A new calcium silicate-based material (Biodentine) for filling radicular perforation in an endodontic-periodontal lesion: a case report

This case report presents an apical radicular perforation management using new calcium silicate-based cement (Biodentine) in a combined endodontic-periodontal lesion. The presence of apical radicular perforation may interfere in the endodontic treatment prognosis. Radicular perforation filling with bioactive cement through endodontic surgery is a possible treatment. This study presents an apical radicular perforation with periodontal involvement, due to alveolar bone loss on the buccal radicular surface from an incorrect intracanal preparation for the fiber post placing. The chosen alternative was a periapical surgery, the perforation was filled with a silicate and calcium chloride bioactive cement (Biodentine; Septodont, Saint-Maur-des-Fosses Cedex, France), and the radicular surface was etched with citric acid, because the access from root canal was impossible. The follow-up was for 8 months, through clinical and radiographic analysis. At the end of the follow-up, radiographic analyses showed the bone healing, and no clinical changes in periodontal probing depth, gingival recession, and the height of the interproximal mesial and distal papillae were observed. The root perforation treatment has a difficult management, especially when the dental root has a simultaneous periodontal commitment. The Biodentine proves to be a promising material for use in these situations.

Calcium silicate-based cements associated with micro-and nanoparticle radiopacifiers: physicochemical properties and bioactivity

The aim of this study was to evaluate the physicochemical properties and bioactivity of two formulations of calcium silicate-based cements containing additives (CSCM) or resin (CSCR), associated with radiopacifying agents zirconium oxide (ZrO2) and niobium oxide (Nb2O5) as micro- and nanoparticles; calcium tungstate (CaWO4); and bismuth oxide (Bi2O3). MTA Angelus was used as control. Methods. Surface features and bioactivity were evaluated by scanning electron microscopy and the chemical composition by energy dispersive X-ray spectrometry (EDS-X). Results. CSCM and CSCR presented larger particle sizes than MTA. Hydroxyapatite deposits were found on the surface of some materials, especially when associated with the radiopacifier with ZrO2 nanoparticles. All the cements presented calcium, silicon, and aluminum in their composition. Conclusion. Both calcium silicate-based cements presented composition and bioactivity similar to MTA when associated with the radiopacifiers evaluated.

Niobium pentoxide as radiopacifying agent of calcium silicate-based material: evaluation of physicochemical and biological properties

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Understanding growth mechanisms and tribocorrosion behaviour of porous TiO2 anodic films containing calcium, phosphorous and magnesium

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A novel gastroretentive floating system for zidovudine, based on calcium-silicate beads

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

Dinâmica populacional de insetos fitófagos e predadores em cana-de-açúcar sob aplicação de silício

Pós-graduação em Agronomia (Entomologia Agrícola) - FCAV

Estudo da reação de dissolução de serpentinitos brasileiros para uso em processo de captura de carbono

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Increased Risk of Chronic Wasting Disease in Rocky Mountain Elk Associated With Decreased Magnesium and Increased Manganese in Brain Tissue

Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy (TSE) of Rocky Mountain elk in North America. Recent studies suggest that tissue and blood mineral levels may be valuable in assessing TSE infection in sheep and cattle. The objectives of this study were to examine baseline levels of copper, manganese, magnesium, zinc, selenium, and molybdenum in the brains of Rocky Mountain elk with differing prion genotypes and to assess the association of mineral levels with CWD infection. Elk with leucine at prion position 132 had significantly lower magnesium levels than elk with 2 copies of methionine. Chronic wasting disease-positive elk had significantly lower magnesium than control elk. The incorporation of manganese levels in addition to magnesium significantly refined explanatory ability, even though manganese alone was not significantly associated with CWD. This study demonstrated that mineral analysis may provide an additional disease correlate for assessing CWD risk, particularly in conjunction with genotype.

