Fabricação de próteses dentárias definitivas em resinas impressas em 3D: avaliação de propriedades físico-mecânicas, ópticas e de estratégias de pós-processamento

Abstract

Additive manufacturing has emerged as a promising alternative for fabricating definitive dental prostheses, providing greater accessibility to the digital workflow and reducing operational costs. However, the physicomechanical, optical properties, and clinical performance of 3D-printed photopolymerizable resins can be significantly influenced by factors such as material composition, restoration thickness, and, most importantly, the post-processing protocols applied. The primary objective of this set of studies was to evaluate the physicomechanical and optical properties of 3D-printed resins used for definitive dental crowns, considering different printing technologies and post-processing strategies. Three specific objectives guided by this research: Objective 1: To evaluate the physicomechanical properties of 3D-printed resins indicated for definitive dental crowns using different printing systems. Objective 2: To evaluate the physicomechanical properties of two 3D-printed resins used for dental crown fabrication, varying the washing and post-curing methods, aiming to support the optimization of post-processing strategies in dental practice. Objective 3: To evaluate the influence of resin type and specimen thickness on light transmission through 3D-printed resins for definitive crowns, using four different light-curing units. Based on these studies, it was concluded that Voxelprint and Ceramic Crown demonstrated the best overall mechanical performance, while OnX Tough 2, despite achieving a high degree of conversion, exhibited a more porous microstructure and inferior mechanical behavior. Sculpture 2.0 showed the highest surface roughness and the lowest flexural and tensile strength. Additionally, it was found that washing methods and post-curing conditions have a direct impact on the mechanical properties of the resins, and high degrees of conversion alone do not guarantee superior structural performance. When comparing different resins, both material thickness and resin composition significantly affected light transmission, with exponential reduction observed in thicker and less translucent materials, potentially compromising the polymerization of the underlying resin cement. The ultraviolet light was totally blocked when the 3D-rpinted resins had more than 1.0 mm. These findings highlight the need for standardized post-processing protocols and the careful selection of materials within the digital workflow, considering their physicochemical, optical, and structural characteristics to ensure longevity, safety, and clinical predictability of 3D-printed dental prostheses.