records for Control Group were: LI=50,1 %, L0=50,3% and L 15=50,6%. For Laser Group the K averages were LI=48,5%, L0=50,0% and L 15=47,7%. And for the Peroxide Group were LI=50,5%, L0=35,9% and L 15=37,3%. The statistical analysis showed no significant difference of the K between the Control Group and the Laser Group, as to LI, L0 and L 15. Only Peroxide Group showed significant statistical difference between LI with L0 and L 15 (0,1%), and L0 in comparison with L 15 did not show any difference. (author)

  17. Techno-economic analysis for the evaluation of three UCG synthesis gas end use approaches

    Science.gov (United States)

    Nakaten, Natalie; Kempka, Thomas; Burchart-Korol, Dorota; Krawczyk, Piotr; Kapusta, Krzysztof; Stańczyk, Krzysztof

    2016-04-01

    production, the UCG synthesis gas should have a calorific value of at least 7 MJ/Nm³. However, UCG feedstock production in view of the underlying geological and chemical boundary conditions can compete on the market. Kempka, T., Plötz, M.L., Hamann, J., Deowan, S.A., Azzam, R. (2010) Carbon dioxide utilisation for carbamide production by application of the coupled UCG-urea process. Energy Procedia 4: 2200-2205. Nakaten, N., Schlüter, R., Azzam, R., Kempka, T. (2014) Development of a techno-economic model for dynamic calculation of COE, energy demand and CO2 emissions of an integrated UCG-CCS process. Energy (in print). Doi 10.1016/j.energy.2014.01.014

  18. Effects of combination of superabsorbent polymers (SAP) with nitrogen fertilizer on growth and photosynthesis of pepper plants%保水剂与氮肥结合对辣椒生长及光合作用的影响

    Institute of Scientific and Technical Information of China (English)

    徐刚; 韩玉玲; 高文瑞; 李德翠; 韩冰; 孙艳军

    2012-01-01

    Pepper variety Chaoyue No. 5 was selected as material to study the effects of combination of superabsorbent polymers (SAP) with nitrogen fertilizer on growth and photosynthesis of pepper during flowering using SAP absorbing carbamide. The combination of SAP with nitrogen fertiliser significantly increased the height, stem diameter, fresh weight, dry weight and chlorophyll content of leaves, as well as the net photosynthetic rate (Pn), intercellular CO2 concentration (Ci) , stomatal conduct (Gs) and transpiration rate (Tr) , but decreased the stomata limitation (Ls) and water efficiency ( WUE) under the same nitrogen application condition. The growth, chlorophyll content, Pn, Ci, Gs and Tr of pepper with the treatment of SAP combining nitrogen of 0. 75 times as many as standard application level were significantly higher than those with the treatment of applying nitrogen at standard level. It indicated that using SAP to absorb urea increased the fertiliser use efficiency, and reduced the loss of fertilizer.%以辣椒品种超越5号为试验材料,采用保水剂吸收尿素溶液的方法,探讨了保水剂与氮肥结合对辣椒开花坐果期植株生长及光合特性的影响.结果表明:在相同的氮肥条件下,保水剂与氮肥结合提高了植株的株高、茎粗、干鲜重、叶绿素含量以及净光合速率(Pn)、胞间CO2浓度(Ci)、气孔导度(Gs)和蒸腾速率(Tr)等光合参数,降低了气孔限制值(Ls)和水分利用效率(WUE);同时保水剂+0.75倍标准氮肥用量处理的叶片生长量、叶绿素含量、Pn、Ci、Gs和Tr都显著高子1倍标准氮肥用量的处理,表明采用保水剂吸收尿素溶液的方式能够提高肥料利用率,降低肥料损失.

