Simulation And Experimental Study On Mechanical Properties Of Nickel-titanium Medical Endodontic Instruments

Endodontic treatment is the best treatment for pulp disease and periapical disease.As the core instrument of endodontic treatment,the performance of endodontic instruments directly affects the therapeutic effect.Due to the complicated shape of endodontic instruments,straightening,unscrewed and even breaking often occur in the process of working.In this paper,the bending and torsion properties of medical endodontic instruments were studied and parameterized by theoretical analysis,experimental test and finite element simulation.The main research contents are as follows:(1)Construction of mathematical model of endodontic instruments.The mathematical models of concentric regular triangle,concentric rectangle and eccentric rectangular cross section endodontic instruments were constructed respectively based on Archimedes helix parameter equation and isometric helix parameter equation.(2)Mechanical analysis of endodontic instruments under bending and torsional loads.Due to the diversity of cross sections of endodontic instruments,the cutting part of endodontic instruments was simplified as thin conical rods.Based on the shape memory alloy multi-linear constitutive model,the stress distribution,bending performance and torsional performance of endodontic instruments under bending and torsional loads were studied theoretically.(3)Test verification of the bending and torsional performance of nickeltitanium endodontic instruments.Finite element simulation and experiment were used to test and compare nickel-titanium wire samples and a medical nickel-titanium endodontic instrument,which verified the applicability and accuracy of the selected constitutive model,and laid a foundation for the subsequent research on the bending-torsion performance of nickel-titanium endodontic instruments by using finite element method.(4)Effect of structural design parameters on mechanical performance of endodontic instruments.Finite element method was used to compare the bending-torsion performance of nickel-titanium endodontic instruments with different sections,different pitch and different taper,and the influence of various parameters on the bending-torsion performance of nickel-titanium endodontic instruments was obtained,which provided reference for the optimal design and clinical application of nickel-titanium endodontic instruments.In this paper,medical endodontic instruments are taken as the research object,carries on the construction of mathematical model of nickel-titanium endodontic instruments,the mechanical analysis of nickel-titanium endodontic instruments under bending and torsional loads,the test verification of the bending and torsional performance of nickel-titanium endodontic instruments,the effect of structural design parameters on mechanical performance of nickeltitanium endodontic instruments and so on,provides theoretical support and guiding to improve the performance of nickel-titanium endodontic instruments and clinical treatment.