Hello,

Here is the correction for the exercise posted on Facebook, February 2020.

The center of rotation is at the intersection of the perpendicular from the points selected as incisal edges and apices.

The direction of the force is given by the line joining the initial center of resistance position to the center of resistance final position.

The moment to force ratio is given by the coordinate grid from Dr. Fiorelli’s E-book.

If D – 14 mm, then the moment to force ratio is 8 which means that a simple force-placed 8mm from CR with the same direction and amplitude will generate the correct movement.

Obviously Class II elastics are not going to deliver the correct force system.