Uso de glazes comerciais para resina ortodôntica im pressa em 3D modificada em função do número de camadas e adição de agente antimicrobiano

Resumo (EN)

Objectives: This work evaluated the mechanical and biological properties of two commercial glazes, respectively, as a function of the number of layers and the addition of an antimicrobial agent.
Material and Methods: the performance of the first commercial glaze onto the resin surface, with no modifications, was evaluated when added to the surface of the corresponding 3D printing acrylic resin from the same manufacturer (Cosmos SplintTM, Yller) using flexural strength and modulus of elasticity. The commercial resin specimens were made in a 3D printer with the stereolithography technique (SLA) with dimensions of 25 × 2 × 2 mm and submitted to the three-point flexure test, after washing for 10 min and post-polymerization for 20 min. Subsequently, a commercial glaze was applied in different amounts of layers: no layer (control group), one, two and three layers. In another stage of the study, the second glaze (of a commercial methacrylate-based one, (PriZmaTM, Marketeck) was compared to its original formulation with the addition of essential oils with antimicrobial properties and was evaluated for cytotoxicity using keratinocytes. For the composition of the experimental glazes, the essential oils of lemongrass, copaiba and peppermint were added to the commercial glaze with magnetic shaking for 10 min. For the cytotoxicity test, the same procedure was performed, but the samples were made up of small, polymerized spheres inside the cell culture plates.
Results: The results revealed that the presence of two layers of glaze promotes favourable conditions for the integrity of the 3D-printed resin for orthodontic applications. The addition of essential oils altered the cell viability of the commercial glaze but was not sufficient to ensure recommended cell viability for the use of this material, although it is already marketed without antimicrobial agents.
Conclusion: The presence of the glaze layer proved important for ensuring the mechanical integrity of the resin. However, adding antimicrobials to these glazes does not guarantee sufficient cell viability when the base glaze possesses high cytotoxicity.