Mejillonesite, a new acid sodium, magnesium phosphate mineral, from Mejillones, Antofagasta, Chile

Mejillonesite, ideally NaMg(2)(PO(3)OH)(PO(4))(OH)center dot H(5)O(2), is a new mineral approved by the CNMNC (IMA 2010-068). It occurs as isolated crystal aggregates in thin zones in fine-grained opal-zeolite aggregate on the north slope of Cerro Mejillones, Antofagasta, Chile. Closely associated minerals are bobierrite, opal, clinoptilolite-Na, clinoptilolite-K, and gypsum. Mejillonesite forms orthorhombic, prismatic, and elongated thick tabular crystals up to 6 mm long, usually intergrown in radiating aggregates. The dominant form is pinacoid {100}. Prisms {hk0}, {h0l}, and {0kl} are also observed. The crystals are colorless, their streak is white, and the luster is vitreous. The mineral is transparent. It is non-fluorescent under ultraviolet light. Mohs' hardness is 4, tenacity is brittle. Cleavage is perfect on {100}, good on {010} and {001}, and fracture is stepped. The measured density is 2.36(1) g/cm(3); the calculated density is 2.367 g/cm(3). Mejillonesite is biaxial (-), alpha= 1.507(2), beta= 1.531(2), gamma= 1.531(2), 2V(meas) = 15(10)degrees, 2V(calc) = 0 degrees (589 nm). Orientation is X= a, Z= elongation direction. The mineral is non-pleochroic. Dispersion is r> v, medium. The IR spectrum contains characteristic bands of the Zundel cation (H(5)O(2)(+), or H(+)center dot 2H(2)O) and the groups P-OH and OH(-). The chemical composition is (by EDS, H(2)O by the Alimarin method, wt%): Na(2)O 9.19, MgO 26.82, P(2)O(5) 46.87, H(2)O 19, total 101.88. The empirical formula, based on 11 oxygen atoms, is Na(0.93)Mg(2.08)(PO(3)OH)(1.00) (PO(4)) (OH)(0.86) .0.95H(5)O(2) The strongest eight X-ray powder-diffraction lines [d in angstrom(I)(hkl)] are: 8.095(100)(200), 6.846(9) (210), 6.470(8)(111), 3.317(5)(302), 2.959(5)(132), 2.706(12)(113), 2.157(19)(333), and 2.153(9) (622). The crystal structure was solved on a single crystal (R = 0.055) and gave the following data: orthorhombic, Pbca, a = 16.295(1), b = 13.009(2), c = 8.434(1) angstrom, V= 1787.9(4) angstrom(3), Z = 8. The crystal structure of mejillonesite is based on a sheet (parallel to the b-c plane) formed by two types of MgO(6) octahedra, isolated tetrahedra PO(4) and PO(3)OH whose apical vertices have different orientation with respect to the sheet. The sheets are connected by interlayer, 5-coordinated sodium ions, proton hydration complexes, and hydroxyl groups. The structure of mejillonesite is related to that of angarfite, NaFe(5)(3+)(PO(4))(4)(OH)(4).4H(2)O and bakhchisaraitsevite, Na(2)Mg(5)(PO(4))(4)center dot 7H(2)O.

Effect of potassium silicate on epidemic components of powdery mildew on melon

The effects of silicon (Si) supplied in the form of potassium silicate (PS) were evaluated on epidemic components of powdery mildew of melon under greenhouse conditions. The PS was applied to the roots or to leaves. In the first experiment, epidemic components were evaluated after inoculation with Podosphaera xanthii. In the second experiment, the disease progress rate was evaluated on plants subjected to natural infection. The area under the disease progress curve was reduced by 65% and 73% in the foliar and root treatments, respectively, compared to control plants, as a consequence of reductions in infection efficiency, colony expansion rate, colony area, conidial production and disease progress rate. However, root application of PS was more effective than foliar application in reducing most of the epidemic components, except for infection efficiency. This can be explained by the high Si concentration in leaf tissues with root application, in contrast to the foliar treatment where Si was only deposited on the external leaf surfaces. The effects of PS reported in this study demonstrated that powdery mildew of melon can be controlled, and that the best results can be achieved when PS is supplied to the roots.

Efficacy of Cosmetic Formulations Containing Dispersion of Liposome with Magnesium Ascorbyl Phosphate, Alpha-Lipoic Acid and Kinetin

The present study aimed to evaluate the photoprotective effects of cosmetic formulations containing a dispersion of liposome with magnesium ascorbyl phosphate (MAP), alpha-lipoic acid (ALA) and kinetin, as well as their effects on the hydration and viscoelastic skin properties. The photoprotection was determined in vitro (antioxidant activity) and in vivo on UV-irradiated hairless mouse skin. The hydration effects were performed with the application of the formulations under study on the forearm of human volunteers and skin conditions were analyzed before and after a single application and daily applications during 4 weeks in terms of transepidermal water loss (TEWL), skin moisture and viscoelastic properties. The raw material under study possessed free-radical scavenging activity and the formulation with it protected hairless mouse skin barrier function against UV damage. After 4 weeks of application on human skin, the formulation under study enhanced stratum corneum skin moisture and also showed hydration effects in deeper layers of the skin. Thus, it can be concluded that the cosmetic formulation containing a dispersion of liposome with MAP, ALA and kinetin under study showed photoprotective effects in skin barrier function as well as pronounced hydration effects on human skin, which suggests that this dispersion has potential antiaging effects.

