The Three Dimension Finite Element Analysis Of The Torque And Torsion Mechanical Properties With Tip-Edge Plus Appliance

Objective: The purpose of this study is to use the finite element method to establish the finite models of different distal tiping Tip-Edge Plus brackets with different size and material arch wires and double wires.To explore the torsion and torque mechanical properties of Tip-Edge Plus brackets with different distal tiping by using double wire technique.And to explore the Tip-Edge Plus bracket’s preset torque expression law of mechanics.Methods: 1.With Pro/E.Wildfire5.0 software we respectively established maxillary incisor and canine brackets model,set up 0.012,0.014,0.016,0.018,0.020 inch round arch wire models with arch wire of 30 mm length.Then we established a 0.0215inch×0.028 inch standard maxillary arch wire model.The assembly models of brackets and different arch wire were established separately according to experimental groups,there were 31 groups in total which were outputted in STEP format.2.Completed assembly models of the Tip-Edge Plus brackets and arch wire were imported into CADfix8.0 software to repair.In MSC.Patran2005 software,the repaired models were grouped according to the brackets and arch wire,ligature wire and the finite mesh elements were divided.All the models were outputted by IGES format.3.In MSC.Marc.Mentat2005R3 software,we established the finite element model of the Tip-Edge Plus brackets and arch wires and set the material properties such as contact relationship of each models,the coefficient of friction,boundary conditions,as well as physical parameters.4.In torsion property group,we set lateral incisor bracket slot center node as the center point,the torsion displacement of 20 degrees was applied in clockwise rotation the in Y-axis horizontal axis.In torque property group,with incisor bracket slot center node as the center point,the torque displacement of 20 degrees was applied in counterclockwise rotation the in X-axis horizontal axis.5.In MSC.Mentat software we ran and calculated each model,collected relevant data of the corresponding torsion moment/torsion angle and drew torque moment/torque angle curve and histogram.Results: 1.The changing of the torsion moment of different distal tiping brackets and the torsion angle had the similar tendency.2.The torsion moment had a tendency to increase with the torsion angled as the arch wire size increasing.The trends of the torsion moment increasing with torsion angle in 0.014,0.016 inch archwire are flat.The trends of the torsion moment increasing with torsion angle in 0.018,0.020 inch archwire are precipitous.The torsion moment of the Australian wire was 2 times of the same size nickel titanium wire.3.The torsion moment of the double wire group were greater than 0.014 and 0.016 inchNiTi single round wire’s group.The torsion moment: 0.014inchNiTi+0.016inchNiTi>0.020inchAus>0.018inchAus>0.014inchNiTi+0.014inchNiT>0.012inchNiTi+0.016inchNiTi>0.016inchAus>0.012inchNiTi+0.014inchNiTi>0.014 inchAus.4.When maxillary incisor Tip-Edge bracket distal tiped 0°,the maximum torque moment was 22.37 Nmm.When maxillary incisor Tip-Edge bracket distal tipping was 25°,the maximum torque moment was 8.93 Nmm.The maximum torque moment had a tendency to decrease with the increasing of distal tipping.When the inclination of the brackets were the same,the maximum torque moment of stainless steel arch wire was 2 times bigger than the Beta-titanium wire’s.Conclusions:1.The law of the torque load expression was basically identical when the brackets had different distal tipping.With the single round wire correcting teeth,the torsion moment of the Australian wire was about 2 times of the same size nickel titanium wire.With the same material arch wire,the torsion moment were multiples of a certain relationship among different archwire each sizes.The multiple relationships of the Australian wire and nickel titanium wire were relatively consistent among the each sizes.The trends of the torsion moment increasing with torsion angle were more precipitous when the arch wire size was bigger than 0.016 inch.2.The application of the double wire showed that the linear stress pattern changed into plane stress model.With the application of auxiliary arch wire,the trends of the torsion moment increasing with torsion angle were apparently obviously.And its amplitude increased more prominent when the auxiliary arch wire’s sizes were increased.While the auxiliary arch wire size changed,the increased amplitude of the torsion moment was much bigger than the amplitude when the main arch wire size changed and torsional stress can be more evenly distributed throughout the brackets.3.Tip-Edge Plus bracket’s torque expression efficiency change with the different inclination of the brackets.With the decreasing of inclination of the bracket,the expression of the maximum torque moment increased gradually and the torque mechanical properties increased.The torque mechanical properties were determined by the horizontal distance and vertical distance between the two central ridge of the bracket.4.In clinical application,severe torsional teeth correcting can choose small size double wire combination,since the torsional force was more gentle,the torsion control performance is stronger.Mild torsional teeth correcting can choose the double wire combination of large size.In terms of torque control,different preset torque angle was choosed according to the different inclination of the bracket’s situation When the inclinations of the brackets were corrected or little inclinations were left,beta titanium arch wire could be considered to load with preset torque,which would create more gentle torque control.5.This research provided some certain theoretical basis for the application of double wire and preset torque in Tip-Edge Plus bracket.