Biomechanical analysis for different mandibular total distalization methods with clear aligners: A finite element...

Area of Science:

• Orthodontics
• Biomechanics
• Dental Materials

Background:

• Clear aligner treatment (CAT) is increasingly used for complex orthodontic movements.
• Understanding the biomechanical principles of mandibular distalization with CAT is crucial for predictable outcomes.
• Finite element method (FEM) provides a valuable tool for analyzing complex biomechanical interactions in orthodontics.

Purpose of the Study:

• To analyze biomechanical differences and tooth displacement patterns in mandibular total distalization using clear aligner treatment (CAT).
• To evaluate the influence of traction direction, methods, and sites on tooth movement during CAT-based distalization.
• To investigate the stress distribution within clear aligners under various distalization scenarios.

Main Methods:

• Four finite element analysis (FEA) models were created to simulate mandibular dentition.
• Distalization forces of 1.5 N were applied to different traction sites (canine or first premolar) and directions (-30° to +30° to occlusal plane).
• Traction methods included precision cut hooks and buttons; analysis focused on initial tooth displacement and von Mises stress in aligners.

Main Results:

• Mandibular total distalization with CAT demonstrated clockwise or counterclockwise rotation of the occlusal plane based on force direction.
• Mesiodistal tipping was more prevalent than bodily movement for individual teeth.
• Tooth displacement patterns were more influenced by the traction site than the traction method.
• Clear aligner elastic deformation contributed to unintended lingual tipping or extrusion of anterior teeth.

Conclusions:

• Tooth displacement during CAT-based mandibular total distalization is significantly influenced by the chosen traction strategy.
• Careful selection and biomechanical understanding of traction sites and directions are essential for successful mandibular distalization.
• FEA provides insights into optimizing CAT protocols for predictable tooth movement and minimizing unwanted side effects.