Comparative analysis of monomer elution, polymerization efficiency, mechanical properties and biocompatibility of 3D-printed provisional and permanent dental resins.

OBJECTIVE: This study compared monomer elution, degree of conversion, mechanical performance, and cytocompatibility of 3D-printed dental resins used for crown and denture-base applications.

METHODS: Four 3D-printed resins: provisional-crown (DTO), permanent-crown (CT), denture-base (DB), and permanent denture-base (DTT) (n = 7 per group). Elution of Triethylene glycol dimethacrylate (TEGDMA), Urethane dimethacrylate (UDMA), Hydroxyethyl methacrylate (HEMA), and Ethoxylated bisphenol-A dimethacrylate (Bis-EMA) into artificial saliva was quantified using Liquid chromatography-mass spectrometry (LC-MS). Fourier-transform infrared spectroscopy (FT-IR) spectroscopy evaluated the polymerization efficiency. Mechanical properties were evaluated using nanoindentation and three-point bending tests. Cytocompatibility was determined by exposing primary human gingival fibroblasts (HGFs) to resin extracts using an MTT assay. Statistical significance was set at α=0.05.

RESULTS: All materials achieved a high degree of conversion (>90%). DTO released significantly higher amounts of UDMA, TEGDMA, and HEMA than CT (p < 0.0001, p < 0.0001, and p = 0.0001, respectively). CT and DTT showed higher nano-hardness and elastic modulus than DB and DTO. DB exhibited higher flexural strength and modulus than DTT (p = 0.0423 and p = 0.0147, respectively). DTO showed the lowest HGF viability (20.98±5.73%), which was significantly lower than CT (43.55±8.18%; p < 0.0001), DB (38.80±9.52%; p = 0.0007), and DTT (41.53±3.71%; p < 0.0001), consistent with its higher monomer elution.

CONCLUSIONS: Within the limitations of the study, it can be concluded that the performance of 3D-printed denture resins varies according to the resin material used. DTO demonstrated the highest monomer elution and the lowest HGF viability, while permanent materials generally had superior nano-hardness and elastic modulus. DB also outperformed DTT in flexural properties.

CLINICAL SIGNIFICANCE: Material selection for 3D-printed denture crowns and bases should be considered by combined chemical, mechanical, and biological performance. Careful post-processing and indication-specific material selection are essential to reduce residual monomer-related biological risks and optimize clinical durability.