  19. Enzymatic Properties of Polyphenol Oxidase from Kidney Bean Pods%菜豆豆荚多酚氧化酶的酶学特性研究

    Institute of Scientific and Technical Information of China (English)

    李雯妮; 赵秀文; 田维娜; 曹建康; 姜微波

    2011-01-01

    Objective: To explore enzymatic properties of polyphenol oxidase(PPO) from kidney bean pods(Phaseolus vulgaris L.cv.Shuangqing).Methods: The optimal pH,temperature,substrate specificity and inhibitors of PPO were evaluated by polyacrylamide gel electrophoresis(PAGE).Results: The optima pH for PPO activity was 6.0.The PPO was relatively stable at 30 ℃ and inactivated at 80 ℃.Catechol was the optimal substrate for the enzyme.Its activity was inhibited by ascorbic acid,β-mercaptoethanol,glycine or L-cysteine.Moreover,the PPO activity was inhibited completely by 1.0 mmol/L β-mercaptoethanol or ascorbic acid;however,it was activated by copper dichloride and carbamide.Conclusion: High temperature,high pH and β-mercaptoethanol or ascorbic acid can inhibit the activity of the PPO enzyme.%目的:了解菜豆豆荚多酚氧化酶(polyphenol Oxidase,PPO)的酶学特性。方法:采用聚丙烯酰氨凝胶电泳(polyacrylamide gel electrophoresis,PAGE)法对菜豆豆荚PPO的最适pH值、最适温度、底物专一性、激活剂及抑制剂进行研究。结果:菜豆豆荚PPO最适pH值为6.0;最适温度为30℃,且温度为30℃时,该酶具有较强的热稳定性,80℃可使其完全失活;该酶对不同酚类物质表现出不同的底物专一性,邻苯二酚为该酶的最适底物;抗坏血酸、L-半胱氨酸、β-巯基乙醇、甘氨酸均能抑制该酶的活性,而1.0mmol/Lβ-巯基乙醇或抗坏血酸可完全抑制其活性;氯化铜、尿素对该酶均有激活作用,其中氯化铜的激活作用明显。结论:高温、偏碱性环境、β-巯基乙醇或抗坏血酸处理均可有效抑制菜豆豆荚PPO活性。

  20. Peroxide bleaching agent effects on enamel surface microhardness, roughness and morphology Efeitos de agentes clareadores à base de peróxidos na microdureza, rugosidade e morfologia superficial do esmalte

    Directory of Open Access Journals (Sweden)

    Cristiane Franco Pinto

    2004-12-01

    Full Text Available The aim of this study was to evaluate the surface roughness, microhardness and morphology of human enamel exposed to six bleaching agents (at baseline and post-treatment. Human dental enamel samples were obtained from human third molars and randomly divided into seven groups (n = 11: control, Whiteness Perfect - 10% carbamide peroxide (10% CP, Colgate Platinum - 10% CP, Day White 2Z - 7.5% hydrogen peroxide (7.5% HP, Whiteness Super - 37% CP, Opalescence Quick - 35% CP and Whiteness HP - 35% HP. Bleaching agents were applied according to manufacturers' instructions. The control group remained not treated and stored in artificial saliva. Microhardness testing was performed with a Knoop indentor and surface roughness was analyzed with a profilometer. Morphologic observations were carried out with scanning electron microscopy (SEM. Results were statistically analyzed by two-way analysis of variance and Tukey's test (5%, and revealed a significant decrease in microhardness values and a significant increase in surface roughness post-bleaching. Changes in enamel morphology after bleaching were observed under SEM. It was concluded that bleaching agents can alter the microhardness, roughness and morphology of dental enamel surface.O objetivo deste estudo foi avaliar a rugosidade, microdureza e morfologia superficial do esmalte dental humano tratado com seis agentes clareadores (antes e depois do tratamento. Amostras de esmalte dental humano foram obtidas de terceiros molares e aleatoriamente distribuídas em sete grupos (n = 11: controle, Whiteness Perfect - peróxido de carbamida a 10% (PC 10%, Colgate Platinum - PC 10%, Day White 2Z - peróxido de hidrogênio a 7,5% (PH 7,5%, Whiteness Super - PC 37%, Opalescence Quick - PC 35% e Whiteness HP - PH 35%. Os agentes clareadores foram aplicados de acordo com as instruções dos fabricantes. O grupo controle permaneceu sem tratamento e armazenado em saliva artificial. O teste de microdureza foi realizado

  1. 桑叶褐斑病病原菌的生物学特性研究%Bilolgical Characteristics of Pathogenic Fungus Causing Brown Spot on Mulberry Leaves

