With the purpose of checking, in vivo, the effect of atraumatic restorative treatment (ART) on the remaining demineralized dentin, 12 primary molars with deep occlusal lesions from children with ages ranging from 3 to 7 were evaluated. After lesion excavation, and before glass ionomer cement placement, dentin samples were collected from the pulpal wall of the cavity. After 3 months, the restorations were removed and new samples were collected. Six microareas of each sample were analyzed by X-ray energy dispersion spectrometer. Samples obtained before treatment were infected and intertubular dentin had a loosely organized collagen matrix, with well-defined collagen fibers. Following treatment, in addition to a drastic reduction of the amount of bacteria, the intertubular dentin was denser, with more compact and closely packed collagen fibers. An increased calcium concentration was observed in dentin collected after treatment (p < 0.001), suggesting tissue remineralization, but fluoride was not detected. We conclude that ART allows a one-session approach, with the purpose of creating more favorable conditions for the healing process.

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Poor oral hygiene has been considered one of the main problems routinely faced in the orthodontic treatment. Orthodontic appliance creates an environment that provides mineral loss from the dental enamel. Such condition is clinically seen as white spot lesions and cavitations in the most severe cases. The aim of this study was to evaluate the effects of a fluoride varnish application as a caries prevention method for clinical orthodontics. The experiment analyzed dental enamel adjacent to orthodontics accessories after treatment. In addition, it was observed the calcium, phosphorus and fluoride contents on enamel treated with a fluoride varnish. The results showed that fluoride varnish application is a simple and fast technique that could be useful in preventing enamel demineralization associated to orthodontic treatment. Scanning electron microscopy revealed significant amount of calcium fluoride-like material deposited on enamel and energy dispersive x-ray analysis demonstrated a large incorporation of calcium and fluoride to the enamel of the treated specimens. It was concluded that fluoride varnish could indeed be considered an efficient preventive method to enhance enamel resistance against the cariogenic challenges during orthodontic therapy.

Serpentine is a versatile mineral family rich in Mg silicate with several polymorphic phases, mainly antigorite and lizardite, all of them with similar chemical composition (Mg 3 Si 2 O 5 (OH) 4 ). Their structures are generally composed of octahedral layers rich in Mg[MgO 2 (OH) 4 ] 6− , attached to a tetrahedral silicate [Si 2 O 5 ] 2− sheet. The unique physicochemical properties of serpentinites and the existence of large reserves in Brazil create new important opportunities for research and technological applications. In this work, serpentinites structures and properties are reviewed, as well as its occurrence and literature describing its applications in construction/ceramics, agriculture, as a silica source, in steel production, as an additive/filler in polymers, in the production of composites, adsorption of cations and organics contaminants, CO 2 capture and catalysis. The presence of harmful chrysotile associated with serpentinites, some of its properties and uses are also described.

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Durante as etapas de processamento mineral, na maioria dos casos, há o envolvimento de suspensões - misturas de minério fino com uma fase líquida. Logo, as operações de processo são influenciadas pela resistência dessas suspensões em se deformar ou fluir, quando submetidas a forças de cisalhamento ou pressão, ou seja, a viscosidade da suspensão influenciará nas etapas de processamento. Nesse trabalho, será feita uma revisão sobre reologia de suspensões e o processamento mineral. Serão abordados aspectos conceituais sobre reologia de suspensão e suas variáveis, classificação reológica dos fluidos e determinações de viscosidade através do viscosímetro rotacional de cilindro concêntrico.
Mineral processing is often carried out on suspensions (usually a mixture of solid particles and liquid). The process is influenced by the resistance to flow resulting from a shear stress or pressure applied in the fluid (suspension). Therefore, the viscosity of suspensions will affect the mineral process. This paper reviews the applications of rheology in mineral processing. This review focuses on conceptual aspects such as fluid classification, variable of rheology and measurements with concentric viscometer

Resumo Com a descoberta de ocorrências de monazita num ambiente geológico incomum, em veios de quartzo na Serra do Espinhaço Meridional, propôs-se estudar a geologia desses depósitos e seus comportamentos químicos em três localidades (Buenópolis, Olhos d'Água e Diamantina), bem como datações geocronoló-gicas U-Pb por abrasão a laser MC-ICP-MS foram efetuadas em amostras de Diamantina e Olhos d'Água. Em Buenópolis, o mineral aparece como indivíduos geminados, em cascalheiras coluvionares na zona de contato do Grupo Macaúbas com o Supergrupo Espinhaço. Na ocorrência de Olhos d'Água, têm sido registrados grandes cristais em bolsões ovalados métricos, hospedados em metapelitos do Grupo Macaúbas. Em Diamantina, foram estudados cristais milimétricos de um depósito coluvionar do Rio Caeté-Mirim. Certamente, no primeiro e no terceiro casos, tais grãos se originaram dos abundantes veios de quartzo que seccionam as seqüências regionais. Análises com microssonda eletrônica mostraram valores de óxidos em geral semelhantes para os três depósitos, entretanto com certas particularidades. As amostras foram caracterizadas como monazitas-(Ce), localmente ricas em neodímio e, embora em geral não tenham revelado semelhanças absolutas para dois depó-sitos, Diamantina e Olhos d'Água apresentaram alguns aspectos químicos preferenciais. Os resultados U-Pb indicaram, supondo-se as idades mais antigas (~491 Ma) como de cristalização do mineral, uma extensão completa de idades na faixa entre 490 e 440 Ma, provavelmente devidas a reaquecimentos tardios. Em termos geotectônicos, tais idades permitem evidenciar as últimas manifestações referentes ao Ciclo Brasiliano na região.Palavras-chave: monazita-(Ce), Serra do Espinhaço, química mineral, geocronologia. Abstract Monazite in quartz-veins from the Southern Espinhaço Range (MG): mineralogy, LA-ICP-MS ages and geological implications.Due to the discovery of monazite occurrences in an uncommon geologic setting, in quartz veins cutting rocks of the Southern Espinhaço Range, a study was carried out on the geology and mineral chemistry of these deposits in three localities (Buenópolis, Olhos d'Água and Diamantina), as well as to make U-Pb laser ablasion MC-ICP-MS geochronological determinations in the Diamantina and Olhos d'Água samples. In Buenópolis, monazite specimens are common as twin crystals, occurring in colluvial gravel deposits in a contact zone between the Espinhaço Supergroup with the Macaúbas Group. The Olhos d'Água occurrence is in metric oval-shaped pockets hosted in metapelitic rocks of the Macaúbas Group, where large crystals have been discovered. In Diamantina, millimeter-size crystals were studied as broken grains recovered in a colluvial deposit near the Caeté-Mirim river. Certainly in the first and in the third cases, such grains came from the abundant regional quartz veins. Electron microprobe analyses showed similar oxide values for the three deposits, but with some chemical specific aspects. The samples have been identified as monazites-(Ce), locally Nd-rich; the Diamanti...

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