Optimizing Polyurethane Root Canal Filling Via 3D Printing Parameters Abstract

To address the critical challenge of microleakage in endodontic therapy (30-58% failure rate in conventional techniques), this study pioneers a digital workflow integrating CBCT-based CAD with precision 3D printing to optimize polyurethane (PU) filler adaptation. • 30 human premolars underwent CBCT scanning (12μm resolution) and Mimics 20.0 3D reconstruction • Systematic scaling variations (100%,97%,96%,95%) tested on OctaveLight R1-50um 405 printer with RSN-201 resin • Quantitative assessment: Volumetric congruence (Geomagic Control X) Adaptation grading Microleakage quantification through dye penetration test 96% scaling achieved minimal volume discrepancy (0.05-0.11mm³) and 99.4-100.4% The 96% scaling ratio demonstrated superior performance with minimal volume discrepancy (0.05-0.11 mm³) and optimal material occupancy (99.40-100.42%). Achieved significantly better adaptation accuracy (filling grade 0.35) compared to other ratios (P<0.05), corresponding to clinically acceptable Class I sealing criteria. Microleakage reduction reached statistical significance at this scaling parameter. CAD/3D printing parameter optimization significantly enhances root canal filling adaptation accuracy. The 96% scaling ratio demonstrates superior performance in polyurethane filler fabrication, providing a precision-driven technical protocol for restorative dentistry.