Study On Mechanical And Biological Properties Of 3D Printed Nickel Titanium Alloy Micro Implant Anchorage

Research purpose: Through finite element analysis and in vitro mechanical property test,the stability of Micro Implant with personalized thread shape,thread spacing and grooved or not was studied under different bone mineral density.Through the biological performance experiment,the effects of titanium alloy micro implant anchorage and nickel titanium alloy micro implant anchorage with low elastic modulus on biological properties at different loading times are compared,which provides a theoretical basis for the clinical selection of loading time and the selection of new implant anchorage materials.Methods: Combined with orthogonal test,through finite element analysis and in vitro mechanical test,the experimental factors are thread shape,pitch,bone condition,notch and pull-out angle.Four levels were determined for each factor.L16(45)orthogonal test was used to determine the influence of the best thread shape and bone tissue on the initial stability of the anchor nail.The best thread shape was implanted into rabbits,and the maximum implantation torque,maximum screw out torque and maximum pull-out force were measured.The effects of different loading time on the anchorage stability of Ni Ti alloy and titanium alloy micro implants were studied.Research results:The orthogonal test results comparing the finite element analysis method and in vitro mechanical experiment show that the anti support thread has good mechanical properties.The thread shape and thread spacing can be selected according to the specific bone conditions.The best thread shape is the anti support thread.The results of animal experiments showed that there was no significant difference between Ni Ti alloy implant anchorage and titanium alloy implant anchorage in the initial stability test.Different loading time has obvious difference on the stability of micro implant.Conclusion: 1.The thread shape design,bone tissue conditions and tensile loading direction are related to the initial stability of the implant.Under different bone conditions,the micro implant anchorage nail with pitch gradient can improve the initial stability of micro implant.2.The anti support thread can improve the stability of micro implant.3.The stability of micro implant is independent of the manufactured material and related to the loading time.