Morphology and adhesion on blood components in root surfaces treated by a piezoelectric ultrasonic: an in vitro study

The aim of this study was to evaluate the morphology and adhesion of blood components on root surfaces instrumented with piezoelectric ultrasonic Piezon Master Surgery. Methods 10 teeth were used in this study. The teeth had their proximal divided into four areas that received different treatments: Group 1: untreated control Group 2: scaling with manual instrument; Group 3: scaling with ultrasound; Group 4: Scaling with manual instruments and ultrasound. We obtained 20 samples, 10 of which were used to analyze the morphology and the other 10 were used for analysis of adhesion of blood components. The specimens were analyzed by scanning electron microscopy. Photomicrographs were analyzed by the scores of adhesion of blood components and the index of root morphology. The results were statistically by the Kruskall-Wallis and Mann-Whitney with a significance level of 95%. Results The morphological analysis showed that the Group 1 had a surface unchanged in relation to other groups (Group 1 X Group 2 = 0.0025; Group 1 X Group 3 = 0.0003; Group 1 X Group 4 = 0.0003) and Group 2 presented a smoother surface compared to Group 1 and groups instrumented with ultrasound (Group 2 X Group 3 = 0.0025; Group 2 X Group 4 = 0.0025) there were no statistical differences between the Groups 3 and 4. analysis of adhesion of blood components showed that the Groups 2, 3 and 4 had no statistically significant differences between themselves, but more biocompatible surfaces promoted the surface untreated control (Group 1 X Group 2 = 0.02; Group 1 X Group 3 = 0.04; Group 1 X Group 4 = 0.005). Conclusion The instrumentation with piezoelectric ultrasonic promoted an irregular root surface, but did not negatively affect the adhesion of blood components.

Effect of different periods of preconditioning with saliva on adhesion of C. albicans to a denture base resin by crystal violet staining and XTT assay.

Aim: The role of saliva on Candida adhesion to biomaterials has not been clearly defined. The present study investigates whether different periods of preconditioning with saliva would influence the adhesion of Candida albicans to a denture base resin. Methods: Ninety samples of acrylic resin with smooth surfaces were made and then divided into five groups: one control without saliva, and four experimental groups conditioned in saliva for periods of 30 min, 1, 3, or 12 h. Candida adhesion was evaluated by crystal violet staining and 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-([phenylamino] carbonyl)-2H-tetrazolium-hydroxide assay. Results: The one-way analysis of variance revealed that there were no significant differences among the mean number of adherent cells or among the mean absorbance for all groups. No significant correlation was found between the two methods used for assessing Candida albicans adhesion. Conclusion: The different periods of preconditioning with saliva had no significant influence on the adhesion of Candida albicans to the denture base acrylic resin.

Effect of human whole saliva on the in vitro adhesion of Candida albicans to a denture base acrylic resin: a focus on collection and preparation of saliva samples

Objective In studies on Candida albicans adhesion to surfaces, diverse protocols have been used for collection and preparation of saliva samples. Thus, this study investigated whether variations in the centrifugation parameters and number of donors of saliva would influence the adhesion of C. albicans to a denture base resin. Methods Resin acrylic samples (n = 72) were made and then divided into four groups: (a) control – specimens were left without preconditioning in saliva; (b) three experimental groups, in which the specimens were preconditioned with saliva collected from 15 volunteers and centrifuged at 12 000 g for 5 min (G1); from 15 volunteers and centrifuged at 18 000 g for 30 min (G2); and from one volunteer and centrifuged at 12 000 g for 5 min (G3). Candida adhesion was evaluated by both the 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT) reduction method and crystal violet staining. Data were analyzed by one-way analyses of variance (P = 0.05). Results For XTT reduction assay, groups G2, G3, and control were not significantly different, whereas group G1 showed significantly higher absorbance value than control. For crystal violet staining there were no significant differences among all groups. Conclusion Variations in the centrifugation parameters and number of donors of saliva may influence C. albicans adhesion to denture base resins.

