970 resultados para Weyl, Herman: Symmetria
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The objective of this study was to assess penetration of adhesive material in enamel bleached with 35% hydrogen peroxide using optical polarized light microscopy. Extracted human teeth were randomly assigned to 5 groups, each representing a specific time interval between bleaching and the application of an adhesive material. They were designated as: (TC) the control group-restorations in unbleached teeth; (T0) comprising restorations carried out immediately after bleaching; (T7) comprising restorations 7 days after bleaching; (T14) comprising restorations 14 days after bleaching; and (T21) comprising restorations 21 days after bleaching. Length of resin tags was measured with an Axiophot photomicroscope at a x 400 magnification, and the results subjected to an ANOVA for a comparison between groups, with a p value of < 0.05. Differences between the groups were verified using a Tukey test at a confidence level of 5%. The specimens in the control group (TC) and experimental groups T7, T14 and T21 showed better penetration of adhesive material into enamel in comparison with experimental group T0. This suggests that a gap of at least 7 days should be left between bleaching enamel with 35% hydrogen peroxide and placing adhesive bonding agents and undertaking resin composite restoration work.
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Here, we present a case report on prosthetic reconstruction of posterior teeth and composite resin restoration of anterior teeth yielding considerable esthetic improvement, reestablishment of disocclusion guides and function.
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Pós-graduação em Física - IFT
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Context: The possibility of bleaching vital teeth with peroxide-based products considerably revolutionized esthetic dentistry. Aim: The aim of this clinical study was to evaluate tooth color change and dental sensitivity after exposure to preloaded film containing a 10% hydrogen peroxide whitening system (Opalescence Trθswhite Supreme). Materials and Methods: A total of 13 volunteers, aged 18 to 25 years, participated in this study. The patients used the whitening system once a day for 60 minutes during the 8-day study. For maxillary incisors and canines, the color change was visually evaluated with the Vita color scale before, immediately, and six months after the treatment. Tooth sensitivity was evaluated during the daily gel applications. All whitening applications were done in office and under the supervision of a dental professional. Statistical Analysis Used: The results were analyzed using the Friedman Test (nonparametric repeated measures ANOVA) at a level of 5%, and Dunn's Multiple Comparison Test at the level of 5%. Results: It was verified that the original mean color values observed at the baseline analysis differed significantly from those observed immediately after bleaching, as well as from those seen in the analysis at six months ( P = 0.001). There was no significant difference between the mean color values observed in the immediate time and in the analysis at six months ( P = 0.474). No tooth sensitivity was observed in any patients. Conclusion: It was concluded that the bleaching technique using the 10% hydrogen peroxide system was effective in a short period of time without tooth sensitivity during applications.
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Objectives: The objective of this study was to evaluate the clinical performance of 124 non-carious cervical lesion restorations at 12 months. Materials And Methods: Three study groups were formed according to the material and technique used. All teeth received 37% phosphoric acid etching in enamel and dentin. The teeth of Group I received the conventional adhesive system Scotch Bond Multi Purpose, followed by resin composite Filtek Z350; teeth of Group II were restored with resin-modified glass-ionomer cement Fuji II LC; teeth of Group III were restored with the same resin-modified glass-ionomer cement however, before it was inserted, 2 coats of primer of the Scotch Bond Multi Purpose adhesive system were applied to dentinal tissue. The teeth were evaluated by 2 examiners with regard to the factors of retention, marginal adaptation, marginal discoloration, color alteration, presence of marginal caries lesion, anatomic shape, and sensitivity. Results: Application of the Kruskal-Wallis test showed no statistically significant difference for anatomic shape, marginal discoloration, color alteration, caries lesion, marginal adaptation, and sensitivity among the three study groups, but the variable retention presented statistically significant difference at 12 months, with Group III presenting a behavior superior to that of Group II but similar to that of Group I. Conclusion: The analyzed restorations of non-carious cervical lesions presented a good clinical performance at 12 months.
