Three-dimensional Finite Element Analysis Of The Mandibular Teeth Distalization With Micro-implant Anchorage

Objectives: The three-dimensional finite element model of mandible,MBT bracket,arch wire and micro-implant was established.By three-dimensional finite element analysis,this study discussed the mandibular teeth distalization with micro-implant anchorage,observed and compared with the mobility case of the individual teeth distalization and the group of the teeth distalization,observed the changes of the arch form and occlusal plane when the group of the teeth distalization.Then it is concluded that the orthodontic force,which is the most suitable for distalizing the teeth from the canine to the second molar,and provided a theoretical basis for the use of the orthodontic clinician.Methods: A young volunteer with individual normal occlusion was choosed as our experimental subject.A CBCT scan was performed on the Stomatognathic System.The CT data of the volunteer was reconstructed by using Mimics software;croe software established the solid model of the bracket 、 arch wires and micro-implants,and the above three-dimensional model was then assembled by means of substantiation,using finite element analysis software Abaqus to analyse.When the micro-implant position between the mandibular first molar and second molar,using 0.019 * 0.025 inches stainless steel wire to stresse 150 g for distalizing the mandibular second molar,then observing the movement trend and initial displacement of its three-dimensional direction;And when the micro-implant position in the external oblique line,using 0.019 * 0.019 inches stainless steel wire to stresse respectively 150 g,200g,250 g,300g,350 g,400g for distalizing the canine to the second molar,then observing the movement trend and initial displacement of its three-dimensional direction and stress distribution of periodontal ligament.Results: When using horizontal force for the mandibular second molar ditalization,the second molar was inclined to move,and with the elongation of the molar;but when the group of the teeth distalization,the mandibular second molar was bodily movement approximately,and there was a intrusion trend in the vertical.The most suitable orthodontic force of the group of the teeth distalization was 250 g.The counterclockwise rotation of the mandibular occlusal plane when the the group of the teeth distalization with micro-implant anchorage.Conclusions: There are significant differences in the two ways of the molar distalization.The group of the teeth distalization is more beneficial to the teeth bodily movement and the vertical control.The most suitable orthodontic force is 250 g to use the micro-implant in the external oblique line for the group of the teeth distalization.