Avaliação dos fatores críticos para a seleção e aplicação clínica dos pinos de fibra: relato de caso cliínico

Teeth that have lost much of their coronal tooth structure need intraradical devices to achieve a desired retention of the restorative material, restoring aesthetics and function to the patient. For this purpose, various types of intracanal posts have been studied, of wich the fiber posts have been highlighted with its increasing use in the dental market. The purpose of this study was to present a clinical case of using fiberglass post. As well as critically analyze the published works and points of controversy described by different authors related to factors such as different protocols cementation, surface treatments pins, fracture toughness and compression, the possibility of microleakage, diameter and length of the pin, and the various materials used in conjunction with the intracanal retainers. Thus, we concluded that fiber posts showed as an excellent alternative for anterior teeth, since have least 2 mm of tooth remaining.

Tratamento de superfície de implantes dentários: SBF

Various surface treatments of dental implants have been developed in order to ensure anchorage to bone tissue, optimization of the determinants of electronic structure, crystallinity, composition and properties. Coating techniques have been proposed in order tocreate unionbiochemicalable to accelerate the early stages ofbone tissue, combining the positive properties of titanium and its alloys bioactivity of ceramic materials. This paper discusses protocol for handling the SBF coating of titanium alloys. The apatite phase nucleation occurs by immersing the substrate in synthetic solution simulating blood plasma (Simulated Body Fluid). The protocol allows manipulation of the SBF solution to establish guidelines regarding the usestreamlinedand organized to make practical application.

Resistência à fadiga de infraestruturas de zircônia: influência da estratégia de cimentação

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

Reparo ósseo em scaffolds de TI6AL4V sinterizados pela tecnologia de sinterização direta de metais a laser (DMLS) submetidos a tratamento de superfície associado à aplicação de ultrassom de baixa intensidade (LIPUS)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação da resistência de união de reparos em resinas compostas convencionais e bulkfill

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caracterização da liga Ti-30Ta após tratamento biomimético associado à incorporação de antibiótico

Surface treatments have been used to modify the surface of titanium alloys. The purpose of this study is to evaluate the surface of Ti-30Ta alloy after biomimetic approach associated to antibiotic incorporation. The ingots were obtained in arc melting furnace, treated and cold-worked by swaging. The surface treatment was performed in two steps: biomimetic treatment and antibiotic incorporation. For biomimetic treatment, first an alkaline treatment (NaOH 1M at 60ºC) was performed, followed by heat treatment and immersion in SBFx5 (Simulated Body Fluid) for a period of 24 hours. In order to incorporate the antibiotic, samples were immersed in a solution formed by drugs plus SBFx5 for 48 hours. The sample surfaces were analyzed by scanning electron microscopy (SEM), X-Ray diffraction (XRD), atomic force microscopy (AFM) and contact angle measurements. The release of antibiotic from coated implants was measured in phosphate buffer saline at pH 7.4 by using UV/VIS spectrometry. Results have shown changes on the surface after incorporating the drug, which is gradually co-precipitated with the Ca-P crystals, forming a uniform and rough layer on the metal surface

Caracterização da liga Ti-30Ta após tratamento biomimético associado à incorporação de antibiótico

Surface treatments have been used to modify the surface of titanium alloys. The purpose of this study is to evaluate the surface of Ti-30Ta alloy after biomimetic approach associated to antibiotic incorporation. The ingots were obtained in arc melting furnace, treated and cold-worked by swaging. The surface treatment was performed in two steps: biomimetic treatment and antibiotic incorporation. For biomimetic treatment, first an alkaline treatment (NaOH 1M at 60ºC) was performed, followed by heat treatment and immersion in SBFx5 (Simulated Body Fluid) for a period of 24 hours. In order to incorporate the antibiotic, samples were immersed in a solution formed by drugs plus SBFx5 for 48 hours. The sample surfaces were analyzed by scanning electron microscopy (SEM), X-Ray diffraction (XRD), atomic force microscopy (AFM) and contact angle measurements. The release of antibiotic from coated implants was measured in phosphate buffer saline at pH 7.4 by using UV/VIS spectrometry. Results have shown changes on the surface after incorporating the drug, which is gradually co-precipitated with the Ca-P crystals, forming a uniform and rough layer on the metal surface

