Development and characterization of 3D-printed denture base resin composites having self-healing potential

Objective: This study aims to develop and characterize 3D-printed denture resin composites containing self-healing polyurea formaldehyde (PUF) microcapsules (TEGDMA as the core healing agent) for arresting microcracks formation and enhancing the mechanical durability of 3D-printed dentures. Methods: The PUF microcapsules containing TEGDMA as core material were synthesized in oil-in-water emulsion and characterized for size, surface morphology and thermal stability. 3D-printed denture base resin with 0, 5, 15, and 25 wt% content of the synthesized PUF were printed and evaluated by degree of conversion, surface morphology, topography, surface hardness, flexural strength, fracture toughness, self-healing efficiency, and fluorescent microscopic visualization of the microcracks’ self-healing event through the in-situ release of rhodamine B labelled healing agent from ruptured PUF microcapsules inside the resin matrices. Results: As compared to the control, a slight decrease was observed in the degree of conversion, surface hardness and flexural strength of the 3D-printed denture base composite modified with the PUF microcapsules. Results demonstrated that an increase in the microcapsule content significantly (p ≤ 0.05) enhances the fracture toughness and self-healing efficiency. The HPLC results analysis of the experimental groups demonstrated a controlled release profile of healing agent over time with the maximum release on day 7. The microscopic visualization findings demonstrated the successful encapsulation and intentional triggered release of the rhodamine B. labelled healing agent in the crack plane. Significance: The 3D-printed denture base resin composites modified with the PUF microcapsules showed a significant potential for microcrack self-healing and enhanced fracture toughness based on the content (wt%) of microcapsules.