Abstract
Background
Compared with traditional fixed appliances, clear aligners (CAs) still lack the ability to accurately control the three-dimensional tooth movement. The present study was devoted to the comparison of treatment outcomes of CAs diaphragms with different elastic modulus and to explore the improvement of the tooth movement efficiency for CAs.
Methods
In present study, the three-dimensional finite element analysis was used to explore the tooth movement effect resulted from CAs with different elastic modulus in five orthodontic treatment conditions (translation, rotation, torque control, root control and extrusion) on a single tooth model.
Results
For translation, the diaphragm M04 with an elastic modulus of 2086.47 MPa performed relatively well. For rotation, torque control and extrusion, the tooth movement efficiency increased with the elevation of the elastic modulus. However, none of the diaphragms showed ideal results for root control. Additionally, under the same working condition, the greater the elastic modulus of the CA diaphragm, the greater the initial force on the tooth and the periodontal supporting tissue stress.
Conclusions
Diaphragms with different elastic modulus should be used to fabricate CAs to achieve better tooth movement in various tooth movement conditions. In the initial stages of tooth movement, CAs with smaller elastic modulus can be used to reduce the initial force on the teeth, and then CAs with larger elastic modulus can be applied to avoid adverse tooth movement, such as the “roller coaster” effect.