Numeric simulation model for long-term orthodontic tooth movement with contact boundary conditions using the finite element method

摘要

Introduction Although many attempts have been made to simulate orthodontic tooth movement using the finite element method, most were limited to analyses of the initial displacement in the periodontal ligament and were insufficient to evaluate the effect of orthodontic appliances on long-term tooth movement. Numeric simulation of long-term tooth movement was performed in some studies; however, neither the play between the brackets and archwire nor the interproximal contact forces were considered. The objectives of this study were to simulate long-term orthodontic tooth movement with the edgewise appliance by incorporating those contact conditions into the finite element model and to determine the force system when the space is closed with sliding mechanics. Methods We constructed a 3-dimensional model of maxillary dentition with 0.022-in brackets and 0.019?×?0.025-in archwire. Forces of 100?cN simulating sliding mechanics were applied. The simulation was accomplished on the assumption that bone remodeling correlates with the initial tooth displacement. Results This method could successfully represent the changes in the moment-to-force ratio: the tooth movement pattern during space closure. Conclusions We developed a novel method that could simulate the long-term orthodontic tooth movement and accurately determine the force system in the course of time by incorporating contact boundary conditions into finite element analysis. It was also suggested that friction is progressively increased during space closure in sliding mechanics. Highlights ? We analyzed long-term tooth movement using contact conditions. ? A test bench to evaluate temporal change of M/F ratio was constructed in silico. ? We examined changes in the force system during space closure in sliding mechanics. ? Interaction between brackets and archwire must be modeled accurately for analysis. ? Friction at posterior teeth is progressively increased in sliding mechanics. ]]>