    Institute of Scientific and Technical Information of China (English)

    吴庭观; 章一鸣; 叶政平; 何永宏; 张泽; 徐升胜; 洪逗

    2014-01-01

    Through cultivating pathogenic fungi of mulberry brown rot disease under 6 conditions such as different media, temperature, carbon source and nitrogen source after 6 days, research on the biological characteristics of pathogenic fungus causing brown spot on mulberry leaves was conducted .The results showed that nutrition , tem-perature and pH had significant influence on mycelial growth . It was found that the best medium for mycelial growth was oatmeal medium , the proper temperature was 20~30℃, the optimal temperature for mycelial growth was 25℃, the light had no obvious promotion effect on mycelial growth .It was also found that the optimal pH was 9 to 10 , the best carbon source and nitrogen source for mycelial grow are α-Galoctaose and Carbamide , and the mycelial could not survive above 55℃more than 10 min.%通过对桑叶褐斑病病原菌在不同种类培养基培养、不同氮源与碳源、不同温度等6种条件下培养6天后,测定菌落直径,观察菌丝颜色和菌落形态,分析了桑褐斑病病原菌的生物学特性。结果表明,在室内培养条件下,不同的营养成分、 pH值、温度、光照都对菌丝的生长有影响。病原菌菌丝生长的最适宜培养基是燕麦片培养基,适宜生长温度范围是20~30℃,最适生长温度为25℃,光照对菌丝生长无显著影响,最适pH值为9~10,最适碳源为α-乳糖,最适氮源为尿素,菌丝在55℃水浴10 min后则不能生长。

  2. Exogenous bleaching evaluation on dentin using chemical activated technique compared with diode laser technique; Avaliacao do clareamento exogeno sobre a dentina realizado pela tecnica por ativacao quimica comparada com a tecnica por ativacao pelo laser de diodo

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Breno Carnevalli Franco de

    2003-07-01

    This in vitro study compared the results of different exogenous bleaching proceedings on dentin after treatment of enamel surface. Thirty human canine were hewn preserving the vestibular half of the crown and 3 mm of root, showing a vestibular-lingual thickness average of 3,5 mm, measuring in the third middle of the crown. Ali teeth were maintained in wet chamber during the experiment. Digital photographs were taken of the dentin surface at 3 experimental times (LI: initial record, L0: immediate pos-bleaching record and L 15: 15 days after bleaching). The teeth were divided into 3 experimental groups of 10 teeth in each. The Control Group did not receive any kind of treatment. The Laser Group received 2 session of laser bleaching, with 3 applications each, using 35% hydrogen peroxide, activated by diode laser during 30 seconds, by scanning the enamel surface from incisal edge to the top of the crown, from mesial to distal portion of the crown and circularly, each movement during 10 seconds. The following parameters being adopted: wavelength of 808 nm, power of 1,5 W and optic fiber with 600 {mu}m (core). The Peroxide Group received 28 daily applications, during 4 hours each application, using 16% carbamide peroxide. The bleaching records were analysed using a computer, through RGBK (red, green , blue and black). The K averages (K=100% for black and K=0% for white) of the records for Control Group were: LI=50,1 %, L0=50,3% and L 15=50,6%. For Laser Group the K averages were LI=48,5%, L0=50,0% and L 15=47,7%. And for the Peroxide Group were LI=50,5%, L0=35,9% and L 15=37,3%. The statistical analysis showed no significant difference of the K between the Control Group and the Laser Group, as to LI, L0 and L 15. Only Peroxide Group showed significant statistical difference between LI with L0 and L 15 (0,1%), and L0 in comparison with L 15 did not show any difference. (author)

  3. Effects of bleaching agents on the microleakage of class Ⅴ cavities restored with glass-ionomer cements%漂白剂对玻璃离子水门汀类材料充填Ⅴ类洞边缘微渗漏的影响

    Institute of Scientific and Technical Information of China (English)

