Propriedades estruturais e espectroscópicas de WO3 e WO3:Eu3+

Used as catalysts even in organic and inorganic molecules, as additives on catalysts, electrochromic films on smart windows the tungsten trioxide have been largely studied on the lasts decades, but there is just a few about it's luminescence. Using as precursors nitric acid and sodium tungstate the tungsten trioxide were been prepared thru wet process then treating on thermic and hydrothermal treatments. Where been evaluated the effects of methodology, nitric acid concentration, duration and temperature of treatments. The samples were characterized by X-ray diffraction (XRD), Raman scattering spectroscopy (RSS), Fourier transformed infrared spectroscopy, photoluminescence spectroscopy (PLS) and X-ray excited optical luminescence (XEOL). Hydrated phases of tungsten trioxide were obtained through hydrothermal treatments and the non-hydrated phases occur with thermic treatments. The acid concentration has the ability to determine the major phase formed as well the temperature determine the hydratation of the product. With lower temperatures dihydrate phase were preferable formed and with the rise of temperature, the water molecules were lost up to the fractionary hydratation and then the non-hydrated phase with higher temperatures depending on the atmosphere used on the thermal treatment. Doping the system with europium ions even substituting tungsten or in the interstices of the matrix were not been successful, as well the XEOL spectroscopy intensity were null and quite low for ultraviolet and visible excitation photoluminescence because of oxygen defect levels localized into the prohibited band.

Relação entre a composição de condicionadores capilares e a formação de cristais líquidos

O Brasil é o terceiro maior consumidor de cosméticos no mundo, representando a segunda colocação em produtos de higiene capilar. Tal colocação está relacionada aos nossos padrões de cuidados estéticos capilares, que muitas vezes, provocam agressões físicas e químicas, deixando os cabelos danificados e quebradiços. Os condicionadores capilares tornam-se uma ferramenta interessante, devido aos inúmeros benefícios protetores oferecidos às superfícies dos fios. A presença de tensoativos catiônicos e álcoois graxos de cadeia longa, unidos à temperatura de fusão dos materiais, velocidade de agitação imposta e resfriamento adequado do produto, podem ser os responsáveis pela formação de cristais líquidos. Tais estruturas conferem estabilidade, viscosidade, melhorias na aparência estética e sensorial do produto e, devido a estas qualidades estão ganhando espaço no mercado cosmético. Assim, o objetivo do trabalho foi desenvolver e formular condicionadores capilares variando-se as concentrações e/ou os tensoativos catiônicos e álcoois graxos, visando obter estruturas líquido-cristalinas associadas aos condicionadores, através da técnica de microscopia de luz polarizada (MLP), caracterização das estruturas pela técnica de espalhamento de raios-X a baixo ângulo (SAXS) e analise do perfil de textura (TPA) das formulações. Foram manipuladas 14 emulsões O/A, variando-se os álcoois graxos de cadeia longa (16 a 18C) e ceras auto emulsionantes catiônicas. Os resultados da MLP foram, em sua maioria, positivos para a presença de estruturas na forma de cruz de malta. A técnica de SAXS confirmou os sistemas sugeridos pela MLP caracterizando a estrutura líquida cristalina do tipo lamelar. A TPA inferiu que a alta estabilidade física apresentada por estas emulsões, e seu particular desempenho no deslizamento dos cabelos, pode estar relacionada à presença de tal organização estrutural nas formulações...

Preparação e caracterização de híbridos orgânico-inorgânicos à base de epoxí-silica

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudo do pH e atividade antimicrobiana sobre Enterococcus faecalis de medicação intracanal à base de hidróxido de cálcio associada ao óleo de melaleuca, clorexidina ou farnesol

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Membranas de biocelulose como substrato para o crescimento de nanofios de ZnO: síntese e aplicação

Pós-graduação em Química - IQ

Resposta dos tecidos periodontais aos cimentos de silicato tricálcico associado ao óxido de zircônio ou óxido de nióbio usados no selamento de perfurações de furca em molares de ratos

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

Propriedades estruturais e espectroscópicas de WO3 e WO3:Eu3+

Used as catalysts even in organic and inorganic molecules, as additives on catalysts, electrochromic films on smart windows the tungsten trioxide have been largely studied on the lasts decades, but there is just a few about it's luminescence. Using as precursors nitric acid and sodium tungstate the tungsten trioxide were been prepared thru wet process then treating on thermic and hydrothermal treatments. Where been evaluated the effects of methodology, nitric acid concentration, duration and temperature of treatments. The samples were characterized by X-ray diffraction (XRD), Raman scattering spectroscopy (RSS), Fourier transformed infrared spectroscopy, photoluminescence spectroscopy (PLS) and X-ray excited optical luminescence (XEOL). Hydrated phases of tungsten trioxide were obtained through hydrothermal treatments and the non-hydrated phases occur with thermic treatments. The acid concentration has the ability to determine the major phase formed as well the temperature determine the hydratation of the product. With lower temperatures dihydrate phase were preferable formed and with the rise of temperature, the water molecules were lost up to the fractionary hydratation and then the non-hydrated phase with higher temperatures depending on the atmosphere used on the thermal treatment. Doping the system with europium ions even substituting tungsten or in the interstices of the matrix were not been successful, as well the XEOL spectroscopy intensity were null and quite low for ultraviolet and visible excitation photoluminescence because of oxygen defect levels localized into the prohibited band.

