Anterior teeth retraction is particularly an interesting aspect of orthodontic treatment with respect to the principles of biomechanics due to the large movement distances involved. There are many techniques utilized for orthodontic space closure, yet little attention has been devoted to the biomechanical principles of space closure. Orthodontic space closure should be individually tailored based on the diagnosis and treatment plane. The selection of any treatment involving any technique, stage, spring, or appliance design, should be based on the desired tooth movement. Consideration of the force system produced by an orthodontic device aids in determining the utility of the device for correcting any specific problem.