Advanced dual-cured resin with excellent mechanical properties, printing accuracy, and biocompatibility for the application of 3D printing denture base

Objective Although DLP-based 3D printing shows great potential for dental restorations, it is still limited by poor fracture toughness and excessive shrinkage of denture base resins. Herein, a novel dual-cured resin formulation was proposed to address these issues. Methods The dual-cured liquid resins were prepared by blending photocurable acrylate (A) and thermally curable epoxy (E) resin at special ratios. Initially, the curing process was monitored, and the physical properties of the resin formulations were examined. Then, the mechanical properties were comprehensively investigated with particular emphasis on their correlation with phase distribution. Dimensional stability, printing accuracy, and biocompatibility were further measured. Results The hybrid resins exhibited satisfactory curing efficiency, reduced volume shrinkage, and proper wettability. Specifically, compared with the pure acrylate resin, the fracture toughness of maximum stress intensity factor and total fracture work of the A6E4 (mass A: mass E = 6:4) improved by approximately 279% and 59%, respectively. Further investigation of phase distribution revealed an interpenetrating network (IPN) that prolonged the crack propagation path and contributed to the brittle-to-ductile transition of the dual-cured resin. Moreover, the application feasibility of the hybrid resin was proven by the excellent printing accuracy and biosafety. Significance This research verified the feasibility of a dual-cured system for DLP printing denture bases, providing an advanced solution for addressing brittleness and polymerization shrinkage in 3D printing denture base materials.