Three-dimensional Finite Element Analysis Of Rapid Canine Tooth Movement In Periodontal Ligament Distraction

Objective:The aim of this article is to discuss canine distal movement and force distribution of periodontium, and provide theory basis for its clinical widespread application, by establishing three-dimensional finite element model of rapid canine movement. Methods:Through 64-slice spiral scanning, the phantom DICOM data of temporomandibular joint(TMJ), the mandible, and lower jaw denture section were obtained. With the Mimics software, Geomagic the Studio 8.0 software, Unigraphics the NX software, and the Ansys11.0 software together, three three-dimensional finite element models were established, including the canine movement under conventional condition(model 1), rapid canine movement through the periodontal ligament distracting osteggenesis(model 2), and rapid canine movement through reducing resistance and distracting method(model 3). The strength were loaded in three kind of models and the stress distribution of the canine, the pericementum, and the tooth socket bone were observed. Results:1. The three-dimensional finite element models of rapid canine movement via periodontium distraction osteggenesis established by the computer imagine analysis system and related software had fine geometrical and mechanical similarity. The canine in this model can be rotated arbitrarily. The modules can be added or reduced to carry on loading and restraining analysis. This model provide a good platform to analysis the biomechanical mechanism in rapid canine movement via periodontium distraction osteggenesis.2. Under the initial loaded stress, the biggest displacements on the three models occurred in canine crown on 1/3, biggest displacement quantity:model 3>model 2>model 1, and the canine crown displacement reduced gradually from crown to the root point. It indicated that in the process of canine distal movement, reducing resistance bone resistance, can accelerate the tooth moving speed effectively, simultaneously, the canine has distal motion tendency. No displacement of the first molar root was observed in the model 2 and 3.3. Under the initial stress, the most greatly equivalent stress in model 1 mainly concentrated in the middle of distal alveolar crest, but the in the mode 2,3 most greatly equivalent stress centralism area shifted to ligual distal alveolar crest. It indicated while under the action of force the canine distal movement, the canine, tended to move ligually.4. During the canine movement via periodontium distraction osteggenesis, there was the tendency of canine lingual rotation. Relevant measures should be taken to avoid the canine lingual rotation. Conclusions:1. The three-dimensional finite element models of rapid canine movement via periodontium distraction osteggenesis established by spiral CT scanning, related engineering softwares including Mimics, UG, et al. is precise and meet the requirement of various traction loading simulation.2. The periodontium distraction osteggenesis can accelerate tooth movement with few anchorage losing. This technique could be taken into consideration for the maximum anchorage and shorten treatment process, but the potential risk should be explained to patients.