Dynamics of the interaction between body fluid and Ti cp: the influence of surface functionalization in the first stages of osseointegration

INTRODUCTION: Regenerative therapies using biomaterials require accurate information on interactions between the implanted material and the human body. To improve the process of bone regeneration it is necessary to obtain a better understanding of the influence of the surfaces on the early stages of osseointegration. This work aims to investigate the dynamic interaction between simulated body fluid (SBF) and titanium surfaces (Ti cp) immediately after their first contact. METHODS: Ti cp samples were passed through physicochemical treatments after immersion in acid solution, alkaline solution and solutions containing TiO2 and Ca2+, to obtain three different surfaces. These were characterized by electron microscopy and free energy estimates. The evaluation of the interaction with SBF was performed by measuring the dynamic contact angles after contacting the surfaces. RESULTS: The effects of SBF wettability were more significant on surfaces according to high energy estimates. A comparative analysis of the three types of surfaces showed that fluid spreading was greater in samples with greater polar components, indicating that the surface nature influences interactions in the early stages of osseointegration. CONCLUSION: The results indicate the influence of polar interactions in the dynamic wettability of the SBF. It is possible that these interactions can also influence cellular viability on surfaces. Based on these results, new experiments are being designed to improve the presented methodology as a tool for the evaluation of biomaterials without the need for in vivo experiments.

Corn productivity in function of surface application of lime in differents management systems and cultural preparation

The evaluation of technologies employed at the agricultural production system such as crop rotation and soil preparation, both associated with crop-livestock integration, is crucial. Therefore, the aim of the present study was to evaluate the incorporation of lime for three no-tillage systems and cultural managements in system of crop-livestock integration, with emphasis on corn grain yield. The experiment was conducted from January 2003 to April 2005 at Selvíria city, MS, in Dystroferric Red Latosol, clay texture. The experimental design was randomized blocks with split plots consisted of three main treatments, aimed the soil physics conditioning and the incorporation of lime: PD - No-no-tillage; CM - minimum no-tillage, and PC - conventional no-tillage; and of two secondary treatments related to the management: rotation and crop succession, with four replications. Data on agronomic traits of maize were analyzed: plant height, stem diameter, height of the first spike insertion, 100 grains weight and grain yield. The results showed that the maize produced under the system of crop-livestock integration is quite feasible, showing that grain yields are comparable to averages in the region and the different soil physical conditioning and incorporation of lime did not influence the corn yield as well as the cultural managements, rotation and succession, did not affect the maize crop behavior after two years of cultivation.

Effect of bleaching agents and soft drink on titanium surface topography

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

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.

SURFACE ROUGHNESS AND CANDIDA ALBICANS BIOFILM FORMATION ON A RELINE RESIN AFTER LONG-TERM CHEMICAL DISINFECTION AND TOOTHBRUSHING

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

Correlation between pH and surface structural changes on human enamel submitted to different tooth whitening agents

The intense valuation of an esthetic pleasant smile guided the dentistry to bleached tooth due the popularity of whitening treatments. The consequence of it is an increasing interest in searching the effect of peroxides in hard dental tissues. The aim of this work was to analyze qualitatively in vitro the human enamel after three different bleaching treatments: Opalescence PF 10%, White Class 7.5% and Opalescence Xtra Boost 38%, correlating the structural changes in the surface of the enamel with its respective pH. A total of 40 sound human pre-molars were randomly divided into four groups of 10 elements, which had been immersed in artificial saliva during all the experiment. Bleaching protocols followed the recommendations of the respective manufacturers. Each bleached sample and control group were submitted to a scanning electronic microscopy analysis and compared with one another. Bleaching agents used in this experiment had modified the morphologic aspect of the surface of the dental enamel; however, it did not have correlation between the degrees of severity of the alterations and pH. There is a correlation between hydrogen peroxide concentration and changes in the enamel, where G4 showed more severe alterations, followed for G3 and G2.

Surface roughness analysis of dental ceramics treated with hydrofl uoric acid and aluminum oxide jet

The aim of this study was to evaluate the surface roughness of 5 indirect restorative materials treated with hydrofluoric acid to 10%, with aluminum oxide jet and a combination of both. The specimens was prepared with 10 mm in diameter and 2 mm thickness, divided into fi ve groups: (1) Ceromer (CeseadII-Kuraray), (2) Leucite crystals ceramics (IPS EmpressIIIvoclarforcasket), (3) glass ceramic with fluorapatite (IPS D. Sign-Ivoclar), (4) lithium disilicate ceramic (IPS Empress II-Ivoclar restorations), (5) ceramics (Cergogold-Degussa). For all groups were performed the controls, and the surfaces with the 3 types of treatment. For testing roughness used the rugosimeter Taylor/Hobson-Precision, model form tracerSV-C525 high sensitivity. After confi rmation of variance analysis with a signifi cance level of 1% (p < 0.01), there was equality between the average roughness of materials from groups 1, 3 and 5, and the group 2 was different from the others. It was also found that the ceramics of the group 5 behaved similar to group 4. However the lowest average roughness was observed in group 2 ceramic. In the evaluation between the types of treatment, the aluminum oxide jet and associations and blasting with hydrofl uoric acid were similar, and different isolated hydrofl uoric acid, and 3 types of treatment signifi cantly higher than the control group. All treatments promoted superfi cial alterations in all tested materials.

