Reabilitação oral estética e funcional em dissilicato de lítio, com técnica cut back modificada

RESUMO

A porcelana fundida ao metal (PFM) é o padrão-ouro para a reabilitação de pacientes com coroa total unitária e prótese parcial fixa (PPF). Ela tem boas propriedades mecânicas e biológicas, com taxas de sobrevivência muito altas. Esteticamente, elas não têm aparência natural. Em contrapartida, surgiram as porcelanas sem metal, com estética superior, mas com resistência inferior à das PFMs (porcelanas fundidas ao metal). No ano 2000, surgiu o dissilicato de lítio (LiO2), um material que combina excelente estética e resistência semelhante à do esmalte dentário (360 a 400 MPa). Nos últimos dez anos, os sistemas metalocerâmicos e livres de metal provaram ser eficazes para a fabricação de coroas e PPFs. O caso apresentado é de uma paciente com 58 anos de idade e alta exigência estética, parcialmente edêntula e apresentando próteses PFM antigas e deterioradas no setor anterior superior. O objetivo foi reabilitar estética e funcionalmente a paciente com coroas e PPFs em LiO2, aplicando uma técnica especial de processamento de LDS chamada “modified cut back”. Para isso, foi fabricada uma infraestrutura monolítica de LDS que cobre toda a parte oclusal, palatina e interproximal funcional dos dentes posteriores e anteriores, proporcionando resistência semelhante à das PFMs e excelente estética, através da aplicação de porcelana com camadas de nanofluorapatita em todo o lado vestibular.

Palavras-chave – Dissilicato de lítio; Próteses parciais fixas; Técnica cut back.

ABSTRACT

Porcelain fused to metal (PFM) is the gold standard, for rehabilitating patients with unitary full crown and fixed partial denture (FPDs). It has good mechanical and biological properties; with very high survival rates. Aesthetically they look unnatural. In contrast, metal-free porcelains appeared, with superior esthetics, but with lower resistance than PFMs. The year 2000 saw the appearance of lithium disilicate (LiO2), a material that combines excellent esthetics and resistance similar to dental enamel (360 to 400 MPa). In the last 10 years, metal-ceramic and metal-free systems have proven to be effective for the fabrication of crowns and FPDs. The case presented is a 58 years-old patient, with high esthetic demands, partially edentulous, with old and deteriorated PFM prosthesis in the upper anterior sector. Our objective is to esthetically and functionally rehabilitate our patient, with crowns and FPDs in LiO2, applying a special LDS processing technique that we call “modified cut back”. For this, we fabricate a monolithic LiO2 infrastructure that covers all the functional occlusal, palatal and interproximal part of the posterior and anterior teeth, giving similar resistance to PFM fixed prosthesis and excellent esthetics, through the application of nano fluorapatite layered porcelain in all the buccal aspects.

Key words – Lithium disilicate; Fixed partial dentures; Cut back technique.

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