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Enamel microabrasion can eliminate enamel irregularities and discoloration defects, improving the appearance of teeth. This article presents the latest treatment protocol of enamel microabrasion to remove stains on the enamel surface. It has been verified that teeth submitted to microabrasion acquire a yellowish color because of the thinness of the remaining enamel, revealing the color of dentinal tissue to a greater degree. In these clinical conditions, correction of the color pattern of these teeth can be obtained with a considerable margin of clinical success using products containing carbamide peroxide in custom trays. Thus, patients can benefit from combined enamel microabrasion/tooth bleaching therapy, which yields attractive cosmetic results. Esthetics plays an important role in contemporary dentistry, especially because the media emphasizes beauty and health. Currently, in many countries, a smile is considered beautiful if it imitates a natural appearance, with clear, well-aligned teeth and defined anatomical shapes.1-3 Enamel microabrasion is one technique that can be used to correct discolored enamel. This technique has been elucidated and strongly advocated by Croll and Cavanaugh since 1986,4 and by other investigators1,2,5-13 who suggested mechanical removal of enamel stains using acidic substances in conjunction with abrasive agents. Enamel microabrasion is indicated to remove intrinsic stains of any color and of hard texture, and is contraindicated for extrinsic stains, dentinal stains, for patients with deficient labial seals, and in cases where there is no possibility to place a rubber dam adequately during the microabrasion procedure.1,2 It should be emphasized that enamel microabrasion causes a microreduction on the enamel surface,3,6,10 and, in some cases, teeth submitted to microabrasion may appear a darker or yellowish color because the thin remaining enamel surface can reveal some of the dentinal tissue color. In these situations, according to Haywood and Heymann in 1989,14 correction of the color pattern of teeth can be obtained through the use of whitening products containing carbamide peroxide in custom trays. A considerable margin of clinical success has been shown when diligence to at-home protocols is achieved by the patient and supervised by the professional.3 Considering these possibilities, this article presents the microabrasion technique for removal of stains on dental enamel, followed by tooth bleaching with carbamide peroxide and composite resin restoration, if required. - See more at: https://www.dentalaegis.com/cced/2011/04/smile-restoration-through-use-of-enamel-microbrasion-associated-with-tooth-bleaching#sthash.N6jz2Bwk.dpuf
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Superficial stains and irregularities of the enamel are generally what prompt patients to seek dental intervention to improve their smile. These stains or defects may be due to hypoplasia, amelogenesis imperfecta, mineralized white spots, or fluorosis, for which enamel microabrasion is primarily indicated. Enamel microabrasion involves the use of acidic and abrasive agents, such as with 37% phosphoric acid and pumice or 6% hydrochloric acid and silica, applied to the altered enamel surface with mechanical pressure from a rubber cup coupled to a rotatory mandrel of a low-rotation micromotor. If necessary, this treatment can be safely combined with bleaching for better esthetic results. Recent studies show that microabrasion is a conservative treatment when the enamel wear is minimal and clinically imperceptible. The most important factor contributing to the success of enamel microabrasion is the depth of the defect, as deeper, opaque stains, such as those resulting from hypoplasia, cannot be resolved with microabrasion, and require a restorative approach. Surface enamel alterations that result from microabrasion, such as roughness and microhardness, are easily restored by saliva. Clinical studies support the efficacy and longevity of this safe and minimally invasive treatment. The present article presents the clinical and scientific aspects concerning the microabrasion technique, and discusses the indications for and effects of the treatment, including recent works describing microscopic and clinical evaluations.
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This is a clinical case report of a patient who presented with dental stains in the buccal and proximal aspects of the anterior teeth. Buccal stains were removed using the enamel microabrasion technique, and vital tooth bleaching with carbamide peroxide was also performed. Restorative procedures employing composite resin were done for a better result in the proximal aspect of teeth. Clinical significance: The authors observed the combination of these esthetic techniques improved the patient's smile. Today, dental esthetics attempts to imitate natural teeth by making them white, well-shaped, and aligned with no spots. This has enabled the development of several esthetic techniques, such as microabrasion to remove dental enamel surface stains and surface irregularities,1-6 and vital tooth bleaching to treat yellowish teeth.7 The enamel microabrasion technique uses different abrasive agents associated with chemical solutions,1,2,4,6 allowing the removal of intrinsic, hard-texture stains, and different coloring spots on the enamel surface, as well as correction of irregularities on the dental buccal surface.1,8 The various microabrasive products include the Opalustre® (Ultradent Products, http://www.ultradent.com)or Prema® Compound (Premier Dental Products, http://www.premusa.com), a low-concentration hydrochloric