    唐健霞; 冯云枝

    2012-01-01

    Objective To evaluate the effects of a bleaching gel and a whitening strip on the microleakage of three different glass-ionomer cements. Methods Forty-five freshly extracted human premolars were used and class V cavity was prepared on the buccal and lingual surfaces. The teeth were randomly assigned to A, B and C groups and restored as follows: Conventional strengthen glass-ionomer cement (Ketac?Molar Easymix), compomer CF2000) and eompomer (Dyract AP). Teeth were kept in distilled water at 37 ? for 7 days. Then the specimens were thermocycled for 500 times. Each group was randomly divided into 3 subgroups which were treated for 21 days with one of the following: Whitening strip (14% hydrogen peroxide), bleaching gel (10% carbamide peroxide), or distilled water (control). After bleaching, the teeth were placed in a solution of basic fuchsin dye for 24 hours, then the teeth were sectioned longitudinally to evaluate the dye penetration. The depth of staining along the tooth restoration interface was recorded with a stereomicroscope. Results There were no signicant differences between the two bleaching agents in microleakage of restorations (ft>0.05\\ The two bleaching agents did not significantly affect the microleakage of compomer (/VO.05), whereas the microleakage of glass-ionomer cement in the experimental groups was higher than that in the control group (P<0.05). Conclusion There are no significant differences in microleakage of restorations between bleaching gel (10% carbamide peroxide) and whitening strip (14% hydrogen peroxide). The two bleaching agents do not significantly affect the microleakage of compomer but adversely affect the microleakage of strengthen glass-ionomer cement.%目的 评估漂白凝胶和洁白牙贴对3种不同的玻璃离子水门汀类材料边缘微渗漏的影响.方法 在45颗离体健康前磨牙的颊舌侧制备V类洞,随机分为A、B、C组,分别使用加强型玻璃离子水门汀KetacTM Molar Easymix,复合体F2000

  4. 不同施肥处理对战骨生长特性和生物量的影响研究%Effects of Different Fertilization Treatments on Grow-th Characteristics and Medicinal Biomass of Premnafulva

    Institute of Scientific and Technical Information of China (English)

    韦霄; 史艳财; 陈宗游; 唐健民; 韦记青

    2014-01-01

    【目的】为提高战骨(Premnafulva )的产量与质量,研究基肥和追施化肥对战骨生长特性及生物量的影响,以期为战骨生产中的合理施肥提供理论依据。【方法】采用随机区组设计方法,在大田种植条件下研究了不同基肥(鸡粪、猪粪、牛粪、火土、鸡粪+猪粪、鸡粪+牛粪、鸡粪+火土、猪粪+牛粪、猪粪+火土、牛粪+火土)、追肥种类(磷肥、钾肥、尿素、复合肥)、追肥量(20g/株、40g/株、60g/株)和追肥次数(1次、2次、3次)对战骨生长特性和生物量的影响。【结果】4种单一基肥中,鸡粪处理后植株的基径、株高、冠幅、茎重和根重都较大;两种基肥混合处理的植株长势和生物量优于猪粪、牛粪和火土3种单一基肥处理;火土和猪粪处理的基径、株高、冠幅、茎重和根重值较大;追肥以复合肥效果最好;追加钾肥和磷肥处理的植株生长指标和生物量较差。【结论】基肥以火土+猪粪(1∶1);追肥以施用复合肥,施用量为40g/株,追肥3次,战骨的产量最高。%Objective]Effects of different fertilization treatments on growth characteristics and medicinal biomass of Premna fulva were discussed in order to provide a theory basis for ra-tional fertilization of Premna fulva production,and yield and quality improvment.[Methods]A field randomized block experiment was used to analyze effects of different basal fertilizer (chicken manure,pig manure,cattle manure,ash soil,chicken manure+pig manure,chicken manure+cattle manure,chicken manure+ash soil,pig manure+cattle manure,pig manure+ash soil and cattle manure+ash soil),different additional fertilization (phosphate fertilizer, potassium fertilizer,carbamide and compound fertilizer),volume (20g/plant,40g/plant,60g/plant)and times of fertilization (once,twice and three times)on Premnafulva growth index and yield.[Results]The ground

  5. Influence of post-bleaching time intervals on dentin bond strength Influência de tempos de espera pós-clareamento na resistência adesiva da dentina

    Directory of Open Access Journals (Sweden)

