Three-dimensional Finite Element Analysis Of Maxillary Second Premolar With Vertical Root Fracture In Early Stage After Root Filling With Different Materials

This study is to investigate the stress distribution and crack propagation trend ofa maxillary second premolar with vertical root fracture in early stage with differentroot filling materials based on constructing a three-dimensional finite element modelof a maxillary second premolar with vertical root fracture in early stage according tofracture mechanics theory. This provides reference to the choice of clinical treatmentthrough a preliminary assessment of the effectiveness of different root fillingmaterials.Objectives1. To reconstruct a meticulous three-dimensional finite element model ofmaxillary second premolar with vertical root fracture in early stage which enduringtwo different loads and to investigate the stress distribution.2. To reconstruct a three-dimensional finite element model of maxillary secondpremolar with ceramic crown and different root filling materials which enduring twodifferent loads and to make finite element analysis.Methods1. An intact maxillary dentition was scanned with a CBCT. Then the sectionalimages of maxillary second premolar were imported to Mimics software and athree-dimensional finite element model was reconstructed. And we get the entitymodels of enamel, dentin, pulp and periodontal membrane and alveolar bone withoptimized surface and curved surface by the Geomagic Studio software. UnigraphicsNX software reading into the various components of the model through March stitched, which generates a complete entity model. Then import the Ansys14.5software and construct crack models with different depth and length and then get acomplete model with crack after meshing. The vertical and oblique force was loadedon the model and the stress distribution was analyzed.2. In order to simulate the clinical root canal filling and ceramic crownrestoration, we reconstruct models of ceramic crown, root canal filling materials(MTA and gutta-percha) and resin-core by Geomagic Studio and Unigraphics NXsoftware. Keep crack module and set the parameters of the correspondingmaterials,then assemble the modules and mesh. Get the three-dimensional finiteelement model of maxillary second premolar with ceramic crown and different rootfilling materials which enduring two different loads to investigate their differentinfluence on stress distribution of crack and crack propagation.Results1. A meticulous three-dimensional finite element model of maxillary secondpremolar with vertical root fracture in early stage was reconstructed. This model canensure that the finite element analysis is reliable.2. Analysis model for vertical and oblique loads distribution images ofmaximum principal stress, stress intensity factor and j-integral. And the extreme valueof stress under vertical loads was significantly greater than that under oblique loads.3. A three-dimensional finite element model of maxillary second premolar withceramic crown and different root filling materials was reconstructed. And the finiteelement analysis showed that extreme value of maximum principal stress, stressintensity factor and j-integral of MTA group were significantly less than gutta-perchagroup.Conclusions1. The three-dimensional finite element model of tooth tissue with crack module reconstructed by CBCT data combined with reverse engineering software Mimics,Geomagic Studio, finite element analysis software Ansys and Unigraphics NX ismeticulous.2. For teeth with early vertical root fracture, MTA filling compared totraditional gutta-percha filling has advantages in reducing the stress concentration inthe roots.3. Vertical loads may play an important role in the development of vertical rootfracture in early stage。...