Mechanical Properties and Surface-Bacteria Interactions of 3D-Printed Dental Photopolymers

Resins printed via stereolithography are increasingly common in digital dentistry, yet the impact of production parameters on their performance remains considerable. This study examined the mechanical, tribological, and antibacterial performance of two stereolithography resins intended for restoration (white) and denture (pink) applications, selecting three different exposure times (4.5, 6, and 7.5 s) as the fabrication parameter. Compression tests showed that the white resin lost ductility with increasing exposure time, presenting statistically significant decreases in failure strain and toughness. In contrast, the pink resin maintained a stable failure strain and reached its peak energy absorption capacity at 4.5 s. Statistical analysis confirmed that the two resins responded differently to UV exposure, demonstrating that the impact of exposure time varied depending on the resin type. Furthermore, increasing exposure time significantly reduced surface roughness without a statistically significant effect on hardness. Antibacterial assessment revealed contact-mediated growth-inhibitory effects depending on strain and resin type. Accordingly, optimal exposure time was resin- and property-dependent: 7.5 s favored white resin surface quality, whereas 4.5 s maximized pink resin strength and toughness. Tailoring exposure time to both the specific resin and targeted property is crucial for enhancing the clinical longevity and structural reliability of dental applications.