    Erica Cappelletto Nogueira Teixeira

    2004-03-01

    Full Text Available It has been reported that bond strength of resin to tooth structure can be reduced when the bonding procedure is carried out immediately after the bleaching treatment. This study evaluated the effect of bleaching of non-vital teeth bleaching on the shear bond strength (SBS of composite resin/bovine dentin interface and the influence of delaying the bonding procedures for different time intervals following internal bleaching. According to a randomized block design, composite resin cylinders (Z100/Single bond - 3M were bonded to the flattened dentin surface of two hundred and fifty-six teeth which had previously been subjected to four different treatments: SPH - sodium perborate + 30% hydrogen peroxide; SPW - sodium perborate + distilled water; CP - 37% carbamide peroxide; and CON - distilled water (control, each one followed by storage in artificial saliva for 0 (baseline, 7, 14, and 21 days after bleaching (n = 16. The bleaching agents in the pulp chambers were replaced every 7 days, over 4 weeks. The SBS test of the blocks was done using a universal testing machine. The ANOVA showed that there was no significant interaction between time and bleaching agents, and that the factor time was not statistically significant (p > 0.05. For the factor bleaching treatment, the Student's t-test showed that [CON = CP] > [SPW = SPH]. The bleaching of non-vital teeth affected the resin/dentin SBS values when sodium perborate mixed with 30% hydrogen peroxide or water was used, independently of the elapsed time following the bleaching treatment.Tem-se sugerido que a qualidade da adesão resina composta-dentina pode ser prejudicada quando restaurações são confeccionadas imediatamente após o tratamento clareador. Este estudo avaliou o efeito da postergação do procedimento adesivo após o clareamento interno realizado com diferentes agentes na resistência ao cisalhamento da interface compósito/dentina. De acordo com um delineamento aleatório em blocos

  6. 半固态播种对水稻生长性状的影响及节水节肥效果研究%Effect of Semi-solid Seeding on Rice Growth Traits, Water and Fertilizer Use Efficiency

    Institute of Scientific and Technical Information of China (English)

    梁玉刚; 黄璜; 张启飞; 李静怡

    2016-01-01

    为破解南方稻田灌溉用水和肥料施用不合理以及资源紧缺等一系列问题,通过水稻半固态播种与泡田整地播种的对比试验,研究水稻前期灌溉用水量及肥料不同施用方式对水稻生长性状的影响。结果表明:与泡田整地播种相比,水稻半固态播种拓宽了破胸稻种的吸水途径,提高了肥料利用效率,避免了有害环境因子的直接作用,有利于水稻出苗及壮苗的形成;同时,节约灌溉水资源2250 m3/hm2,提高水分利用率;尿素施用减少20.75 kg/hm2,利用率增加11.06%;复合肥施用减少78.27~88.79 kg/hm2,利用率增加16.31%~18.50%;显著减少无效穗,增加有效穗,提高成穗率;显著增加每穗实粒数,提高每穗穗重和结实率;实现水稻增产,增幅为2.02%~5.06%。采用相应配套施肥方式,使水稻剑叶和倒二叶的SPAD维持在较高水平;延缓籽粒灌浆期间剑叶叶绿素a与叶绿素b的降解速率,实现了水稻高产栽培的节水节肥和资源高效利用。%In order to solve a serious of problems of unreasonable use of irrigation water, fertilizer and resource shortages in southern paddy, research the effect of different irrigation water consumptions and fertilizer application methods on rice growth traits by the contrast test of semi-solid rice sowing and steeping ifeld tillage sowing. The results showed that: compare with the steeping ifeld tillage sowing, semi-solid rice sowing broaden the water absorption pathway of the breaking chest rice, improve the fertilizer use efifciency, avoid the direct effect of harmful environmental factors, beneifcial to the formation of rice seedling emergence and sound seedling. At the same time, saving irrigation water 2250 m3/hm2, increase water use efifciency; carbamide application was reduced by 20.75 kg/hm2, and the utilization rate increased by 11.06%; compound fertilizer reduced 78.27-88.79 kg/hm2, utilization rate increased

