Effective tooth-bleaching protocols capable of reducing H2O2 diffusion through enamel and dentine

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of Adhesive Restorations on Diffusion of H2O2 Released from a Bleaching Agent and Its Toxic Effects on Pulp Cells

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of calcium on the osmotic dehydration kinetics and quality of pineapple

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effect of Post-silanization Heat Treatments of Silanized Feldspathic Ceramic on Adhesion to Resin Cement

Purpose: To evaluate the effect of post-silanization heat treatment of a silane agent and rinsing with hot water of silanized CAD/CAM feldspathic ceramic surfaces on the microtensile bond strength between resin cement and the ceramic, before and after mechanical cycling.Materials and Methods: Blocks measuring 10 x 5.7 x 3.25 mm(3) were produced from feldspathic ceramic cubes (VITA Mark II, VITA Zanhfabrik). Each ceramic block was duplicated in composite resin using a template made of polyvinylsiloxane impression material. Afterwards, ceramic and corresponding resin composite blocks were ultrasonically cleaned and randomly divided according to the 5 strategies used for conditioning the ceramic surface (n = 10): GHF: etching with hydrofluoric acid 10% + rinsing with water at room temperature + silanization at 20 degrees C; G20: silanization; G77: silanization + oven drying at 77 degrees C; G20r: silanization + hot water rinsing; G77r: silanization + oven drying at 77 C + hot water rinsing. The resin and ceramic blocks were cemented using a dual-curing resin cement. Every group was divided in two subgroups: aging condition (mechanical cycling, designated as a) or non-aging (designated as n). All the bonded assemblies were sectioned into microsticks for microtensile bond strength (mu TBS) testing. The failure mode of the tested specimens was assessed and mu TBS data were statistically analyzed in two ways: first 2-way ANOVA (GHF, G20 and G77 in non-aging/aging conditions) and 3-way ANOVA (temperature x rinsing x aging factors, excluding GHF), followed by Tukey's test (p = 0.05).Results: The 2-way ANOVA revealed that the mu TBS was significantly affected by the surface treatment (p < 0.001) but not by aging (p = 0.68), and Tukey's test showed that G77-n/G77-a (18.0 MPa) > GHF-n/GHF-a (12.2 MPa) > G20-n/G20-a (9.1 MPa). The 3-way ANOVA revealed that the mu TBS was significantly affected by the heat treatment and rinsing factors (p < 0.001), but not affected by aging (p = 0.36). The rinsing procedure decreased, while oven drying increased the bond strengths. Group G77, in both non-aging and aging conditions (18.6-17.4 MPa), had the highest bond values. Failure modes were mainly mixed for all groups.Conclusion: Oven drying at 77 degrees C improved the bond strength between the resin cement and feldspathic ceramic, but hot water rinsing reduced the bond strength and should not be recommended.

Low-temperature degradation of a Y-TZP ceramic after surface treatments

The purpose of this study was to evaluate the influence of zirconia surface treatments on low-temperature degradation (LTD). Disc-shaped specimens were subjected to one of four surface treatments, denoted as C (controlno surface treatment), Si (air abrasion with 30 mu m silica-modified alumina particles), Al (air abrasion with 30 mu m alumina particles), and Gr (grinding with 120 grit diamond discs). Half of the samples were submitted to autoclave treatment for 12 h (127 degrees C, 1.5 bar). Samples were characterized by x-ray diffraction and profilometer analysis and were subjected to biaxial flexural strength test. All of the groups exhibited an increase in the amount of monoclinic phase (m-phase) after LTD. The tm transformation was remarkable for the specimens from the C group, which also exhibited a significant increase in strength. The Gr group also exhibited an increase in strength but lower initial roughness, which probably suppressed LTD on the zirconia surface. The specimens subjected to air abrasion exhibited higher initial amounts of m-phase and a small increase in m-phase after LTD; the strength was not affected in these groups. The effects of LTD were different with each surface treatment applied. Apparently, LTD may be suppressed by smoother surfaces or the presence of an initial amount of m-phase on zirconia surface. (c) 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 101B: 1387-1392, 2013.

Influence of Concentration and Activation on Hydrogen Peroxide Diffusion through Dental Tissues In Vitro

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of Different Surface Treatments on Bond Strength of Resin Composite Using the Intrinsic Characterization Technique