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.

Electrical conductivity of silicate glasses with tetravalent cations substituting Si

The effects of substituting Si by M4+ cations in soda-lime silica glasses were analyzed by impedance spectroscopy in the frequency range of 1 Hz-1 MHz. The glass composition was (mol%) 22Na(2)O center dot 8CaO center dot 65SiO(2)center dot 5MO(2), M = Si, Ti, Ge, Zr, Sn, and Ce. Although the Na+ concentration in the glasses is constant, the Zr-containing glass exhibits the highest dc conductivity and the lowest activation energy, while the Ce-containing glass exhibits the lowest conductivity. The activation energies obtained experimentally agree with those obtained by a theoretical equation proposed by Anderson and Stuart. The differences in electrical conductivity presented by the several M-containing glasses are attributed to the effect that the M4+ ion has on the mobility of the diffusing Na+ ion. (C) 2012 Elsevier B.V. All rights reserved.

Changes in the surface of four calcium silicate-containing endodontic materials and an epoxy resin-based sealer after a solubility test

Aim To compare the changes in the surface structure and elemental distribution, as well as the percentage of ion release, of four calcium silicate-containing endodontic materials with a well-established epoxy resin-based sealer, submitted to a solubility test. Methodology Solubility of AH Plus, iRoot SP, MTA Fillapex, Sealapex and MTA-Angelus (MTA-A) was tested according to ANSI/ADA Specification 57. The deionized water used in the solubility test was submitted to atomic absorption spectrophotometry to determine and quantify Ca2+, Na+, K+, Zn2+, Ni2+ and Pb2+ ions release. In addition, the outer and inner surfaces of nonsubmitted and submitted samples of each material to the solubility test were analysed by means of scanning electron microscopy and energy-dispersive spectroscopy (SEM/EDX). Statistical analysis was performed by using one-way anova and Tukeys post hoc tests (a = 0.05). Results Solubility results, in percentage, sorted in an increasing order were -1.24 +/- 0.19 (MTA-A), 0.28 +/- 0.08 (AH Plus), 5.65 +/- 0.80 (Sealapex), 14.89 +/- 0.73 (MTA Fillapex) and 20.64 +/- 1.42 (iRoot SP). AH Plus and MTA-A were statistically similar (P > 0.05), but different from the other materials (P < 0.05). High levels of Ca2+ ion release were observed in all groups except AH Plus sealer. MTA-A also had the highest release of Na2+ and K+ ions. Zn+2 ion release was observed only with AH Plus and Sealapex sealers. After the solubility test, all surfaces had morphological changes. The loss of matrix was evident and the filler particles were more distinguishable. EDX analysis displayed high levels of calcium and carbon at the surface of Sealapex, MTA Fillapex and iRoot SP. Conclusions AH Plus and MTA-A were in accordance with ANSI/ADAs requirements regarding solubility whilst iRoot SP, MTA Fillapex and Sealapex did not fulfil ANSI/ADAs protocols. High levels of Ca2+ ion release were observed in all materials except AH Plus. SEM/EDX analysis revealed that all samples had morphological changes in both outer and inner surfaces after the solubility test. High levels of calcium and carbon were also observed at the surface of all materials except AH Plus and MTA-A.

Use of Chlorine to Remove Magnesium from Molten Aluminum

Removal of Mg from aluminum scraps, known as demagging, has been widely applied in the,aluminum industry. This work discusses bubble-formation theories and magnesium kinetic removal from aluminum scraps using chlorine and inert gas fluxing. The interfacial area of the bubbles and residence time were estimated using a mathematical model. To inject gaseous chlorine, three types of nozzles were used with varying internal diameter. In addition, a porous plug, as well as varying input chlorine flow and concentration were used. The use of lower chlorine concentration improves efficiency because the interfacial tension is reduced therefore, more and smaller bubbles are formed. The model proposed herein is consistent with the experimental data. [doi:10.2320/matertrans.M2011256]