Evaluation of Printability, Color Difference, Translucency, and Surface Roughness over Time in a 3D-Printed TiO2-Containing Denture Base Resin: A Pilot Study

Recent evidence suggests that nano-TiO2 particles improve antimicrobial and physical properties when incorporated into dental prosthetic materials. However, there exists a paucity of information regarding their impact on material properties when the prosthetic materials are 3D-printed over time. The purpose of this study was to evaluate the time-dependent printability and surface property changes occurring in a 3D-printed denture base resin containing nano-titanium dioxide (TiO2) particles. A 0.4 wt% concentration of 30 nm rutile TiO2 nanoparticles was ultrasonically dispersed into a denture base resin. Disks were printed weekly using a Form 2 SLA printer until printing failed. Printability, surface roughness (Ra), color difference (ΔEab), and translucency parameters were measured across timepoints. Surface roughness was assessed via profilometry, while color and translucency were evaluated using a spectrophotometer under standardized conditions. Print failure occurred at week 8, beyond which the resin could no longer reliably produce full specimens. Ra roughness decreased from 3.83 µm to 0.48 µm, which denoted a significant time-dependent decrease (ρ = −0.733, p = 0.016). Color difference with the unmodified control declined from 26.32 to 17.13 ΔEab units (ρ = −0.976, p < 0.001). All printed samples exceeded the clinically acceptable thresholds for both Ra (0.2 µm) and ΔEab (<3.7). Although the printability of the resin–TiO2 mixture was maintained for 7 weeks, mixture homogeneity declined over time. TiO2 additions to a denture polymer produced significant changes in surface roughness and color that were not clinically acceptable. Results from this study illustrate the time dependence required for retaining surface properties in 3D-printed dentures containing nano-TiO2.