Design and validation of an innovative Nickel-Titanium endodontic instrument with hollow cross-sectional design

This research introduces an innovative hollow cross-sectional design for rotary endodontic instruments to enhance their mechanical performances. The study begins with a theoretical framework analyzing the mechanical limitations of conventional solid-core instruments, particularly their susceptibility to cyclic fatigue and torsional stresses. A parallelogram-shaped cross-section was selected to balance cutting efficiency with mechanical strength. Finite Element Analysis (FEA) was employed to simulate stress distributions and predict failure points, followed by experimental validation through mechanical testing, including bending, cyclic fatigue, and torsional resistance assessments. Results demonstrated that the hollow instrument significantly reduced stress concentrations while improving flexibility, cyclic fatigue and torsional stress distribution thereby enhancing its performance in clinical applications. The integration of Electrical Discharge Machining (EDM) enabled precise manufacturing of the hollow structure without compromising the material’s superelastic properties. The findings suggest that this novel design optimizes endodontic instrumentation by improving mechanical performances and reducing instrument fracture risks, paving the way for further refinements and clinical adoption.