Evaluation of long-term orthodontic tooth movement considering bone remodeling process and in the presence of alveolar bone loss using finite element method

Abstract

Purpose

In the presence of alveolar bone loss, magnitudes of orthodontic forces should be modified, so that the desired tooth movement could be achieved without further bone loss. The main scope of this research was to investigate the effects of force magnitudes on the long-term tipping movements of the teeth with different degrees of bone loss.

Materials and methods

Five finite element models of an incisor with different degrees of bone loss were developed. The long-term tooth movements were simulated in a 4-week period based on a bone remodeling theory. Under a 1.00 N force, the tooth displacements of models were evaluated. Under forces of 0.25–1.00 N, teeth rotations were also evaluated.

Results

As the height of the bone decreased, for a constant magnitude of force, the amount of tooth movement increased and reached to the maximum amount of 2.60 mm in the model with 6.00 mm of bone loss. By increasing the applied force from 0.25 N to 1.00 N, the degree of teeth rotations in the models with 6.00 mm of bone loss and normal bone height increased 9% and 81% respectively.

Conclusion

Though the amount of tooth movement increased by increasing the force magnitude in all models with different bone heights, this increase was only pronounced in milder degrees of bone loss. This study suggests that applied force magnitude can be remarkably reduced in the patients with reduced bone height, particularly in the cases with extreme bone loss.

Keywords:

• Alveolar bone loss
• Bone remodeling theory
• Finite element method
• Tipping tooth movement

Acknowledgement

The authors would like to appreciate HPCRC (High Performance Computing Research Center) of the Amirkabir University of Technology for supporting this investigation.