Abstract:

Objective To investigate the displacement trend of maxillary first molar and the stress of periodontal tissue when the screw split-base appliance was moved 0.2 mm away from the maxillary first molar. Methods Cone-beam CT (CBCT) was used to scan volunteers’ maxillofacial oral conditions. Mimics 20.0 software was introduced to process the CBCT data. Geometric and physical modeling was performed using Geomagic Studio 2014 reverse engineering software and NX 1911 software. The model of maxilla-upper dentition-periodontal membrane-mucperiosteum-screw split-base appliance was established. The finite element software Ansys Workbench 2019 was used to move the model of screw split-base appliance to the maxillary first molar by 0.2 mm. The displacement trend, stress size and stress distribution of periodontal membrane of maxillary first molar were discussed. Results ①The single displacement of distal movement of maxillary first molar with screw splint-based appliance was large, and the teeth tended to move obliquely. ②When the appliance was used to remove the maxillary first molar, the stress was mainly distributed on the maxillary first molar and the maximum of the equivalent stress was located at the root bifurcation of the distal buccal root of the first molar. Conclusion The screw split-base appliance is recommended for the treatment of first molar with fully developed roots and mesial inclination of the first molar.

Key words: screw split-base appliance, three dimensional finite element, molar distalization