Effect of clear aligner type on maxillary full-arch intrusion: 3D analysis using finite element method

Area of Science:

• Orthodontics
• Biomaterials Engineering
• Dental Mechanics

Background:

• Vertical maxillary excess (VME) is a common orthodontic concern, with clear aligner intrusion offering a potential non-surgical alternative.
• Understanding aligner material properties is crucial for predicting tooth movement during intrusion.
• Temporary anchorage devices (TADs) are often used with aligners for complex movements like intrusion.

Purpose of the Study:

• To evaluate tooth displacements during full maxillary arch intrusion using clear aligners and TADs.
• To assess both desirable intrusion and undesirable side effects like tipping and rotation.
• To compare potential tooth movements across different clear aligner materials.

Main Methods:

• Finite element analysis of maxillary arch and clear aligners using SolidWorks.
• Simulation of anterior and posterior intrusion forces (80g and 300g) applied via attachments.
• Analysis of vertical and anteroposterior tooth displacements for four aligner brands (Leon, Duran, Duran Plus, Essix Plus).

Main Results:

• Maximal intrusion observed at the buccal aspect of molars, with minimal intrusion at the palatal aspect and incisors.
• All teeth exhibited mesial displacement at the crown/occlusal surface, except incisors which moved distally.
• Apical segments of all teeth showed a distal displacement trend.

Conclusions:

• Full maxillary arch intrusion with clear aligners and TADs can lead to unintended tooth movements.
• Observed side effects include molar buccal tipping and mesial rotation, incisor retrusion, and mesial displacement of other teeth.
• Careful treatment planning is necessary to manage these associated tooth movements during clear aligner therapy.