Investigation of Sequential Aligner Treatment: Perspectives from a Mechanical Analysis

  • Dr Yuriko Nagara, Depertment of Orthodontics, School of Dentistry, Showa University, Japan
  • Ms Sachiyo Shimada, Graduate School of Science and Engineering, Tokyo Institute of Technology, Japan
  • Prof Michihiko Koseki, Graduate School of Science and Engineering, Tokyo Institute of Technology, Japan
  • Prof Hitoshi Kimura, Graduate School of Science and Engineering, Tokyo Institute of Technology, Japan
  • Kazutaka Hara, Graduate School of Science and Engineering, Tokyo Institute of Technology, Japan
  • Dr Taisei Fujikawa, Depertment of Orthodontics, School of Dentistry, Showa University, Japan
  • Prof Norio Inou, Graduate School of Science and Engineering, Tokyo Institute of Technology, Japan
  • Prof Koutaro Maki, Depertment of Orthodontics, School of Dentistry, Showa University, Japan

From the 3-Dimensional observation by Cone Beam X-ray CT and mechanical analyses, characteristics of aligner treatment in extraction case were evaluated.
Displacement of the experimental apparatus which simulated aligner treatment of crowding dentition was measured by laser beam. In FEM, orthodontic forces with an arbitrary scale could be calculated. This method estimated orthodontic forces and stress of periodontal ligament combining these results by use of a scaling law. Changes of mechanical condition in different loading delivered from various situations by aligner were demonstrated 3-dimensioanaly.
From the results, the mechanism of the case with "bowing effect" at the stage of anterior retraction was discussed. The effective setting of tooth axis to avoid the unexpected inclination was proposed. Understanding of differences among simulation and actual movement in the aligner's treatment, might help the clinician to set the suitable treatment plan.