Resistência à corrosão de liga experimental Ti-10Mo: efeito do tratamento térmico e de enxaguatório bucal à base de diclonato de clorexidina
Arquivos
Data
2010-09-22
Autores
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Embora a liga Ti-6Al-4V seja ainda empregada na área biomédica devido as suas excelentes propriedades mecânicas e resistência à corrosão, estudos tem demonstrado que a liberação de íons de vanádio e alumínio pode acarretar problemas de saúde a longo prazo, o que tem levado ao desenvolvimento de novas ligas de titânio. Ademais, implantes dentários de titânio podem sofrer destruição e repassivação do filme de óxido formado após sua implantação pela adsorção de proteínas contidas na saliva, enxaguatórios, cremes dentários, agentes clareadores e demais substâncias de trânsito bucal tornando-os susceptíveis à corrosão, reduzindo suas propriedades mecânicas ou comprometendo sua biocompatibilidade, potencial alergênico e desempenho clínico. Na atualidade novas formulações para ligas odontológicas à base de titânio têm sido propostas agregando elementos químicos com qualidades físicas e biológicas satisfatórias, tais como resistência ao desgaste, baixo módulo de elasticidade e comportamento biológico facilitador da osseointegração. O objetivo deste trabalho foi avaliar a resistência à corrosão da liga experimental Ti-10Mo quando submetida ao tratamento térmico e à ação de enxaguatório bucal contendo 0.12% diclonato de clorexidina. As medidas potenciodinâmicas foram realizadas em potenciostato PAR283 e célula de vidro convencional de parede dupla para termostatização. Utilizou-se eletrodo de referência Ag/AgCl, KClsat e auxiliar espiral de platina. Como grupo controle foi utilizada a liga experimental Ti-10Mo não tratada termicamente e sob ação da mesma solução higienizadora. Os resultados apontaram a formação de camada de óxido mais espessa e menos porosa quando a liga recebeu tratamento térmico. Concluiu-se que o tratamento térmico permitiu a formação de filme passivo com características protetoras.
Although the Ti-6Al-4V is still employed in the biomedical area due to its excellent mechanical properties and corrosion resistance, studies have shown that the release of vanadium ions and aluminum can cause health problems in the long term, which has led the development of new titanium alloys. Moreover, titanium dental implants may suffer destruction and repassivation of the oxide film formed after its deployment by the adsorption of proteins contained in saliva, mouthwash, dental creams, bleaching agents and other substances of oral transit making them susceptible to corrosion, reducing its mechanical properties or compromising its biocompatibility, allergenic potential and clinical performance. At present new formulations for dental alloys based on titanium have been proposed adding chemicals with satisfactory physical and biological qualities, such as wear resistance, low modulus and biological behavior of the facilitator osseointegration. The aim of this study was to evaluate the corrosion resistance of Ti-10Mo experimental alloy when subjected to heat treatment and the action of mouthwash containing 0.12% chlorhexidine diclonato. The potentiodynamic measurements were performed in cell and potentiostat PAR283 conventional glass double wall to thermostatization. We used the reference electrode Ag / AgCl, auxiliary spiral KClsat and platinum. The control group was used Ti-10Mo experimental alloy not heat treated and not subjected to the cleanser. The results indicated the formation of oxide layer thicker and less porous when the alloy received heat treatment. It was concluded that heat treatment allowed the formation of passive film with protective features in the presence of 0.12% chlorhexidine diclonato mouthwash.
Although the Ti-6Al-4V is still employed in the biomedical area due to its excellent mechanical properties and corrosion resistance, studies have shown that the release of vanadium ions and aluminum can cause health problems in the long term, which has led the development of new titanium alloys. Moreover, titanium dental implants may suffer destruction and repassivation of the oxide film formed after its deployment by the adsorption of proteins contained in saliva, mouthwash, dental creams, bleaching agents and other substances of oral transit making them susceptible to corrosion, reducing its mechanical properties or compromising its biocompatibility, allergenic potential and clinical performance. At present new formulations for dental alloys based on titanium have been proposed adding chemicals with satisfactory physical and biological qualities, such as wear resistance, low modulus and biological behavior of the facilitator osseointegration. The aim of this study was to evaluate the corrosion resistance of Ti-10Mo experimental alloy when subjected to heat treatment and the action of mouthwash containing 0.12% chlorhexidine diclonato. The potentiodynamic measurements were performed in cell and potentiostat PAR283 conventional glass double wall to thermostatization. We used the reference electrode Ag / AgCl, auxiliary spiral KClsat and platinum. The control group was used Ti-10Mo experimental alloy not heat treated and not subjected to the cleanser. The results indicated the formation of oxide layer thicker and less porous when the alloy received heat treatment. It was concluded that heat treatment allowed the formation of passive film with protective features in the presence of 0.12% chlorhexidine diclonato mouthwash.
Descrição
Palavras-chave
Higiene bucal, Titânio, Ligas dentárias, Oral hygiene