  7. 水溶性叶面肥对豇豆产量的影响%Effect of Water Soluble Foliar Fertilizer on Cowpea Yield

    Institute of Scientific and Technical Information of China (English)

    张慧亮; 许恩光; 王顺德

    2013-01-01

    To investigate the effects of foliar fertilizer on the yield of cowpea, eight different foliar fertilizers were sprayed in cowpea vegetative growth stage for 3 times. Results showed that the yield increased 67%by spraying 4.3%fulvic acid foliar fertilizer, increased 57% by spraying 8% fulvic acid+(N+P2O5+K2O), increased 48.2% by spraying major elements and trace elements[(N+P2O5+K2O≥23% 9∶6∶8)+(Fe+B+Z≥1%)], increased 43.2% by spraying 4%potassium humate+major elements+trace elements[(N+P2O5+K2O≥23% 9∶6∶8)+(Fe+B+Zn≥1%)], increased 40.8%by spraying 3% potassium humate+vitamin+carbamide urea+potassium sulfate≥7%; increased 39.5% by spraying major elements+tace elements[(N+P2O5+K2O≥35% 12∶10∶13)+(Fe+B+Zn≥0.6%)]; increased 33.7% by spraying 3%potassium humate+major elements and trace elements [(N+P2O5+K2O≥35% 12∶10∶13)+(Fe+B+Zn≥0.6%)];increased 15.9%by spraying 4%potassium humate. The most obvious of yield increase was fulvic acid, the effect of trace elements was better than that of major elements, potassium humate was the lowest, potassium humate+major elements+trace elements was less than major elements+trace elements.%使用8个不同配方叶面肥在豇豆营养生长阶段喷施3次,调查叶面肥对豇豆产量的影响。结果表明,与对照相比,喷施4.3%黄腐酸叶面肥处理增产67.0%;8%黄腐酸+氮磷钾增产57.1%;大量元素+微量元素[(N+P2O5+K2O≥23%9∶6∶8)+(F e+B+Z n≥1%)]的增产48.2%;4%腐植酸钾+大量元素+微量元素[(N+P2O5+K2O≥23%9∶6∶8)+(Fe+B+Zn≥1%)]增产43.2%(添加腐植酸钾不利于提高产量);3%腐植酸钾+维生素+尿素+硫酸钾≥7%增产40.8%;大量元素+微量元素[(N+P2O5+K2O≥35%12∶10∶13)+(F e+B+Z n≥0.6%)]增产39.5%;3%腐植酸钾+大量元素+微量元素[(N+P2O5+K2O≥35%12∶10∶13)+(F e+B+Z n≥0.6%)]增产33.7%;4%腐植酸钾增产15.9%。黄腐酸增产效果最明显,微量元素增产效果比大量元素明显,腐植酸

  8. Underground coal gasification with extended CO2 utilization as economic and carbon neutral approach to address energy and fertilizer supply shortages in Bangladesh

    Science.gov (United States)

    Nakaten, Natalie; Islam, Rafiqul; Kempka, Thomas

    2014-05-01

    injected in the scope of the scheduled EGR operation. Our techno-economic modeling results considering EGR reservoir simulations demonstrate that an economic and carbon neutral operation of UCG combined with fertilizer production and CCS is feasible. The suggested approach may provide a bridging technology to tackle fertilizer and power supply shortages in Bangladesh, and in addition support further production from depleting natural gas deposits. References Kempka, T., Plötz, M.L., Hamann, J., Deowan, S.A., Azzam, R. (2010) Carbon dioxide utilisation for carbamide production by application of the coupled UCG-urea process. Energy Procedia 4: 2200-2205. Nakaten, N., Schlüter, R., Azzam, R., Kempka, T. (2014) Development of a techno-economic model for dynamic calculation of COE, energy demand and CO2 emissions of an integrated UCG-CCS process. Energy (in print). Doi 10.1016/j.energy.2014.01.014

  9. 内蒙古马铃薯枯萎病病原菌鉴定及其生物学特性%Pathogen Identification and Biological Characteristics of Potato Wilt in Inner Mongolia

    Institute of Scientific and Technical Information of China (English)

