Different Orthodontic Archwire Damping Properties Of Dynamic Three-dimensional Finite Element Analysis

Objective:This study was designed using CT scanning with a variety of graphics software, to build three-dimensional finite element model, and to assembled nickel titanium orthodontic archwire and stainless-steel orthodontic archwire between central incisors. The purpose of the study was to clarify the difference between the both archwires on occlusal force transmission during orthodontic treatment.and to provide theoretical guidance.Methods:1,The three-dimensional finite element model.By spiral CT scanning , a young female volunteers to get head CT images , integrated application Mimics, Rapidform, and Abaqus software to build three-dimensional finite element model,Finally, three groups was divide: no arch wires finite element model of maxillary (Wireless Model, WL model); with stainless steel wire of the maxillary arch finite element model (StainlessSteel Model, SLS model); and with nickel titanium arch wire finite element model of maxillary (TiNiAlloy Model, TNA model).2,Loads and calculation.The boundary condition was set as fixed constraint on the basal portion of maxillary ; the loading condition of force was applied on the occlusal surfaces of the teeth supposedly as an occlusal force,load curve was a trapezoidal form of square wave pulse load, load size 50N, load duration 0.1ms.Calculated and plotted out the load condition of the root, periodontal ligament of the stress distribution and stress-time curve.Results:1,Three groups under the same load model, the load side of tooth movement showed a gradual decay over time, the law, the maximum amplitude of vibration occurred in the first period. Orthodontic archwire and the assembly will reduce the frequency response correction system, an increase in the vibration cycle incisors. SLS model will be compared with the TNA model, SLS's response frequency is slightly lower, slightly longer period. Not loaded side of tooth movement were gradually increased over time first and then gradually decay over time the law. SLS model the longest decay time, TNA model and WL model for time spent close to decay. SLS models, TNA model and WL model for non-load side of the central incisors of the time compared to the maximum amplitude displacement curve, the former increased by 3.03 times, while the latter increased by 48.7%.2,Three groups under the same load model, the load side of the incisor periodontal ligament in the maximum Von Mises stress appears time TNA model similar to WL model (t = 0.13*10-3s, the maximum stress occurs in the neck near the buccal side), SLS model appeared at the latest (t = 0.39*10-3s, the maximum stress occurred in the central incisor distal neck). Non-load side of the incisor periodontal ligament in the maximum Von Mises stress appears time were WL TNA> WL.3,Three groups under the same load model, the load side of the root of the maximum Von Mises stress of size, time of occurrence and the occurrence of similar position. Load side of the root of the maximum Von Mises stress appears time were WL TNA> WL.Conclusion:The results showed that high damping capacity of nickel titanium arch wire had an obvious ability to buffer the transmission of occlusal force to the PDL than stainless steel arch wires.