Microbiological behavior of 3D printing materials for indirect restorations: A scoping review.

Background: Although 3D-printed indirect restorations offer precision and reduced fabrication time, the literature still lacks consensus regarding their surface characteristics and microbiological behavior, factors that may reduce restoration longevity, reinforcing the need to consolidate the available evidence. The purpose of this scoping review was to map the available evidence on the microbiological behavior of 3D printing materials for indirect restorations. Material and Methods: The scoping review was conducted according to the guidelines of Arksey and O'Malley and the Joanna Briggs Institute, following the PRISMA-ScR checklist. The literature search was performed in PubMed, Scopus, and Web of Science databases, including in vitro, in vivo, in situ, and clinical studies addressing this topic. Results: Among the 20 included studies, 19 were conducted in vitro and only one in vivo. The main factors identified as reducing microbial adhesion were the incorporation of nanoparticles (such as ZrO2, TiO2, graphene, and silanized chitosan), appropriate surface polishing, and controlled post-curing, which decreased surface roughness and enhanced antimicrobial properties. Conversely, the absence of surface finishing, insufficient post-curing time, and certain polymer compositions were associated with increased bacterial adhesion. Conclusions: Both material modification and post-fabrication treatment are key determinants of the microbiological behavior of 3D-printed resins. Furthermore, factors such as printing parameters and finishing and polishing protocols have a direct influence on the microbiological performance of these materials.