Objective: This study evaluated the influence of different surface treatments on the resin bond strength/light-cured characterizing materials (LCCMs), using the intrinsic characterization technique. The intrinsic technique is characterized by the use of LCCMs between the increments of resin composite (resin/thin film of LCCM/external layer of resin covering the LCCM).Materials and Methods: Using a silicone matrix, 240 blocks of composite (Z350/3M ESPE) were fabricated. The surfaces received different surface treatments, totaling four groups (n=60): Group C (control group), no surface treatment was used; Group PA, 37% phosphoric acid for one minute and washing the surface for two minutes; Group RD, roughening with diamond tip; and Group AO, aluminum oxide. Each group was divided into four subgroups (n=15), according to the LCCMs used: Subgroup WT, White Tetric Color pigment (Ivoclar/Vivadent) LCCM; Subgroup BT, Black Tetric Color pigment (Ivoclar/Vivadent) LCCM; Subgroup WK, White Kolor Plus pigment (Kerr) LCCM; Subgroup BK, Brown Kolor Plus pigment (Kerr) LCCM. All materials were used according to the manufacturer's instructions. After this, block composites were fabricated over the LCCMs. Specimens were sectioned and submitted to microtensile testing to evaluate the bond strength at the interface. Data were submitted to two-way analysis of variance (ANOVA) (surface treatment and LCCMs) and Tukey tests.Results: ANOVA presented a value of p<0.05. The mean values (+/- SD) for the factor surface treatment were as follows: Group C, 30.05 MPa (+/- 5.88)a; Group PA, 23.46 MPa (+/- 5.45)b; Group RD, 21.39 MPa (+/- 6.36)b; Group AO, 15.05 MPa (+/- 4.57)c. Groups followed by the same letters do not present significant statistical differences. The control group presented significantly higher bond strength values than the other groups. The group that received surface treatment with aluminum oxide presented significantly lower bond strength values than the other groups.Conclusion: Surface treatments of composite with phosphoric acid, diamond tip, and aluminum oxide significantly diminished the bond strength between composite and the LCCMs.

Clostridium perfringens in ingredients of poultry feed and control of contamination by chemical treatments

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Comparative study of toxicity of azo dye Procion Red MX-5B following biosorption and biodegradation treatments with the fungi Aspergillus niger and Aspergillus terreus

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Diffusion of Lambda(c) in hot hadronic medium and its impact on Lambda(c)/D ratio

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Translucent tin dioxide ceramics obtained by natural sintering

Dense SnO2-based ceramics (relative density >95%) have been obtained by natural sintering at a moderate temperature (less than or equal to 1300 degrees C) with the help of a small amount of manganese, Further thermal treatments above 1500 degrees C result in grain growth and transport of manganese toward the sample surface. If the ceramic is embedded inside alumina powder, the diffusion of Mn out of the sample and into alumina during such heat treatments leads to a manganese-free body (<40 ppm) which is translucent. The transmission in the visible region depends on sample thickness; 61% was achieved for a 0.05 mm thick sample.

Degradation of dipyrone by electrogenerated H2O2 combined with Fe2+ using a modified gas diffusion electrode

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Dentin microhardness during and after whitening treatments

Objective: This in vitro study aimed to evaluate the effect of bleaching agents on dentin microhardness during and after bleaching. Method and materials: Specimens were randomly assigned to seven groups (n = 15): Nite White Excel 2 Z [NW] 10% and 22%; Rembrandt [REM] 10% and 22%; Opalescence [OPA] 10% and 20%; and a placebo agent. The 42-day whitening treatment consisted of daily application of the agents to the dentin surfaces for 8 hours, followed by immersion in artificial saliva for 16 hours. After the bleaching treatment, specimens were kept immersed in artificial saliva for 14 days. Microhardness was measured at baseline, 8 hours, and 7, 14, 21, 28, 35, and 42 days of bleaching and during the posttreatment period (7 and 14 days). Results: The analysis of variance for split-plot showed a significant effect on the interaction between bleaching agent and time. Tukey's test and regression analyses revealed that during the bleaching period, the agents NW 10%, NW 22%, and OPA 20%, which did not differ from each other, did not alter dentin microhardness, showing constant microhardness values. There were no differences among REM 10%, REM 22%, and OPA 10%, which showed significant reductions in microhardness after day 14 compared to other agents. After bleaching procedures, there was an increase in dentin microhardness for all groups. Conclusion: Throughout the bleaching treatment, depending on the agent applied, dentin showed a transitory decrease in microhardness values. In the posttreatment period, artificial saliva presented a remineralizing effect on the bleached surfaces.

An Informatics Technical Note on Interaction of DNA - Graphene Chemical Sensor System as Reaction-Diffusion Wave-Based Computing System in Ionised Gaseous environments and their Applications Using Theoretical Studies and Scientific Computation Overview

The physics of plasmas encompasses basic problems from the universe and has assured us of promises in diverse applications to be implemented in a wider range of scientific and engineering domains, linked to most of the evolved and evolving fundamental problems. Substantial part of this domain could be described by R–D mechanisms involving two or more species (reaction–diffusion mechanisms). These could further account for the simultaneous non-linear effects of heating, diffusion and other related losses. We mention here that in laboratory scale experiments, a suitable combination of these processes is of vital importance and very much decisive to investigate and compute the net behaviour of plasmas under consideration. Plasmas are being used in the revolution of information processing, so we considered in this technical note a simple framework to discuss and pave the way for better formalisms and Informatics, dealing with diverse domains of science and technologies. The challenging and fascinating aspects of plasma physics is that it requires a great deal of insight in formulating the relevant design problems, which in turn require ingenuity and flexibility in choosing a particular set of mathematical (and/or experimental) tools to implement them.