Three-dimensional finite element analysis of maxillary first molar orthodontics

The stress distribution in periodontal ligament and alveolar bone has been analyzed. The movements (displacement, tilt and rotation) of the maxillary first molar have been computed and the locations of root resorption and the alveolar bone have been observed and forecasted. Finite element model of alveolar bone, the tooth and the periodontal ligament (PDL) has been established. Three-dimensional finite element analysis with the software of MSC. Patran has been accomplished. The stress distributions in periodontal ligament and alveolar bone are different and the displacement of tooth in buccal technique differs from that in lingual technique. When horizontal orthodontic forces are applied at the lingual crown surface, the compressive stress in the tooth and periodontal ligament is smaller than the tooth which forces are applied at the buccal crown surface. So it is more healthful for periodontal ligament in lingual technique than in buccal technique and there is less root resorption of the maxillary first molar in lingual technique than in buccal technique.