In Situ Effect of Dentifrices Associated to CO2 Laser in the Permeability of Eroded Root Dentin

Objective: The aim of this study was to evaluate, through a crossover 2 x 2 in situ trial, the effect of a desensitizing dentifrice associated with CO2 laser irradiation to control the permeability of eroded root dentin. Background data: Facing the increased prevalence of erosive lesion and the need for preventive means to control painful symptoms related to them. Methods: Eighty slabs of bovine root dentin were subjected to initial erosive challenge (citric acid 0.3%, 2 h), followed by a remineralizing period in artificial saliva (24 h). Specimens were then divided according to dentin treatment: desensitizing dentifrice, desensitizing dentifrice + CO2 laser, fluoride anticavity dentifrice. and fluoride anticavity dentifrice + CO2 laser. After a 2-day lead-in period, 10 volunteers wore an intraoral palatal appliance containing four root dentin slabs, in two phases of 5 days each. During the intraoral phase, one side of the appliance was immersed in 0.3% citric acid, and the opposite side was immersed in deionized water, four times a day. One hour after the immersions, all specimens were brushed with dentifrice slurry provided by the researcher. After a 7-day washout period, volunteers were crossed over on the different dentifrice group. Each phase having been completed, the specimens were evaluated for permeability through an optical microscope. Results: Data were analyzed using ANOVA and no significant difference (p = 0.272) was found between the surface treatments performed on bovine root dentin. Conclusions: It can be concluded that fluoride anticavity or desensitizing dentifrice, regardless of the association with the CO2 laser irradiation, was able to control the permeability of eroded root dentin.

Effect of Nitrogen Ion Implantation on the Flexibility of Rotary Nickel-Titanium Instruments

Introduction: The aim of this study was to assess the effect of nitrogen ion implantation on the flexibility of rotary nickel-titanium (NiTi) instruments as measured by the load required to bend implanted and nonimplanted instruments at a 30 degrees angle. Methods: Thirty K3 files, size #40, 0.02 taper and 25-mm length, were allocated into 2 groups as follows: group A, 15 files exposed to nitrogen ion implantation at a dose of 2.5 x 10(17) ions/cm(2), voltage 200 KeV, current density 1 mu A/cm(2), temperature 130 degrees C, and vacuum conditions of 10 x 10(-6) mm Hg for 6 hours; and group B, 15 nonimplanted files. One extra file was used for process control. All instruments were subjected to bend testing on a modified troptometer, with measurement of the load required for flexure to an angle of 30 degrees. The Mann-Whitney U test was used for statistical analysis. Findings with P <.05 were considered significant. Results: The mean load required to bend instruments at a 30 degrees angle was 376.26 g for implanted instruments and 383.78 g for nonimplanted instruments. The difference was not statistically significant. Conclusions: Our findings show that nitrogen ion implantation has no appreciable effect on the flexibility of NiTi instruments. (J Endod 2012;38:673-675)

Titanium surfaces with nanotopography modulate cytokine production in cultured human gingival fibroblasts

Implant topography is an important factor that influences many cell types. To understand the role of topography in the inflammatory events, we evaluated the response of human gingival fibroblasts (HGFs) by the release pattern of cytokines. HGFs were cultured on Ti discs for 24 and 48 h. Four different surface treatments were used: machining method (turned), blasting followed by an acid-etching method (BAE), oxidative nanopatterning (ON) method, and an association of blasting followed by an acid-etching plus oxidative nanopatterning (BAE+ON) method. Extracellular levels of IL-6, IL-8, transforming growth factor beta (TGF-beta), IL-4, and IL-10 were measured by enzyme-linked immunosorbant assay. Increased levels of IL-6 and IL-8 were observed in all surfaces after 24 h which decreased after 48 h. BAE, ON, and BAE+ON surfaces showed a reduction in IL-6 levels compared with the turned after 48 h (p < 0.05). On one hand, IL-8 production was lower in BAE+ON in comparison to the turned surface (p < 0.05). On the other hand, IL-4 showed increased levels with 48 h, which were significantly different between turned, BAE, and ON surfaces, but not with BAE+ON. Additionally, TGF-beta and IL-10 production were not detected. This study indicates that nanotopography might be important in the modulation of the inflammatory response in cultured HGFs. (c) 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A 100A:2629-2636, 2012.

