Three-Dimensional Finite Element Analysis of Maxillary Molar Distalization Using Different Attachments with Clear Aligners
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Jingwen Chi, Yicong Liu, Lixia Yang, Shengteng Sun, Wen LIU
Objectives: To compare biomechanical characteristics of maxillary tooth in molar distalization against different orthodontic attachment. Materials and Methods: Three-dimensional finite models of maxilla molar distalization with clear aligner containing the different components(teeth,periodontal ligament,maxillary bone,clear aligner,attachment)was generated from a computed tomographic scan. According to the shapes of different attachment, four models were set up: non-attachment (model A), horizontal rectangular attachment (model B), vertical rectangular attachment (model C) and combine attachment (model D). Next, a finite element analysis was used to simulate the modalities of molar distalization. Results: The displacement rotation center of second molar of model A and B were located at the root furcation. In model C, the displacement rotation center of the buccal sides was located at the middle third of the mesiobuccal root, and the palate side was located at the coronal third of the palate root. In model D, the displacement rotation center of the buccal and palate side were located at the middle thirds of root. All the displacements of the anchorage tooth in the four groups tended were found mesial tipping movement. Conclusions: Applying attachments was more efficient for tooth displacement patterns. The second molars of the four groups all showed a clockwise tendencies of distal crown tipping and mesial root tipping. The model with a combined attachment of tooth movement was the most efficient, followed by traditional attachment models. When applying the molar distraction technique in clinical practice, care should be taken to strengthen the support to avoid unnecessary labial tipping of the anterior teeth.
Attachment, Finite element, Clear aligner, Molar distalization