Effect of mouth rinses exposure on bleached enamel and the correlation between enamel roughness and color change

Orientador: Débora Alves Nunes Leite LimaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: Avaliar, in vitro, os efeitos do uso de enxaguatórios bucais na superfície e subsuperfície do esmalte clareado com peróxido de hidrogênio a 35% (PH) e a correlação entre a rugosidade do esmalte e alteração de cor. Métodos: No capítulo 1, blocos bovinos de esmalte/dentina (4x4x2 mm) foram clareados (PH) e imersos duas vezes ao dia, por 14 dias, nos enxaguatórios (n=10): água destilada (C, controle); 225 ppm de NaF (FM, Colgate® Plax Classic); óleo essencial (EM, Listerine® Tartar Control); peróxido de hidrogênio a 1,5% (HPM, Colgate® Plax Whitening); peróxido de hidrogénio a 2% + pirofosfatos e 225 ppm de NaF (HPM+P, Colgate® Luminous White)... O resumo poderá ser visualizado no texto completo da tese digitalAbstract: To evaluate, in vitro, the effect of mouth rinse exposure on bleached enamel with 35% hydrogen peroxide (HP) and the correlation between enamel roughness and color change of tooth. Methods: In chapter 1, enamel/dentine bovine blocks (4x4x2 mm) were bleached and were submitted to immersion twice daily, for 14 days, with different rinses (n=10), including: distilled water (C, control); 225 ppm NaF (FM, Colgate® Plax Classic); essential oil (EM, Listerine® Tartar Control); 1.5% hydrogen peroxide (HPM, Colgate® Plax Whitening); and 2% hydrogen peroxide + pyrophosphates and 225 ppm NaF (HPM + P, Colgate® Luminous White)... The abstract is available with the full electronic documentDoutoradoDentísticaDoutor em Clínica Odontológic

Effect of different toothpastes application prior to dental bleaching on enamel physical properties and mineral content