Streptococcus mutans adhesion and releasing of metallic ions in dental alloys

AIM: To evaluate the adherence of Streptococcus mutans to the surface of the amalgam and copper/aluminum alloy samples and also evaluate the release of metallic ions. METHODS: The prepared medium was changed every 72 h and analyzed by atomic absorption spectrophotometer. Samples were removed from the prepared medium at 15, 30, 48 and 60 days. RESULTS: The result shows that ions released were statistically different among all groups, and so were both biofilm and pits formation and the corrosion induced by the S. mutans in both types of samples. SEM observation of the samples immersed in the prepared medium with S. mutans showed adherence of microorganisms on the whole surface, in all groups. CONCLUSIONS: The S. mutans adhere to both amalgam and copper/aluminum alloy causing corrosion of those restorations. S. mutans produced a greater ions release in Cu/Al alloy; in amalgam, the ions release was not influenced by exposure to S. mutans.

Can Application of Universal Primers Alone Be a Substitute for Airborne-Particle Abrasion to Improve Adhesion of Resin Cement to Zirconia?

Purpose: To determine whether universal primers alone can deliver similar levels of adhesion of resin cement to zirconia ceramic when compared to their application in conjunction with airborne-particle abrasion.Materials and Methods: Sintered zirconia blocks (N = 160) (Lava, 3M ESPE), (5.25 x 5.25 x 3 mm(3)) were embedded in acrylic resin, polished, and randomly distributed into 16 groups (n = 10 per group), according to the factors "universal primer" (8 levels) and "air-particle abrasion" (2 levels): 1. ctr: control, without application of a universal primer; 2. AP: Alloy Primer; 3. MP: Monobond Plus; 4. MZP: Metal Zirconia Primer; 5. MZ: MZ Primer; 6. Sg: Signum Zirconia Bond; 7. SbU: Singlebond Universal; 8. ZP: Z Prime Plus. The universal primers were also used after air abrasion (A) of zirconia to form the following 8 groups: Ctr-A, AP-A, MP-A, MZP-A, MZ-A, Sg-A, SbU-A, and ZP-A. After ultrasonic cleaning, air abrasion was performed using Al2O3 particles (110 mu m, 2.5 bar, 20 s at 10 mm) in a chairside air-abrasion device. After ultrasonic cleaning again, universal primers were applied according to each manufacturer's recommendation. The resin cement (RelyX ARC, 3M ESPE) was built up incrementally and photo-polymerized on the zirconia surface using a silicone mold (empty set = 3.5, height = 3 mm). All specimens were stored in distilled water (60 days at 37 degrees C) and then subjected to shear bond strength testing (SBS) in a universal testing machine (1 mm/min). On a separate set of zirconia specimens, contact angle measurements were made using the sessile drop technique with a goniometer after the application of universal primers on control and air-abraded zirconia surfaces. Data (MPa) were analyzed using one-way ANOVA, Tukey's test, and Student's t-test (alpha = 0.05).Results: When universal primers were used alone, SbU presented significantly higher mean SBS (19.5 +/- 5.8) that did the other primers (0 to 9.9 +/- 6.6) (p = 0.001). When air abraded, the groups AP-A (14.1 +/- 6.1), MP-A (15.9 +/- 5.4), ZP-A (16.9 +/- 7.3), SG-A (19.1 +/- 2.1), SbU-A (12 +/- 1.5) showed significant differences (p = 0.03). Adhesive performance of all universal primers was enhanced after air abrasion, with the exception of the SbU and MZ primers. After air abrasion, contact angle measurements were lower for the each primer (without air abrasion: 28.9 to 83.9; with air abrasion: 27.1 to 63.0), except for MZP.Conclusion: Air abrasion with 110 mu m Al2O3 followed by universal primer application increased the bond strength of tested resin cement to zirconia, with the exception of SbU and MZ.

