Impact of isopropanol post-washing duration and post-polymerization devices on flexural properties of 3D-printed denture base: An in-vitro study

This study evaluated the effects of varying post-washing times and different post-polymerization devices on the flexural properties of a 3D-printed denture base in an in-vitro study. A total of 48 specimens were printed using one 3D-printing denture base resin (Detax FreePrint Denture) and prepared according to ISO 20795-1:2013. The specimens were divided into two groups based on the independent variables: post-washing duration (6, 12, 90, and 720 mins) and post-polymerization devices (Otoflash in nitrogen gas [OTN], Otoflash in air [OTA], Otoflash in glycerol [OTG], NextDent LC-3D print box [ND], and a nail salon unit [NS]). Flexural strength and modulus were assessed, and SEM analysis was conducted to examine ductile fracture phenomena. Statistical analysis was performed using one-way ANOVA with Tukey and Bonferroni post hoc tests (α = 0.05). Both post-washing duration and post-polymerizing devices significantly influenced the flexural properties, though all values exceeded ISO standard requirements. Flexural strength for the post-washing duration ranged from 92.28 ± 5.56 MPa (6 mins) to 104.81 ± 3.71 MPa (12 mins), while flexural modulus varied from 2711.14 ± 19.54 MPa (720 mins) to 2962.04 ± 83.70 MPa (90 mins). Post-polymerization devices affected flexural strength (83.91 ± 2.68 MPa for NS to 113.97 ± 9.94 MPa for ND) and modulus (2320.47 ± 115.79 MPa for NS to 2997.55 ± 87.55 MPa for ND). Different isopropanol washing times and post-polymerization devices influenced the flexural properties of the 3D-printed denture base resin, although all results exceeded the ISO standard requirements. A 12-min washing time and the NextDent post-polymerization device produced the highest values. However, it is still recommended that users follow the manufacturer's instructions to ensure optimal and consistent outcomes.