The Accurate Mechanical Modeling And Orthodontics Analysis Of Submaxilla Dentition

During the Orthodontics treatment, when the force loaded on the tooth is applied to the malposed tooth, the periodontal tissues are remold and the alveolar bone moves, finally tooth moves to a new place. The stress distribution in periodontal tissue plays a very important role in determining tooth movement. Therefore, it is useful and important for making treat scheme accurately to know about the pattern of stress and strain distribution of periodontal tissues by finite element method combined with the mechanical behavior of appliance. There are many reports on periodontal tissue stress analysis, but at present stress analysis is confined to single tooth other than dentition.Multiloop Edgewise Arch Wire (MEAW) technique, which was the valid method in the treatment of openbite and crossbite. The main characters of MEAW were: Controlling the tooth positions in three dimension (3D); The level and vertical parts of"L"can adjust the tooth respectively. Its arch wire is long, the changes of the rate is low, the power is soft and last long.In this paper, using CT rebuilding technique , finite element method , a series geometric and finite element models of the submaxilla dentition were developed at unify coordinate including periodontal ligament and alveolar bone, for simulating the anatomy and biomechanical characters of dentognathic tissue. Then loading was loaded on the tooth and the submaxilla dentition, simulating reacting force of the MEAW loaded in brackets was loaded to dentition. By the finite element analysis, the laws of stress on the teeth and displacement of the teeth and their periodontal tissues were shown. It will help to direct the clinical uses and modify MEAW in overbite in future.Conclusion: (1) The highest stresses were observed in the tooth surface, the lowest in the periodontal ligament, the alveolar bone between them. The periodontal ligament plays an important role in the transmission and cushion of forces acting on teeth, and its three kinds of principal stress are consistent. (2) Under vertical loading, the movement trend of tooth is downwards, appearing the smaller displacement at the direction of tongue .The clinical application ideal producing the movement along with the tooth major axis is very difficult. (3) The 2N tongue toward force add to the different part of the tooth , the tooth all expresses an inclination move. To obtain the whole movement of the tooth, a force and a moment are needed at the same time. (4) Using MEAW bow, the long elastics at MEAW the result is better, can carry out pressing the front tooth , the treatment purpose that open to bite is coming true .