    陈慧; 薛玉凤; 蒙美莲; 马志伟; 刘智慧; 胡俊

    2016-01-01

    In recent years, the potato wilt is becoming more and more serious in Inner Mongolia. In order to identify the pathogen, some suspected samples were collected, isolated and identified in Inner Mongolia from 2009 to 2014. Morphologic characteristics, pathogenicity test and molecular method were used to identify the pathogen. The results showed that the main pathogen causing potato wilt was Fusarium oxysporum, F. tricinctum and F. solani in Inner Mongolia. For the growth of F. oxysporum, its optimal temperature was 25 ℃; the optimal pH was 7; the best culture medium was PDA, PSA and Bilais; the optimal carbon source was starch and maltose, and nitrogen source was peptone. For the growth of F. tricinctum, its optimal temperature was 20 ℃; the optimal pH was 7; the best culture medium was cornmeal agar and oatmeal media; and the optimal carbon source and nitrogen source were starch and carbamide. For the growth of F. solani, its optimal temperature was 30℃;the optimal pH was 7;the best culture medium was PSA;the optimal carbon source were glucose and sucrose, and nitrogen source was potassium nitrate.%马铃薯枯萎病在内蒙古马铃薯种植区发生日趋严重。为明确其病原,2009~2014年对采自内蒙古各地的马铃薯枯萎病病样进行病原菌分离和鉴定。通过形态学鉴定和rDNA-ITS测序、同源性比对,得知引起内蒙古马铃薯枯萎病病原菌主要为尖孢镰刀菌(Fusarium oxysporum)、三线镰刀菌(F. tricinctum)和茄病镰刀菌(F. solani)。生物学特性研究结果表明,尖孢镰刀菌的最适生长温度为25℃,最适pH为7,最适合生长的培养基为PDA、PSA、Bilais培养基,最适碳源为淀粉和麦芽糖,最适氮源为蛋白胨;三线镰刀菌的最适生长温度为20℃,最适pH为7,最适生长的培养基为玉米粉和燕麦粉培养基,最适碳源为淀粉,最适氮源为尿素;茄病镰刀菌的最适温度为30℃,最适pH为7,最适合生

  10. The growth and petroleum degradation characteristics of bacteria in coastal beach%一株沿海滩涂细菌的降油及生长特性研究

    Institute of Scientific and Technical Information of China (English)

    王斌; 周雅飞; 张兴; 郑峰伟; 高钰婷; 何洁; 周一兵

    2012-01-01

    The bacteria that have capability to degrade crude oil were isolated from the coastal beach polluted by crude oil with the basal medium crude oil as only carbon source. The original degradation rate of diesel oil by the i-solated strains was determined. In addition, the degradation rate of diesel oil by the isolated strain was determined with the basal medium diesel oil including different concentration of glucose (0, 1,2,4,8, 16 g/L) , the different concentrations of yeast extract, peptone, carbamide, (NH4)2SO4( according to the content of nitrogen; 0. 5, 1,2 g/L) and NaH2P04(0, 4, 8 , 16 g/L) . The isolated strain was identified and growth characteristics were studied. The results showed: 5 strains bacteria grew on the basal medium crude oil as only carbon source. One of these stains had a maximum original degradation rate (19.0% ) and was numbered as Y-3. The degradation rate of Y-3 increased and reached to 79. 9% in the diesel oil medium supplemented with glucose (4 g/L). The degradation rate was increased in Y-3 in addition of yeast extract and peptone also, but not notable in added urea, (NH4)2S04 and NaH2PO4. The Y-3 was identified as Pseudomonas putida according to the result of the morphology, physiological characteristics and 16S rDNA sequence analysis. The Y-3 had fitting growth at temperature of 30 ℃ , pH 8, and NaCl concentration of 0-30 g/L.%采用以原油为唯一碳源的基础培养基,从原油污染的沿海滩涂土壤中分离筛选具有降油性能的细菌;采用柴油培养基测定分离菌株对柴油的原始降解率;通过在柴油培养基中添加不同浓度的葡萄糖(0、1、2、4、8、16 g/L),及不同浓度的酵母膏、蛋白胨、尿素、硫酸铵(以氮计,浓度为0.5、1、2 g/L)和磷酸二氢钠(0、4、8、12 g/L)后,测定分离菌株的降油性能;鉴定分离菌株并研究其生长特性.结果表明:共分离到5株能以原油为唯一碳源生长的细菌,其中1株原始降油率最高(19.0

