Effects of Postpolymerization and Aging Printed Denture Base Resin

Objectives: This study aims to investigate the effects of post-polymerization conditions on
the mechanical properties of 3D-printed denture base materials and evaluate
their performance after artificial aging under various post-polymerization
settings.
Methods: Specimens were fabricated using Digital Light Processing (DLP) technology
with denture base resin (FREEPRINT ® Denture, Detax GmbH). The printed
specimens were divided into three groups based on post-curing conditions: air
(A), vacuum (V), and nitrogen (N). After thermal aging (10,000 cycles),
changes in specimen performance were evaluated through tests for surface
roughness, hardness, flexural strength and modulus, and degree of
conversion (DC). Statistical analyses were conducted using one-way analysis
of variance (ANOVA), Tukey’s post hoc test, and regression analysis (α=0.05).
Additionally, the fracture surface characteristics were examined using
scanning electron microscopy (SEM).
Results: Before aging, the A group exhibited higher flexural strength and VHN, while the N group demonstrated superior flexural modulus and impact strength. Except for flexural modulus, no significant differences were observed among the three groups. After aging, all groups showed significant decreases in flexural strength, modulus, impact strength, and VHN, except for the V group, which maintained stable flexural strength and modulus. Two-way ANOVA revealed a significant interaction effect between post-polymerization atmospheres and artificial aging on flexural modulus and VHN (p < 0.001). The degree of conversion (DC) and cytotoxicity under different post-polymerization atmospheres met ISO standards, confirming acceptable material properties and biocompatibility.
Conclusions: This study confirmed that different post-polymerization atmospheres have no significant impact on the performance of DLP resin materials, while artificial aging significantly affects their properties. The DC and cytotoxicity of all groups met ISO standards, indicating good biocompatibility. These results demonstrate the clinical application potential of DLP resins, and future research is recommended to optimize conditions and evaluate long-term stability.