Microtensile bond strength of composite resin to glass-infiltrated alumina composite conditioned with Er,Cr:YSGG laser

Tribochemical silica-coating is the recommended conditioning method for improving glass-infiltrated alumina composite adhesion to resin cement. High-intensity lasers have been considered as an alternative for this purpose. This study evaluated the morphological effects of Er,Cr:YSGG laser irradiation on aluminous ceramic, and verified the microtensile bond strength of composite resin to ceramic following silica coating or laser irradiation. In-Ceram Alumina ceramic blocks were polished, submitted to airborne particle abrasion (110 mu m Al(2)O(3)), and conditioned with: (CG) tribochemical silica coating (110 mu m SiO(2)) + silanization (control group); (L1-L10) Er,Cr:YSGG laser (2.78 mu m, 20 Hz, 0.5 to 5.0 W) + silanization. Composite resin blocks were cemented to the ceramic blocks with resin cement. These sets were stored in 37A degrees C distilled water (24 h), embedded in acrylic resin, and sectioned to produce bar specimens that were submitted to microtensile testing. Bond strength values (MPa) were statistically analyzed (alpha a parts per thousand currency sign0.05), and failure modes were determined. Additional ceramic blocks were conditioned for qualitative analysis of the topography under SEM. There were no significant differences among silicatization and laser treatments (p > 0.05). Microtensile bond strength ranged from 19.2 to 27.9 MPa, and coefficients of variation ranged from 30 to 55%. Mixed failure of adhesive interface was predominant in all groups (75-96%). No chromatic alteration, cracks or melting were observed after laser irradiation with all parameters tested. Surface conditioning of glass-infiltrated alumina composite with Er,Cr:YSGG laser should be considered an innovative alternative for promoting adhesion of ceramics to resin cement, since it resulted in similar bond strength values compared to the tribochemical treatment.

Shear bond strength of repairs in porcelain conditioned with laser

The aim of this study was to evaluate the shear bond strength of repairs in porcelain conditioned with laser. Sixty porcelain discs were made and six groups were formed (n = 10): G1: conditioning with laser with potency 760 mW; G2: conditioning with laser with potency 760 mW and application of 37% phosphoric acid for 15 s; G3: conditioning with laser with potency 900 mW; G4: conditioning with laser with potency 900 mW and application of 37% phosphoric acid for 15 s; G5: application of 37% phosphoric acid for 15 s (group control) and G6: application of 10% hydrofluoric acid for 2 min. The composite resin was insert of incremental layers at the porcelain surface aided with a metal matrix, and photoactivation for 20 s each increment. The specimens were submitted to a thermal cycling by 1000 cycles of 30 s in each bath with temperature between 5 and 55 degrees C. After the thermal cycling, specimens were submitted to the shear bond strength. The results were evaluated statistically through analysis of variance and Tukey's tests with 5% significance. The averages and standard deviation founded were: G1, 11.25 (+/- 3.10); G2, 12.32 (+/- 2.65); G3, 14.02 (+/- 2.38); G4, 13.44 (+/- 2,07); G5, 9.91 (-/+ 2,18); G6, 12.74 (+/- 2.67). The results showed that the femtosecond laser produced a shear bond strength of repairs in porcelain equal to the hydrofluoric acid and significantly superior to the use of phosphoric acid. Microsc. Res. Tech., 2012. (C) 2012 Wiley Periodicals, Inc.

