Analysis Of Stress Distribution Of Maxillary Embedded Canine Periodontium And Dynamic Simulation Of Its Movement Under Orthodontic Force

The treatment of malocclusion is to use force originating from appliance on tooth. In the clinic of orthodontics, how to use correct force is a very interesting problem for every orthodontist. It is very important to know the distribution of stress in the movement of tooth. With the rapid development of computer technology, finite element method becomes a very effective way in the study of oral biomechanics. As a numerical analysis method, finite element method was used in orthodontic tooth movement extensively. But most of studies in this field, especially about the treatment of embedded canine, were under static station. There are lack of dynamic reports presently.Purpose:The three dimensional finite element model of a maxillary embedded canine and its supporting tissue were established using CT method and finite element method. A 150g pull was used to embedded canine vertically. The purpose of this study was to analyze the stress distribution of periodontal tissues in different periods, and simulate dynamic course of tooth movement.Method:A patient with a completely bone embedded maxillary canine was chosen. The CAD model of the canine and its surrounding tissues was established using CT equipment Mimics and Unigraphic. The latter force analysis was carried using three-dimensional finite element software.Results:1. A similar model of maxillary embedded canine periodontium and its supporting tissue were established.2. Under 150g pulling, there was a very high mechanical stress value area located at toot tip and cuspis of the embedded tooth, and there was a stress concentration area at the side facing drawing forces, and the biggest stress also emerged at the cuspis. In a period of tooth movement, the stress distributions were similar at every stage.3. In a period of tooth movement(28days), the embedded canine moved 0.589mm at the first stage(0-7days), and 0.713mm at the second stage(8～21days), and 0.276mm at the third stage(22-28days).Conclusion:1. The FEM models of maxillary embedded canine established by CT,Mimics,UG and MSC have good degrees of accuracy and geometry similarity that can meet the needs of simulation loading.2. In a period of tooth movement, the stress force distributions of embedded tooth were similar in different stage. There was a very high mechanical stress value area located at toot tip and cuspis of the embedded tooth, and there was a stress concentration area at the side facing drawing forces, and the biggest stress also emerged at the cuspis.3. The graph of tooth movement in a period(28days) can represent the movement trend of embedded tooth.