Surface degradation of lithium disilicate ceramic after immersion in acid and fluoride solutions

Purpose: To analyze whether immersion in sodium fluoride (NaF) solutions and/or common acidic beverages (test solutions) would affect the surface roughness or topography of lithium disilicate ceramic. Methods: 220 ceramic discs were divided into four groups, each of which was subdivided into five subgroups (n = 11). Control group discs were immersed in one of four test beverages for 4 hours daily or in artificial saliva for 21 days. Discs in the experimental groups were continuously immersed in 0.05% NaF, 0.2% NaF, or 1.23% acidulated phosphate fluoride (APF) gel for 12, 73, and 48 hours, respectively, followed by immersion in one of the four test beverages or artificial saliva. Vickers microhardness, surface roughness, scanning electron microscopy (SEM) associated with energy dispersive spectroscopy, and atomic force microscopy (AFM) assessments were made. Data were analyzed by nested analysis of variance (ANOVA) and Tukey's test (alpha = 0.05). Results: Immersion in the test solutions diminished the microhardness and increased the surface roughness of the discs. The test beverages promoted a significant reduction in the Vickers microhardness in the 0.05% and 0.2% NaF groups. The highest surface roughness results were observed in the 0.2% NaF and 1.23% APF groups, with similar findings by SEM and AFM. Acidic beverages affected the surface topography of lithium disilicate ceramic. Fluoride treatments may render the ceramic surface more susceptible to the chelating effect of acidic solutions.

Influence of Nd:YAG or Er:YAG laser surface treatment on microtensile bond strength of indirect resin composites to resin cement. Lasers surface treatment of indirect resin composites

This study evaluated the influence of the surface pretreatment of indirect resin composite (Signum, Admira Lab and Sinfony) on the microtensile bond strength of a resin cement. Sixty samples made of each brand were divided into 6 groups, according to surface treatment: (1) control; (2) controlled-air abrasion with Al2O3; (3) Er:YAG Laser 200 mJ, 10 Hz, for 10s; (4) Er: YAG Laser 300 mJ, 10 Hz, for 10 s; (5) Nd:YAG 80 mJ, S15Hz for 1 min; (6) Nd:YAG 120mJ, 15 Hz for 1 min. After treatments, all the groups received an application of 37% phosphoric acid and adhesive. The pair of blocks of the same brand were cemented to each other with dual resin cement. The blocks were sectioned to obtain resin-resin sticks (1 x1 mm) and analyzed by microtensile bond testing. The bond strength values were statistically different, irrespective of the surface treatment performed, with highest values for Sinfony (43.81 MPa) and lowest values for Signum (32.33 MPA). The groups treated with the Nd:YAG laser showed the lowest bond strength values and power did not interfere in the results, both for Nd:YAG laser and Er:YAG. Controlled-air abrasion with Al203 is an efficient surface treatment method and the use of the Nd:YAG and Er:YAG lasers reduced bond strength, irrespective of the intensity of energy used.

Titanium surface topography after brushing with fluoride and fluoride-free toothpaste simulating 10 years of use