  11. 中药海尔福口服液对砷中毒小鼠的解毒效果研究%Detoxification effects of traditional Chinese medicine of Haier Fu oral liquid on mice with arsenic poisoning

    Institute of Scientific and Technical Information of China (English)

    何胜; 陆晓峰; 银彩林; 李红妃; 梁海燕; 林洁; 周国荃; 张树球

    2012-01-01

    with large dose. Moreover, set groups of poisoned without treatment ( model group 1 ) and normal ( control) group. The experiment was made for 30 consecutive days. Hemoglobin was tested before and after the exposure and after treatment. At the end of the experiment, drew blood from eyes, separated blood serum and tested alanine aminotransferase ( ALT) and carbamide, executed the animals and then made pathological study with liver, took cerebral homogenate and made the homogenate at 10% . The rate of superoxide anion free radical was tested. Results The hemoglobin( Hb)of normal group, model group, treatment group 1 and treatment group 2 were compared before modeling, this difference, however, was not statistically significant ( P >0.05). After modeling ( before treatment) , hemoglobin were 143. 77 ± 7.11 , 120.47 ± 14.23, 117. 66 ± 7. 01, 125. 66 ± 6. 86 ( g / L) , the normal group was significantly higher than that of three model groups ( P 0. 05 ). The result of pathological study showed that arsenic has damage effect on liver, model groups damaged comparatively serious and then were treatment groups. Conclusion Arsenic has obvious inhibitory effect on hematopoietic system and has damage effect on liver, while the function recovers significantly after treatment with Haier Fu oral liquid.

  12. 黄芪注射液对高通透性腹膜透析大鼠透析效能及腹膜结构的影响%Huangqi Injection's Effect on the Dialysis Efficiency and Structure of Peritoneal Dialysis Rat with High Permeable Perineum

    Institute of Scientific and Technical Information of China (English)

    刁金囡; 盛梅笑; 朱萱萱; 王宁皎; 朱长乐; 何伟明

    2011-01-01

    (Group D). Rats in Group B, C and D received intraperitoneal injection respectively with 4.25 % glucose icodextrin, Huangqi injection of low concentration, and Huangqi injection of high concentration (25m/1) for 10 days. The peritoneal function test was taken at day 11 through observing the level changes of D/ Purea of urea nitrogen, D/PCr of creatinine, D/DoGlu of glucose in peritoneal cavity for 0,30、60、90 and 120 mins , levels changes of Curea, CCr, UF and NetUF for 120 mins and the morphostructure changes of peritoneum. RESULTS ① the D/PCr levels of Group B,C and D at different time were higher than that of Group A;the D/DoGlu levels of Group B, C and D lower than that of Group A (P<0.05) ;the UF、NetUF levels of Group B were lower than that of Group A(P<0. 05) ;②D/Purea levels of Group C and D(60 mins) were lower than that of Group B(P<0.05) ;D/PCr levels of Group D after 60 and 90 mins were higher than those of Group B (p< 0.05) ;D/DoGlu level of Group D was lower than that of Group B(P< o. 05). ③ Group C and D showed significant difference in the levels of D/Purea、 D/PCr(30、60、90mins) and D/DoGlu(30、60min) (P<0.05) ;④ The level of Curea、 CCr、 UF and NetUF of Group D were higher than those of Group B (P<0.05) ;⑤ The condition of peritoneal incrassation and mesothelial cells dropping improved compared with that of Group B. CONCLUSION Peritoneal diailysis fluid of 4.25 % glucose can destroy the mesothelial cells, improve the permeability, and reduce ultrafiltration volume in the peritoneum. Huangqi injection of different concentration can protect the mesothelial level, improve the clearance of carbamide and creatinine and enhance the peritoneal dialysis efficacy, without increasing peritoneum's absorption of glucose. Besides, Huangqi dialysate of high concentration can promote peritoneum' s clearance of water and increase the dialysis hyperfiltration.