Ground reaction forces during level ground walking with body weight unloading

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

The influence of handrim design on the contact forces on hands'surface: a preliminary study

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Heat treatment of pre-hydrolyzed silane increases adhesion of phosphate monomer-based resin cement to glass ceramic

This study evaluated the influence of different forms of heat treatment on a pre-hydrolyzed silane to improve the adhesion of phosphate monomer-based (MDP) resin cement to glass ceramic. Resin and feldspathic ceramic blocks (n=48, n=6 for bond test, n=2 for microscopy) were randomly divided into 6 groups and subject to surface treatments: G1: Hydrofluoric acid (HF) 9.6% for 20 s + Silane + MDP resin cement (Panavia F); G2: HF 9.6% for 20 s + Silane + Heat Treatment (oven) + Panavia F; G3: Silane + Heat Treatment (oven) + Panavia F; G4: HF 9.6% for 20 s + Silane + Heat Treatment (hot air) + Panavia F; G5: Silane + Heat Treatment (hot air) + Panavia F; G6: Silane + Panavia F. Microtensile bond strength (MTBS) test was performed using a universal testing machine (1 mm/min). After debonding, the substrate and adherent surfaces were analyzed using stereomicroscope and scanning electron microscope (SEM) to categorize the failure types. Data were analyzed statistically using two-way test ANOVA and Tukey's test (=0.05). Heat treatment of the silane containing MDP, with prior etching with HF (G2: 13.15 ± 0.89a; G4: 12.58 ± 1.03a) presented significantly higher bond strength values than the control group (G1: 9.16 ± 0.64b). The groups without prior etching (G3: 10.47 ± 0.70b; G5: 9.47 ± 0.32b) showed statistically similar bond strength values between them and the control group (G1). The silane application without prior etching and heat treatment resulted in the lowest mean bond strength (G6: 8.05 ± 0.37c). SEM analysis showed predominantly adhesive failures and EDS analysis showed common elements of spectra (Si, Na, Al, K, O, C) characterizing the microstructure of the glass-ceramic studied. Heat treatment of the pre-hydrolyzed silane containing MDP in an oven at 100 °C for 2 min or with hot air application at 50 ± 5 ºC for 1 min, was effective in increasing the bond strength values between the ceramic and resin cement containing MDP.

Effect of tyrosol on adhesion of Candida albicans and Candida glabrata to acrylic surfaces

The prevention of adhesion of Candida cells to acrylic surfaces can be regarded as an alternative to prevent denture stomatitis. The use of quorum sensing molecules, such as tyrosol, could potentially interfere with the adhesion process. Therefore, the aim of this study was to assess the effect of tyrosol on adhesion of single and mixed cultures of Candida albicans and Candida glabrata to acrylic resin surfaces. Tyrosol was diluted in each yeast inoculum (10(7) cells/ml in artificial saliva) at 25, 50, 100, and 200 mM. Then, each dilution was added to wells of 24-well plates containing the acrylic specimens, and the plates were incubated at 37°C for 2 h. After, the effect of tyrosol was determined by total biomass quantification, metabolic activity of the cells and colony-forming unit counting. Chlorhexidine gluconate (CHG) was used as a positive control. Data were analyzed using analysis of variance (ANOVA) and the Holm-Sidak post hoc test (α = 0.05). The results of total biomass quantification and metabolic activity revealed that the tyrosol promoted significant reductions (ranging from 22.32 to 86.16%) on single C. albicans and mixed cultures. Moreover, tyrosol at 200 mM and CHG significantly reduced (p < 0.05) the number of adhered cells to the acrylic surface for single and mixed cultures of both species, with reductions ranging from 1.74 to 3.64-log10. In conclusion, tyrosol has an inhibitory effect on Candida adhesion to acrylic resin, and further investigations are warranted to clarify its potential against Candida infections.

Interface tailoring for adhesion enhancement of diamond-like carbon thin films

We have explored the suitability and characteristics of interface tailoring as a tool for enhancing the adhesion of hydrogen-free diamond-like carbon (DLC) thin films to silicon substrates. DLC films were deposited on silicon with and without application of an initial high energy carbon ion bombardment phase that formed a broad Si-C interface of gradually changing Si:C composition. The interface depth profile was calculated using the TRIDYN simulation program, revealing a gradient of carbon concentration including a region with the stoichiometry of silicon carbide. DLC films on silicon, with and without interface tailoring, were characterized using Raman spectroscopy, scanning electron microscopy, atomic force microscopy and scratch tests. The Raman spectroscopy results indicated sp3-type carbon bonding content of up to 80%. Formation of a broadened Si:C interface as formed here significantly enhances the adhesion of DLC films to the underlying silicon substrate. (C) 2012 Elsevier B.V. All rights reserved.