Objectives: To conduct a controlled study contrasting titanium surface topography after procedures that simulated 10 years of brushing using toothpastes with or without fluoride. Methods: Commercially pure titanium (cp Ti) and Ti-6Al-4V disks (6 mm circle divide x 4 mm) were mirror-polished and treated according to 6 groups (n = 6) as a function of immersion (I) or brushing (B) using deionised water (W), fluoride-free toothpaste (T) and fluoride toothpaste (FT). Surface topography was evaluated at baseline (pretreatment) and post-treatment, using atomic force microscope in order to obtain three-dimensional images and mean roughness. Specimens submitted to immersion were submerged in the vehicles without brushing. For brushed specimens, procedures were conducted using a linear brushing machine with a soft-bristled toothbrush. Immersion and brushing were performed for 244 h. IFT and BFT samples were analysed under scanning electron microscope with Energy-Dispersive X-ray Spectroscopy (EDS). Pre and post-treatment values were compared using the paired Student T-test (alpha = .05). Intergroup comparisons were conducted using one-way ANOVA with Tukey post-test (alpha = .05). Results: cp Ti mean roughness (in nanometers) comparing pre and post-treatment were: IW, 2.29 +/- 0.55/2.33 +/- 0.17; IT, 2.24 +/- 0.46/2.02 +/- 0.38; IFT, 2.22 +/- 0.53/1.95 +/- 0.36; BW, 2.22 +/- 0.42/3.76 +/- 0.45; BT, 2.27 +/- 0.55/16.05 +/- 3.25; BFT, 2.27 +/- 0.51/22.39 +/- 5.07. Mean roughness (in nanometers) measured in Ti-6Al-4V disks (pre/post-treatment) were: IW, 1.79 +/- 0.25/2.01 +/- 0.25; IT, 1.61 +/- 0.13/1.74 +/- 0.19; IFT, 1.92 +/- 0.39/2.29 +/- 0.51; BW, 2.00 +/- 0.71/2.05 +/- 0.43; BT, 2.37 +/- 0.86/11.17 +/- 2.29; BFT, 1.83 +/- 0.50/15.73 +/- 1.78. No significant differences were seen after immersions (p > .05). Brushing increased the roughness of cp Ti and of Ti-6Al-4V (p < .01); cp Ti had topographic changes after BW, BT and BFT treatments whilst Ti-6Al-4V was significantly different only after BT and BTF. EDS has not detected fluoride or sodium ions on metal surfaces. Conclusions: Exposure to toothpastes (immersion) does not affect titanium per se; their use during brushing affects titanium topography and roughness. The associated effects of toothpaste abrasives and fluorides seem to increase roughness on titanium brushed surfaces. (C) 2012 Elsevier Ltd. All rights reserved.

Reducing Water and Chloride Penetration Through Silicate Treatments for Concrete as a Mean to Control Corrosion Kinetics

There are currently many types of protective materials for reinforced concrete structures and the influence of these materials in the chloride diffusion coefficient and water penetration still needs more research. The aim of this work is to analyze the contributions regarding the typical three surface concrete protection systems (coatings, linings and pore blockers) and discusses the results of three pore blockers (sodium silicate) tested in this work. To this end, certain tests were used: one involving permeability mechanism (low pressure-immersion absorption), one involving capillary water absorption, and the last, a migration test used to estimate the effective chloride diffusion coefficient in saturated condition. Results indicated reduction in chloride diffusion coefficients and capillary water absorption, therefore, restrictions to water penetration from external environmental. As a consequence, a reduction of the corrosion kinetics and a control of the chloride ingress are expected.

CTAB, Triton X-100 and freezing-thawing treatments of Candida guilliermondii: Effects on permeability and accessibility of the glucose-6-phosphate dehydrogenase, xylose reductase and xylitol dehydrogenase enzymes

Cells of Candida guilliermondii (ATCC 201935) were permeabilised with surfactant treatment (CTAB or Triton X-100) or a freezing-thawing procedure. Treatments were monitored by in situ activities of the key enzymes involved in xylose metabolism, that is, glucose-6-phosphate dehydrogenase (G6PD), xylose reductase (XR) and xylitol dehydrogenase (XD). The permeabilising ability of the surfactants was dependent on its concentration and incubation time. The optimum operation conditions for the permeabilisation of C. guilliermondii with surfactants were 0.41 mM (CTAB) or 2.78 mM (Triton X-100), 30 degrees C, and pH 7 at 200 rpm for 50 min. The maximum permeabilisation measured in terms of the in situ G6PD activity observed was, in order, as follows: CTAB (122.4 +/- 15.7 U/g(cells)) > freezing-thawing, , (54.3 +/- 1.9 U/g(cells)) > Triton X-100 (23.5 +/- 0.0 U/g(cells)). These results suggest that CTAB surfactant is more effective in the permeabilisation of C. guilliermondii cells in comparison to the freezing-thawing and Triton X-100 treatments. Nevertheless, freezing-thawing was the only treatment that allowed measurable in situ XR activity. Therefore, freezing-thawing permeabilised yeast cells could be used as a source of xylose reductase for analytical purposes or for use in biotransformation process such as xylitol preparation from xylose. The level of in situ xylose reductase was found to be 13.2 +/- 0.1 U/g(cells).

Effects of cryogenic and stress relief treatments on temper carbide precipitation in AISI D2 tool steel

The effects of cryogenic and stress relief treatments on temper carbide precipitation in the cold work tool steel AISI D2 were studied. For the cryogenic treatment the temperature was −196°C and the holding time was 2, 24 or 30 h. The stress relief heat treatment was carried at 130°C/90 min, when applied. All specimens were compared to a standard thermal cycle. Specimens were studied using metallographic characterisation, X-ray diffraction and thermoelectric power measurements. The metallographic characterisation used SEM (scanning electron microscopy) and SEM-FEG (SEM with field emission gun), besides OM (optical microscopy). No variation in the secondary carbides (micrometre sized) precipitation was found. The temper secondary carbides (nanosized) were found to be more finely dispersed in the matrix of the specimens with cryogenic treatment and without stress relief. The refinement of the temper secondary carbides was attributed to a possible in situ carbide precipitation during tempering.

