Initial force systems during bodily tooth movement with plastic aligners and composite attachments: A...

Area of Science:

• Orthodontics
• Biomaterials
• Computational Mechanics

Background:

• Clear aligners are widely used for orthodontic treatment.
• Achieving precise tooth movement, such as bodily translation, can be challenging with aligners alone.

Purpose of the Study:

• To investigate the force systems generated by plastic aligners with and without composite attachments during upper canine bodily movement.
• To analyze the biomechanical effects of composite attachments on tooth movement patterns using a finite element model.

Main Methods:

• A three-dimensional finite element (FE) model was created, including an upper canine, periodontal ligament, alveolar bone, and a plastic aligner.
• Simulated distal movement of 0.15 mm was applied to the aligner, with and without composite attachments, to analyze stress distribution and movement patterns.

Main Results:

• Without attachments, uncontrolled distal inclination with rotation occurred.
• With attachments, uniform stress distribution was observed, leading to controlled distal bodily movement (translation).
• Composite attachments generated the necessary force system for bodily movement and exhibited compression on their active surfaces.

Conclusions:

• Biomechanically supplementary composite attachments are essential for generating the force system required for bodily tooth movement with plastic aligners.
• The absence of composite attachments can lead to undesired tooth inclination during translation movements.