Effect of Attachment on Movement Control of the Central Incisor Using Invisible Orthodontics: In-Silico Finite Element Analysis

We aimed to study the influence of attachment on central incisor movement control using invisible orthodontics with different translation or rotation targets. In this study, cone-beam computerised tomography was used to scan one 15-year-old volunteer’s teeth. Three-dimensional models of the mandibular central incisor, removable orthodontic appliance, and a rectangular attachment were reconstructed. A non-linear finite element simulation was used to analyse the influence of attachment on the stress distribution of the periodontal ligament of the central incisor under tooth rotation, mesial translation, and labial-lingual translation. For mandibular central incisor correction, using rectangular attachments increased the translation by up to 9.6%, increased the maximum stress on the periodontal ligament during the mesial translation correction, and reduced unwanted labial-lingual tilt by up to 40% during the rotation of the tooth. However, wearing an attachment during labial-lingual translation had no significant effect on the orthodontic results of the mandibular central incisor. In the mandibular central incisor’s invisible orthodontic, the rectangular attachment appliance increased the displacement and alleviated the side effect after applying mesial translation and tooth rotation. For labial-lingual translation, the application of a rectangular attachment had no pronounced effect on the results.