关键词: 隐形矫治, 附件, 厚度, 尖牙, 三维有限元分析

Abstract:

Objective To analyze the effects of different clear aligner thicknesses and attachment designs on the distal movement of the maxillary canine using the three-dimensional finite element method. Methods Based on imaging data from a patient treated in the Department of Orthodontics, Stomatology Hospital, Zhejiang University School of Medicine in 2023, a three-dimensional finite element model was established simulating the extraction of the maxillary first premolar and distal movement of the maxillary canine. Nine groups (A-I) were created according to aligner thickness (0.70 mm, 0.75 mm, 0.80 mm) and attachment type (no attachment, vertical rectangular attachment, torque control attachment). Stress distribution in the tooth and periodontal ligament, as well as three-dimensional displacement trends of the canine, were analyzed. Results Stress distribution was relatively uniform in all models without significant concentration. The canine exhibited distal tipping movement accompanied by palatal and intrusive displacement. Under the same attachment condition, the 0.75 mm aligner achieved the greatest distal movement. With the same aligner thickness, the torque control attachment group showed the smallest tipping angle, while the vertical rectangular attachment group achieved greater distal movement and optimal vertical control. The no-attachment group exhibited the largest displacement in both buccolingual and vertical directions. Conclusion The 0.75 mm thick aligner demonstrated the most sufficient displacement expression and the highest achievement rate of distal movement. Adding attachments significantly improved the efficiency of bodily tooth movement. Movement under the torque control attachment was closest to pure translation, while the vertical rectangular attachment provided a higher rate of distal movement and better vertical control.

Key words: invisible orthodontics, attachment, thickness, canine, three-dimensional finite element analysis