Three Dimensional Finite Element Anaysis of the Initial Tooth Displacement in Different Micro Implant-bone Interfaces using Micro-inplant Anchorage System

The purpose of this study was to compare the initial tooth displacement in different micro implant-bone interfaces (the initial stability, full osseointegration and fiberal integration) using micro-implant anchorage system. Three-dimensional finite elemental models of maxillary dentition were constructed. It included the space for extraction of two first premolars, the periodontal ligament, alveolar bone, micro-implant, arch wire (0.018times0.025 inch), straight wire bracket and Ni-Ti spring. Under the same orthodontic force of 1.5 N, the trend of the maxillary anterior tooth initial displacement in the different implant-bone interfaces was same, but the amount was different. No significant differences were noted of the maximum initial displacement in the full osseointegration and liberal integration implant-bone interface situations. But in the initial stability situation, the maximum displacement was significantly less than the other two situations. The results showed that the micro implant can provide stable anchorage in the full osseointegration and Liberal integration situations. But the orthodontic force transferred to teeth would be significantly declined in the initial stability situation, so it should be cautious handling.