Monte Carlo Simulations of Novel Scintillator Detectors and Dosimetry Calculations

Monte Carlo (MC) simulation techniques are becoming very common in the Medical Physicists community. MC can be used for modeling Single Photon Emission Computed Tomography (SPECT) and for dosimetry calculations. 188Re, is a promising candidate for radiotherapeutic production and understanding the mechanisms of the radioresponse of tumor cells "in vitro" is of crucial importance as a first step before "in vivo" studies. The dosimetry of 188Re, used to target different lines of cancer cells, has been evaluated by the MC code GEANT4. The simulations estimate the average energy deposition/per event in the biological samples. The development of prototypes for medical imaging, based on LaBr3:Ce scintillation crystals coupled with a position sensitive photomultiplier, have been studied using GEANT4 simulations. Having tested, in the simulation, surface treatments different from the one applied to the crystal used in our experimental measurements, we found out that the Energy Resolution (ER) and the Spatial Resolution (SR) could be improved, in principle, by machining in a different way the lateral surfaces of the crystal. We have then studied a system able to acquire both echographic and scintigraphic images to let the medical operator obtain the complete anatomic and functional information for tumor diagnosis. The scintigraphic part of the detector is simulated by GEANT4 and first attempts to reconstruct tomographic images have been made using as method of reconstruction a back-projection standard algorithm. The proposed camera is based on slant collimators and LaBr3:Ce crystals. Within the Field of View (FOV) of the camera, it possible to distinguish point sources located in air at a distance of about 2 cm from each other. In particular conditions of uptake, tumor depth and dimension, the preliminary results show that the Signal to Noise Ratio (SNR) values obtained are higher than the standard detection limit.

Studio della superficie degli impianti dentali in titanio: La nanotecnologia nella valutazione delle nuove superfici implantari in rapporto all'osteointegrazione dei mascellari

Il presente lavoro parte dalla descrizione dei processi di rimodellamento osseo mascellare a seguito della perdita di elementi dentari e la successiva riabilitazione mediante impianto dentale osteointegrato. Approfondiremo proprio i complessi aspetti dell’osteointegrazione su superfici implantari in titanio sia a livello micro che macroscopico. Nel campo dell’implantologia, infatti, il titanio risulta essere il materiale maggiormente impiegato in virtù della sua eccellente biocompatibilità e resistenza. Successivamente prenderemo in analisi i trattamenti di superficie implantare ad oggi più diffusi, lavorati prevalentemente a livello microscopico e infine confronteremo una sistematica trattata tradizionalmente con una innovativa trattata superficialmente a livello nanometrico. Il confronto avverrà in vivo, paragonando i risultati ottenuti clinicamente e radiograficamente tra le 2 sistematiche implantari, utilizzate per ripristinare la funzione masticatoria nei pazienti arruolati.

Compatibility of ultra high performance concrete as repair material : bond characterization with concrete under different loading scenarios

The rehabilitation of concrete structures, especially concrete bridge decks, is a major challenge for transportation agencies in the United States. Often, the most appropriate strategy to preserve or rehabilitate these structures is to provide some form of a protective coating or barrier. These surface treatments have typically been some form of polymer, asphalt, or low-permeability concrete, but the application of UHPC has shown promise for this application mainly due to its negligible permeability, but also as a result of its excellent mechanical properties, self-consolidating nature, rapid gain strength, and minimal creep and shrinkage characteristics. However, for widespread acceptance, durability and performance of the composite system must be fully understood, specifically the bond between UHPC and NSC often used in bridge decks. It is essential that the bond offers enough strength to resist the stress due to mechanical loading or thermal effects, while also maintaining an extended service-life performance. This report attempts to assess the bond strength between UHPC and NSC under different loading configurations. Different variables, such as roughness degree of the concrete substrates, age of bond, exposure to freeze-thaw cycles and wetting conditions of the concrete substrate, were included in this study. The combination of splitting tensile test with 0, 300, 600 and 900 freeze-thaw cycles was carried out to assess the bond performance under severe ambient conditions. The slant-shear test was utilized with different interface angles to provide a wide understanding of the bond performance under different combinations of compression and shear stresses. The pull-off test is the most accepted method to evaluate the bond strength in the field. This test which studies the direct tensile strength of the bond, the most severe loading condition, was used to provide data that can be correlated with the other tests that only can be used in the laboratory. The experimental program showed that the bond performance between UHPC and NSC is successful, as the strength regardless the different degree of roughness of the concrete substrate, the age of the composite specimens, the exposure to freeze-thaw cycles and the different loading configurations, is greater than that of concrete substrate and largely satisfies with ACI 546.3R-06.