Three Dimensional Finite Element Study Of Rapid Maxillary Expansion Using Implant Anchorage

Intraversion is a common malocclusion . Rapid maxilla expansion is an utility method that applied to correct arch constrict and active maxillary transversal growth . It can produce orthopedic effect to expansion palatal suture , that increment dental arch of maxilla to a dolescent . Half of the expansion is suture effect , and the other is tooth effect . However , the bony suture of adult tend to close , It is difficult to separate adult's palatal structure using conventional expansion method . By during expansion , abutment teeth can buccal tip , lingua tip downward sagging , which is side effect .As a new anchorage , implant has been widespread application . It can help to heighten teeth,intrusion,straighten,endoducte anterior teeth,distoplacement of molar and adjust intermaxillary relation . Implant had solve incoordinate of anteroposterior and vertical axes at present , but in trans-malocclusion seldom .Finite element method (FEM) is an accurate, efective biomechanical method , it has been applied to description of physical form changes and stress distribution in craniofacial structures with orthopedic force . It has been ten-more years to apply in stomatology . In Orthodontics , prosthodontics , implantodontics , and maxillofacial surgery , and other areas , scholars at home and abroad have done a lot of oral biomechanical research using FEM . Now, with the development of computer technology , finite element analysis has become an effective method for the study of the various branches of oral health care , teaching and research with a lot of theory . Objective The purpose of this study was to evaluate the biomechanical effect of RME with different anchorage and the same load conditions by using a 3D FEM . Provide a theoretical basis to decrease the adverse reaction during RME , improved RME method , increase the RME effect , raising the age of RME .Methods Spiral CT scanning , Mimics and Ansys software were employed in the study to construct the three-dimensional finite element model of maxilla . model 1: A three-dimensional finite element model , consisting of median palatine sutures, the first premolar and first molar with periodontal ligaments . In the basis of model 1 , put the implant into the bone during the maxillary second premolar and the first molar root perpendicular to the bone surface , from the alveolar ridge margin of about 10 mm formed model 2 . Loading 20 N force along the X-axis on model 1 and model 2 simulated clinical RME , calculated the displacement of the X-axis , Y-axis and Z-axis . Evaluation the jaw and the teeth stress distribution and displacement trends .Result In model 1 , the von-mises stress of the first premolar and first molar are larger than model 2 . The tensile stress of median palatine sutures in model 1 are slightly smaller than model 2 . Cross-sectional, two models median palatine sutures former open larger . Pyramidal displacement of maxilla a way from the midline was evident from the frontal view . The base of the pyramid was located on the oral side and the apex faced the nasal bone . the first premolar and first molar crown to buccal and root to tongue shift. But the displacement of model 1 are obviously . Sagittal upward , the jaw , alveolar and teeth of the two models trend to advancement . In the vertical direction, the maxillary alveolar displacement has a downward trend . in model 1 the palatal ortated forward and upward may lead to open bit . In model 2 , the first premolar and first molar has a small upward displacement .Conclusionâ‘ It is feasibile to use spiral CT tomography , Mimics and ANSYS software to construct the 3D finite element model of maxillary . In particular , it has a high degree of editorial and can be rotation arbitrary , free cutting , delete , extract any part . It can be observe and analysis in any way . The model provide a reliable basis to the biomechanical study of the jaw .â‘¡Normal maxillary complex has a strong decentralization under the expansion loading , its stress and displacement were small , that it can carry large external force . Median palatine sutures former open larger . Pyramidal displacement of maxilla a way from the midline was evident from the frontal view . The base of the pyramid was located on the oral side and the apex faced the nasal bone .â‘¢Compared to RME of fixed screw commonly , rapid maxillary expansion using implant anchorage can increase bone effects , reducing the effect of the teeth .â‘£RME using implant anchorage can increase bone effects , but it does not completely eliminate the effect of teeth . For adults , RME using implant anchorage can partly replacement surgery . However , it is only through surgery to solve severe stenosis .