Evaluation of torque expression with varied bracket positions and varying crown-root angles of maxillary central incisor – A 3 dimensional finite element study

To evaluate the torque expression of right permanent maxillary central incisor with varying bracket positions and to compare the torque expression of the same tooth with different crown-root angulations. Finite Element Models of Maxillary Central Incisor were used for simulation of torque expression with various crown-root angles. Three FEM models of a Maxillary Central Incisor with different crown-root angles (170˚,175˚,180˚, and 165°) were constructed with varying bracket heights and subjected to a 30° labial root torque and the resultant torque expressions were evaluated. The model with the maximum variation in crown-root angle (165˚) showed the maximum torque expression at 6mm and minimum at 3mm bracket height while the model with a minimum variation in crown-root angle (180°) showed the minimum torque expression both and 3mm and 6mm bracket height. With increase in the crown-root angles of a tooth, the torque expression away from the incisal edge increases.