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Cimentação de onlays com resinas compostas aquecidas: uma revisão da literatura
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Os avanços na Dentisteria levaram à demanda de restaurações estéticas posteriores com longa durabilidade. Os onlays em resina composta, caracterizados pelas suas boas propriedades estéticas e mecânicas e pela sua fácil reparação, surgiram como uma resposta a esta demanda. Atualmente são cimentados à estrutura dentária mediante a utilização de cimentos resinosos que permitem uma adesão micromecânica da restauração à dentina. A principal causa da falha das restaurações indiretas está relacionada com a deterioração da integridade marginal e da eficácia da adesão, consequente de uma selagem incompleta da interface entre o dente e a restauração. Desde a introdução do bisfenol-glicidilmetacrilato na Dentisteria que a composição das resinas compostas tem evoluído continuamente, melhorando as suas propriedades físicas e expandindo os seus campos de aplicação clínica. Estas são frequentemente caracterizadas consoante o seu mecanismo de ativação em auto-polimerizáveis, de dupla-polimerização e foto-polimerizáveis. De forma a melhorar as propriedades das resinas compostas, foi proposto o seu aquecimento em dispositivos próprios previamente à sua utilização. Desta forma, resinas compostas com maior teor de partículas de carga, e, consequentemente, maior viscosidade, poder-se-iam tornar mais fluídas, facilitando a sua adaptação e penetração na dentina, e manter as suas boas propriedades mecânicas. Além disso, o aquecimento das resinas iria ter influência na polimerização, na medida em que a mobilidade dos radicais livres seria aumentada, levando a um maior grau de polimerização e, consequentemente, melhores propriedades mecânicas dos polímeros. Desta forma é importante estudar os efeitos do aquecimento de resinas compostas para posteriormente serem utilizadas como agente de cimentação de restaurações indiretas. Existem, no entanto, poucos estudos sobre o assunto em questão e a maioria debruça-se sobre as resinas de dupla polimerização, onde as desvantagens parecem superar as vantagens devido à drástica redução do seu tempo de trabalho que as torna, muitas vezes, inutilizáveis.
The advances on Dentistry resulted on the demand of esthetical posterior restorations with high durability. Composite onlays, characterized by their great esthetical and mechanical properties and their ease of repair, appeared as a response to this demand. Currently these are luted to the tooth with resin cements, which allows a micromechanical bond of the restoration to the dentin. The main reason for an indirect restoration failure is related to the deterioration of the marginal integrity and bond efficiency as result of an incomplete interface sealing between the tooth and the restoration. Since the introduction of Bisphenol-glycidyl methacrylate on Dentistry, resin composite formulations have been continuously evolving, improving their physical properties and expanding their clinical applications. These are frequently characterized by their means of activation in auto-cured, dual cured and photo-cured. In order to enhance composite resin properties, their pre-heating in specific devices was proposed. With it resins with higher filler content and, consequently, higher viscosity, could become more flowable, facilitating its adaptation and dentin penetration while keeping its good mechanical properties. Besides, resin heating would influence polymerization as the free radical mobility would be enhanced, resulting on a greater monomer conversion and better polymer mechanical properties. Therefore, it’s important to study the effects of pre-heating resins to be used as an indirect restorations luting agent. However, there’s few studies about this theme and the majority of them address dual-cured resins which seem to have greater disadvantages then vantages due to the drastic working time reduction, sometimes turning them unusable.
The advances on Dentistry resulted on the demand of esthetical posterior restorations with high durability. Composite onlays, characterized by their great esthetical and mechanical properties and their ease of repair, appeared as a response to this demand. Currently these are luted to the tooth with resin cements, which allows a micromechanical bond of the restoration to the dentin. The main reason for an indirect restoration failure is related to the deterioration of the marginal integrity and bond efficiency as result of an incomplete interface sealing between the tooth and the restoration. Since the introduction of Bisphenol-glycidyl methacrylate on Dentistry, resin composite formulations have been continuously evolving, improving their physical properties and expanding their clinical applications. These are frequently characterized by their means of activation in auto-cured, dual cured and photo-cured. In order to enhance composite resin properties, their pre-heating in specific devices was proposed. With it resins with higher filler content and, consequently, higher viscosity, could become more flowable, facilitating its adaptation and dentin penetration while keeping its good mechanical properties. Besides, resin heating would influence polymerization as the free radical mobility would be enhanced, resulting on a greater monomer conversion and better polymer mechanical properties. Therefore, it’s important to study the effects of pre-heating resins to be used as an indirect restorations luting agent. However, there’s few studies about this theme and the majority of them address dual-cured resins which seem to have greater disadvantages then vantages due to the drastic working time reduction, sometimes turning them unusable.
Descrição
Tese de mestrado, Medicina Dentária, Universidade de Lisboa, Faculdade de Medicina Dentária, 2016
Palavras-chave
Materiais dentários Restauração dentária Resinas compostas Teses de mestrado - 2016