Finite Element Traction Position Different Mobile Mandibular Anterior Teeth Analysis

Location of anterior teeth is crucial to facial aesthetic in orthodontic treatment, it often needs to adjust the position of the anterior teeth to get the best relationship of lips and teeth. It provides important guiding significance to find out rules of teeth movement and to study the mechanisms of periodontal ligament, alveolar bone remodeling and root resorption through analysing the sress-strain characteristics of teeth,periodontal ligament and alveolar bone under different forces, and guide orthodontists to use the forces.Correction of malocclusion is mainly applied orthodontic force through the appliance, acting on the dislocation of the teeth and periodontal tissue, the dislocation teeth corrected or changed to the jaw, the restoration and reconstruction of the jaw force balance. The effect of orthodontic force under the tooth, study of stress and strain of periodontal tissue and alveolar bone, are of important guiding significance to further study the mechanism of orthodontic teeth movement and periodontal membrane, alveolar bone remodeling and root resorption, so as to guide the orthodontic clinicians correctly grasp and use the optimal orthodontic forces.With the rapid development of computer, the finite element analysis method has been an effective means of oral biomechanics. Clinical orthodontic tooth movement is a continuous and dynamic process, tooth force is continuous and the position change of teeth and change. In this study, in order to simplify the calculation, is the study of the tooth stress in the initial state under orthodontic force analysis, static analysis, need to be combined with the actual situation in clinical orthodontic treatment. Objective:To establish a three-dimensional finite element model including the tooth structure, periodontal ligament, pulp, alveolar bone, and the arch wire appliance of mandibular incisiors and canines, The stress on the lower jaw traction role in the mandibular anterior teeth and canines distribution and displacement were compared and analyzed to explore the stress on the teeth, periodontal ligament and alveolar bone when forces were pulled in different positions. And to provide a theoretical basis for predicting trends of teeth movement in orthodontics. Methods:Select three mandibular incisors and canines with normal tooth morphology, use spiral CT to scan the teeth and get the data of three-dimensional shape of every tooth. Establish a three-dimensional finite element model of mandibularteeth-periodontal ligament-alveolar bone-the arch wire appliance using software Mimics10.0and ANSYS14.0, then the model were carried out on two simulated loading, that is sressing150g on the hook mesio or distal the canine, analysis the initial stress distribution and displacement of incisors and canines. Results:In this study, a three-dimensional finite element model of mandibular teeth periodontal ligament-alveolar bone-the arch wire appliance were analyzed as the object, the stress and displacement of mandibular teeth,periodontal ligament and alveolar bone when the forces were loaded on different positions using ANSYS14.0.The conclusions follows:1. The varing rules of the stress on the same tooth were the same basicly under different loading.2. Under the two loading ways, maximum displacement of central incisor, lateral incisor equals approximately,the moving trend of both was mesial-labial tipping or translation,while the canine was distal-lingual. Under the first loading, the maximum displacement of canine was greater than the second one;the incisors and canines elongated coronally under the first way, but under the second one, the central incisors elongated coronally, while the lateral incisors and canines intruded rootly.3.Maximum stress on periodontal ligament of central incisors, lateral incisors and canines appeared around the alveolar crest,it increased gradually from the apical to the alveolar crest. Under the first loading, the maximum stress on periodontal ligament of incisors and canines was greater than the second way, but lateral incisor was just the opposite.