Fabricação de microeletrodos para aplicações em microscopia eletroquímica de varredura / Fabrication of microelectrodes for applications in scanning electrochemical microscopy

AUTOR(ES)

Pollyana Souza Castro

FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

19/08/2011

RESUMO

In this study, platinum microelectrodes were fabricated with a Micropipette Puller and used in Scanning Electrochemical Microscopy (SECM) to obtain information on the acid erosion of tooth enamel. The sealing and polishing of the active area of the fabricated devices are considered critical steps in the construction process, hence a vacuum pump was used to enhance the efficiency of the seal of the glass microfiber. The parameters of the equipment were optimized allowing a reproducible and efficient method to be developed. Thus, microelectrodes of various materials and dimensions were constructed and evaluated for use in SECM. An alternative method for reducing the size of the probe was also proposed. A careful polishing of the probe was done and by comparing theoretical and experimental approach curves, microelectrodes with RG values near to 15 were obtained. The acid erosion of dental enamel was investigated using SECM and a platinum microelectrode as a probe to H+ ions. The obtained images revealed a significant and relatively fast consumption of H+ ions at the interface enamel-acid solution, as a consequence of the demineralization reaction of the protective layer. SECM images also showed topographical differences with respect to the tooth enamel and after an exhaustive process of acid demineralization, the thickness of the layer of eroded enamel was estimated. By using approach curves it was concluded that the thickness of the eroded enamel layer was around 18 µm after 48 hours of exposure, this value being enhanced to 25 µm after 96 hours. Atomic Force Microscopy was also used to confirm the morphological changes after exposing the enamel to different beverages with high acidity. Accordingly, one can conclude that the acid erosion of enamel exposes the dentin to the oral environment and creates problems associated with dental hypersensitivity.

ASSUNTO(S)

acid erosion dental enamel erosão ácida esmalte dentário microelectrodes microeletrodos secm secm

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