ABSTRACT

Objectives

To determine the different impact of moment-to-force ratio (M:F) variation for each tooth and spatial plane and to develop a mathematical model to predict the orthodontic movement for every tooth.

Materials and Methods

Two full sets of teeth were obtained combining cone-beam computed tomography (CBCT) and optical scans for two patients. Subsequently, a finite element analysis was performed for 510 different force systems for each tooth to evaluate the centers of rotation.

Results

The center of CROT locations were analyzed, showing that the M:F effect was related to the spatial plane on which the moment was applied, to the force direction, and to the tooth morphology. The tooth dimensions on each plane were mathematically used to derive their influence on the tooth movement.

Conclusion

This study established the basis for an orthodontist to determine how the teeth move and their axes of resistance, depending on their morphology alone. The movement is controlled by a parameter (k), which depends on tooth dimensions and force system features. The k for a tooth can be calculated using a CBCT and a specific set of covariates.

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Author notes

a

Assistant Professor, Center for Dental Research, School of Dentistry, Loma Linda University, Loma Linda, Calif.

b

Adjunct Associate Professor, Center for Dental Research, School of Dentistry, Loma Linda University, Loma Linda, Calif.

c

Assistant Professor, Dental Education Services, School of Dentistry, Loma Linda University, Loma Linda, Calif.