Encapsulation of titanium (IV) silsesquioxane into the NH4USY zeolite: Preparation, characterization and application

This work describes the encapsulation of titanium (IV) silsesquioxane into the supercavities of NH4USY ultra stabilized zeolite, after chemical treatment. The modified zeolite was characterized by Fourier transform infrared spectra, Nuclear magnetic resonance, scanning electronic microscopy, X-ray diffraction and thermogravity. This encapsulated titanium (IV) silsesquioxane can adsorb Azure A chloride after treatment with H3PO4, without modifier leaching problems. In an electrochemical study, the cyclic voltammograms of the graphite paste modified electrode, shows two redox couples with formal potential (E-0) -0. 1 V and 0.21 V to I and II redox couples respectively (v = 700 mV s(-1); Britton Robinson buffer (B-R) solution, pH 3) versus SCE ascribed to a monomer and dimmer of azure. This paper shows the use of ultra stabilized zeolite in the electrochemical field as host for molecules with nanometric dimensions. (c) 2006 Elsevier Ltd. All rights reserved.

Voltammetric studies of titanium (IV) phosphate modified with copper hexacyanoferrate and electroanalytical determination of N-acetylcysteine

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

Voltammetric Studies of Cobalt Hexacyanoferrate Formed on the Titanium (IV) Phosphate Surface and its Application to the Determination of Sulfite

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

Preparation and Voltammetric Studies of Titanium (IV) Phosphate Modified with Silver Hexacyanoferrate to a Voltammetric Determination of L-Cysteine

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

Analyse titanium surface irradiated with laser, with and without deposited of durapatite

OBJETIVO: Estudar a superfície de implantes osseointegráveis utilizando discos de titânio irradiados com feixe de laser. MÉTODOS: A amostra foi irradiada com feixes de laser de alta intensidade (Nd-YAG), posteriormente depositado hidróxiapatita e submetido a tratamento térmico. Foi analisada sob MEV (Microscópio Eletrônico de Varredura) e realizada análise morfológica qualitativa com microfotografias em vários aumentos. RESULTADOS: A superfície irradiada com laser apresentou deformidade superficial e característica isomórfica; a aplicação de hidroxiapatita pelo método de biomimético aumentou quantitativamente a área da superfície de titânio. CONCLUSÃO: A deposição de hidroxiapatita apresentou melhor característica isomórfica e aumento quantitativo da área superficial estudada, a amostra demonstrou características não encontradas nos implantes disposto no mercado.

Surface and Biomechanical Study of Titanium Implants Modified by Laser With and Without Hydroxyapatite Coating, in Rabbits

Surface and biomechanical analysis of titanium implant surfaces modified by laser beam with and without hydroxyapatite. Titanium implants with 3 different surfaces were inserted into the tibias of 30 rabbits: group I (GI) machined surface (control group), group II irradiated with laser (GII), and group III irradiated with laser and hydroxyapatite coating applied-biomimetic method (GIII). Topographical analysis with scanning electron microscopy was made before surgery in the tibia. These rabbits were distributed into 2 periods of observation: 4 and 8 weeks postsurgery, after which biomechanical analysis (removal torque) was conducted. Statistical analysis used the Student-Newman-Keuls method. Surface showed roughness in GII and GIII. Biomechanical analysis demonstrated values with significant differences in GII and GIII. Titanium implants modified by laser irradiation can increase osseointegration during the initial phase.

Anterior Tooth Rehabilitation With Frozen Homogenous Bone Graft and Immediately Loaded Titanium Implant Using Computer-Guided Surgery

Computed tomographic scanning is a precise, noinvasive surveying technique that enables the professionals to improve the precision of implant placement by building a prototype that allows the confection of surgical guides. The authors present a clinical case of anterior tooth rehabilitation with frozen homogenous bone graft and immediately loaded titanium implant using computer-guided surgery. A multislice computed tomography was realized, and a prototype was built. All the procedures were previously realized in the prototype before started in the patient. This technique allows a better surgical planning, makes the procedures more accurate, and reduces surgery time.