Relação entre a composição de condicionadores capilares e a formação de cristais líquidos

O Brasil é o terceiro maior consumidor de cosméticos no mundo, representando a segunda colocação em produtos de higiene capilar. Tal colocação está relacionada aos nossos padrões de cuidados estéticos capilares, que muitas vezes, provocam agressões físicas e químicas, deixando os cabelos danificados e quebradiços. Os condicionadores capilares tornam-se uma ferramenta interessante, devido aos inúmeros benefícios protetores oferecidos às superfícies dos fios. A presença de tensoativos catiônicos e álcoois graxos de cadeia longa, unidos à temperatura de fusão dos materiais, velocidade de agitação imposta e resfriamento adequado do produto, podem ser os responsáveis pela formação de cristais líquidos. Tais estruturas conferem estabilidade, viscosidade, melhorias na aparência estética e sensorial do produto e, devido a estas qualidades estão ganhando espaço no mercado cosmético. Assim, o objetivo do trabalho foi desenvolver e formular condicionadores capilares variando-se as concentrações e/ou os tensoativos catiônicos e álcoois graxos, visando obter estruturas líquido-cristalinas associadas aos condicionadores, através da técnica de microscopia de luz polarizada (MLP), caracterização das estruturas pela técnica de espalhamento de raios-X a baixo ângulo (SAXS) e analise do perfil de textura (TPA) das formulações. Foram manipuladas 14 emulsões O/A, variando-se os álcoois graxos de cadeia longa (16 a 18C) e ceras auto emulsionantes catiônicas. Os resultados da MLP foram, em sua maioria, positivos para a presença de estruturas na forma de cruz de malta. A técnica de SAXS confirmou os sistemas sugeridos pela MLP caracterizando a estrutura líquida cristalina do tipo lamelar. A TPA inferiu que a alta estabilidade física apresentada por estas emulsões, e seu particular desempenho no deslizamento dos cabelos, pode estar relacionada à presença de tal organização estrutural nas formulações...

Preparação e caracterização de híbridos orgânico-inorgânicos à base de epoxí-silica

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effect of the root canal final rinse protocols on the debris and smear layer removal and on the push-out strength of an epoxy-based sealer

The aim of the present study was to evaluate the efficacy of QMiX, SmearClear, and 17% EDTA for the debris and smear layer removal from the root canal and its effects on the push-out bond strength of an epoxy-based sealer by scanning electron microscopy (SEM). Forty extracted human canines (n = 10) were assigned to the following final rinse protocols: G1-distilled water (control), G2–17% EDTA, G3-SmearClear, and G4-QMiX. The specimens were submitted to a SEM analysis to evaluate the presence of debris and smear layer, respectively, in the apical or cervical segments. In sequence, forty extracted human maxillary canines with the root canals instrumented were divided into four groups (n = 10) similar to the SEM analysis study. After the filling with AH Plus, the roots were transversally sectioned to obtain dentinal slices. The specimens were submitted to a push-out bond strength test using an electromechanical testing machine. The statistical analysis for the SEM and push-out bond strength studies were performed using the Kruskal–Wallis and Dunn tests (α = 5%). There was no difference among the G2, G3, and G4 efficacy in removing the debris and smear layer (P > 0.05). The efficacy of these groups was superior to the control group. The push-out bond strength values of G2, G3, and G4 were superior to the control group. The ability to remove the debris and smear layer by SmearClear and QMiX was as effective as the 17% EDTA. The final rinse with these solutions promoted similar push-out bond strength values.

Effect of passive ultrassonic instrumentation as a final irrigation protocol on debris and smear layer removal

This study sought to evaluate the efficacy of passive ultrasonic irrigation (PUI) on removing the smear layer and debris from root dentin using scanning electron microscopy (SEM). Twenty-five bovine incisors were manually prepared and divided into three groups according to the final irrigation protocol: EDTA, final irrigation with 12 mL of 17% EDTA for 3 minutes followed by 5 mL of 2.5% NaOCl; EDTA=PUI, final flush with 4 mL of 17% EDTA and PUI for 30 seconds. These procedures were repeated three times to standardize the volume of the irrigant. Control group, after preparation, the specimens were irrigated only with 17 mL of 2.5% NaOCl. The roots were fractured and analyzed using SEM. The intragroup analysis revealed that the EDTA=PUI protocol removed a higher amount of debris at the cervical third (P 5 0.03). The intergroup analysis revealed that EDTA=PUI presented the lowest amount of debris at the cervical third (P 5 0.007). Smear layer scores were higher in the control group compared with the EDTA and EDTA=PUI groups, but only at the cervical third (P 50.02). None of the final irrigant protocols completely removed the smear layer and debris. EDTA=PUI only improved the removal of debris at the cervical third.