Influence of HSM cutting parameters on the surface integrity characteristics of hardened AISI H13 steel

The purpose of this study is to evaluate the influence of the cutting parameters of high-speed machining milling on the characteristics of the surface integrity of hardened AISI H13 steel. High-speed machining has been used intensively in the mold and dies industry. The cutting parameters used as input variables were cutting speed (v c), depth of cut (a p), working engagement (a e) and feed per tooth (f z ), while the output variables were three-dimensional (3D) workpiece roughness parameters, surface and cross section microhardness, residual stress and white layer thickness. The subsurface layers were examined by scanning electron and optical microscopy. Cross section hardness was measured with an instrumented microhardness tester. Residual stress was measured by the X-ray diffraction method. From a statistical standpoint (the main effects of the input parameters were evaluated by analysis of variance), working engagement (a e) was the cutting parameter that exerted the strongest effect on most of the 3D roughness parameters. Feed per tooth (f z ) was the most important cutting parameter in cavity formation. Cutting speed (v c) and depth of cut (a p) did not significantly affect the 3D roughness parameters. Cutting speed showed the strongest influence on residual stress, while depth of cut exerted the strongest effect on the formation of white layer and on the increase in surface hardness.

Innovative treatments for shelf-life extension of whole and fresh-cut fruit

Maintaining the postharvest quality of whole and fresh-cut fruit during storage and distribution is the major challenge facing fruit industry. For this purpose, industry adopt a wide range of technologies to enable extended shelf-life. Many factors can lead to loss of quality in fresh product, hence the common description of these products as ‘perishable’. As a consequence normal factors such as transpiration and respiration lead ultimately to water loss and senescence of the product. Fruits and vegetables are living commodities and their rate of respiration is of key importance to maintenance of quality. It has been commonly observed that the greater the respiration rate of a product, the shorter the shelf-life. The principal problem for fresh-cut fruit industries is the relative shorter shelf-life of minimally processed fruit (MPF) compared to intact product. This fact is strictly connected with the higher ethylene production of fruit tissue stimulated during fresh-cut processing (peeling, cutting, dipping). 1-Methylcyclopropene (1-MCP) is an inhibitor of ethylene action and several researches have shown its effectiveness on the inhibition of ripening and senescence incidence for intact fruit and consequently on their shelf-life extension. More recently 1-MCP treatment has been tested also for shelf-life extension of MPF but discordant results have been obtained. Considering that in some countries 1-MCP is already a commercial product registered for the use on a number of horticultural products, the main aim of this actual study was to enhance our understanding on the effects of 1-MCP treatment on the quality maintenance of whole and fresh-cut climacteric and non-climacteric fruit (apple, kiwifruit and pineapple). Concerning the effects of 1-MCP on whole fruit, was investigated the effects of a semi-commercial postharvest treatment with 1-MCP on the quality of Pink Lady apples as functions of fruit ripening stage, 1-MCP dose, storage time and also in combination with controlled atmospheres storage in order to better understand what is the relationship among these parameters and if is possible to maximize the 1-MCP treatment to meet the market/consumer needs and then in order to put in the market excellent fruit. To achieve this purpose an incomplete three-level three-factor design was adopted. During the storage were monitored several quality parameters: firmness, ripening index, ethylene and carbon dioxide production and were also performed a sensory evaluations after 6 month of storage. In this study the higher retention of firmness (at the end of storage) was achieved by applying the greatest 1-MCP concentration to fruits with the lowest maturity stage. This finding means that in these semi-commercial conditions we may considerate completely blocked the fruit softening. 1-MCP was able to delay also the ethylene and CO2 production and the maturity parameters (soluble solids content and total acidity). Only in some cases 1-MCP generate a synergistic effect with the CA storage. The results of sensory analyses indicated that, the 1-MCP treatment did not affect the sweetness and whole fruit flavour while had a little effect on the decreasing cut fruit flavour. On the contrary the treated apple was more sour, crisp, firm and juicy. The effects of some treatment (dipping and MAP) on the nutrient stability were also investigated showing that in this case study the adopted treatments did not have drastic effects on the antioxidant compounds on the contrary the dipping may enhance the total antioxidant activity by the accumulation of ascorbic acid on the apple cut surface. Results concerning the effects of 1-MCP in combination with MAP on the quality parameters behaviour of the kiwifruit were not always consistent and clear: in terms of colour maintenance, it seemed to have a synergistic effect with N2O MAP; as far as ripening index is concerned, 1-MCP had a preservative effect, but just for sample packed in air.