Effect of 4% titanium tetrafluoride solution on the erosion of permanent and deciduous human enamel: an in situ/ex vivo study

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Effect of a 4% titanium tetrafluoride (TiF4) varnish on demineralisation and remineralisation of bovine enamel in vitro

Objectives: This in vitro study assessed the effect of a 4% TiF4 varnish on demineralisation and remineralisation of sound enamel and artificial carious enamel lesions, respectively.Methods: Bovine sound and carious enamel (n = 110) were randomly allocated to each type of varnish: Duraphat (R))-D (NaF, 2.26%F, pH 4.5, Colgate-Brazil, n = 30), Duofluorid (R)-F (NaF, 2.71%F, pH 8.0, FGM-Brazil, n = 30), TiF4-T (2.45%F, pH 1.0, FGM-Brazil, n = 30) and no-fluoride-P (FGM-Brazil, pH 5.0, n = 20). For the formation of artificial enamel caries, half of the blocks were immersed in 32 mL buffer acetate solution (16 h), whereas the other half was maintained sound. The varnishes were applied onto the enamel surfaces. Thus, the samples were subjected to pH cycles (37 degrees C) for 7 days. The response variables tested were surface and cross-sectional hardness. Data were tested using Kruskal-Wallis test (p < 0.05).Results: All F varnishes significantly reduced demineralisation and increased remineralisation in comparison to placebo. The TiF4 did not significantly reduce the surface enamel softening when compared with the other F varnishes, but it decreased the loss of subsurface hardness to the same extent. In enamel blocks with previous artificial carious lesions, the TiF4 significantly improved the rehardening compared to the other varnishes up to 30 mu m depth.Conclusions: The TiF4 varnish was able to decrease the demineralisation and increase the remineralisation of previously sound and carious enamel, respectively. It was equally effective compared to NaF varnishes on reducing the demineralisation at subsurface, but it was more effective on improving the remineralisation at surface and subsurface. (c) 2007 Elsevier Ltd. All rights reserved.

Force system evaluation of symmetrical beta-titanium T-loop springs preactivated by curvature and concentrated bends

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Analysis of failed commercially pure titanium dental implants: A scanning electron microscopy and energy-dispersive spectrometer X-ray study

Background: the failure of osseointegration in oral rehabilitation has gained importance in current literature and in clinical practice. The integration of titanium dental implants in alveolar bone has been partly ascribed to the biocompatibility of the implant surface oxide layer. The aim of this investigation was to analyze the surface topography and composition of failed titanium dental implants in order to determine possible causes of failure.Methods: Twenty-one commercially pure titanium (cpTi) implants were retrieved from 16 patients (mean age of 50.33 +/- 11.81 years). Fourteen implants were retrieved before loading (early failures), six after loading (late failures), and one because of mandibular canal damage. The failure criterion was lack of osseointegration characterized as dental implant mobility. Two unused implants were used as a control group. All implant surfaces were examined by scanning electron microscopy (SEM) and energy-dispersive spectrometer x-ray (EDS) to element analysis. Evaluations were performed on several locations of the same implant.Results: SEM showed that the surface of all retrieved implants consisted of different degrees of organic residues, appearing mainly as dark stains. The surface topography presented as grooves and ridges along the machined surface similar to control group. Overall, foreign elements such as carbon, oxygen, sodium, calcium, silicon, and aluminum were detected in failed implants. The implants from control group presented no macroscopic contamination and clear signs of titanium.Conclusion: These preliminary results do not suggest any material-related cause for implant failures, although different element composition was assessed between failed implants and control implants.

The Effect of Coating Patterns with Spinel-Based Investment on the Castability and Porosity of Titanium Cast into Three Phosphate-Bonded Investments

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Fatigue and Fluoride Corrosion on Streptococcus mutans Adherence to Titanium-Based Implant/Component Surfaces

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The effect of oestrogen and alendronate therapies on postmenopausal bone loss around osseointegrated titanium implants

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Homeopathic Symphytum officinale increases removal torque and radiographic bone density around titanium implants in rats

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