Orientadores: José Roberto Lovadino, Debora Alves Nunes Leite LimaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: Objetivo: Avaliar o efeito de dentifrícios com diferentes princípios ativos aplicados previamente ao clareamento dental com peróxido de hidrogênio 35% (PH) nas propriedades físicas e cromáticas do esmalte, conteúdo mineral e na morfologia superficial. Métodos: Blocos de esmalte bovino foram submetidos a protocolos de tratamento na máquina simuladora de escovação (n = 10): 1) escovação com água destilada e exposição ao gel placebo (PLA - controle negativo) ou 2) gel clareador (PH - controle positivo), escovação com diferentes dentifrícios previamente ao clareamento com PH, sendo: 3) dentifrício com nitrato de potássio e fluoreto de sódio (PN), 4) com monoflúorfosfato de sódio (FT), à base de 5) arginina 8%, Pro-Argin¿ (PA), 6) arginina 1,5%, Neutraçúcar¿ (SAN), ou 7) com vidro bioativo NovaMin¿ (NM). No capítulo 1 foi realizada nos tempos inicial e final a análise da rugosidade superficial (Ra) e cor pelo sistema Cie L*a*b* (?E, ?L, ?a e ?b). No tempo final foi avaliada a microdureza superficial (SMH) e a microdureza em profundidade (CSMH - 10, 25, 50, 75 e 100?m). No capítulo 2, a concentração iônica de fósforo no gel [P] foi analisada e determinada o nível elementar (%) de Ca, Na, P e proporção entre Ca / P por espectroscopia de energia dispersiva por raios-x (EDS) e a morfologia de superfície por microscopia eletrônica de varredura (MEV). Os dados foram submetidos a teste Proc-Mixed de medidas repetidas (Ra), ANOVA (SMH, Nível elementar, [P] e Cor), ANOVA de parcelas subdivididas (CSMH) e teste de Tukey (p PA = SAN > outros grupos). O clareamento aumentou a Ra em comparação ao PLA, todos os grupos tiveram aumento da Ra, exceto NM que não diferiu de PLA. Os valores de ?E, ?L e ?b não diferiram entre os grupos experimentais e o controle positivo (PH). O grupo PH aumentou a perda de fósforo [P], entretanto NM não diferiu de PLA. PH diminuiu os valores de % Ca em comparação PLA, no entanto PA não diferiu de PLA. MEV, apenas os grupos PH e FT demonstraram alteração de morfologia. Conclusão: O clareamento dental alterou as propriedades e conteúdo mineral do esmalte, entretanto a utilização prévia de dentifrícios preveniu os efeitos negativos, sem interferir na eficácia do tratamento. O dentifrício com vidro bioativo demonstrou potencial efeito benéfico na terapia clareadoraAbstract: Objective: Evaluate the effect of toothpastes with different active agents applied prior to dental bleaching with 35% hydrogen peroxide on enamel properties, whiteness effectiveness, enamel mineral content and morphology surface. Methods: 70 enamel blocks (4x4x2 mm) were submitted to in vitro treatment protocols in tooth-brushing machine (n=10): 1) with distilled water and exposure to placebo gel (PLA) or 2) bleaching with 35% hydrogen peroxide (HP); brushing with different toothpaste was performed prior the bleaching treatment (HP), being: 3) potassium nitrate toothpaste (PN) containing NaF, 4) conventional MFP fluoridated toothpaste (FT), 5) arginine-carbonate (8% arginine) based toothpaste (PA), 6) arginine-carbonate (1.5% arginine) based toothpaste (SAN) and 7) toothpaste containing bioactive glass (NM). In chapter 1, the color changes were characterized using the Cie L*a*b* system (?E, ?L, ?a and ?b) and roughness (Ra) analysis was performed before and after treatments, surface microhardness (SMH) and cross- sectional microhardness (CSMH) were analyzed after treatments. In chapter 2, the phosphorus concentration in gel ([P]) was performed and the elemental levels (%) of Ca, Na, P and proportion between Ca/P were determined by Energy Dispersive X- ray Spectrometer (EDS) and morphology surface by Scanning Electron Microscopy (SEM). Data were analyzed PROC MIXED (Ra), ANOVA (SMH, %, [P], ?E, ?L, ?a and ?b), ANOVA split plot (CSMH) and Tukey's test post hoc (p PA = SAN > all others groups) or decreased HP effects (CSMH). Ra increased in all bleached groups, with exception in NM that did not differ to PLA. HP increased the [P] loss, however only NM group application prior to HP did not differ of PLA. EDS analysis showed that HP decreased the % Ca values differing to PLA, the % P was increased in bleaching groups, however the PA group did not differ to PLA. SEM analysis presented the decrease of demineralization effect in groups submitted the toothpaste application prior to HP, with exception the HP and MFP group that demonstrated morphology alteration. Conclusion: Dental bleaching affect the enamel properties and mineral content however toothpastes showed a potential effect in reducing the bleaching effects on the enamel properties without influence on the whiteness effectiveness. Furthermore, the toothpaste containing bioactive glass showed potential beneficial effect for bleaching therapyMestradoDentísticaMestre em Clínica Odontológic

Correlation between alteration of enamel roughness and tooth color

To establish the correlation between enamel roughness and color change of tooth. Enamel/dentin blocks (5 x 5 x 3.2 mm) were serially ground with the following abrasive paper: 1200-grit, 800-grit, and 600-grit SiC papers. In the paired model, the analyses of color (L*, a*, b*, ?E) and roughness (Ra) were performed among the sandpaper exposure. The data were subjected to ANOVA using models for repeated measures followed by the Tukey test. The Pearson correlation test was used to determine whether there was a relationship between Ra values and color results (? = 0.05). The L* values decreased in accordance with the increase of Ra, with statistical difference between all the times (p0.05). The alteration of enamel roughness acted on the lightness and the green-red axis of tooth color. However, there was no significant correlation between the alteration of roughness of enamel and general color change of tooth

Immediate and long-term microshear bond strength of resin-based cements to core build-up materials

To evaluate the microshear bond strength (?-SBS) between resin-based cements and core build-up materials after water storage. Material and Methods: Cylinders (1x1 mm) of conventional dual-cure resin cement (RelyX ARC, 3M ESPE), universal du

