This systematic review synthesizes available evidence on biomedical 3D-printed scaffolds intended to support root canal disinfection and regenerative endodontics. Regenerative endodontic procedures aim to restore a functional pulp–dentin complex, particularly in necrotic immature teeth, but successful outcomes depend on reducing intracanal microbial load without harming resident or recruited progenitor cells. Emerging additive-manufactured platforms promise tailored architecture, controlled drug release, and improved handling compared with conventional scaffolds. We identified open-access original studies evaluating 3D-printed or 3D-bioprinted constructs relevant to antimicrobial delivery and, or pulp–dentin regeneration. Evidence includes extrusion-printed gelatin hydrogels loaded with quaternary ammonium antimicrobials, and polymer, ceramic or polymer, bioactive composite scaffolds assessed with human dental pulp stem cells. Overall, current data suggest that 3D-printed scaffolds can be engineered to balance cytocompatibility and antimicrobial activity, while promoting odontogenic, osteogenic marker expression and mineralized tissue formation. However, the evidence base largely remains preclinical, with limited direct intracanal regenerative models and scarce clinical translation. Standardized outcome measures, head-to head comparisons with established disinfection protocols, and well-designed in vivo studies within true endodontic spaces are needed to clarify safety, efficacy, and real-world feasibility.