acid product associated with silica microparticles that is certainly effective for microabrasion technique,4,6,9,10 providing a good safety profile for the patient and professional. The microabrasion technique also promotes micro-reduction on the adamantine surface.4,5,10 In some cases, after its completion, microabrasion may cause teeth to become darker or yellowish because of the thinner remaining enamel surface, leading to more evident observation of the dentinal tissue, which in general determines tooth color. In these clinical conditions, correction of the color pattern of dental elements can be obtained with carbamide peroxide products applied in custom trays, such as the bleaching products Whiteness Perfect at 10% or 16% (FGM Productos Odontologicos, http://www.fgm.ind.br) or Opalescence® at 10% or 15% (Ultradent Products), with a considerable margin of clinical success, provided it is well indicated, well performed, and supervised by the professional.4,6,9,10 Considering all the aforementioned aspects, the authors present a clinical case about a dental-enamel microabrasion technique used to remove buccal enamel surface stains associated with dental vital bleaching and restorative procedures in the proximal aspect of anterior teeth. - See more at: https://www.dentalaegis.com/cced/2010/08/different-esthetic-techniques-used-in-combination-to-recover-the-smile#sthash.McFoH7El.dpuf
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Enamel microabrasion can eliminate enamel irregularities and discoloration defects, improving the appearance of teeth. This article presents the latest treatment protocol of enamel microabrasion to remove stains on the enamel surface. It has been verified that teeth submitted to microabrasion acquire a yellowish color because of the thinness of the remaining enamel, revealing the color of dentinal tissue to a greater degree. In these clinical conditions, correction of the color pattern of these teeth can be obtained with a considerable margin of clinical success using products containing carbamide peroxide in custom trays. Thus, patients can benefit from combined enamel microabrasion/tooth bleaching therapy, which yields attractive cosmetic results. Esthetics plays an important role in contemporary dentistry, especially because the media emphasizes beauty and health. Currently, in many countries, a smile is considered beautiful if it imitates a natural appearance, with clear, well-aligned teeth and defined anatomical shapes.1-3 Enamel microabrasion is one technique that can be used to correct discolored enamel. This technique has been elucidated and strongly advocated by Croll and Cavanaugh since 1986,4 and by other investigators1,2,5-13 who suggested mechanical removal of enamel stains using acidic substances in conjunction with abrasive agents. Enamel microabrasion is indicated to remove intrinsic stains of any color and of hard texture, and is contraindicated for extrinsic stains, dentinal stains, for patients with deficient labial seals, and in cases where there is no possibility to place a rubber dam adequately during the microabrasion procedure.1,2 It should be emphasized that enamel microabrasion causes a microreduction on the enamel surface,3,6,10 and, in some cases, teeth submitted to microabrasion may appear a darker or yellowish color because the thin remaining enamel surface can reveal some of the dentinal tissue color. In these situations, according to Haywood and Heymann in 1989,14 correction of the color pattern of teeth can be obtained through the use of whitening products containing carbamide peroxide in custom trays. A considerable margin of clinical success has been shown when diligence to at-home protocols is achieved by the patient and supervised by the professional.3 Considering these possibilities, this article presents the microabrasion technique for removal of stains on dental enamel, followed by tooth bleaching with carbamide peroxide and composite resin restoration, if required.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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This study concerned the reaction of yellow passion fruit ‘Maguary’ and ‘Afruvec’ to the phytonematode Meloidogyne incognita race 3 in greenhouse conditions. An entirely randomized experimental design with 3 treatments (‘Maguary’, ‘Afruvec’, and tomato cv. ‘Rutgers’) and 4 repetitions was used, each plot consisting of 1 vase containing 1 plant. After 6 months, an evaluation was made of the index of galls and egg mass in the yellow passion fruit varieties and in the tomato cv. ‘Rutgers’. The classification of resistance to the phytonematode was made by criterion of the reproduction factor (RF). ‘Maguary’ presented a zero index of galls and egg mass, while ‘Afruvec’ showed a low index of galls and egg mass in relation to the tomato cv. Rutgers. According to the RF, ‘Maguary’ was characterized as immune to the phytonematode, while ‘Afruvec’ was resistant, and the tomato cv. ‘Rutgers’ was susceptible.
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This collection consists of an autographed copy of Herman F. Arnold’s “Dixie”. The music scale is inscribed with “At the request of Miss Minnie Parker the copy of Dixie is presented to Winthrop College [in 1923] by Prof. Herman F. Arnold + the score in 159 of + who wrote Dixie and was made the war tune of the south at the inauguration of Jefferson Davis Feb. 18th 1861 at Montgomery, Ala.” There is also a note stating that this score is “One of the Four Autograph Copies of the Score of Dixie.” Minnie Barker was curator of the Winthrop museum and the music score was displayed there until Tillman Science Building was razed in 1962 which housed the museum.