Bond strength of composite to dentin: effect of acid etching and laser irradiation through an uncured self-etch adhesive system

This study evaluated the effect on micro-tensile bond strength (mu-TBS) of laser irradiation of etched/unetched dentin through an uncured self-etching adhesive. Dentinal surfaces were treated with Clearfil SE Bond Adhesive (CSE) either according to the manufacturer's instructions (CSE) or without applying the primer (CSE/NP). The dentin was irradiated through the uncured adhesive, using an Nd: YAG laser at 0.75 or 1 W power settings. The adhesive was cured, composite crowns were built up, and the teeth were sectioned into beams (0.49 mm(2)) to be stressed under tension. Data were analyzed using one-way ANOVA and Tukey statistics (alpha = 5%). Dentin of the fractured specimens and the interfaces of untested beams were observed under scanning electron microscopy (SEM). The results showed that non-etched irradiated surfaces presented higher mu-TBS than etched and irradiated surfaces (p < 0.05). Laser irradiation alone did not lead to differences in mu-TBS (p > 0.05). SEM showed solidification globules on the surfaces of the specimens. The interfaces were similar on irradiated and non-irradiated surfaces. Laser irradiation of dentin through the uncured adhesive did not lead to higher mu-TBS when compared to the suggested manufacturer's technique. However, this treatment brought benefits when performed on unetched dentin, since bond strengths were higher when compared to etched dentin.

Chemical composition and lipoxygenase activity in soybeans (Glycine max L. Merr.) submitted to gamma irradiation

Soybeans are an important food due to their functional and nutritional characteristics. However, consumption by western populations is limited by the astringent taste of soybeans and their derivatives which results from the action of lipoxygenase, an enzyme activated during product processing. The aim of this study was to evaluate the effect of gamma irradiation on the chemical composition and specific activity of lipoxygenase in different soybean cultivars. Soybeans were stored in plastic bags and irradiated with doses of 2.5, 5 and 10 kGy. The chemical composition (moisture, protein, lipids, ashes, crude fiber, and carbohydrates) and lipoxygenase specific activity were determined for each sample. Gamma irradiation induced a small increase of protein and lipid content in some soybean cultivars, which did not exceed the highest content of 5% and 26%, respectively, when compared to control. Lipoxygenase specific activity decreased in the three cultivars with increasing gamma irradiation dose. In conclusion, the gamma irradiation doses used are suitable to inactivate part of lipoxygenase while not causing expressive changes in the chemical composition of the cultivars studied. (C) 2014 Elsevier Ltd. All rights reserved.

Structural and electronic analysis of the atomic scale nucleation of Ag on alpha-Ag2WO4 induced by electron irradiation

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

Effect of gamma irradiation on the nutritional quality of Agaricus bisporus strains cultivated in different composts

The effect of irradiation doses (0, 125, 250 and 500 Gy) on the nutritional quality of A. bisporus mushrooms (strains ABI-07/06, ABI-05/03 and PB-1) cultivated in composts based on oat straw (Avena sativa) and brachiaria (Brachiaria sp.) was evaluated. The experimental design was 4 x 3 x 2 factorial scheme (irradiation doses x strains x composts), with 24 treatments, consisting of two repetitions each, totaling 48 experimental units (samples of mushrooms). The samples were irradiated in Cobalt-60 irradiator, model Gammacell 220 kGy, with dose rate of 0.740 kGy h(-1), according to the treatments proposed. Subsequently, the control (unirradiated) and the other treatments were maintained at 4 +/- 1 degrees C and 90% RH in a climatic chamber for carrying out the chemical analysis of the mushrooms on the 1st and 14th day of storage. It was found that all A. bisporus strains evaluated were food with excellent nutritional value, because they presented high protein and fiber contents and low ethereal extract content; the chemical characterization of the mushrooms was influenced by the compost type in which they were cultivated; gamma irradiation influenced the chemical composition of mushrooms.

Investigation of Bulk and DTMOS triple-gate devices under 60 MeV proton irradiation

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Desenvolvimento de um protocolo de dosimetria para o tratamento de total skin irradiation (TSI)

A técnica radioterápica Total Skin Irradiation (TSI), utilizada para tratamento de Micose Fungóide e doenças similares, apresenta grande complexidade na sua dosimetria e implementação nos Serviços de Radioterapia. No SUS – Sistema Único de Saúde - do Brasil, só há esse tratamento no Serviço de Radioterapia do Hospital das Clínicas da UNICAMP (Campinas) e no Instituto Nacional do Câncer (INCA) (Rio de Janeiro). O objetivo deste trabalho é o estudo e o desenvolvimento de um protocolo de controle de qualidade e dosimetria a ser implementado na técnica utilizada no Serviço de Radioterapia do Hospital de Clínicas da Universidade Estadual de Campinas (HC - UNICAMP). Todos os estudos e análises para a elaboração do protocolo foram baseados no Report 23[1] da AAPM – American Association of Physicists in Medicine - e no TRS-398[3] da IAEA – International Atomic Energy Agency. A metodologia e os resultados obtidos apresentam-se descritos neste relatório

Monitoramento do perfil microbiológico de dentes com infecção endodôntica primária durante terapia com diferentes medicações intracanal

Pós-graduação em Odontologia Restauradora - ICT

Ethyl biodiesel: Microwave irradiation aiding ethanolysis of waste cooking oil.