Effect of in-office bleaching gels with calcium or fluoride on color, roughness, and enamel microhardness

Commercial bleaching gels with remineralizing agents were developed to reduce the adverse effects of dental bleaching. The present study evaluated the effects on teeth of in-office bleaching gels containing 35-40% hydrogen peroxide (HP) with Calcium (Ca) or Fluoride (F). Bovine enamel/dentin blocks (4x4x2.5 mm) were randomly divided into the following groups (n=12): no treatment (control); 35% HP (Whiteness HP, FGM); 35% HP with Ca (Whiteness HP Blue, FGM); 40% HP with F (Opalescence Boost, Ultradent). The specimens were analyzed for color (?L*, ?a*, ?b*, and ?E), roughness (Ra), and Knoop microhardness (KHN). The color and KHN data were submitted to ANOVA and Tukey?s test, while Ra values were analyzed using mixed models for repeated measures and Tukey-Kramer?s test (?=0.05). The bleached groups did not exhibit statistical differences among them for color. For roughness, 35% HP provided a slight increase of Ra, which was statistically different from the control. For microhardness, 35% HP and 40% HP with F presented KHN values that were statistically lower from the control, while the 35% HP with Ca did not statistically differ from the control. The presence of Ca or F in bleaching gels did not interfere with bleaching efficacy. However, only the enamel exposed to the bleaching gel containing Ca obtained microhardness values similar to unbleached enamel

Characterization of whitening toothpastes and their effect on the physical properties of bulk-fill composites

Objective: To characterize activated charcoal and 2% hydrogen peroxide-based toothpastes and investigate their effects on roughness, color change, and gloss of bulk-fill composite resin. Methodology: Composite resin specimens (Aura Bulk Fill, SDI) were subjected to 5,000 brushing cycles with regular toothpaste (Colgate Total 12, [RT]), activated charcoal toothpaste (Bianco Dental Carbon, [AC]), or hydrogen peroxide-containing toothpaste (Colgate Luminous White Advanced, [HP]), with or without coffee exposure. The pH, particle characterization by scanning electron microscopy (SEM), and weight% of solid particles in the toothpaste were assessed. Roughness (Ra) was evaluated using a surface profile-measuring device, color change (∆Eab/∆E00) by reflectance spectrophotometer, and gloss unit (GU) by glossmeter. Kruskal–Wallis, Dunn, Friedman, and Nemenyi tests were used, and the correlation coefficient test was performed between Ra and GU (α=0.05). Results: RT presented a higher Ra after brushing and did not change after staining with coffee; moreover, the ∆Eab/∆E00 values were higher for RT than HP. Regarding gloss, AC and HP obtained higher values compared to RT. A significant negative correlation between gloss and Ra was found for RT exposed to coffee. All toothpastes had a neutral pH; however, RT had the largest percentage of solids by weight. SEM images showed particles of many sizes: irregular shape (RT), more regular particles (AC), and spherical clusters (HP). Although surface roughness, color change, and gloss may compromise the longevity of restorations, the whitening toothpastes tested did not promote more morphology changes than regular toothpastes

Current status of whitening agents and enzymes in Dentistry

This study reviews the knowledge on the use of conventional dental whitening and the use of enzymes as a new approach in bleaching. A review of the literature was based on academic articles and on patents related to the use of enzymes in dental bleaching. Tooth whitening techniques used nowadays are well reported in the literature, and its mechanism of action consists of an oxidoreduction reaction with the release of free radicals. The great instability of radicals, when in contact with the tissues, promotes oxidation and reduction in the size of the pigment chains incorporated into them. These pigments are eventually broken down into smaller and smaller molecular chains and end up being diffused from the dental structure. In turn, the use of enzymes aimed at tooth whitening can be a less harmful alternative to the tooth because their specificity regarding the substrate makes them of great interest to perform specific reactions, reducing collateral effects. The use of proteolytic enzymes and oxidoreductases paired with the application of peroxides, can be a promising alternative for obtaining even better results in the dental bleaching process