The stress analysis of the anterior teeth of the molar distalization with clear aligner

• 1、Department of Orthodontics, School of Stomatology, Lanzhou University, China

Abstract：Objective: Use the finite element method to analyze the biomechanical effects of the anterior teeth during the process of molar distalization by applying different anchorage values and discuss the needs of anchorage for molar distalization. Methods: A three-dimensional finite element model of the maxillary denture- periodontal membrane- alveolar bone-clear aligner was established. According to the different forms of the molar distalization, it is divided into groupⅠ (second molar moved only) and groupⅡ (first molar and second molar moved at the same time). According to the value of the anchorage applied to the canine, the group is divided into:ⅠA (0g),ⅠB (100g),ⅠC (150g), andⅠD (200g);ⅡA (0g),ⅡB (100g),ⅡC (200g),ⅡD (300g). The stress of the periodontal ligament and the displacement trend of the anterior tooth are compared and analyzed in the finite element analysis software. Results: When groupⅠusing clear aligner to move a molar far away, applying 100g anchorage to the canine can effectively reduce the anterior teeth labial displacement, while the periodontal ligament stress is the smallest. When groupⅡusing clear aligner to move two molars far away, applying 300g anchorage to the canine can effectively reduce the anterior teeth labial displacement, while the periodontal ligament stress is the smallest. Conclusion: Choose different forms of molar distalization, the anchorage of the corresponding force value can be increased. When the "A" mode to push one molar away was chosen, 100g anchorage force can be applied. When the "V" mode to push two molars away at the same time was chosen, 300g anchorage force can be applied.

Keywords： Orthodontics molar distalization clear aligner stress analysis finiteelement method