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

Laser irradiation and thermal treatment inducing selective crystallization in Sb2O3-Sb2S3 glassy films

The influence of both thermal treatment and laser irradiation on the structural and optical properties of films in the Sb 2 O 3 –Sb 2 S 3 system was investigated. The films were prepared by RF-sputtering using glass compositions as raw materials. Irreversible photodarkening effect was observed after exposure the films to a 458nm solid state laser. It is shown, for the first time, the use of holographic technique to measure “in situ”, simultaneously and independently, the phase and amplitude modulations in glassy films. The films were also photo-crystallized and analysed “in situ” using a laser coupled to a micro-Raman equipment. Results showed that Sb 2 S 3 crystalline phase was obtained after irradiation. The effect of thermal annealing on the structure of the films was carried out. Different from the result obtained by irradiation, thermal annealing induces the crystallization of the Sb 2 O 3 phase. Photo and thermal induced effects on films were studied using UV–Vis and Raman spectroscopy, atomic force microscopy (AFM), thermal analysis (DSC), X-ray diffraction, scanning electron microscopy (MEV) and energy-dispersive X-ray spectroscopy (EDX).

Avaliação in vitro do pH do hidróxido de cálcio usado como medicação intracanal em associação com clorexidina e racealfatocoferol

Objective: The aim of this study was to evaluate the pH of calcium hydroxide (CalenTM) when associated or not with chlorhexidine 0.4%, and when associated with chlorhexidine with the addition of 20% or 10% of alphatocopherol (AchéTM), assessed in several periods of time. Methods: Fourty dentine tubes 20 mm, properly standardized, were made from bovine anterior teeth roots. Following, a perforation was achieved in the roots distal face at 7 mm from the cervical radicular line by using a #1/2 carbide bur. After complete root sealing is made, except in the perforation local, the radicular canals were filled with one of the following associations: Group I – Calen®; Group II – Calen™ with chlorehxidine at 0.4%; Group III – Calen™ with chlorhexidine at 0.4% with the addition of 20% (weight) of alhatocopherol compound and Group IV – Calen™ with chlorhexidine at 0.4% with the addition of 10% (weight) alphatocopherol. After cervical sealing is accomplished, the roots were immersed in water MiliQ and the pH, assessed in 24h, 7, 14, 21, 28 and 45 days. Results and Conclusion: In all periods tested, the pH of the calcium hydroxide (Calen™) was similar to the pH of the calcium hydroxide (Calen™) associated with chlorhexidine 0.4% and 10% alphatocopherol (p > 0.05). The association of 20% alphatocopherol obtained the pH lower than the association with 10% (p < 0.05). The pH of the association with chlorhexidine was similar to the pure calcium hydrocide (Calen™) after the 14th day (p > 0.05) only. Therefore, on the 45th day, this difference was significant again (p < 0.05).

Human dental enamel and dentin structural effects after Er:yag laser irradiation

Ideally projected to be applied on soft tissues, infrared lasers were improved by restorative dentistry to be used in hard dental tissues cavity preparations-namely enamel and dentin. This paper evidentiates the relevant aspects of infrared Erbium laser's action mechanism and its effects, and characterizes the different effects deriving from the laser's beams emission. The criteria for use and selection of optimal parameters for the correct application of laser systems and infuence of supporting factors on the process, such as water amount and its presence in the ablation process, protection exerted by the plasma shielding and structural factors, which are indispensable in dental tissues cavity preparation related to restorative technique, are subordinated to optical modifcations caused by the interaction of the energy dissipated by these laser light emission systems in the targeted tissue substrate. Clinical relevance: Differences in the action of infrared Erbium laser system in regard to the nature of the ablation process and variations on the morphological aspects observed in the super-fcial structure of the target tissue irradiated, may be correlated to the structural optical modifcations of the substrate produced by an interaction of the energy propagated by laser systems.

Effects of Er, Cr:YSGG laser irradiation on external adaptation of restorations in caries-affected cavities

This study evaluated the effect of Er,Cr:YSGG laser irradiation on the external adaptation of composite resin restorations in caries-affected cavities. Mixed class V cavity preparations were performed in 36 intact human third molars, in half of which caries was artificially induced. Both healthy and carious dentin were etched with 35% phosphoric acid (Ultradent Products Inc., South Jordan, Utah, USA), and the teeth were divided into three groups, i.e., (a) untreated etched dentin, (b) application of the Er, Cr:YSGG laser and (c) use of chlorhexidine as an adjunct in the bonding process. Restorations were fabricated with Z350 XT FiltekTM composite resin (3M ESPE) and subsequently the specimens were subjected to thermocycling to simulate artificial ageing. Quantitative analysis of external adaptation was performed by scanning electron microscopy in both healthy and affected dentin using epoxy resin replicas. It was concluded that the application of laser and chlorhexidine did not affect the percentages of marginal adaptation of class V restorations. Furthermore, thermocycling may influence adaptation values.