Immune receptors and adhesion molecules in human pulmonary leptospirosis

Pulmonary involvement in leptospirosis has been increasingly reported in the last 20 years, being related to the severity and mortality of the disease. The pathogenesis of pulmonary hemorrhage in leptospirosis is not understood. Lung endothelial cells have been proposed as targets in the pathogenesis of lung involvement in leptospirosis through the activation of Toll-like receptor 2 or the complement system, which stimulates the release of cytokines that lead to the activation of adhesion molecules. The aim of this study was to investigate the involvement of immune pathways and of the intercellular and vascular cell adhesion molecules (intercellular adhesion molecule and vascular cell adhesion molecule, respectively) in the lungs of patients with pulmonary involvement of leptospirosis. We studied the lungs of 18 patients who died of leptospirosis and compared them with 2 groups of controls: normal and noninfectious hemorrhagic lungs. Using immunohistochemistry and image analysis, we quantified the expression of the C3a anaphylatoxin receptor, intercellular adhesion molecule, vascular cell adhesion molecule, and Toll-like receptor 2 in small pulmonary vessels and in the alveolar septa. There was an increased expression of intercellular adhesion molecule (P <.03) and C3a anaphylatoxin receptor (P <.008) in alveolar septa in the leptospirosis group compared with the normal and hemorrhagic controls. In the vessels of the leptospirosis group, there was an increased expression of intercellular adhesion molecule (P=.004), vascular cell adhesion molecule (P=.030), and Toll-like receptor 2 (P=.042) compared with the normal group. Vascular cell adhesion molecule expression in vessels was higher in the leptospirosis group compared with the hemorrhagic group (P=.015). Our results indicate that immune receptors and adhesion molecules participate in the phenomena leading to pulmonary hemorrhage in leptospirosis. (C) 2012 Elsevier Inc. All rights reserved.

Evaluation of rhamnolipid and surfactin to reduce the adhesion and remove biofilms of individual and mixed cultures of food pathogenic bacteria

Biofilms represent a great concern for food industry, since they can be a source of persistent contamination leading to food spoilage and to the transmission of diseases. To avoid the adhesion of bacteria and the formation of biofilms, an alternative is the pre-conditioning of surfaces using biosurfactants, microbial compounds that can modify the physicochemical properties of surfaces changing bacterial interactions and consequently adhesion. Different concentrations of the biosurfactants, surfactin from Bacillus subtilis and rhamnolipids from Pseudomonas aeruginosa, were evaluated to reduce the adhesion and to disrupt biofilms of food-borne pathogenic bacteria. Individual cultures and mixed cultures of Staphylococcus aureus, Listeria monocytogenes and Salmonella Enteritidis were studied using polystyrene as the model surface. The pre-conditioning with surfactin 0.25% reduced by 42.0% the adhesion of L monocytogenes and S. Enteritidis, whereas the treatment using rhamnolipids 1.0% reduced by 57.8% adhesion of L monocytogenes and by 67.8% adhesion of S. aureus to polystyrene.Biosurfactants were less effective to avoid adhesion of mixed cultures of the bacteria when compared with individual cultures. After 2 h contact with surfactin at 0.1% concentration, the pre-formed biofilms of S. aureus were reduced by 63.7%, L. monocytogenesby 95.9%, S. Enteritidis by 35.5% and the mixed culture biofilm by 58.5%. The rhamnolipids at 0.25% concentration removed 58.5% the biofilm of S. aureus, 26.5% of L monocytogenes, 23.0% of S. Enteritidis and 24.0% the mixed culture after 2 h contact. In general, the increase in concentration of biosurfactants and in the time of contact decreased biofilm removal percentage. These results suggest that surfactin and rhamnolipids can be explored to control the attachment and to disrupt biofilms of individual and mixed cultures of the food-borne pathogens. (C) 2011 Elsevier Ltd. All rights reserved.