Movimento ortodôntico depois de tratamento endodôntico, inclusive com perfuração: 30 dias

Um questionamento muito frequente: qual o tempo que se deve esperar para movimentar um dente submetido a tratamento endodôntico, inclusive os de perfuração radicular? A extrapolação dos fenômenos observados em outras regiões da raiz e a fundamentação experimental com base em situações correlatas permitem afirmar que 30 dias correspondem a um período mais do que razoável para o reparo periapical estar em fase avançada de maturação e síntese. As forças ortodônticas são muito leves e dissipantes - muito mais do que o traumatismo dentário, o trauma oclusal e as forças mastigatórias normais -, e não devem interferir na patogenicidade e virulência das microbiotas envolvidas nas necroses e lesões periapicais crônicas, assim como não devem interferir nos fenômenos celulares e teciduais durante a reorganização dos tecidos apicais e periapicais.

Analysis of the color alteration and radiopacity promoted by bismuth oxide in calcium silicate cement

The aim of the study was to determine if the increase in radiopacity provided by bismuth oxide is related to the color alteration of calcium silicate-based cement. Calcium silicate cement (CSC) was mixed with 0%, 15%, 20%, 30% and 50% of bismuth oxide (BO), determined by weight. Mineral trioxide aggregate (MTA) was the control group. The radiopacity test was performed according to ISO 6876/2001. The color was evaluated using the CIE system. The assessments were performed after 24 hours, 7 and 30 days of setting time, using a spectrophotometer to obtain the ΔE, Δa, Δb and ΔL values. The statistical analyses were performed using the Kruskal-Wallis/Dunn and ANOVA/ Tukey tests (p < 0.05). The cements in which bismuth oxide was added showed radiopacity corresponding to the ISO recommendations ( > 3 mm equivalent of Al). The MTA group was statistically similar to the CSC / 30% BO group (p > 0.05). In regard to color, the increase of bismuth oxide resulted in a decrease in the ΔE value of the calcium silicate cement. The CSC group presented statistically higher ΔE values than the CSC / 50% BO group (p < 0.05). The comparison between 24 hours and 7 days showed higher ΔE for the MTA group, with statistical differences for the CSC / 15% BO and CSC / 50% BO groups (p < 0.05). After 30 days, CSC showed statistically higher ΔE values than CSC / 30% BO and CSC / 50% BO (p < 0.05). In conclusion, the increase in radiopacity provided by bismuth oxide has no relation to the color alteration of calcium silicate-based cements.

Optimizing endodontic irrigation: advantages of negative apical pressure technology

FAPESP #2010/16002-4

In vivo evaluation of tissue response to new endodontic sealers

Introduction: The sealers can be in direct contact with the periapical tissues. Thus, these materials must have appropriate physical and biological properties, providing conditions for repair to occur. Objective: The aim of this study was to evaluate the response of rat subcutaneous tissue to endodontics sealers. Material and methods: Three materials comprised the groups: group I – Zinc Oxide, Eugenol and Iodoform paste, group II – Portland cement with propylene glycol, and group III – MTA Fillapex® (Angelus). These materials were placed in polyethylene tubes and implanted into dorsal connective tissue of Wistar rats for seven and 15 days. The specimens were stained with hematoxylin and eosin and evaluated regarding to inflammatory reaction parameters through a light microscope. The data were compared using Kruskal-Wallis test with significance level of 5%. The intensity of inflammatory response against the sealers was analyzed by two blinded and previously calibrated observers for all experimental periods. Results: The histological evaluation showed that all the materials caused a moderated inflammatory reaction at seven days which decreased with time. A greater inflammatory reaction was observed at seven days in group I. The other specimens had significantly less inflammatory cells when compared to this group. Tubes with MTA Fillapex® presented some giant cells, macrophages and lymphocytes after seven days. At 15 days, the presence of fibroblasts and collagen fibers was observed indicating normal tissue healing. The group II showed similar results to those observed in MTA Fillapex® already at seven days. At 15 days the inflammatory reaction presented was almost absent at the tissue, with many collagen fibers indicating normal tissue healing. Statistical analysis showed a significant statistical difference amongst the group I (seven days) and II (15 days) (p < 0.05). In the other groups no (Continue)