Biocompatibility of Intracanal Medications Based on Calcium Hydroxide

The aim of this study was to evaluate the rat subcutaneous tissue reaction to calcium hydroxide-based intracanal medicaments, UltraCal XS (calcium hydroxide, barium sulphate, aqueous matrix), Hydropast (calcium hydroxide, barium sulphate, and propyleneglycol), and Calen (Calcium hydroxide, zinc oxide, colophony, and polyethyleneglycol), used as a control. Methods. Forty-eight rats (Rattus Norvegicus Holtzman) were distributed in three groups: Calen, UltraCal XS, and Hydropast. Polyethylene tubes filled with one of the medicaments were implanted in the dorsal subcutaneous. After 7 and 30 days, the implants were removed and the specimens were fixed and embedded in paraffin. Morphological and quantitative analyses were carried out in the HE-stained sections. The numerical density of inflammatory cells in the capsule was evaluated and statistical analyses were performed (P>/0.05). Results. At 7 days, all materials induced an inflammatory reaction in the subcutaneous tissue adjacent to the implants. In all groups, a significant reduction in the number of inflammatory cells and giant cells was verified in the period of 30 days. Conclusion. These results indicate that the calcium hydroxide-based medicaments evaluated present biocompatibility similar to Calen.

Use of nanoparticulate zinc oxide as intracanal medication in endodontics: pH and antimicrobial activity

The aim of this study was to evaluate the pH and antimicrobial activity of micro or nanoparticulate zinc oxide (ZnO) pastes with or without calcium hydroxide (CH). The following medications were evaluated: microparticulate ZnO + polyethylene glycol (PEG) 400; nanoparticulate ZnO + PEG 400; PEG 400; CH + microparticulate ZnO + PEG 400 and CH + nanoparticulate ZnO + PEG 400. The pH was assessed between 12 hours and 28 days, using a digital pH meter. The antimicrobial activity against Enterococcus faecalis (ATCC-9212), Candida albicans (ATCC-10231), Pseudomonas aeruginosa (ATCC-27853), Staphylococcus aureus (ATCC-6538) and Kocuria rhizophila (ATCC-9341) was determined in triplicate using agar diffusion test. The results were submitted to Kruskal-Wallis/Dunn and ANOVA/Tukey tests with 5% significance. The highest pH values were found for CH+ZnO, with higher values for nanoparticulate ZnO after 12 hours and 21 days (p<0.05). CH+ZnO medication promoted higher growth inhibition against P. aeruginosa and lower against E. faecalis. Calcium hydroxide pastes have higher pH and antimicrobial activity when associated with either micro- or nanoparticulate zinc oxide.

Atividade antimicrobiana residual de pastas à base de hidróxido de cálcio e associações como medicação intracanal

A resistência do biofilme endodôntico pode requerer um período maior de permanência da medicação intracanal a fim de prolongar sua ação antimicrobiana. O objetivo deste estudo foi avaliar a ação antimicrobiana residual das medicações intracanal: G1) hidróxido de cálcio + soro; G2) Calen; G3) Calen + PMCC; G4) Calen + clorexidina 0,4% e G5) clorexidina gel 2% frente à Enterococcus faecalis, Candida albicans, Pseudomonas aeruginosa, Staphylococcus aureus e Kocuria rhizophila em 60 canais radiculares bovinos. Os canais radiculares foram instrumentados e preenchidos com as medicações intracanal, as quais foram removidas após os períodos experimentais (15, 30, 60 e 90 dias) e empregadas na técnica de difusão em ágar. Os halos de inibição foram evidenciados por gel de TTC e então mensurados. Os dados de halos de inibição foram submetidos à análise estatística dos testes Kruskall-Wallis e Dunn, com nível de significância de 5%. O Ca(OH)2 + soro apresentou efeito até o período de 15 dias. A pasta Calen demonstrou efeito residual aos 60 dias frente ao S. aureus, enquanto Calen/PMCC até o período de 90 dias frente à S. aureus e K. rhizophila e aos 30 dias para E. faecalis. A pasta Calen associado à clorexidina foi efetiva frente à E. faecalis até o período de 60 dias. A clorexidina gel 2% apresentou ação residual em todos os períodos, com exceção de E. faecalis aos 90 dias, também apresentou atividade antimicrobiana mais prolongada, seguido das associações do hidróxido de cálcio com clorexidina e PMCC.