The influence of "C-factor" and light activation technique on polymerization contraction forces of resin composite

Objectives: This study evaluated the influence of the cavity configuration factor ("C-Factor") and light activation technique on polymerization contraction forces of a Bis-GMA-based composite resin (Charisma, Heraeus Kulzer). Material and Methods: Three different pairs of steel moving bases were connected to a universal testing machine (Emic DL 500): groups A and B - 2x2 mm (CF=0.33), groups C and D - 3x2 mm (CF=0.66), groups E and F - 6x2 mm (CF=1.5). After adjustment of the height between the pair of bases so that the resin had a volume of 12 mm(3) in all groups, the material was inserted and polymerized by two different methods: pulse delay (100 mW/cm(2) for 5 s, 40 s interval, 600 mW/cm(2) for 20 s) and continuous pulse (600 mW/cm(2) for 20 s). Each configuration was light cured with both techniques. Tensions generated during polymerization were recorded by 120 s. The values were expressed in curves (Force(N) x Time(s)) and averages compared by statistical analysis (ANOVA and Tukey's test, p<0.05). Results: For the 2x2 and 3x2 bases, with a reduced C-Factor, significant differences were found between the light curing methods. For 6x2 base, with high C-Factor, the light curing method did not influence the contraction forces of the composite resin. Conclusions: Pulse delay technique can determine less stress on tooth/restoration interface of adhesive restorations only when a reduced C-Factor is present.

Effects of replica running shoes upon external forces and muscle activity during running

Twelve participants ran (9 km . h(-1)) to test two types of running shoes: replica and original shoes. Ground reaction force, plantar pressure and electromyographic activity were recorded. The shoes were tested randomly and on different days. Comparisons between the two experimental conditions were made by analysis of variance (ANOVA) test (P <= 0.05). The time to first peak, loading rate of the first peak and impulse of the first 75 ms of stance were significantly different between the shoes (P <= 0.05), revealing an increase of impact forces for the replica shoes. The peak plantar pressure values were significantly higher (P <= 0.05) when wearing replica shoes. During running, the contact area was significantly smaller (P <= 0.05) for the replica shoe. The electromyographic activity of the analysed muscles did not show changes between the two shoes in running. These findings suggest that the use of replica running shoes can increase the external load applied to the human body, but may not change the muscle activity pattern during locomotion. This new mechanical situation may increase the risk of injuries in these movements.

Focal adhesion kinase governs cardiac concentric hypertrophic growth by activating the AKT and mTOR pathways

The heart responds to sustained overload by hypertrophic growth in which the myocytes distinctly thicken or elongate on increases in systolic or diastolic stress. Though potentially adaptive, hypertrophy itself may predispose to cardiac dysfunction in pathological settings. The mechanisms underlying the diverse morphology and outcomes of hypertrophy are uncertain. Here we used a focal adhesion kinase (FAK) cardiac-specific transgenic mice model (FAK-Tg) to explore the function of this non-receptor tyrosine kinase on the regulation of myocyte growth. FAK-Tg mice displayed a phenocopy of concentric cardiac hypertrophy, reflecting the relative thickening of the individual myocytes. Moreover, FAK-Tg mice showed structural, functional and molecular features of a compensated hypertrophic growth, and preserved responses to chronic pressure overload. Mechanistically, FAK overexpression resulted in enhanced myocardial FAK activity, which was proven by treatment with a selective FAK inhibitor to be required for the cardiac hypertrophy in this model. Our results indicate that upregulation of FAK does not affect the activity of Src/ERK1/2 pathway, but stimulated signaling by a cascade that encompasses PI3K, AKT, mTOR, S6K and rpS6. Moreover, inhibition of the mTOR complex by rapamycin extinguished the cardiac hypertrophy of the transgenic FAK mice. These findings uncover a unique role for FAK in regulating the signaling mechanisms that governs the selective myocyte growth in width, likely controlling the activity of PI3K/AKT/mTOR pathway, and suggest that FAK activation could be important for the adaptive response to increases in cardiac afterload. This article is part of a Special Issue entitled "Local Signaling in Myocytes". (C) 2011 Elsevier Ltd. All rights reserved.