A Three-dimensional Finite Element Study Of The Stress On The Tooth Roots And Periodontal Tissue With The Change Of The Rocking Chair Archwire Diameter

ObjectiveThe objective of this study was to offer some insight into the “rocking- chair” archwire biomechanical system by constructing three-dimensional finite element model of the “rocking- chair” archwire and to analysis changes of stress on tooth roots and periodontal tissue with different wires in rocking chair archwire system. MethodsImages of teeth and mandible was got by 64 spiral CT scanner,and then was imported into Mimics 15 software for 3D reconstruction.Geomagic Studio 2013 software made surface model and NX8.5 built brackets and wires models respectively. The model was meshed in Ansys workbench 13.0, contact relation was set and materials were assigned. Brackets were loaded according by reacting fore.The finite element model was integrated in Ansys software and was evaluated at the end of the article. Constructing finite element model of mandible、teeth 、periodontal tissue and rocking chair round archwire with curve of 10。,depth of 2mm,diameter of 0.014in、0.016in、0.018in、0.020 in.Using Ansys workbench model to divide grid,setting the contact relation and assigning materials of each model.The strain on tooth root and periodontal tissue was calculated. ResultsIn paper 1,a mechanical model was established including mandible、dentition、periodontal tissue、MBT brackets and “rocking- chair” archwire. In paper 2,by using the three-dimensional finite element model established in paper 1,we found that force loaded on the tooth root was increased generally with the increasing diameter of arch wires. Stress on the first molar is smaller and on the incisor is bigger relatively,incisors and second molar tended to be intruded, canine and premolar tended to be extruded, and the lower dentition was tended to be leveled.ConclusionStress on tooth root and periodontal tissue changed with different diameters of archwire. Therefore, the diameter of the archwire should not be more than 0.018 in.