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Finite Element Analysis of Fixed Orthodontic Retainers
Sebastian Hetzler1, Stefan Rues1, Andreas Zenthöfer1
1Department of Prosthodontics, University of Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany.
Bioengineering (Basel, Switzerland)
|April 27, 2024
Summary
Orthodontic retainer stiffness and tooth resilience significantly impact force transmission and stress. Excessively stiff retainers may increase bonding failure risk, especially with resilient teeth.
Area of Science:
- Orthodontics
- Biomaterials Engineering
- Biomechanics
Background:
- Orthodontic retainers are crucial for maintaining treatment results.
- Understanding retainer biomechanics is essential for preventing relapse and bonding failures.
Purpose of the Study:
- To investigate the biomechanical behavior of orthodontic retainers.
- To analyze the influence of retainer stiffness and tooth resilience on force transmission and stress distribution.
Main Methods:
- A finite element model of the lower jaw with an attached retainer was developed.
- Simulations varied tooth resilience and retainer bending stiffness (type, diameter, material).
- Axial and oblique loads were applied to a central incisor.
Main Results:
- Increased tooth resilience and retainer stiffness amplified force transmission (2% to 65%).
- Smaller retainer diameter led to uneven stress distribution and concentrated stress peaks.
- Higher retainer stiffness, tooth resilience, and oblique loading increased stress at bonding interfaces, risking failure.
Conclusions:
- Retainer stiffness and tooth resilience are critical factors in orthodontic treatment stability.
- Excessively stiff retainers should be used cautiously, particularly in patients with high tooth resilience.
- Optimizing retainer design and material selection can mitigate bonding failure risks.
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