Estudo in vitro de braquetes ortodônticos: avaliação biomecânica e liberação de íons
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Data
2008-08-05
Autores
Guimarães, Andréia Cecilia May [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Braquetes ortodônticos são feitos de diversos tipos de materiais, tais como, metais, cerâmicas e polímeros. Entre todos os materiais metálicos, o aço inoxidável é o mais empregado devido ao seu baixo custo associado a sua resistência à corrosão. No ambiente oral, eles estão sujeitos a fluídos agressivos e variações de pH, levando a liberação de íons nos tecidos e fluídos. Modificações na superfície destas ligas foram realizados utilizando tratamentos mecânicos, eletroquímicos, químicos e físicos. O carbono amorfo hidrogenado (a-C: H) preparado para técnicas de deposição apresentam muitas propriedades atraentes como alta dureza, serem químicamente inertes e biocompatíveis. Neste estudo in vitro, filmes de a-C:H foram depositados em braquetes ortodônticos pela técnica de deposição química por plasma de radiofreqüência (PECVD) e inibiu a liberação de íons níquel. Após o tratamento de superfície, os braquetes foram colados em incisivos bovinos com uma resina composta e as amostras foram imersas em soro fisiológico por 30 dias à 37 º C. Durante o tempo de imersão as amostras foram lavadas e imersas em flúor diariamente. Antes da imersão, o arranjo estrutural dos filmes foi analisado por espectroscopia de Raman e medidas do ângulo de contato foram realizadas, a fim de avaliar a molhabilidade da superfície. Espectrometria de absorção atômica foi usada para medir a liberação de elementos a partir de amostras e a análise superficial foi realizada em microscópio eletrônico de varredura (MEV). Os resultados mostraram que o revestimento previne a liberação de Ni dos braquetes nos testes estatísticos e o níquel foi liberado de outros grupos sem tratamento de superfície . A análise de variância não indicou diferença significativa entre os grupos depois do ensaio de cisalhamento.
Orthodontics brackets have been made from a variety of materials such as metals, ceramics and polymers. Among all the metallic materials, stainless steel are the most popular due low cost associated with reasonable corrosion resistance. In oral environment, they are subject aggressive fluids and pH variation can be leave nickel ions release to body tissues and fluids. Surface modifications of these alloys have been realized using mechanical, electrochemical, chemical and physical treatments. Hydrogenated amorphous carbon (a-C:H) prepared by deposition techniques have very attractive properties such as high hardness, chemical inertness and biocompatibility. In this in vitro study, a-C:H films were deposited on orthodontics brackets by r.f. plasmaenhanced chemical vapour deposition (PECVD) from inhibited nickel ions release. After treatment, brackets were bonded to bovine incisors with a composite resin and samples were immersed in physiological serum for 30 days at 37 ºC. During immersion time samples were brushed and/or immersed in mouthwashes daily. Prior immersion, the structural arrangement of films was probed by Raman spectroscopy and contact angle measurements were carried out in order to evaluate the wettability of surface. Atomic absorption spectrophotometry was used to measure the release of elements from the samples and SEM for surface analysis. Results showed that the coating prevents Ni release of brackets for statistic test and nickel was released for others groups. Analysis of variance no indicated significance different among groups after shear testing.
Orthodontics brackets have been made from a variety of materials such as metals, ceramics and polymers. Among all the metallic materials, stainless steel are the most popular due low cost associated with reasonable corrosion resistance. In oral environment, they are subject aggressive fluids and pH variation can be leave nickel ions release to body tissues and fluids. Surface modifications of these alloys have been realized using mechanical, electrochemical, chemical and physical treatments. Hydrogenated amorphous carbon (a-C:H) prepared by deposition techniques have very attractive properties such as high hardness, chemical inertness and biocompatibility. In this in vitro study, a-C:H films were deposited on orthodontics brackets by r.f. plasmaenhanced chemical vapour deposition (PECVD) from inhibited nickel ions release. After treatment, brackets were bonded to bovine incisors with a composite resin and samples were immersed in physiological serum for 30 days at 37 ºC. During immersion time samples were brushed and/or immersed in mouthwashes daily. Prior immersion, the structural arrangement of films was probed by Raman spectroscopy and contact angle measurements were carried out in order to evaluate the wettability of surface. Atomic absorption spectrophotometry was used to measure the release of elements from the samples and SEM for surface analysis. Results showed that the coating prevents Ni release of brackets for statistic test and nickel was released for others groups. Analysis of variance no indicated significance different among groups after shear testing.
Descrição
Palavras-chave
Ions - Liberação, Tratamento de superfície, Braquetes ortodônticos, Nickel release, Surface treatment, Orthodontic bracket
Como citar
GUIMARÃES, Andréia Cecilia May. Estudo in vitro de braquetes ortodônticos: avaliação biomecânica e liberação de íons. 2008. 79 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculade de Engenharia de Guaratinguetá, 2008.