Evaluation of Post-Processing Time's Influence on Biocompatibility of 3D-Printed Denture Base Resins

In the continuous development of additive technologies and light-sensitive resins, the biological performance of 3D-printed resins is strongly dependent on photopolymerization efficiency and post-processing conditions. This study evaluated the effect of post-curing duration on the cellular response to two denture base resins using direct contact and indirect eluate-based pathways. Human gingival fibroblasts were assessed through viability, membrane integrity, nitric oxide production, fluorescence live/dead staining, and caspase-3/7 activity. As a result of contact between the cells and the surface interface of the specimen disks, reduced metabolic activity was noticed compared with the control under direct exposure, indicating cellular stress. Extended polymerization has been demonstrated to improve metabolic activity and reduce apoptotic signals for the V-Print dentbase resin, whereas FotoDent Denture presented a less uniform response under the same parameters. Therefore, for evaluating the cytotoxicity of light-sensitive resins, it is not sufficient to assess only the saliva-soluble substances released from the resin, such as residual monomers, but also the 3D printing parameters.